1
|
Takayesu A, Mahoney BJ, Goring AK, Jessup T, Ogorzalek Loo RR, Loo JA, Clubb RT. Insight into the autoproteolysis mechanism of the RsgI9 anti-σ factor from Clostridium thermocellum. Proteins 2024. [PMID: 38597224 DOI: 10.1002/prot.26690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 03/19/2024] [Accepted: 03/26/2024] [Indexed: 04/11/2024]
Abstract
Clostridium thermocellum is a potential microbial platform to convert abundant plant biomass to biofuels and other renewable chemicals. It efficiently degrades lignocellulosic biomass using a surface displayed cellulosome, a megadalton sized multienzyme containing complex. The enzymatic composition and architecture of the cellulosome is controlled by several transmembrane biomass-sensing RsgI-type anti-σ factors. Recent studies suggest that these factors transduce signals from the cell surface via a conserved RsgI extracellular (CRE) domain (also called a periplasmic domain) that undergoes autoproteolysis through an incompletely understood mechanism. Here we report the structure of the autoproteolyzed CRE domain from the C. thermocellum RsgI9 anti-σ factor, revealing that the cleaved fragments forming this domain associate to form a stable α/β/α sandwich fold. Based on AlphaFold2 modeling, molecular dynamics simulations, and tandem mass spectrometry, we propose that a conserved Asn-Pro bond in RsgI9 autoproteolyzes via a succinimide intermediate whose formation is promoted by a conserved hydrogen bond network holding the scissile peptide bond in a strained conformation. As other RsgI anti-σ factors share sequence homology to RsgI9, they likely autoproteolyze through a similar mechanism.
Collapse
Affiliation(s)
- Allen Takayesu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
- UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, USA
| | - Brendan J Mahoney
- UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, USA
| | - Andrew K Goring
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
- UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, USA
| | - Tobie Jessup
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
| | - Rachel R Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
- UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
- UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, USA
| | - Robert T Clubb
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California, USA
- UCLA-DOE Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, California, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California, USA
| |
Collapse
|
2
|
Wei B, Lantz C, Loo RRO, Campuzano IDG, Loo JA. Internal Fragments Enhance Middle-Down Mass Spectrometry Structural Characterization of Monoclonal Antibodies and Antibody-Drug Conjugates. Anal Chem 2024; 96:2491-2499. [PMID: 38294207 PMCID: PMC11001303 DOI: 10.1021/acs.analchem.3c04526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Monoclonal antibodies (mAbs) and antibody-drug conjugates (ADCs) are important large biotherapeutics (∼150 kDa) and high structural complexity that require extensive sequence and structure characterization. Middle-down mass spectrometry (MD-MS) is an emerging technique that sequences and maps subunits larger than those released by trypsinolysis. It avoids potentially introducing artifactual modifications that may occur in bottom-up MS while achieving higher sequence coverage compared to top-down MS. However, returning complete sequence information by MD-MS is still challenging. Here, we show that assigning internal fragments in direct infusion MD-MS of a mAb and an ADC substantially improves their structural characterization. For MD-MS of the reduced NIST mAb, including internal fragments recovers nearly 100% of the sequence by accessing the middle sequence region that is inaccessible by terminal fragments. The identification of important glycosylations can also be improved after the inclusion of internal fragments. For the reduced lysine-linked IgG1-DM1 ADC, we show that considering internal fragments increases the DM1 conjugation sites coverage to 80%, comparable to the reported 83% coverage achieved by peptide mapping on the same ADC (Luo et al. Anal. Chem. 2016, 88, 695-702). This study expands our work on the application of internal fragment assignments in top-down MS of mAbs and ADCs and can be extended to other heterogeneous therapeutic molecules such as multispecifics and fusion proteins for more widespread applications.
Collapse
Affiliation(s)
- Benqian Wei
- Department of Chemistry and Biochemistry, University of California Los Angeles-Los Angeles, CA, USA
| | - Carter Lantz
- Department of Chemistry and Biochemistry, University of California Los Angeles-Los Angeles, CA, USA
| | - Rachel R. Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles-Los Angeles, CA, USA
- UCLA-DOE Institute, University of California-Los Angeles, Los Angeles, CA, USA
- Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA, USA
| | - Iain D. G. Campuzano
- Center for Research Acceleration by Digital Innovation, Molecular Analytics, Amgen Research, Thousand Oaks, CA, USA
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles-Los Angeles, CA, USA
- Department of Biological Chemistry, University of California-Los Angeles, Los Angeles, CA, USA
- UCLA-DOE Institute, University of California-Los Angeles, Los Angeles, CA, USA
- Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA, USA
| |
Collapse
|
3
|
Lantz C, Lopez J, Goring AK, Zenaidee MA, Biggs K, Whitelegge JP, Ogorzalek Loo RR, Klärner FG, Schrader T, Bitan G, Loo JA. Characterization of Molecular Tweezer Binding on α-Synuclein with Native Top-Down Mass Spectrometry and Ion Mobility-Mass Spectrometry Reveals a Mechanism for Aggregation Inhibition. J Am Soc Mass Spectrom 2023; 34:2739-2747. [PMID: 37936057 PMCID: PMC10959575 DOI: 10.1021/jasms.3c00281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Parkinson's disease, a neurodegenerative disease that affects 15 million people worldwide, is characterized by deposition of α-synuclein into Lewy Bodies in brain neurons. Although this disease is prevalent worldwide, a therapy or cure has yet to be found. Several small compounds have been reported to disrupt fibril formation. Among these compounds is a molecular tweezer known as CLR01 that targets lysine and arginine residues. This study aims to characterize how CLR01 interacts with various proteoforms of α-synuclein and how the structure of α-synuclein is subsequently altered. Native mass spectrometry (nMS) measurements of α-synuclein/CLR01 complexes reveal that multiple CLR01 molecules can bind to α-synuclein proteoforms such as α-synuclein phosphorylated at Ser-129 and α-synuclein bound with copper and manganese ions. The binding of one CLR01 molecule shifts the ability for α-synuclein to bind other ligands. Electron capture dissociation (ECD) with Fourier transform-ion cyclotron resonance (FT-ICR) top-down (TD) mass spectrometry of α-synuclein/CLR01 complexes pinpoints the locations of the modifications on each proteoform and reveals that CLR01 binds to the N-terminal region of α-synuclein. CLR01 binding compacts the gas-phase structure of α-synuclein, as shown by ion mobility-mass spectrometry (IM-MS). These data suggest that when multiple CLR01 molecules bind, the N-terminus of α-synuclein shifts toward a more compact state. This compaction suggests a mechanism for CLR01 halting the formation of oligomers and fibrils involved in many neurodegenerative diseases.
Collapse
Affiliation(s)
- Carter Lantz
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095 USA
| | - Jaybree Lopez
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095 USA
| | - Andrew K. Goring
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095 USA
| | - Muhammad A. Zenaidee
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095 USA
- Australian Proteome Analysis Facility, Macquarie University, Macquarie Park, NSW, Australia
| | - Karl Biggs
- Department of Neurology and Brain Research Institute, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, CA 90095 USA
| | - Julian P. Whitelegge
- The Pasarow Mass Spectrometry Laboratory, The Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, CA 90095 USA
| | - Rachel R. Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095 USA
| | | | - Thomas Schrader
- Institute of Chemistry, University of Duisburg-Essen, Essen, Germany
| | - Gal Bitan
- Australian Proteome Analysis Facility, Macquarie University, Macquarie Park, NSW, Australia
- Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA, 90095 USA
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095 USA
- Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA, 90095 USA
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, CA 90095 USA
| |
Collapse
|
4
|
Abskharon R, Pan H, Sawaya MR, Seidler PM, Olivares EJ, Chen Y, Murray KA, Zhang J, Lantz C, Bentzel M, Boyer DR, Cascio D, Nguyen BA, Hou K, Cheng X, Pardon E, Williams CK, Nana AL, Vinters HV, Spina S, Grinberg LT, Seeley WW, Steyaert J, Glabe CG, Ogorzalek Loo RR, Loo JA, Eisenberg DS. Structure-based design of nanobodies that inhibit seeding of Alzheimer's patient-extracted tau fibrils. Proc Natl Acad Sci U S A 2023; 120:e2300258120. [PMID: 37801475 PMCID: PMC10576031 DOI: 10.1073/pnas.2300258120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 08/21/2023] [Indexed: 10/08/2023] Open
Abstract
Despite much effort, antibody therapies for Alzheimer's disease (AD) have shown limited efficacy. Challenges to the rational design of effective antibodies include the difficulty of achieving specific affinity to critical targets, poor expression, and antibody aggregation caused by buried charges and unstructured loops. To overcome these challenges, we grafted previously determined sequences of fibril-capping amyloid inhibitors onto a camel heavy chain antibody scaffold. These sequences were designed to cap fibrils of tau, known to form the neurofibrillary tangles of AD, thereby preventing fibril elongation. The nanobodies grafted with capping inhibitors blocked tau aggregation in biosensor cells seeded with postmortem brain extracts from AD and progressive supranuclear palsy (PSP) patients. The tau capping nanobody inhibitors also blocked seeding by recombinant tau oligomers. Another challenge to the design of effective antibodies is their poor blood-brain barrier (BBB) penetration. In this study, we also designed a bispecific nanobody composed of a nanobody that targets a receptor on the BBB and a tau capping nanobody inhibitor, conjoined by a flexible linker. We provide evidence that the bispecific nanobody improved BBB penetration over the tau capping inhibitor alone after intravenous administration in mice. Our results suggest that the design of synthetic antibodies that target sequences that drive protein aggregation may be a promising approach to inhibit the prion-like seeding of tau and other proteins involved in AD and related proteinopathies.
Collapse
Affiliation(s)
- Romany Abskharon
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - Hope Pan
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - Michael R. Sawaya
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - Paul M. Seidler
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | | | - Yu Chen
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Molecular Instrumentation Center, UCLA, Los Angeles, CA90095
| | - Kevin A. Murray
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - Jeffrey Zhang
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - Carter Lantz
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
| | - Megan Bentzel
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - David R. Boyer
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - Duilio Cascio
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - Binh A. Nguyen
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - Ke Hou
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - Xinyi Cheng
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - Els Pardon
- VIB-Vrije Universiteit Brussel Center for Structural Biology, VIB and Vrije Universiteit Brussel, BrusselsB-1050, Belgium
| | - Christopher K. Williams
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA90095
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA90095
| | - Alissa L. Nana
- Department of Neurology, University of California San Francisco Weill Institute for Neurosciences, University of California, San Francisco, CA94143
| | - Harry V. Vinters
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA90095
- Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA90095
| | - Salvatore Spina
- Department of Neurology, University of California San Francisco Weill Institute for Neurosciences, University of California, San Francisco, CA94143
| | - Lea T. Grinberg
- Department of Neurology, University of California San Francisco Weill Institute for Neurosciences, University of California, San Francisco, CA94143
- Department of Pathology, University of California, San Francisco, CA94143
| | - William W. Seeley
- Department of Neurology, University of California San Francisco Weill Institute for Neurosciences, University of California, San Francisco, CA94143
- Department of Pathology, University of California, San Francisco, CA94143
| | - Jan Steyaert
- VIB-Vrije Universiteit Brussel Center for Structural Biology, VIB and Vrije Universiteit Brussel, BrusselsB-1050, Belgium
| | - Charles G. Glabe
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA92697
| | - Rachel R. Ogorzalek Loo
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| | - David S. Eisenberg
- Department of Chemistry and Biochemistry, UCLA,Los Angeles, CA90095
- Department of Biological Chemistry, UCLA, Los Angeles, CA90095
- HHMI, UCLA, Los Angeles, CA90095
- UCLA-Department of Energy Institute, Molecular Biology Institute, UCLA, Los Angeles, CA90095
| |
Collapse
|
5
|
Wei B, Lantz C, Liu W, Viner R, Loo RRO, Campuzano IDG, Loo JA. Added Value of Internal Fragments for Top-Down Mass Spectrometry of Intact Monoclonal Antibodies and Antibody-Drug Conjugates. Anal Chem 2023; 95:9347-9356. [PMID: 37278738 PMCID: PMC10954349 DOI: 10.1021/acs.analchem.3c01426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Monoclonal antibodies (mAbs) and antibody-drug conjugates (ADCs) are two of the most important therapeutic drug classes that require extensive characterization, whereas their large size and structural complexity make them challenging to characterize and demand the use of advanced analytical methods. Top-down mass spectrometry (TD-MS) is an emerging technique that minimizes sample preparation and preserves endogenous post-translational modifications (PTMs); however, TD-MS of large proteins suffers from low fragmentation efficiency, limiting the sequence and structure information that can be obtained. Here, we show that including the assignment of internal fragments in native TD-MS of an intact mAb and an ADC can improve their molecular characterization. For the NIST mAb, internal fragments can access the sequence region constrained by disulfide bonds to increase the TD-MS sequence coverage to over 75%. Important PTM information, including intrachain disulfide connectivity and N-glycosylation sites, can be revealed after including internal fragments. For a heterogeneous lysine-linked ADC, we show that assigning internal fragments improves the identification of drug conjugation sites to achieve a coverage of 58% of all putative conjugation sites. This proof-of-principle study demonstrates the potential value of including internal fragments in native TD-MS of intact mAbs and ADCs, and this analytical strategy can be extended to bottom-up and middle-down MS approaches to achieve even more comprehensive characterization of important therapeutic molecules.
Collapse
Affiliation(s)
- Benqian Wei
- Department of Chemistry and Biochemistry, University of California Los Angeles-Los Angeles, CA, 90095 USA
| | - Carter Lantz
- Department of Chemistry and Biochemistry, University of California Los Angeles-Los Angeles, CA, 90095 USA
| | - Weijing Liu
- Thermo Fisher Scientific, San Jose, CA, 95134 USA
| | - Rosa Viner
- Thermo Fisher Scientific, San Jose, CA, 95134 USA
| | - Rachel R. Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles-Los Angeles, CA, 90095 USA
- UCLA-DOE Institute, University of California-Los Angeles, Los Angeles, CA, 90095 USA
- Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA, 90095 USA
| | - Iain D. G. Campuzano
- Amgen Research, Center for Research Acceleration and Digital Innovation, Molecular Analytics, Thousand Oaks, CA, 91320 USA
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles-Los Angeles, CA, 90095 USA
- Department of Biological Chemistry, University of California-Los Angeles, Los Angeles, CA, 90095 USA
- UCLA-DOE Institute, University of California-Los Angeles, Los Angeles, CA, 90095 USA
- Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA, 90095 USA
| |
Collapse
|
6
|
Jenner M, Hai Y, Nguyen HH, Passmore M, Skyrud W, Kim J, Garg NK, Zhang W, Ogorzalek Loo RR, Tang Y. Elucidating the molecular programming of a nonlinear non-ribosomal peptide synthetase responsible for fungal siderophore biosynthesis. Nat Commun 2023; 14:2832. [PMID: 37198174 PMCID: PMC10192304 DOI: 10.1038/s41467-023-38484-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 04/25/2023] [Indexed: 05/19/2023] Open
Abstract
Siderophores belonging to the ferrichrome family are essential for the viability of fungal species and play a key role for virulence of numerous pathogenic fungi. Despite their biological significance, our understanding of how these iron-chelating cyclic hexapeptides are assembled by non-ribosomal peptide synthetase (NRPS) enzymes remains poorly understood, primarily due to the nonlinearity exhibited by the domain architecture. Herein, we report the biochemical characterization of the SidC NRPS, responsible for construction of the intracellular siderophore ferricrocin. In vitro reconstitution of purified SidC reveals its ability to produce ferricrocin and its structural variant, ferrichrome. Application of intact protein mass spectrometry uncovers several non-canonical events during peptidyl siderophore biosynthesis, including inter-modular loading of amino acid substrates and an adenylation domain capable of poly-amide bond formation. This work expands the scope of NRPS programming, allows biosynthetic assignment of ferrichrome NRPSs, and sets the stage for reprogramming towards novel hydroxamate scaffolds.
Collapse
Affiliation(s)
- Matthew Jenner
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK.
- Warwick Integrative Synthetic Biology Centre (WISB), University of Warwick, Coventry, CV4 7AL, UK.
| | - Yang Hai
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, USA.
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, USA.
| | - Hong H Nguyen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
- Transmed Co., Ltd., Ho Chi Minh City, Vietnam
| | - Munro Passmore
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Will Skyrud
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, USA
- Arzeda, 3421 Thorndyke Ave W, Seattle, WA 98119, USA
| | - Junyong Kim
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Neil K Garg
- Department of Chemistry and Biochemistry, University of California, Los Angeles, USA
| | - Wenjun Zhang
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, USA
| | | | - Yi Tang
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, USA
| |
Collapse
|
7
|
Wei B, Zenaidee MA, Lantz C, Williams BJ, Totten S, Ogorzalek Loo RR, Loo JA. Top-down mass spectrometry and assigning internal fragments for determining disulfide bond positions in proteins. Analyst 2022; 148:26-37. [PMID: 36399030 PMCID: PMC9772244 DOI: 10.1039/d2an01517j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Disulfide bonds in proteins have a substantial impact on protein structure, stability, and biological activity. Localizing disulfide bonds is critical for understanding protein folding and higher-order structure. Conventional top-down mass spectrometry (TD-MS), where only terminal fragments are assigned for disulfide-intact proteins, can access disulfide information, but suffers from low fragmentation efficiency, thereby limiting sequence coverage. Here, we show that assigning internal fragments generated from TD-MS enhances the sequence coverage of disulfide-intact proteins by 20-60% by returning information from the interior of the protein sequence, which cannot be obtained by terminal fragments alone. The inclusion of internal fragments can extend the sequence information of disulfide-intact proteins to near complete sequence coverage. Importantly, the enhanced sequence information that arise from the assignment of internal fragments can be used to determine the relative position of disulfide bonds and the exact disulfide connectivity between cysteines. The data presented here demonstrates the benefits of incorporating internal fragment analysis into the TD-MS workflow for analyzing disulfide-intact proteins, which would be valuable for characterizing biotherapeutic proteins such as monoclonal antibodies and antibody-drug conjugates.
Collapse
Affiliation(s)
- Benqian Wei
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA.
| | - Muhammad A Zenaidee
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA.
- Australian Proteome Analysis Facility, Macquarie University, Macquarie Park, NSW, Australia
| | - Carter Lantz
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA.
| | | | | | - Rachel R Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA.
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA, USA
| |
Collapse
|
8
|
Lantz C, Wei B, Zhao B, Jung W, Goring AK, Le J, Miller J, Loo RRO, Loo JA. Native Top-Down Mass Spectrometry with Collisionally Activated Dissociation Yields Higher-Order Structure Information for Protein Complexes. J Am Chem Soc 2022; 144:21826-21830. [PMID: 36441927 PMCID: PMC10017227 DOI: 10.1021/jacs.2c06726] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Native mass spectrometry (MS) of proteins and protein assemblies reveals size and binding stoichiometry, but elucidating structures to understand their function is more challenging. Native top-down MS (nTDMS), i.e., fragmentation of the gas-phase protein, is conventionally used to derive sequence information, locate post-translational modifications (PTMs), and pinpoint ligand binding sites. nTDMS also endeavors to dissociate covalent bonds in a conformation-sensitive manner, such that information about higher-order structure can be inferred from the fragmentation pattern. However, the activation/dissociation method used can greatly affect the resulting information on protein higher-order structure. Methods such as electron capture/transfer dissociation (ECD and ETD, or ExD) and ultraviolet photodissociation (UVPD) can produce product ions that are sensitive to structural features of protein complexes. For multi-subunit complexes, a long-held belief is that collisionally activated dissociation (CAD) induces unfolding and release of a subunit, and thus is not useful for higher-order structure characterization. Here we show not only that sequence information can be obtained directly from CAD of native protein complexes but that the fragmentation pattern can deliver higher-order structural information about their gas- and solution-phase structures. Moreover, CAD-generated internal fragments (i.e., fragments containing neither N-/C-termini) reveal structural aspects of protein complexes.
Collapse
Affiliation(s)
- Carter Lantz
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - Benqian Wei
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - Boyu Zhao
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - Wonhyeuk Jung
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - Andrew K Goring
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - Jessie Le
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - Justin Miller
- Molecular Biology Institute, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - Rachel R Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States.,UCLA-DOE Institute, University of California-Los Angeles, Los Angeles, California 90095, United States.,Molecular Biology Institute, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States.,Department of Biological Chemistry, University of California-Los Angeles, Los Angeles, California 90095, United States.,UCLA-DOE Institute, University of California-Los Angeles, Los Angeles, California 90095, United States.,Molecular Biology Institute, University of California-Los Angeles, Los Angeles, California 90095, United States
| |
Collapse
|
9
|
Fu JY, Muroski JM, Arbing MA, Salguero JA, Wofford NQ, McInerney MJ, Gunsalus RP, Loo JA, Ogorzalek Loo RR. Dynamic acylome reveals metabolite driven modifications in Syntrophomonas wolfei. Front Microbiol 2022; 13:1018220. [PMID: 36419437 PMCID: PMC9676460 DOI: 10.3389/fmicb.2022.1018220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/05/2022] [Indexed: 11/09/2022] Open
Abstract
Syntrophomonas wolfei is an anaerobic syntrophic microbe that degrades short-chain fatty acids to acetate, hydrogen, and/or formate. This thermodynamically unfavorable process proceeds through a series of reactive acyl-Coenzyme A species (RACS). In other prokaryotic and eukaryotic systems, the production of intrinsically reactive metabolites correlates with acyl-lysine modifications, which have been shown to play a significant role in metabolic processes. Analogous studies with syntrophic bacteria, however, are relatively unexplored and we hypothesized that highly abundant acylations could exist in S. wolfei proteins, corresponding to the RACS derived from degrading fatty acids. Here, by mass spectrometry-based proteomics (LC–MS/MS), we characterize and compare acylome profiles of two S. wolfei subspecies grown on different carbon substrates. Because modified S. wolfei proteins are sufficiently abundant to analyze post-translational modifications (PTMs) without antibody enrichment, we could identify types of acylations comprehensively, observing six types (acetyl-, butyryl-, 3-hydroxybutyryl-, crotonyl-, valeryl-, and hexanyl-lysine), two of which have not been reported in any system previously. All of the acyl-PTMs identified correspond directly to RACS in fatty acid degradation pathways. A total of 369 sites of modification were identified on 237 proteins. Structural studies and in vitro acylation assays of a heavily modified enzyme, acetyl-CoA transferase, provided insight on the potential impact of these acyl-protein modifications. The extensive changes in acylation-type, abundance, and modification sites with carbon substrate suggest that protein acylation by RACS may be an important regulator of syntrophy.
Collapse
Affiliation(s)
- Janine Y. Fu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, United States
| | - John M. Muroski
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, United States
| | - Mark A. Arbing
- UCLA-DOE Institute, University of California, Los Angeles, CA, United States
| | - Jessica A. Salguero
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, United States
| | - Neil Q. Wofford
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
| | - Michael J. McInerney
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, United States
| | - Robert P. Gunsalus
- UCLA-DOE Institute, University of California, Los Angeles, CA, United States
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA, United States
- UCLA Molecular Biology Institute, University of California, Los Angeles, CA, United States
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, United States
- UCLA-DOE Institute, University of California, Los Angeles, CA, United States
- UCLA Molecular Biology Institute, University of California, Los Angeles, CA, United States
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, United States
| | - Rachel R. Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, United States
- UCLA-DOE Institute, University of California, Los Angeles, CA, United States
- UCLA Molecular Biology Institute, University of California, Los Angeles, CA, United States
- *Correspondence: Rachel R. Ogorzalek Loo,
| |
Collapse
|
10
|
Brown SL, Zenaidee MA, Loo JA, Loo RRO, Donald WA. On the Mechanism of Theta Capillary Nanoelectrospray Ionization for the Formation of Highly Charged Protein Ions Directly from Native Solutions. Anal Chem 2022; 94:13010-13018. [DOI: 10.1021/acs.analchem.2c01654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Susannah L. Brown
- School of Chemistry, University of New South Wales, Sydney 2052, Australia
| | - Muhammad A. Zenaidee
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States of America
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States of America
| | - Rachel R. Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States of America
| | - William A. Donald
- School of Chemistry, University of New South Wales, Sydney 2052, Australia
| |
Collapse
|
11
|
Muroski JM, Fu JY, Nguyen HH, Wofford NQ, Mouttaki H, James KL, McInerney MJ, Gunsalus RP, Loo JA, Ogorzalek Loo RR. The acyl-proteome of Syntrophus aciditrophicus reveals metabolic relationships in benzoate degradation. Mol Cell Proteomics 2022; 21:100215. [PMID: 35189333 PMCID: PMC8942843 DOI: 10.1016/j.mcpro.2022.100215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 01/13/2022] [Accepted: 02/17/2022] [Indexed: 11/08/2022] Open
Abstract
Syntrophus aciditrophicus is a model syntrophic bacterium that degrades fatty and aromatic acids into acetate, CO2, formate, and H2 that are utilized by methanogens and other hydrogen-consuming microbes. S. aciditrophicus benzoate degradation proceeds by a multistep pathway with many intermediate reactive acyl-coenzyme A species (RACS) that can potentially Nε-acylate lysine residues. Herein, we describe the identification and characterization of acyl-lysine modifications that correspond to RACS in the benzoate degradation pathway. The amounts of modified peptides are sufficient to analyze the post-translational modifications without antibody enrichment, enabling a range of acylations located, presumably, on the most extensively acylated proteins throughout the proteome to be studied. Seven types of acyl modifications were identified, six of which correspond directly to RACS that are intermediates in the benzoate degradation pathway including 3-hydroxypimeloylation, a modification first identified in this system. Indeed, benzoate-degrading enzymes are heavily represented among the acylated proteins. A total of 125 sites were identified in 60 proteins. Functional deacylase enzymes are present in the proteome, indicating a potential regulatory system/mechanism by which S. aciditrophicus modulates acylation. Uniquely, Nε-acyl-lysine RACS are highly abundant in these syntrophic bacteria, raising the compelling possibility that post-translational modifications modulate benzoate degradation in this and potentially other, syntrophic bacteria. Our results outline candidates for further study of how acylations impact syntrophic consortia. Abundant lysine modifications in microbes enable unbiased global acylation profiling. Seven types of acyl modifications are found; six from benzoate degradation intermediates. Benzoate-degrading enzymes are prominent among the 60 acylated proteins. Abundant acylation/active deacylases suggest PTMs modulate syntrophic metabolism.
Collapse
|
12
|
Zenaidee MA, Lantz C, Perkins T, Jung W, Ogorzalek Loo RR, Loo JA. Correction to "Internal Fragments Generated by Electron Ionization Dissociation Enhance Protein Top-Down Mass Spectrometry". J Am Soc Mass Spectrom 2022; 33:211. [PMID: 34878272 DOI: 10.1021/jasms.1c00357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
|
13
|
Zenaidee MA, Wei B, Lantz C, Wu HT, Lambeth TR, Diedrich JK, Loo RRO, Julian RR, Loo JA. Internal Fragments Generated from Different Top-Down Mass Spectrometry Fragmentation Methods Extend Protein Sequence Coverage. J Am Soc Mass Spectrom 2021; 32:1752-1758. [PMID: 34101447 PMCID: PMC9090460 DOI: 10.1021/jasms.1c00113] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Top-down mass spectrometry (TD-MS) of intact proteins results in fragment ions that can be correlated to the protein primary sequence. Fragments generated can either be terminal fragments that contain the N- or C-terminus or internal fragments that contain neither termini. Traditionally in TD-MS experiments, the generation of internal fragments has been avoided because of ambiguity in assigning these fragments. Here, we demonstrate that in TD-MS experiments internal fragments can be formed and assigned in collision-based, electron-based, and photon-based fragmentation methods and are rich with sequence information, allowing for a greater extent of the primary protein sequence to be explained. For the three test proteins cytochrome c, myoglobin, and carbonic anhydrase II, the inclusion of internal fragments in the analysis resulted in approximately 15-20% more sequence coverage, with no less than 85% sequence coverage obtained. Combining terminal fragment and internal fragment assignments results in near complete protein sequence coverage. Hence, by including both terminal and internal fragment assignments in TD-MS analysis, deep protein sequence analysis, allowing for the localization of modification sites more reliably, can be possible.
Collapse
Affiliation(s)
- Muhammad A. Zenaidee
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095
| | - Benqian Wei
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095
| | - Carter Lantz
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095
| | - Hoi Ting Wu
- Department of Chemistry, University of California Riverside, Riverside, CA 92521
| | - Tyler R. Lambeth
- Department of Chemistry, University of California Riverside, Riverside, CA 92521
| | - Jolene K. Diedrich
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037
| | - Rachel R. Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095
| | - Ryan R. Julian
- Department of Chemistry, University of California Riverside, Riverside, CA 92521
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, CA 90095
| |
Collapse
|
14
|
Lantz C, Zenaidee MA, Wei B, Hemminger Z, Ogorzalek Loo RR, Loo JA. ClipsMS: An Algorithm for Analyzing Internal Fragments Resulting from Top-Down Mass Spectrometry. J Proteome Res 2021; 20:1928-1935. [PMID: 33650866 DOI: 10.1021/acs.jproteome.0c00952] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Top-down mass spectrometry (TD-MS) of peptides and proteins results in product ions that can be correlated to polypeptide sequence. Fragments can either be terminal fragments, which contain either the N- or the C-terminus, or internal fragments that contain neither termini. Normally, only terminal fragments are assigned due to the computational difficulties of assigning internal fragments. Here we describe ClipsMS, an algorithm that can assign both terminal and internal fragments generated by top-down MS fragmentation. Further, ClipsMS can be used to locate various modifications on the protein sequence. Using ClipsMS to assign TD-MS generated product ions, we demonstrate that for apo-myoglobin, the inclusion of internal fragments increases the sequence coverage up to 78%. Interestingly, many internal fragments cover complementary regions to the terminal fragments that enhance the information that is extracted from a single top-down mass spectrum. Analysis of oxidized apo-myoglobin using terminal and internal fragment matching by ClipsMS confirmed the locations of oxidation sites on the two methionine residues. Internal fragments can be beneficial for top-down protein fragmentation analysis, and ClipsMS can be a valuable tool for assigning both terminal and internal fragments present in a top-down mass spectrum. Data are available via the MassIVE community resource with the identifiers MSV000086788 and MSV000086789.
Collapse
Affiliation(s)
- Carter Lantz
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Muhammad A Zenaidee
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Benqian Wei
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Zachary Hemminger
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California 90095, United States.,Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California 90095, United States
| |
Collapse
|
15
|
Muroski JM, Fu JY, Nguyen HH, Loo RRO, Loo JA. Leveraging Immonium Ions for Targeting Acyl-Lysine Modifications in Proteomic Datasets. Proteomics 2021; 21:e2000111. [PMID: 32896103 PMCID: PMC8742405 DOI: 10.1002/pmic.202000111] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 08/03/2020] [Indexed: 11/08/2022]
Abstract
Acyl modifications vary greatly in terms of elemental composition and site of protein modification. Developing methods to identify acyl modifications more confidently can help to assess the scope of these modifications in large proteomic datasets. The utility of acyl-lysine immonium ions is analyzed for identifying the modifications in proteomic datasets. It is demonstrated that the cyclized immonium ion is a strong indicator of acyl-lysine presence when its rank or relative abundance compared to other ions within a spectrum is considered. Utilizing a stepped collision energy method in a shotgun experiment highlights the immonium ion. By implementing an analysis that accounted for features within each MS2 spectrum, the method clearly identifies peptides with short chain acyl-lysine modifications from complex lysates. Immonium ions can also be used to validate novel acyl modifications; in this study, the first examples of 3-hydroxylpimelyl-lysine modifications are reported and they are validated using immonium ions. Overall these results solidify the use of the immonium ion as a marker for acyl-lysine modifications in complex proteomic datasets.
Collapse
Affiliation(s)
- John M. Muroski
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Janine Y. Fu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Hong Hanh Nguyen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Rachel R. Ogorzalek Loo
- David Geffen School of Medicine, Department of Biological Chemistry, University of California, Los Angeles, CA, USA
- UCLA-DOE Institute, University of California, Los Angeles, CA, USA
- UCLA Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
- David Geffen School of Medicine, Department of Biological Chemistry, University of California, Los Angeles, CA, USA
- UCLA-DOE Institute, University of California, Los Angeles, CA, USA
- UCLA Molecular Biology Institute, University of California, Los Angeles, CA, USA
| |
Collapse
|
16
|
Zenaidee MA, Lantz C, Perkins T, Jung W, Ogorzalek Loo RR, Loo JA. Internal Fragments Generated by Electron Ionization Dissociation Enhance Protein Top-Down Mass Spectrometry. J Am Soc Mass Spectrom 2020; 31:1896-1902. [PMID: 32799534 PMCID: PMC7485267 DOI: 10.1021/jasms.0c00160] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Top-down proteomics by mass spectrometry (MS) involves the mass measurement of an intact protein followed by subsequent activation of the protein to generate product ions. Electron-based fragmentation methods like electron capture dissociation and electron transfer dissociation are widely used for these types of analyses. Recently, electron ionization dissociation (EID), which utilizes higher energy electrons (>20 eV) has been suggested to be more efficient for top-down protein fragmentation compared to other electron-based dissociation methods. Here, we demonstrate that the use of EID enhances protein fragmentation and subsequent detection of protein fragments. Protein product ions can form by either single cleavage events, resulting in terminal fragments containing the C-terminus or N-terminus of the protein, or by multiple cleavage events to give rise to internal fragments that include neither the C-terminus nor the N-terminus of the protein. Conventionally, internal fragments have been disregarded, as reliable assignments of these fragments were limited. Here, we demonstrate that internal fragments generated by EID can account for ∼20-40% of the mass spectral signals detected by top-down EID-MS experiments. By including internal fragments, the extent of the protein sequence that can be explained from a single tandem mass spectrum increases from ∼50 to ∼99% for 29 kDa carbonic anhydrase II and 8.6 kDa ubiquitin. When searching for internal fragments during data analysis, previously unassigned peaks can be readily and accurately assigned to confirm a given protein sequence and to enhance the utility of top-down protein sequencing experiments.
Collapse
Affiliation(s)
- Muhammad A. Zenaidee
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095
| | - Carter Lantz
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095
| | - Taylor Perkins
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095
| | - Wonhyuek Jung
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095
| | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, University of California-Los Angeles, Los Angeles, CA 90095
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095
- Department of Biological Chemistry, University of California-Los Angeles, Los Angeles, CA 90095
| |
Collapse
|
17
|
Takemori A, Butcher DS, Harman VM, Brownridge P, Shima K, Higo D, Ishizaki J, Hasegawa H, Suzuki J, Yamashita M, Loo JA, Loo RRO, Beynon RJ, Anderson LC, Takemori N. PEPPI-MS: Polyacrylamide-Gel-Based Prefractionation for Analysis of Intact Proteoforms and Protein Complexes by Mass Spectrometry. J Proteome Res 2020; 19:3779-3791. [PMID: 32538093 DOI: 10.1021/acs.jproteome.0c00303] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Prefractionation of complex mixtures of proteins derived from biological samples is indispensable for proteome analysis via top-down mass spectrometry (MS). Polyacrylamide gel electrophoresis (PAGE), which enables high-resolution protein separation based on molecular size, is a widely used technique in biochemical experiments and has the potential to be useful in sample fractionation for top-down MS analysis. However, the lack of a means to efficiently recover the separated proteins in-gel has always been a barrier to its use in sample prefractionation. In this study, we present a novel experimental workflow, called Passively Eluting Proteins from Polyacrylamide gels as Intact species for MS ("PEPPI-MS"), which allows top-down MS of PAGE-separated proteins. The optimization of Coomassie brilliant blue staining followed by the passive extraction step in the PEPPI-MS workflow enabled the efficient recovery of proteins, separated on commercial precast gels, from a wide range of molecular weight regions in under 10 min. Two-dimensional separation combining offline PEPPI-MS with online reversed-phase liquid chromatographic separation resulted in identification of over 1000 proteoforms recovered from the target region of the gel (≤50 kDa). Given the widespread availability and relatively low cost of traditional sodium dodecyl sulfate (SDS)-PAGE equipment, the PEPPI-MS workflow will be a powerful prefractionation strategy for top-down proteomics.
Collapse
Affiliation(s)
- Ayako Takemori
- Division of Analytical Bio-Medicine, Advanced Research Support Center, Ehime University, Toon 791-0295, Ehime, Japan
| | - David S Butcher
- Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Victoria M Harman
- Centre for Proteome Research, Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K
| | - Philip Brownridge
- Centre for Proteome Research, Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K
| | - Keisuke Shima
- Shimadzu Corporation, Nakagyo-ku, Kyoto 604-8511, Japan
| | - Daisuke Higo
- Thermo Fisher Scientific K.K., Yokohama 221-0022, Kanagawa, Japan
| | - Jun Ishizaki
- Department of Hematology, Clinical Immunology and Infectious Diseases, Graduate School of Medicine, Ehime University, Toon 791-0295, Ehime, Japan
| | - Hitoshi Hasegawa
- Department of Hematology, Clinical Immunology and Infectious Diseases, Graduate School of Medicine, Ehime University, Toon 791-0295, Ehime, Japan
| | - Junpei Suzuki
- Department of Immunology, Graduate School of Medicine, Ehime University, Toon 791-0295, Ehime, Japan
| | - Masakatsu Yamashita
- Department of Immunology, Graduate School of Medicine, Ehime University, Toon 791-0295, Ehime, Japan
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California 90095, United States.,Department of Biological Chemistry, UCLA/DOE Institute for Genomics and Proteomics, and UCLA Molecular Biology Institute, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, UCLA/DOE Institute for Genomics and Proteomics, and UCLA Molecular Biology Institute, University of California-Los Angeles, Los Angeles, California 90095, United States
| | - Robert J Beynon
- Centre for Proteome Research, Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K
| | - Lissa C Anderson
- Ion Cyclotron Resonance Program, National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Nobuaki Takemori
- Division of Analytical Bio-Medicine, Advanced Research Support Center, Ehime University, Toon 791-0295, Ehime, Japan
| |
Collapse
|
18
|
Sue CK, McConnell SA, Ellis-Guardiola K, Muroski J, McAllister RA, Yu J, Alvarez AI, Chang C, Ogorzalek Loo RR, Loo JA, Ton-That H, Clubb RT. Kinetics and Optimization of the Lysine-Isopeptide Bond Forming Sortase Enzyme from Corynebacterium diphtheriae. Bioconjug Chem 2020; 31:1624-1634. [PMID: 32396336 PMCID: PMC8153732 DOI: 10.1021/acs.bioconjchem.0c00163] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Site-specifically modified protein bioconjugates have important applications in biology, chemistry, and medicine. Functionalizing specific protein side chains with enzymes using mild reaction conditions is of significant interest, but remains challenging. Recently, the lysine-isopeptide bond forming activity of the sortase enzyme that builds surface pili in Corynebacterium diphtheriae (CdSrtA) has been reconstituted in vitro. A mutationally activated form of CdSrtA was shown to be a promising bioconjugating enzyme that can attach Leu-Pro-Leu-Thr-Gly peptide fluorophores to a specific lysine residue within the N-terminal domain of the SpaA protein (NSpaA), enabling the labeling of target proteins that are fused to NSpaA. Here we present a detailed analysis of the CdSrtA catalyzed protein labeling reaction. We show that the first step in catalysis is rate limiting, which is the formation of the CdSrtA-peptide thioacyl intermediate that subsequently reacts with a lysine ε-amine in NSpaA. This intermediate is surprisingly stable, limiting spurious proteolysis of the peptide substrate. We report the discovery of a new enzyme variant (CdSrtAΔ) that has significantly improved transpeptidation activity, because it completely lacks an inhibitory polypeptide appendage ("lid") that normally masks the active site. We show that the presence of the lid primarily impairs formation of the thioacyl intermediate and not the recognition of the NSpaA substrate. Quantitative measurements reveal that CdSrtAΔ generates its cross-linked product with a catalytic turnover number of 1.4 ± 0.004 h-1 and that it has apparent KM values of 0.16 ± 0.04 and 1.6 ± 0.3 mM for its NSpaA and peptide substrates, respectively. CdSrtAΔ is 7-fold more active than previously studied variants, labeling >90% of NSpaA with peptide within 6 h. The results of this study further improve the utility of CdSrtA as a protein labeling tool and provide insight into the enzyme catalyzed reaction that underpins protein labeling and pilus biogenesis.
Collapse
Affiliation(s)
- Christopher K. Sue
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - Scott A. McConnell
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - Ken Ellis-Guardiola
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - John Muroski
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - Rachel A. McAllister
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - Justin Yu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - Ana I. Alvarez
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - Chungyu Chang
- Molecular Biology Institute and the University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- Division of Oral Biology and Medicine, School of Dentistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - Rachel R. Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- Molecular Biology Institute and the University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - Hung Ton-That
- Molecular Biology Institute and the University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- Division of Oral Biology and Medicine, School of Dentistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| | - Robert T. Clubb
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
- Molecular Biology Institute and the University of California, Los Angeles, 611 Charles Young Drive East, Los Angeles, CA 90095
| |
Collapse
|
19
|
Herrera A, Muroski J, Sengupta R, Nguyen HH, Agarwal S, Ogorzalek Loo RR, Mattoo S, Loo JA, Satchell KJF. N-terminal autoprocessing and acetylation of multifunctional-autoprocessing repeats-in-toxins (MARTX) Makes Caterpillars Floppy-like effector is stimulated by adenosine diphosphate (ADP)-Ribosylation Factor 1 in advance of Golgi fragmentation. Cell Microbiol 2019; 22:e13133. [PMID: 31658406 DOI: 10.1111/cmi.13133] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 09/26/2019] [Accepted: 10/11/2019] [Indexed: 12/17/2022]
Abstract
Studies have successfully elucidated the mechanism of action of several effector domains that comprise the multifunctional-autoprocessing repeats-in-toxins (MARTX) toxins of Vibrio vulnificus. However, the biochemical linkage between the cysteine proteolytic activity of Makes Caterpillars Floppy (MCF)-like effector and its cellular effects remains unknown. In this study, we identify the host cell factors that activate in vivo and in vitro MCF autoprocessing as adenosine diphosphate (ADP)-Ribosylation Factor 1 (ARF1) and ADP-Ribosylation Factor 3 (ARF3). Autoprocessing activity is enhanced when ARF1 is in its active [guanosine triphosphate (GTP)-bound] form compared to the inactive [guanosine diphosphate (GDP)-bound] form. Subsequent to auto-cleavage, MCF is acetylated on its exposed N-terminal glycine residue. Acetylation apparently does not dictate subcellular localization as MCF is found localized throughout the cell. However, the cleaved form of MCF gains the ability to bind to the specialized lipid phosphatidylinositol 5-phosphate enriched in Golgi and other membranes necessary for endocytic trafficking, suggesting that a fraction of MCF may be subcellularly localized. Traditional thin-section electron microscopy, high-resolution cryoAPEX localization, and fluorescent microscopy show that MCF causes Golgi dispersal resulting in extensive vesiculation. In addition, host mitochondria are disrupted and fragmented. Mass spectrometry analysis found no reproducible modifications of ARF1 suggesting that ARF1 is not post-translationally modified by MCF. Further, catalytically active MCF does not stably associate with ARF1. Our data indicate not only that ARF1 is a cross-kingdom activator of MCF, but also that MCF may mediate cytotoxicity by directly targeting another yet to be identified protein. This study begins to elucidate the biochemical activity of this important domain and gives insight into how it may promote disease progression.
Collapse
Affiliation(s)
- Alfa Herrera
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - John Muroski
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California
| | - Ranjan Sengupta
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana
| | - Hong Hanh Nguyen
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California
| | - Shivangi Agarwal
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine, UCLA Molecular Biology Institute, University of California-Los Angeles, Los Angeles, California.,UCLA/DOE Institute of Genomics and Proteomics, University of California-Los Angeles, Los Angeles, California
| | - Seema Mattoo
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana.,Purdue Institute for Inflammation, Immunology and Infectious Diseases, Purdue University, West Lafayette, Indiana
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California.,Department of Biological Chemistry, David Geffen School of Medicine, UCLA Molecular Biology Institute, University of California-Los Angeles, Los Angeles, California
| | - Karla J F Satchell
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| |
Collapse
|
20
|
James KL, Kung JW, Crable BR, Mouttaki H, Sieber JR, Nguyen HH, Yang Y, Xie Y, Erde J, Wofford NQ, Karr EA, Loo JA, Ogorzalek Loo RR, Gunsalus RP, McInerney MJ. Syntrophus aciditrophicus uses the same enzymes in a reversible manner to degrade and synthesize aromatic and alicyclic acids. Environ Microbiol 2019; 21:1833-1846. [PMID: 30895699 PMCID: PMC6488403 DOI: 10.1111/1462-2920.14601] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 03/12/2019] [Accepted: 03/19/2019] [Indexed: 12/12/2022]
Abstract
Syntrophy is essential for the efficient conversion of organic carbon to methane in natural and constructed environments, but little is known about the enzymes involved in syntrophic carbon and electron flow. Syntrophus aciditrophicus strain SB syntrophically degrades benzoate and cyclohexane-1-carboxylate and catalyses the novel synthesis of benzoate and cyclohexane-1-carboxylate from crotonate. We used proteomic, biochemical and metabolomic approaches to determine what enzymes are used for fatty, aromatic and alicyclic acid degradation versus for benzoate and cyclohexane-1-carboxylate synthesis. Enzymes involved in the metabolism of cyclohex-1,5-diene carboxyl-CoA to acetyl-CoA were in high abundance in S. aciditrophicus cells grown in pure culture on crotonate and in coculture with Methanospirillum hungatei on crotonate, benzoate or cyclohexane-1-carboxylate. Incorporation of 13 C-atoms from 1-[13 C]-acetate into crotonate, benzoate and cyclohexane-1-carboxylate during growth on these different substrates showed that the pathways are reversible. A protein conduit for syntrophic reverse electron transfer from acyl-CoA intermediates to formate was detected. Ligases and membrane-bound pyrophosphatases make pyrophosphate needed for the synthesis of ATP by an acetyl-CoA synthetase. Syntrophus aciditrophicus, thus, uses a core set of enzymes that operates close to thermodynamic equilibrium to conserve energy in a novel and highly efficient manner.
Collapse
Affiliation(s)
- Kimberly L. James
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| | - Johannes W. Kung
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| | - Bryan R. Crable
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| | - Housna Mouttaki
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| | - Jessica R. Sieber
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| | - Hong H. Nguyen
- Department of Chemistry & Biochemistry, University of
California, Los Angeles 90095
| | - Yanan Yang
- Department of Chemistry & Biochemistry, University of
California, Los Angeles 90095
| | - Yongming Xie
- Department of Chemistry & Biochemistry, University of
California, Los Angeles 90095
| | - Jonathan Erde
- Department of Chemistry & Biochemistry, University of
California, Los Angeles 90095
| | - Neil Q. Wofford
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| | - Elizabeth A. Karr
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
- Price Family Foundation Institute of Structural Biology,
University of Oklahoma, Norman, OK, 73019
| | - Joseph A. Loo
- UCLA DOE Institute, University of California, Los Angeles
CA 90095
- Department of Chemistry & Biochemistry, University of
California, Los Angeles 90095
| | - Rachel R. Ogorzalek Loo
- UCLA DOE Institute, University of California, Los Angeles
CA 90095
- Department of Chemistry & Biochemistry, University of
California, Los Angeles 90095
| | - Robert P. Gunsalus
- Department of Microbiology, Immunology, and Molecular
Genetics, University of California, Los Angeles, CA, USA
- UCLA-Molecular Biology Institute, University of California,
Los Angeles, CA USA
- UCLA DOE Institute, University of California, Los Angeles
CA 90095
| | - Michael J. McInerney
- Department of Microbiology and Plant Biology, University of
Oklahoma, Norman, OK, 73019
| |
Collapse
|
21
|
Simonian M, Shirasaki D, Lee VS, Bervini D, Grace M, Loo RRO, Loo JA, Molloy MP, Stoodley MA. Proteomics identification of radiation-induced changes of membrane proteins in the rat model of arteriovenous malformation in pursuit of targets for brain AVM molecular therapy. Clin Proteomics 2018; 15:43. [PMID: 30602943 PMCID: PMC6305998 DOI: 10.1186/s12014-018-9217-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 12/12/2018] [Indexed: 12/27/2022] Open
Abstract
Background Rapid identification of novel targets and advancement of a vascular targeting strategy requires a comprehensive assessment of AVM endothelial membrane protein changes in response to irradiation. The aim of this study is to provide additional potential target protein molecules for evaluation in animal trials to promote intravascular thrombosis in AVM vessels post radiosurgery. Methods We employed in vivo biotinylation methodology that we developed, to label membrane proteins in the rat model of AVM post radiosurgery. Mass spectrometry expression (MSE) analysis was used to identify and quantify surface protein expression between irradiated and non irradiated rats, which mimics a radiosurgical treatment approach. Results Our proteomics data revealed differentially expressed membrane proteins between irradiated and non irradiated rats, e.g. profilin-1, ESM-1, ion channel proteins, annexin A2 and lumican. Conclusion This work provides additional potential target protein molecules for evaluation in animal trials to promote intravascular thrombosis in AVM vessels post radiosurgery. Electronic supplementary material The online version of this article (10.1186/s12014-018-9217-x) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Margaret Simonian
- 1Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW Australia.,2Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles (UCLA), 611 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Dyna Shirasaki
- 2Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles (UCLA), 611 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Vivienne S Lee
- 1Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW Australia
| | - David Bervini
- 1Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW Australia.,3Neurosurgery Department, Bern University Hospital, Bern, Switzerland
| | - Michael Grace
- 4Genesis Cancer Care, Macquarie University Hospital, Sydney, NSW Australia
| | - Rachel R Ogorzalek Loo
- 2Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles (UCLA), 611 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Joseph A Loo
- 2Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles (UCLA), 611 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Mark P Molloy
- 5Department of Chemistry and Bimolecular Sciences, Australian Proteome Analysis Facility (APAF), Macquarie University, Sydney, NSW Australia.,Lawrence Penn Chair of Bowel Cancer Research, Faculty of Medicine and Health, Northern Clinical School, Sydney, Australia
| | - Marcus A Stoodley
- 1Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW Australia
| |
Collapse
|
22
|
McConnell SA, Amer BR, Muroski J, Fu J, Chang C, Ogorzalek Loo RR, Loo JA, Osipiuk J, Ton-That H, Clubb RT. Protein Labeling via a Specific Lysine-Isopeptide Bond Using the Pilin Polymerizing Sortase from Corynebacterium diphtheriae. J Am Chem Soc 2018; 140:8420-8423. [PMID: 29927249 PMCID: PMC6230430 DOI: 10.1021/jacs.8b05200] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Proteins that are site-specifically modified with peptides and chemicals can be used as novel therapeutics, imaging tools, diagnostic reagents and materials. However, there are few enzyme-catalyzed methods currently available to selectively conjugate peptides to internal sites within proteins. Here we show that a pilus-specific sortase enzyme from Corynebacterium diphtheriae (CdSrtA) can be used to attach a peptide to a protein via a specific lysine-isopeptide bond. Using rational mutagenesis we created CdSrtA3M, a highly activated cysteine transpeptidase that catalyzes in vitro isopeptide bond formation. CdSrtA3M mediates bioconjugation to a specific lysine residue within a fused domain derived from the corynebacterial SpaA protein. Peptide modification yields greater than >95% can be achieved. We demonstrate that CdSrtA3M can be used in concert with the Staphylococcus aureus SrtA enzyme, enabling dual, orthogonal protein labeling via lysine-isopeptide and backbone-peptide bonds.
Collapse
Affiliation(s)
- Scott A. McConnell
- Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics and the Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Brendan R. Amer
- Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics and the Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - John Muroski
- Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics and the Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Janine Fu
- Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics and the Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Chungyu Chang
- Department of Microbiology & Molecular Genetics, University of Texas Health Science Center, Houston, TX, USA
| | - Rachel R. Ogorzalek Loo
- Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics and the Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics and the Molecular Biology Institute, University of California, Los Angeles, CA, USA
| | - Jerzy Osipiuk
- Structural Biology Center, Argonne National Laboratory, Argonne, IL, USA
| | - Hung Ton-That
- Department of Microbiology & Molecular Genetics, University of Texas Health Science Center, Houston, TX, USA
| | - Robert T. Clubb
- Department of Chemistry and Biochemistry, UCLA-DOE Institute for Genomics and Proteomics and the Molecular Biology Institute, University of California, Los Angeles, CA, USA
| |
Collapse
|
23
|
Chang C, Amer BR, Osipiuk J, McConnell SA, Huang IH, Hsieh V, Fu J, Nguyen HH, Muroski J, Flores E, Ogorzalek Loo RR, Loo JA, Putkey JA, Joachimiak A, Das A, Clubb RT, Ton-That H. In vitro reconstitution of sortase-catalyzed pilus polymerization reveals structural elements involved in pilin cross-linking. Proc Natl Acad Sci U S A 2018; 115:E5477-E5486. [PMID: 29844180 PMCID: PMC6004493 DOI: 10.1073/pnas.1800954115] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Covalently cross-linked pilus polymers displayed on the cell surface of Gram-positive bacteria are assembled by class C sortase enzymes. These pilus-specific transpeptidases located on the bacterial membrane catalyze a two-step protein ligation reaction, first cleaving the LPXTG motif of one pilin protomer to form an acyl-enzyme intermediate and then joining the terminal Thr to the nucleophilic Lys residue residing within the pilin motif of another pilin protomer. To date, the determinants of class C enzymes that uniquely enable them to construct pili remain unknown. Here, informed by high-resolution crystal structures of corynebacterial pilus-specific sortase (SrtA) and utilizing a structural variant of the enzyme (SrtA2M), whose catalytic pocket has been unmasked by activating mutations, we successfully reconstituted in vitro polymerization of the cognate major pilin (SpaA). Mass spectrometry, electron microscopy, and biochemical experiments authenticated that SrtA2M synthesizes pilus fibers with correct Lys-Thr isopeptide bonds linking individual pilins via a thioacyl intermediate. Structural modeling of the SpaA-SrtA-SpaA polymerization intermediate depicts SrtA2M sandwiched between the N- and C-terminal domains of SpaA harboring the reactive pilin and LPXTG motifs, respectively. Remarkably, the model uncovered a conserved TP(Y/L)XIN(S/T)H signature sequence following the catalytic Cys, in which the alanine substitutions abrogated cross-linking activity but not cleavage of LPXTG. These insights and our evidence that SrtA2M can terminate pilus polymerization by joining the terminal pilin SpaB to SpaA and catalyze ligation of isolated SpaA domains in vitro provide a facile and versatile platform for protein engineering and bio-conjugation that has major implications for biotechnology.
Collapse
Affiliation(s)
- Chungyu Chang
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, TX 77030
| | - Brendan R Amer
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
- University of California, Los Angeles-US Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA 90095
| | - Jerzy Osipiuk
- Center for Structural Genomics of Infectious Diseases, Argonne National Laboratory, Argonne, IL 60439
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637
| | - Scott A McConnell
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
- University of California, Los Angeles-US Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA 90095
| | - I-Hsiu Huang
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Van Hsieh
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
- University of California, Los Angeles-US Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA 90095
| | - Janine Fu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
- University of California, Los Angeles-US Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA 90095
| | - Hong H Nguyen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
- University of California, Los Angeles-US Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA 90095
| | - John Muroski
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
- University of California, Los Angeles-US Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA 90095
| | - Erika Flores
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, TX 77030
| | - Rachel R Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
- University of California, Los Angeles-US Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA 90095
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
- University of California, Los Angeles-US Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA 90095
| | - John A Putkey
- Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX 77030
| | - Andrzej Joachimiak
- Center for Structural Genomics of Infectious Diseases, Argonne National Laboratory, Argonne, IL 60439
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637
| | - Asis Das
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030
| | - Robert T Clubb
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095;
- University of California, Los Angeles-US Department of Energy Institute of Genomics and Proteomics, University of California, Los Angeles, CA 90095
| | - Hung Ton-That
- Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, TX 77030;
| |
Collapse
|
24
|
Nshanian M, Lakshmanan R, Chen H, Ogorzalek Loo RR, Loo JA. Enhancing Sensitivity of Liquid Chromatography-Mass Spectrometry of Peptides and Proteins Using Supercharging Agents. Int J Mass Spectrom 2018; 427:157-164. [PMID: 29750076 PMCID: PMC5937529 DOI: 10.1016/j.ijms.2017.12.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Trifluoroacetic acid (TFA) is often used as a mobile phase modifier to enhance reversed phase chromatographic performance. TFA adjusts solution pH and is an ion-pairing agent, but it is not typically suitable for electrospray ionization-mass spectrometry (ESI-MS) and liquid chromatography/MS (LC/MS) because of its significant signal suppression. Supercharging agents elevate peptide and protein charge states in ESI, increasing tandem MS (MS/MS) efficiency. Here, LC/MS protein supercharging was effected by adding agents to LC mobile phase solvents. Significantly, the ionization suppression generally observed with TFA was, for the most part, rescued by supercharging agents, with improved separation efficiency (higher number of theoretical plates) and lowered detection limits.
Collapse
Affiliation(s)
- Michael Nshanian
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095
| | - Rajeswari Lakshmanan
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095
| | - Hao Chen
- Center for Intelligent Chemical Instrumentation, Department of Chemistry and Biochemistry, Edison Biotechnology Institute, Ohio University, Athens, OH 45701
| | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Molecular Biology Institute, and UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, CA 90095
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Molecular Biology Institute, and UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, CA 90095
| |
Collapse
|
25
|
Li H, Nguyen HH, Ogorzalek Loo RR, Campuzano IDG, Loo JA. An integrated native mass spectrometry and top-down proteomics method that connects sequence to structure and function of macromolecular complexes. Nat Chem 2018; 10:139-148. [PMID: 29359744 PMCID: PMC5784781 DOI: 10.1038/nchem.2908] [Citation(s) in RCA: 152] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 11/06/2017] [Indexed: 12/23/2022]
Abstract
Mass spectrometry (MS) has become a crucial technique for the analysis of protein complexes. Native MS has traditionally examined protein subunit arrangements, while proteomics MS has focused on sequence identification. These two techniques are usually performed separately without taking advantage of the synergies between them. Here we describe the development of an integrated native MS and top-down proteomics method using Fourier-transform ion cyclotron resonance (FTICR) to analyse macromolecular protein complexes in a single experiment. We address previous concerns of employing FTICR MS to measure large macromolecular complexes by demonstrating the detection of complexes up to 1.8 MDa, and we demonstrate the efficacy of this technique for direct acquirement of sequence to higher-order structural information with several large complexes. We then summarize the unique functionalities of different activation/dissociation techniques. The platform expands the ability of MS to integrate proteomics and structural biology to provide insights into protein structure, function and regulation.
Collapse
Affiliation(s)
- Huilin Li
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
| | - Hong Hanh Nguyen
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
| | - Rachel R Ogorzalek Loo
- Department of Chemistry and Biochemistry, UCLA/DOE Institute of Genomics and Proteomics, and UCLA Molecular Biology Institute, University of California, Los Angeles, California 90095, USA
| | - Iain D G Campuzano
- Discovery Analytical Sciences, Amgen, Thousand Oaks, California 91320, USA
| | - Joseph A Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA.,Department of Chemistry and Biochemistry, UCLA/DOE Institute of Genomics and Proteomics, and UCLA Molecular Biology Institute, University of California, Los Angeles, California 90095, USA
| |
Collapse
|
26
|
Zhang J, Loo RRO, Loo JA. Structural Characterization of a Thrombin-Aptamer Complex by High Resolution Native Top-Down Mass Spectrometry. J Am Soc Mass Spectrom 2017; 28:1815-1822. [PMID: 28755259 PMCID: PMC5711526 DOI: 10.1007/s13361-017-1751-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 06/11/2017] [Accepted: 06/30/2017] [Indexed: 05/12/2023]
Abstract
Native mass spectrometry (MS) with electrospray ionization (ESI) has evolved as an invaluable tool for the characterization of intact native proteins and non-covalently bound protein complexes. Here we report the structural characterization by high resolution native top-down MS of human thrombin and its complex with the Bock thrombin binding aptamer (TBA), a 15-nucleotide DNA with high specificity and affinity for thrombin. Accurate mass measurements revealed that the predominant form of native human α-thrombin contains a glycosylation mass of 2205 Da, corresponding to a sialylated symmetric biantennary oligosaccharide structure without fucosylation. Native MS showed that thrombin and TBA predominantly form a 1:1 complex under near physiological conditions (pH 6.8, 200 mM NH4OAc), but the binding stoichiometry is influenced by the solution ionic strength. In 20 mM ammonium acetate solution, up to two TBAs were bound to thrombin, whereas increasing the solution ionic strength destabilized the thrombin-TBA complex and 1 M NH4OAc nearly completely dissociated the complex. This observation is consistent with the mediation of thrombin-aptamer binding through electrostatic interactions and it is further consistent with the human thrombin structure that contains two anion binding sites on the surface. Electron capture dissociation (ECD) top-down MS of the thrombin-TBA complex performed with a high resolution 15 Tesla Fourier transform ion cyclotron resonance (FTICR) mass spectrometer showed the primary binding site to be at exosite I located near the N-terminal sequence of the heavy chain, consistent with crystallographic data. High resolution native top-down MS is complementary to traditional structural biology methods for structurally characterizing native proteins and protein-DNA complexes. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Jiang Zhang
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Molecular Biology Institute, and UCLA/DOE Institute for Genomics and Proteomics, University of California, Los Angeles, CA, 90095, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA.
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Molecular Biology Institute, and UCLA/DOE Institute for Genomics and Proteomics, University of California, Los Angeles, CA, 90095, USA.
| |
Collapse
|
27
|
Takemori N, Takemori A, Wongkongkathep P, Nshanian M, Loo RRO, Lermyte F, Loo JA. Top-down/Bottom-up Mass Spectrometry Workflow Using Dissolvable Polyacrylamide Gels. Anal Chem 2017; 89:8244-8250. [PMID: 28723075 DOI: 10.1021/acs.analchem.7b00357] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Biologists' preeminent toolbox for separating, analyzing, and visualizing proteins is SDS-PAGE, yet recovering the proteins embedded in these polyacrylamide media as intact species is a long-standing challenge for mass spectrometry. In conventional workflows, protein mixtures from crude biological samples are electrophoretically separated at high-resolution within N,N'-methylene-bis-acrylamide cross-linked polyacrylamide gels to reduce sample complexity and facilitate sensitive characterization. However, low protein recoveries, especially for high molecular weight proteins, often hinder characterization by mass spectrometry. We describe a workflow for top-down/bottom-up mass spectrometric analyses of proteins in polyacrylamide slab gels using dissolvable, bis-acryloylcystamine-cross-linked polyacrylamide, enabling high-resolution protein separations while recovering intact proteins over a broad size range efficiently. The inferior electrophoretic resolution long associated with reducible gels has been overcome, as demonstrated by SDS-PAGE of crude tissue extracts. This workflow elutes intact proteins efficiently, supporting MS and MS/MS from proteins resolved on biologists' preferred separation platform.
Collapse
Affiliation(s)
- Nobuaki Takemori
- Proteo-Science Center, Division of Proteomics Research, Ehime University , Shitsukawa, Toon, Ehime, 791-0295, Japan
| | - Ayako Takemori
- Proteo-Science Center, Division of Proteomics Research, Ehime University , Shitsukawa, Toon, Ehime, 791-0295, Japan.,The United Graduate School of Agricultural Sciences, Ehime University , Matsuyama, Ehime, 790-8566, Japan
| | - Piriya Wongkongkathep
- Department of Chemistry and Biochemistry, University of California-Los Angeles , Los Angeles, California 90095, United States
| | - Michael Nshanian
- Department of Chemistry and Biochemistry, University of California-Los Angeles , Los Angeles, California 90095, United States
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, UCLA/DOE Institute for Genomics and Proteomics, and UCLA Molecular Biology Institute, University of California-Los Angeles , Los Angeles, California 90095, United States
| | - Frederik Lermyte
- Department of Chemistry, University of Antwerp , Universiteitsplein 1, B-2610 Wilrijk-Antwerp, Belgium
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles , Los Angeles, California 90095, United States.,Department of Biological Chemistry, UCLA/DOE Institute for Genomics and Proteomics, and UCLA Molecular Biology Institute, University of California-Los Angeles , Los Angeles, California 90095, United States
| |
Collapse
|
28
|
Briegel A, Oikonomou CM, Chang YW, Kjær A, Huang AN, Kim KW, Ghosal D, Nguyen HH, Kenny D, Ogorzalek Loo RR, Gunsalus RP, Jensen GJ. Morphology of the archaellar motor and associated cytoplasmic cone in Thermococcus kodakaraensis. EMBO Rep 2017; 18:1660-1670. [PMID: 28729461 DOI: 10.15252/embr.201744070] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 06/29/2017] [Accepted: 07/04/2017] [Indexed: 11/09/2022] Open
Abstract
Archaeal swimming motility is driven by archaella: rotary motors attached to long extracellular filaments. The structure of these motors, and particularly how they are anchored in the absence of a peptidoglycan cell wall, is unknown. Here, we use electron cryotomography to visualize the archaellar basal body in vivo in Thermococcus kodakaraensis KOD1. Compared to the homologous bacterial type IV pilus (T4P), we observe structural similarities as well as several unique features. While the position of the cytoplasmic ATPase appears conserved, it is not braced by linkages that extend upward through the cell envelope as in the T4P, but rather by cytoplasmic components that attach it to a large conical frustum up to 500 nm in diameter at its base. In addition to anchoring the lophotrichous bundle of archaella, the conical frustum associates with chemosensory arrays and ribosome-excluding material and may function as a polar organizing center for the coccoid cells.
Collapse
Affiliation(s)
- Ariane Briegel
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Catherine M Oikonomou
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Yi-Wei Chang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Andreas Kjær
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Audrey N Huang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Ki Woo Kim
- School of Ecology and Environmental System, Kyungpook National University, Sangju, South Korea
| | - Debnath Ghosal
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Hong H Nguyen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Dorothy Kenny
- Department of Microbiology, Immunology and Molecular Genetics, The UCLA DOE Institute, University of California, Los Angeles, CA, USA
| | - Rachel R Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA
| | - Robert P Gunsalus
- Department of Microbiology, Immunology and Molecular Genetics, The UCLA DOE Institute, University of California, Los Angeles, CA, USA
| | - Grant J Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA .,Howard Hughes Medical Institute, Pasadena, CA, USA
| |
Collapse
|
29
|
Simonian M, Loo RRO, Rannulu N, Loo JA, Molloy MP, Stoodley MA. Identification of protein targets in cerebral endothelial cells for brain arteriovenous malformation (AVMs) molecular therapies. Clin Proteomics 2017; 14:17. [PMID: 28522939 PMCID: PMC5434588 DOI: 10.1186/s12014-017-9151-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 04/26/2017] [Indexed: 12/13/2022] Open
Abstract
Background To develop a new molecular targeted treatment for brain (AVMs), identification of membrane proteins that are localised on the AVM endothelium is crucial. Current treatment methods are surgery and radiosurgery. However, complete occlusion post radiosurgery are achieved within 3 years, while patient remain at risk of haemorrhage. This study aims to identify potential protein targets in AVM endothelial cells that discriminate these vessels from normal vessels; these proteins targets will be investigated for the molecular therapy of brain AVMs to promote rapid thrombosis after radiosurgery. Methods We employed in vitro biotinylation that we developed, and mass spectrometry to detect cell surface-exposed proteins in cultures of murine cerebral endothelial cells (bEnd.3). Two forms of mass spectrometry were applied (iTRAQ-MS and MSE) to identify and quantify membrane protein expression at various time-points following irradiation which simulates a radiosurgical treatment approach. Immunocytochemistry was used to confirm the expression of selected membrane proteins. ProteinPilot V4.0 software was used to analyse the iTRAQ-MS data and the MSE data was analysed using ProteinLynx Global Server version 2.5 software. Results The proteomics data revealed several differentially expressed membrane proteins between irradiated and non-irradiated cells at specific time points, e.g. PECAM-1, cadherin-5, PDI, EPCR and integrins. Immunocytochemistry data confirmed the expression of these proteins. Conclusion Cell surface protein biotinylation and proteomics analysis successfully identified membrane proteins from murine brain endothelial cells in response to irradiation. This work suggests potential target protein molecules for evaluation in animal models of brain-AVM. Electronic supplementary material The online version of this article (doi:10.1186/s12014-017-9151-3) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Margaret Simonian
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, North Ryde, NSW 2109 Australia.,David Geffen School of Medicine, Department of Biological Chemistry, University of California Los Angeles (UCLA), 611 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Rachel R Ogorzalek Loo
- David Geffen School of Medicine, Department of Biological Chemistry, University of California Los Angeles (UCLA), 611 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Nalaka Rannulu
- David Geffen School of Medicine, Department of Biological Chemistry, University of California Los Angeles (UCLA), 611 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Joseph A Loo
- David Geffen School of Medicine, Department of Biological Chemistry, University of California Los Angeles (UCLA), 611 Charles E. Young Drive East, Los Angeles, CA 90095 USA
| | - Mark P Molloy
- Australian Proteome Analysis Facility (APAF), Department of Chemistry and Bimolecular Sciences, Macquarie University, North Ryde, NSW 2109 Australia
| | - Marcus A Stoodley
- Department of Clinical Medicine, Faculty of Medicine and Health Sciences, Macquarie University, North Ryde, NSW 2109 Australia
| |
Collapse
|
30
|
Zimmer RK, Ferrier GA, Kim SJ, Ogorzalek Loo RR, Zimmer CA, Loo JA. Keystone predation and molecules of keystone significance. Ecology 2017; 98:1710-1721. [PMID: 28376248 DOI: 10.1002/ecy.1849] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 01/24/2017] [Accepted: 03/27/2017] [Indexed: 11/09/2022]
Abstract
Keystone species structure ecological communities and are major determinants of biodiversity. A synthesis of research on keystone species is nonetheless missing a critical component - the sensory mechanisms for behavioral interactions that determine population- and community-wide attributes. Here, we establish the chemosensory basis for keystone predation by sea stars (Pisaster ochraceus) on mussels. This consumer-resource interaction is prototypic of top-down driven trophic cascades. Each mussel species (Mytilus californianus and M. galloprovincialis) secretes a glycoprotein orthologue (29.6 and 28.1 kDa, respectively) that acts, singularly, to evoke the sea star predatory response. The orthologues (named "KEYSTONEin") are localized in the epidermis, extrapallial fluid, and organic shell coating (periostracum) of live, intact mussels. Thus, KEYSTONEin contacts chemosensory receptors on tube feet as sea stars crawl over rocky surfaces in search of prey. The complete nucleotide sequences reveal that KEYSTONEin shares 87% (M. californianus) or 98% (M. galloprovincialis) homology with a calcium-binding protein in the shell matrix of a closely related congener, M. edulis. All three molecules cluster tightly within the Complement Component 1 Domain Containing (C1qDC) protein family; each exhibits a large globular domain, low complexity region(s), coiled coil, and at least four of five histidine-aspartic acid tandem motifs. Collective results support the hypothesis that KEYSTONEin evolved ancestrally in immunological, and later, in biomineralization roles. More recently, the substance has become exploited by sea stars as a contact cue for prey recognition. As the first identified compound to evoke keystone predation, KEYSTONEin provides valuable sensory information, promotes biodiversity, and shapes community structure and function. Without this molecule, there would be no predation by sea stars on mussels.
Collapse
Affiliation(s)
- Richard K Zimmer
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, 90095, USA.,Moreton Bay Research Station, Centre for Marine Science, School of Biological Sciences, University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Graham A Ferrier
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, 90095, USA
| | - Steven J Kim
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, 90095, USA
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, 90095, USA.,UCLA/DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California, 90095, USA
| | - Cheryl Ann Zimmer
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, California, 90095, USA.,Moreton Bay Research Station, Centre for Marine Science, School of Biological Sciences, University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, 90095, USA.,Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, 90095, USA.,UCLA/DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California, 90095, USA
| |
Collapse
|
31
|
Abstract
Enhanced Filter Aided Sample Preparation (eFASP) incorporates plastics passivation and digestion-enhancing surfactants into the traditional FASP workflow to reduce sample loss and increase hydrophobic protein representation in qualitative and quantitative proteomics experiments. Resulting protein digests are free of contaminants and can be analyzed directly by LC-MS.
Collapse
Affiliation(s)
- Jonathan Erde
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA, 90095, USA
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, University of California-Los Angeles, Los Angeles, CA, 90095, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA, 90095, USA. .,Department of Biological Chemistry, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
| |
Collapse
|
32
|
Crable BR, Sieber JR, Mao X, Alvarez-Cohen L, Gunsalus R, Ogorzalek Loo RR, Nguyen H, McInerney MJ. Membrane Complexes of Syntrophomonas wolfei Involved in Syntrophic Butyrate Degradation and Hydrogen Formation. Front Microbiol 2016; 7:1795. [PMID: 27881975 PMCID: PMC5101538 DOI: 10.3389/fmicb.2016.01795] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 10/25/2016] [Indexed: 11/18/2022] Open
Abstract
Syntrophic butyrate metabolism involves the thermodynamically unfavorable production of hydrogen and/or formate from the high potential electron donor, butyryl-CoA. Such redox reactions can occur only with energy input by a process called reverse electron transfer. Previous studies have demonstrated that hydrogen production from butyrate requires the presence of a proton gradient, but the biochemical machinery involved has not been clearly elucidated. In this study, the gene and enzyme systems involved in reverse electron transfer by Syntrophomonas wolfei were investigated using proteomic and gene expression approaches. S. wolfei was grown in co-culture with Methanospirillum hungatei or Dehalococcoides mccartyi under conditions requiring reverse electron transfer and compared to both axenic S. wolfei cultures and co-cultures grown in conditions that do not require reverse electron transfer. Blue native gel analysis of membranes solubilized from syntrophically grown cells revealed the presence of a membrane-bound hydrogenase, Hyd2, which exhibited hydrogenase activity during in gel assays. Bands containing a putative iron-sulfur (FeS) oxidoreductase were detected in membranes of crotonate-grown and butyrate grown S. wolfei cells. The genes for the corresponding hydrogenase subunits, hyd2ABC, were differentially expressed at higher levels during syntrophic butyrate growth when compared to growth on crotonate. The expression of the FeS oxidoreductase gene increased when S. wolfei was grown with M. hungatei. Additional membrane-associated proteins detected included FoF1 ATP synthase subunits and several membrane transporters that may aid syntrophic growth. Furthermore, syntrophic butyrate metabolism can proceed exclusively by interspecies hydrogen transfer, as demonstrated by growth with D. mccartyi, which is unable to use formate. These results argue for the importance of Hyd2 and FeS oxidoreductase in reverse electron transfer during syntrophic butyrate degradation.
Collapse
Affiliation(s)
- Bryan R. Crable
- Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, USA
| | - Jessica R. Sieber
- Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, USA
| | - Xinwei Mao
- Department of Civil and Environmental Engineering, University of California, Berkeley, BerkeleyCA, USA
| | - Lisa Alvarez-Cohen
- Department of Civil and Environmental Engineering, University of California, Berkeley, BerkeleyCA, USA
| | - Robert Gunsalus
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los AngelesCA, USA
| | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, University of California, Los Angeles, Los AngelesCA, USA
| | - Hong Nguyen
- Department of Biological Chemistry, University of California, Los Angeles, Los AngelesCA, USA
| | - Michael J. McInerney
- Department of Microbiology and Plant Biology, University of Oklahoma, NormanOK, USA
| |
Collapse
|
33
|
James KL, Ríos-Hernández LA, Wofford NQ, Mouttaki H, Sieber JR, Sheik CS, Nguyen HH, Yang Y, Xie Y, Erde J, Rohlin L, Karr EA, Loo JA, Ogorzalek Loo RR, Hurst GB, Gunsalus RP, Szweda LI, McInerney MJ. Pyrophosphate-Dependent ATP Formation from Acetyl Coenzyme A in Syntrophus aciditrophicus, a New Twist on ATP Formation. mBio 2016; 7:e01208-16. [PMID: 27531911 PMCID: PMC4992975 DOI: 10.1128/mbio.01208-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 07/12/2016] [Indexed: 11/29/2022] Open
Abstract
UNLABELLED Syntrophus aciditrophicus is a model syntrophic bacterium that degrades key intermediates in anaerobic decomposition, such as benzoate, cyclohexane-1-carboxylate, and certain fatty acids, to acetate when grown with hydrogen-/formate-consuming microorganisms. ATP formation coupled to acetate production is the main source for energy conservation by S. aciditrophicus However, the absence of homologs for phosphate acetyltransferase and acetate kinase in the genome of S. aciditrophicus leaves it unclear as to how ATP is formed, as most fermentative bacteria rely on these two enzymes to synthesize ATP from acetyl coenzyme A (CoA) and phosphate. Here, we combine transcriptomic, proteomic, metabolite, and enzymatic approaches to show that S. aciditrophicus uses AMP-forming, acetyl-CoA synthetase (Acs1) for ATP synthesis from acetyl-CoA. acs1 mRNA and Acs1 were abundant in transcriptomes and proteomes, respectively, of S. aciditrophicus grown in pure culture and coculture. Cell extracts of S. aciditrophicus had low or undetectable acetate kinase and phosphate acetyltransferase activities but had high acetyl-CoA synthetase activity under all growth conditions tested. Both Acs1 purified from S. aciditrophicus and recombinantly produced Acs1 catalyzed ATP and acetate formation from acetyl-CoA, AMP, and pyrophosphate. High pyrophosphate levels and a high AMP-to-ATP ratio (5.9 ± 1.4) in S. aciditrophicus cells support the operation of Acs1 in the acetate-forming direction. Thus, S. aciditrophicus has a unique approach to conserve energy involving pyrophosphate, AMP, acetyl-CoA, and an AMP-forming, acetyl-CoA synthetase. IMPORTANCE Bacteria use two enzymes, phosphate acetyltransferase and acetate kinase, to make ATP from acetyl-CoA, while acetate-forming archaea use a single enzyme, an ADP-forming, acetyl-CoA synthetase, to synthesize ATP and acetate from acetyl-CoA. Syntrophus aciditrophicus apparently relies on a different approach to conserve energy during acetyl-CoA metabolism, as its genome does not have homologs to the genes for phosphate acetyltransferase and acetate kinase. Here, we show that S. aciditrophicus uses an alternative approach, an AMP-forming, acetyl-CoA synthetase, to make ATP from acetyl-CoA. AMP-forming, acetyl-CoA synthetases were previously thought to function only in the activation of acetate to acetyl-CoA.
Collapse
Affiliation(s)
- Kimberly L James
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Luis A Ríos-Hernández
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Neil Q Wofford
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Housna Mouttaki
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Jessica R Sieber
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Cody S Sheik
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Hong H Nguyen
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Yanan Yang
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Yongming Xie
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Jonathan Erde
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Lars Rohlin
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, USA
| | - Elizabeth A Karr
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, California, USA Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, University of California Los Angeles, Los Angeles, California, USA
| | - Gregory B Hurst
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
| | - Robert P Gunsalus
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, Los Angeles, California, USA
| | - Luke I Szweda
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Michael J McInerney
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma, USA
| |
Collapse
|
34
|
Lohnes K, Quebbemann NR, Liu K, Kobzeff F, Loo JA, Ogorzalek Loo RR. Combining high-throughput MALDI-TOF mass spectrometry and isoelectric focusing gel electrophoresis for virtual 2D gel-based proteomics. Methods 2016; 104:163-9. [PMID: 26826592 PMCID: PMC4930893 DOI: 10.1016/j.ymeth.2016.01.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/13/2016] [Accepted: 01/25/2016] [Indexed: 01/07/2023] Open
Abstract
The virtual two-dimensional gel electrophoresis/mass spectrometry (virtual 2D gel/MS) technology combines the premier, high-resolution capabilities of 2D gel electrophoresis with the sensitivity and high mass accuracy of mass spectrometry (MS). Intact proteins separated by isoelectric focusing (IEF) gel electrophoresis are imaged from immobilized pH gradient (IPG) polyacrylamide gels (the first dimension of classic 2D-PAGE) by matrix-assisted laser desorption/ionization (MALDI) MS. Obtaining accurate intact masses from sub-picomole-level proteins embedded in 2D-PAGE gels or in IPG strips is desirable to elucidate how the protein of one spot identified as protein 'A' on a 2D gel differs from the protein of another spot identified as the same protein, whenever tryptic peptide maps fail to resolve the issue. This task, however, has been extremely challenging. Virtual 2D gel/MS provides access to these intact masses. Modifications to our matrix deposition procedure improve the reliability with which IPG gels can be prepared; the new procedure is described. Development of this MALDI MS imaging (MSI) method for high-throughput MS with integrated 'top-down' MS to elucidate protein isoforms from complex biological samples is described and it is demonstrated that a 4-cm IPG gel segment can now be imaged in approximately 5min. Gel-wide chemical and enzymatic methods with further interrogation by MALDI MS/MS provide identifications, sequence-related information, and post-translational/transcriptional modification information. The MSI-based virtual 2D gel/MS platform may potentially link the benefits of 'top-down' and 'bottom-up' proteomics.
Collapse
Affiliation(s)
- Karen Lohnes
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Neil R Quebbemann
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kate Liu
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Fred Kobzeff
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Joseph A Loo
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; DOE/UCLA Institute of Genomics and Proteomics and UCLA Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; DOE/UCLA Institute of Genomics and Proteomics and UCLA Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA.
| |
Collapse
|
35
|
Loo RRO, Loo JA. Salt Bridge Rearrangement (SaBRe) Explains the Dissociation Behavior of Noncovalent Complexes. J Am Soc Mass Spectrom 2016; 27:975-90. [PMID: 27052739 PMCID: PMC4865452 DOI: 10.1007/s13361-016-1375-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Revised: 02/28/2016] [Accepted: 03/01/2016] [Indexed: 05/11/2023]
Abstract
Native electrospray ionization-mass spectrometry, with gas-phase activation and solution compositions that partially release subcomplexes, can elucidate topologies of macromolecular assemblies. That so much complexity can be preserved in gas-phase assemblies is remarkable, although a long-standing conundrum has been the differences between their gas- and solution-phase decompositions. Collision-induced dissociation of multimeric noncovalent complexes typically distributes products asymmetrically (i.e., by ejecting a single subunit bearing a large percentage of the excess charge). That unexpected behavior has been rationalized as one subunit "unfolding" to depart with more charge. We present an alternative explanation based on heterolytic ion-pair scission and rearrangement, a mechanism that inherently partitions charge asymmetrically. Excessive barriers to dissociation are circumvented in this manner, when local charge rearrangements access a lower-barrier surface. An implication of this ion pair consideration is that stability differences between high- and low-charge state ions usually attributed to Coulomb repulsion may, alternatively, be conveyed by attractive forces from ion pairs (salt bridges) stabilizing low-charge state ions. Should the number of ion pairs be roughly inversely related to charge, symmetric dissociations would be favored from highly charged complexes, as observed. Correlations between a gas-phase protein's size and charge reflect the quantity of restraining ion pairs. Collisionally-facilitated salt bridge rearrangement (SaBRe) may explain unusual size "contractions" seen for some activated, low charge state complexes. That some low-charged multimers preferentially cleave covalent bonds or shed small ions to disrupting noncovalent associations is also explained by greater ion pairing in low charge state complexes. Graphical Abstract ᅟ.
Collapse
Affiliation(s)
- Rachel R Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
| | - Joseph A Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
- UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA, 90095, USA.
| |
Collapse
|
36
|
Ogorzalek Loo RR, Bierbaum VM. Focus on Mass Spectrometry as a Probe of Higher Order Protein Structure, Honoring Prof. Brian T. Chait, Recipient of the 2015 ASMS Award for a Distinguished Contribution in Mass Spectrometry : Editorial: A Turning Point for Biological Mass Spectrometry. J Am Soc Mass Spectrom 2016; 27:949-951. [PMID: 27044025 DOI: 10.1007/s13361-016-1387-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Rachel R Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine and UCLA/DOE Institute, University of California-Los Angeles, Los Angeles, CA, USA
| | - Veronica M Bierbaum
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA.
| |
Collapse
|
37
|
Nguyen HHT, Nguyen PH, Gunsalus RP, McInerney MJ, Loo JA, Ogorzalek Loo RR. Metabolite‐Driven Modifications: Protein Acylations Elucidate Substrate Metabolism in Syntrophic Bacteria. FASEB J 2016. [DOI: 10.1096/fasebj.30.1_supplement.864.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | - Robert P. Gunsalus
- Department of Microbiology, Immunology, & Molecular GeneticsUCLALos AngelesCA
| | | | | | | |
Collapse
|
38
|
Nguyen HHT, Loo JA, Ogorzalek Loo RR. Simultaneously Revealing All Lysine Acylations in an Organism to Elucidate Substrate Metabolism. FASEB J 2016. [DOI: 10.1096/fasebj.30.1_supplement.831.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
39
|
Wongkongkathep P, Li H, Zhang X, Loo RRO, Julian RR, Loo JA. Enhancing Protein Disulfide Bond Cleavage by UV Excitation and Electron Capture Dissociation for Top-Down Mass Spectrometry. Int J Mass Spectrom 2015; 390:137-145. [PMID: 26644781 PMCID: PMC4669582 DOI: 10.1016/j.ijms.2015.07.008] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The application of ion pre-activation with 266 nm ultraviolet (UV) laser irradiation combined with electron capture dissociation (ECD) is demonstrated to enhance top-down mass spectrometry sequence coverage of disulfide bond containing proteins. UV-based activation can homolytically cleave a disulfide bond to yield two separated thiol radicals. Activated ECD experiments of insulin and ribonuclease A containing three and four disulfide bonds, respectively, were performed. UV-activation in combination with ECD allowed the three disulfide bonds of insulin to be cleaved and the overall sequence coverage to be increased. For the larger sized ribonuclease A with four disulfide bonds, irradiation from an infrared laser (10.6 µm) to disrupt non-covalent interactions was combined with UV-activation to facilitate the cleavage of up to three disulfide bonds. Preferences for disulfide bond cleavage are dependent on protein structure and sequence. Disulfide bonds can reform if the generated radicals remain in close proximity. By varying the time delay between the UV-activation and the ECD events, it was determined that disulfide bonds reform within 10-100 msec after their UV-homolytic cleavage.
Collapse
Affiliation(s)
- Piriya Wongkongkathep
- Department of Chemistry and Biochemistry, University of California-Los Angeles Los Angeles, CA 90095
| | - Huilin Li
- Department of Biological Chemistry, University of California-Los Angeles Los Angeles, CA 90095
| | - Xing Zhang
- Department of Chemistry, University of California-Riverside, Riverside, CA 92521
| | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, University of California-Los Angeles Los Angeles, CA 90095
| | - Ryan R. Julian
- Department of Chemistry, University of California-Riverside, Riverside, CA 92521
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles Los Angeles, CA 90095
- Department of Biological Chemistry, University of California-Los Angeles Los Angeles, CA 90095
- UCLA/DOE Institute of Genomics and Proteomics, University of California-Los Angeles Los Angeles, CA 90095
- Corresponding author at: University of California-Los Angeles, Department of Chemistry and Biochemistry, 402 Boyer Hall, Molecular Biology Institute, Los Angeles, CA, United States, Tel.: +1 310 794 7023; fax: +1 310 206 4038, (J.A. Loo)
| |
Collapse
|
40
|
Jiang J, Chan H, Cash DD, Miracco EJ, Ogorzalek Loo RR, Upton HE, Cascio D, O'Brien Johnson R, Collins K, Loo JA, Zhou ZH, Feigon J. Structure of Tetrahymena telomerase reveals previously unknown subunits, functions, and interactions. Science 2015; 350:aab4070. [PMID: 26472759 DOI: 10.1126/science.aab4070] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 09/01/2015] [Indexed: 12/17/2022]
Abstract
Telomerase helps maintain telomeres by processive synthesis of telomere repeat DNA at their 3'-ends, using an integral telomerase RNA (TER) and telomerase reverse transcriptase (TERT). We report the cryo-electron microscopy structure of Tetrahymena telomerase at ~9 angstrom resolution. In addition to seven known holoenzyme proteins, we identify two additional proteins that form a complex (TEB) with single-stranded telomere DNA-binding protein Teb1, paralogous to heterotrimeric replication protein A (RPA). The p75-p45-p19 subcomplex is identified as another RPA-related complex, CST (CTC1-STN1-TEN1). This study reveals the paths of TER in the TERT-TER-p65 catalytic core and single-stranded DNA exit; extensive subunit interactions of the TERT essential N-terminal domain, p50, and TEB; and other subunit identities and structures, including p19 and p45C crystal structures. Our findings provide structural and mechanistic insights into telomerase holoenzyme function.
Collapse
Affiliation(s)
- Jiansen Jiang
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA. Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA 90095, USA. California Nanosystems Institute, UCLA, Los Angeles, CA 90095, USA
| | - Henry Chan
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Darian D Cash
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Edward J Miracco
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | | | - Heather E Upton
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Duilio Cascio
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA. UCLA-U.S. Department of Energy (DOE) Institute of Genomics and Proteomics, UCLA, Los Angeles, CA 90095, USA
| | - Reid O'Brien Johnson
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Kathleen Collins
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA. Department of Biological Chemistry, UCLA, Los Angeles, CA 90095, USA. UCLA-U.S. Department of Energy (DOE) Institute of Genomics and Proteomics, UCLA, Los Angeles, CA 90095, USA
| | - Z Hong Zhou
- Department of Microbiology, Immunology, and Molecular Genetics, UCLA, Los Angeles, CA 90095, USA. California Nanosystems Institute, UCLA, Los Angeles, CA 90095, USA
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA. California Nanosystems Institute, UCLA, Los Angeles, CA 90095, USA. UCLA-U.S. Department of Energy (DOE) Institute of Genomics and Proteomics, UCLA, Los Angeles, CA 90095, USA.
| |
Collapse
|
41
|
Leon DR, Ytterberg AJ, Boontheung P, Kim U, Loo JA, Gunsalus RP, Ogorzalek Loo RR. Mining proteomic data to expose protein modifications in Methanosarcina mazei strain Gö1. Front Microbiol 2015; 6:149. [PMID: 25798134 PMCID: PMC4350412 DOI: 10.3389/fmicb.2015.00149] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Accepted: 02/09/2015] [Indexed: 12/11/2022] Open
Abstract
Proteomic tools identify constituents of complex mixtures, often delivering long lists of identified proteins. The high-throughput methods excel at matching tandem mass spectrometry data to spectra predicted from sequence databases. Unassigned mass spectra are ignored, but could, in principle, provide valuable information on unanticipated modifications and improve protein annotations while consuming limited quantities of material. Strategies to "mine" information from these discards are presented, along with discussion of features that, when present, provide strong support for modifications. In this study we mined LC-MS/MS datasets of proteolytically-digested concanavalin A pull down fractions from Methanosarcina mazei Gö1 cell lysates. Analyses identified 154 proteins. Many of the observed proteins displayed post-translationally modified forms, including O-formylated and methyl-esterified segments that appear biologically relevant (i.e., not artifacts of sample handling). Interesting cleavages and modifications (e.g., S-cyanylation and trimethylation) were observed near catalytic sites of methanogenesis enzymes. Of 31 Methanosarcina protein N-termini recovered by concanavalin A binding or from a previous study, only M. mazei S-layer protein MM1976 and its M. acetivorans C2A orthologue, MA0829, underwent signal peptide excision. Experimental results contrast with predictions from algorithms SignalP 3.0 and Exprot, which were found to over-predict the presence of signal peptides. Proteins MM0002, MM0716, MM1364, and MM1976 were found to be glycosylated, and employing chromatography tailored specifically for glycopeptides will likely reveal more. This study supplements limited, existing experimental datasets of mature archaeal N-termini, including presence or absence of signal peptides, translation initiation sites, and other processing. Methanosarcina surface and membrane proteins are richly modified.
Collapse
Affiliation(s)
- Deborah R Leon
- Department of Chemistry and Biochemistry, University of California, Los Angeles Los Angeles, CA, USA
| | - A Jimmy Ytterberg
- Department of Chemistry and Biochemistry, University of California, Los Angeles Los Angeles, CA, USA
| | - Pinmanee Boontheung
- Department of Chemistry and Biochemistry, University of California, Los Angeles Los Angeles, CA, USA
| | - Unmi Kim
- Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles Los Angeles, CA, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles Los Angeles, CA, USA ; Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles Los Angeles, CA, USA ; UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles Los Angeles, CA, USA
| | - Robert P Gunsalus
- Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles Los Angeles, CA, USA ; UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles Los Angeles, CA, USA
| | - Rachel R Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles Los Angeles, CA, USA ; UCLA-DOE Institute for Genomics and Proteomics, University of California, Los Angeles Los Angeles, CA, USA
| |
Collapse
|
42
|
Zhang J, Ogorzalek Loo RR, Loo JA. Increasing Fragmentation of Disulfide-Bonded Proteins for Top-Down Mass Spectrometry by Supercharging. Int J Mass Spectrom 2015; 377:546-556. [PMID: 26028988 PMCID: PMC4448141 DOI: 10.1016/j.ijms.2014.07.047] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The disulfide bond is an important post-translational modification to form and maintain the native structure and biological functions of proteins. Characterization of disulfide bond linkages is therefore of essential interest in the structural elucidation of proteins. Top-down mass spectrometry (MS) of disulfide-bonded proteins has been hindered by relatively low sequence coverage due to disulfide cross-linking. In this study, we employed top-down ESI-MS with Fourier-transform ion cyclotron resonance (FT-ICR) MS with electron capture dissociation (ECD) and collisionally activated dissociation (CAD) to study the fragmentation of supercharged proteins with multiple intramolecular disulfide bonds. With charge enhancement upon the addition of sulfolane to the analyte solution, improved protein fragmentation and disulfide bond cleavage efficiency was observed for proteins including bovine β-lactoglobulin, soybean trypsin inhibitor, human proinsulin, and chicken lysozyme. Both the number and relative abundances of product ions representing disulfide cleavage increase with increasing charge states for the proteins studied. Our studies suggest supercharging ESI-MS is a promising tool to aid in the top-down MS analysis of disulfide-bonded proteins, providing potentially useful information for the determination of disulfide bond linkages.
Collapse
Affiliation(s)
- Jiang Zhang
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California, 90095, United States
| | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, California, 90095, United States
- UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, California, 90095, United States
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, California, 90095, United States
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, California, 90095, United States
- UCLA/DOE Institute for Genomics and Proteomics, University of California-Los Angeles, Los Angeles, California, 90095, United States
- Corresponding author. Tel.: +1 310 794 7023; fax: +1 310 206 4038. (J.A. Loo)
| |
Collapse
|
43
|
Zhang X, Li H, Moore B, Wongkongkathep P, Ogorzalek Loo RR, Loo JA, Julian RR. Radical-directed dissociation of peptides and proteins by infrared multiphoton dissociation and sustained off-resonance irradiation collision-induced dissociation with Fourier transform ion cyclotron resonance mass spectrometry. Rapid Commun Mass Spectrom 2014; 28:2729-34. [PMID: 25380495 PMCID: PMC4237167 DOI: 10.1002/rcm.7068] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 10/01/2014] [Accepted: 10/02/2014] [Indexed: 05/19/2023]
Abstract
RATIONALE Recent experiments utilizing photodissociation in linear ion traps have enabled significant development of Radical-Directed Dissociation (RDD) for the examination of peptides and proteins. The increased mass accuracy and resolution available in Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) should enable further progress in this area. Preliminary experiments with photoactivated radicals are reported herein. METHODS A 266 nm Nd:YAG laser is coupled to a FTICR or linear ion trap mass spectrometer. Radical peptides and proteins are generated by ultraviolet photodissociation (PD) and further activated by collisions or infrared photons. RESULTS A 266 nm UV laser and an IR laser can be simultaneously coupled to a 15 Tesla FTICR mass spectrometer. The ultra-low-pressure environment in FTICR-MS makes collisional cooling less competitive, and thus more secondary fragments are generated by UVPD than in linear ion traps. Activation by sustained off-resonance irradiation collision-induced dissociation (SORI-CID) or infrared multiphoton dissociation (IRMPD) also yields additional secondary fragmentation relative to CID in an ion trap. Accurate identification of RDD fragments is possible in FTICR-MS. CONCLUSIONS Relative to linear ion trap instruments, PD experiments in FTICR-MS are more difficult to execute due to poor ion cloud overlap and the low pressure environment. However, the results can be more easily interpreted due to the increased resolution and mass accuracy.
Collapse
Affiliation(s)
- Xing Zhang
- Department of Chemistry, University of California, Riverside, California, 92521, USA
| | - Huilin Li
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, 90095, USA
| | - Benjamin Moore
- Department of Chemistry, University of California, Riverside, California, 92521, USA
| | - Piriya Wongkongkathep
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, 90095, USA
| | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, 90095, USA
- UCLA/DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California, 90095, USA
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California, 90095, USA
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, California, 90095, USA
- UCLA/DOE Institute for Genomics and Proteomics, University of California, Los Angeles, California, 90095, USA
- To whom correspondence should be addressed: and
| | - Ryan R. Julian
- Department of Chemistry, University of California, Riverside, California, 92521, USA
- To whom correspondence should be addressed: and
| |
Collapse
|
44
|
Li H, Wongkongkathep P, Van Orden SL, Loo RRO, Loo JA. Revealing ligand binding sites and quantifying subunit variants of noncovalent protein complexes in a single native top-down FTICR MS experiment. J Am Soc Mass Spectrom 2014; 25:2060-8. [PMID: 24912433 PMCID: PMC4444062 DOI: 10.1007/s13361-014-0928-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 05/09/2014] [Accepted: 05/12/2014] [Indexed: 05/11/2023]
Abstract
"Native" mass spectrometry (MS) has been proven to be increasingly useful for structural biology studies of macromolecular assemblies. Using horse liver alcohol dehydrogenase (hADH) and yeast alcohol dehydrogenase (yADH) as examples, we demonstrate that rich information can be obtained in a single native top-down MS experiment using Fourier transform ion cyclotron mass spectrometry (FTICR MS). Beyond measuring the molecular weights of the protein complexes, isotopic mass resolution was achieved for yeast ADH tetramer (147 kDa) with an average resolving power of 412,700 at m/z 5466 in absorption mode, and the mass reflects that each subunit binds to two zinc atoms. The N-terminal 89 amino acid residues were sequenced in a top-down electron capture dissociation (ECD) experiment, along with the identifications of the zinc binding site at Cys46 and a point mutation (V58T). With the combination of various activation/dissociation techniques, including ECD, in-source dissociation (ISD), collisionally activated dissociation (CAD), and infrared multiphoton dissociation (IRMPD), 40% of the yADH sequence was derived directly from the native tetramer complex. For hADH, native top-down ECD-MS shows that both E and S subunits are present in the hADH sample, with a relative ratio of 4:1. Native top-down ISD of the hADH dimer shows that each subunit (E and S chains) binds not only to two zinc atoms, but also the NAD/NADH ligand, with a higher NAD/NADH binding preference for the S chain relative to the E chain. In total, 32% sequence coverage was achieved for both E and S chains.
Collapse
Affiliation(s)
- Huilin Li
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA, 90095, USA
| | - Piriya Wongkongkathep
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
| | | | - Rachel R. Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA, 90095, USA
| | - Joseph A. Loo
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California, Los Angeles, CA, 90095, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, 90095, USA
- Correspondence to: Joseph A. Loo;
| |
Collapse
|
45
|
Ogorzalek Loo RR, Lakshmanan R, Loo JA. What protein charging (and supercharging) reveal about the mechanism of electrospray ionization. J Am Soc Mass Spectrom 2014; 25:1675-93. [PMID: 25135609 PMCID: PMC4163133 DOI: 10.1007/s13361-014-0965-1] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 06/13/2014] [Accepted: 07/08/2014] [Indexed: 05/11/2023]
Abstract
Understanding the charging mechanism of electrospray ionization is central to overcoming shortcomings such as ion suppression or limited dynamic range, and explaining phenomena such as supercharging. Towards that end, we explore what accumulated observations reveal about the mechanism of electrospray. We introduce the idea of an intermediate region for electrospray ionization (and other ionization methods) to account for the facts that solution charge state distributions (CSDs) do not correlate with those observed by ESI-MS (the latter bear more charge) and that gas phase reactions can reduce, but not increase, the extent of charging. This region incorporates properties (e.g., basicities) intermediate between solution and gas phase. Assuming that droplet species polarize within the high electric field leads to equations describing ion emission resembling those from the equilibrium partitioning model. The equations predict many trends successfully, including CSD shifts to higher m/z for concentrated analytes and shifts to lower m/z for sprays employing smaller emitter opening diameters. From this view, a single mechanism can be formulated to explain how reagents that promote analyte charging ("supercharging") such as m-NBA, sulfolane, and 3-nitrobenzonitrile increase analyte charge from "denaturing" and "native" solvent systems. It is suggested that additives' Brønsted basicities are inversely correlated to their ability to shift CSDs to lower m/z in positive ESI, as are Brønsted acidities for negative ESI. Because supercharging agents reduce an analyte's solution ionization, excess spray charge is bestowed on evaporating ions carrying fewer opposing charges. Brønsted basicity (or acidity) determines how much ESI charge is lost to the agent (unavailable to evaporating analyte).
Collapse
Affiliation(s)
- Rachel R Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, CA, 90095, USA,
| | | | | |
Collapse
|
46
|
Ogorzalek Loo RR, Lakshmanan R, Loo JA. What protein charging (and supercharging) reveal about the mechanism of electrospray ionization. J Am Soc Mass Spectrom 2014; 25:1675-1693. [PMID: 25135609 DOI: 10.1007/s13361-014-0870-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 06/13/2014] [Accepted: 07/08/2014] [Indexed: 05/25/2023]
Abstract
Understanding the charging mechanism of electrospray ionization is central to overcoming shortcomings such as ion suppression or limited dynamic range, and explaining phenomena such as supercharging. Towards that end, we explore what accumulated observations reveal about the mechanism of electrospray. We introduce the idea of an intermediate region for electrospray ionization (and other ionization methods) to account for the facts that solution charge state distributions (CSDs) do not correlate with those observed by ESI-MS (the latter bear more charge) and that gas phase reactions can reduce, but not increase, the extent of charging. This region incorporates properties (e.g., basicities) intermediate between solution and gas phase. Assuming that droplet species polarize within the high electric field leads to equations describing ion emission resembling those from the equilibrium partitioning model. The equations predict many trends successfully, including CSD shifts to higher m/z for concentrated analytes and shifts to lower m/z for sprays employing smaller emitter opening diameters. From this view, a single mechanism can be formulated to explain how reagents that promote analyte charging ("supercharging") such as m-NBA, sulfolane, and 3-nitrobenzonitrile increase analyte charge from "denaturing" and "native" solvent systems. It is suggested that additives' Brønsted basicities are inversely correlated to their ability to shift CSDs to lower m/z in positive ESI, as are Brønsted acidities for negative ESI. Because supercharging agents reduce an analyte's solution ionization, excess spray charge is bestowed on evaporating ions carrying fewer opposing charges. Brønsted basicity (or acidity) determines how much ESI charge is lost to the agent (unavailable to evaporating analyte).
Collapse
Affiliation(s)
- Rachel R Ogorzalek Loo
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, CA, 90095, USA,
| | | | | |
Collapse
|
47
|
Shen S, Loo RRO, Wanner IB, Loo JA. Addressing the needs of traumatic brain injury with clinical proteomics. Clin Proteomics 2014; 11:11. [PMID: 24678615 PMCID: PMC3976360 DOI: 10.1186/1559-0275-11-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 02/10/2014] [Indexed: 12/15/2022] Open
Abstract
Background Neurotrauma or injuries to the central nervous system (CNS) are a serious public health problem worldwide. Approximately 75% of all traumatic brain injuries (TBIs) are concussions or other mild TBI (mTBI) forms. Evaluation of concussion injury today is limited to an assessment of behavioral symptoms, often with delay and subject to motivation. Hence, there is an urgent need for an accurate chemical measure in biofluids to serve as a diagnostic tool for invisible brain wounds, to monitor severe patient trajectories, and to predict survival chances. Although a number of neurotrauma marker candidates have been reported, the broad spectrum of TBI limits the significance of small cohort studies. Specificity and sensitivity issues compound the development of a conclusive diagnostic assay, especially for concussion patients. Thus, the neurotrauma field currently has no diagnostic biofluid test in clinical use. Content We discuss the challenges of discovering new and validating identified neurotrauma marker candidates using proteomics-based strategies, including targeting, selection strategies and the application of mass spectrometry (MS) technologies and their potential impact to the neurotrauma field. Summary Many studies use TBI marker candidates based on literature reports, yet progress in genomics and proteomics have started to provide neurotrauma protein profiles. Choosing meaningful marker candidates from such ‘long lists’ is still pending, as only few can be taken through the process of preclinical verification and large scale translational validation. Quantitative mass spectrometry targeting specific molecules rather than random sampling of the whole proteome, e.g., multiple reaction monitoring (MRM), offers an efficient and effective means to multiplex the measurement of several candidates in patient samples, thereby omitting the need for antibodies prior to clinical assay design. Sample preparation challenges specific to TBI are addressed. A tailored selection strategy combined with a multiplex screening approach is helping to arrive at diagnostically suitable candidates for clinical assay development. A surrogate marker test will be instrumental for critical decisions of TBI patient care and protection of concussion victims from repeated exposures that could result in lasting neurological deficits.
Collapse
Affiliation(s)
| | | | | | - Joseph A Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095, USA.
| |
Collapse
|
48
|
Abstract
The integrity of quantitative proteomic experiments depends on the reliability and the robustness of the protein extraction, solubilization, and digestion methods utilized. Combinations of detergents, chaotropes, and mechanical disruption can yield successful protein preparations; however, the methods subsequently required to eliminate these added contaminants, in addition to the salts, nucleic acids, and lipids already in the sample, can result in significant sample losses and incomplete contaminant removal. A recently introduced method for proteomic sample preparation, filter-aided sample preparation (FASP), cleverly circumvents many of the challenges associated with traditional protein purification methods but is associated with significant sample loss. Presented here is an enhanced FASP (eFASP) approach that incorporates alternative reagents to those of traditional FASP, improving sensitivity, recovery, and proteomic coverage for processed samples. The substitution of 0.2% deoxycholic acid for urea during eFASP digestion increases tryptic digestion efficiency for both cytosolic and membrane proteins yet obviates needed cleanup steps associated with use of the deoxycholate sodium salt. For classic FASP, prepassivating Microcon filter surfaces with 5% TWEEN-20 reduces peptide loss by 300%. An express eFASP method uses tris(2-carboxyethyl)phosphine and 4-vinylpyridine to alkylate proteins prior to deposition on the Microcon filter, increasing alkylation specificity and speeding processing.
Collapse
Affiliation(s)
- Jonathan Erde
- Department of Chemistry and Biochemistry and ‡Department of Biological Chemistry, University of California-Los Angeles , Los Angeles, California 90095, United States
| | | | | |
Collapse
|
49
|
Abstract
Mass spectrometry of protein assemblies reveals size and stoichiometry. In this issue of Structure, Hall and colleagues demonstrate that gas-phase dissociations can recapitulate solution structure for complexes with few intersubunit salt bridges, high charge density, inflexible subunits, or small intersubunit interfaces.
Collapse
Affiliation(s)
- Rachel R Ogorzalek Loo
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | | |
Collapse
|
50
|
Chen CK, Benchaar SA, Phan M, Grintsevich EE, Loo RRO, Loo JA, Reisler E. Cofilin-induced changes in F-actin detected via cross-linking with benzophenone-4-maleimide. Biochemistry 2013; 52:5503-9. [PMID: 23862734 DOI: 10.1021/bi400715z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cofilin is a member of the actin depolymerizing factor (ADF)/cofilin family of proteins. It plays a key role in actin dynamics by promoting disassembly and assembly of actin filaments. Upon its binding, cofilin has been shown to bridge two adjacent protomers in filamentous actin (F-actin) and promote the displacement and disordering of subdomain 2 of actin. Here, we present evidence for cofilin promoting a new structural change in the actin filament, as detected via a switch in cross-linking sites. Benzophenone-4-maleimide, which normally forms intramolecular cross-linking in F-actin, cross-links F-actin intermolecularly upon cofilin binding. We mapped the cross-linking sites and found that in the absence of cofilin intramolecular cross-linking occurred between residues Cys374 and Asp11. In contrast, cofilin shifts the cross-linking by this reagent to intermolecular, between residue Cys374, located within subdomain 1 of the upper protomer, and Met44, located in subdomain 2 of the lower protomer. The intermolecular cross-linking of F-actin slows the rate of cofilin dissociation from the filaments and decreases the effect of ionic strength on cofilin-actin binding. These results are consistent with a significant role of filament flexibility in cofilin-actin interactions.
Collapse
Affiliation(s)
- Christine K Chen
- Department of Chemistry and Biochemistry, Molecular Biology Institute and Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | | | | | | | | | | | | |
Collapse
|