1
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Escobar EE, Yang W, Lanzillotti MB, Juetten KJ, Shields S, Siegel D, Zhang YJ, Brodbelt JS. Tracking Inhibition of Human Small C-Terminal Domain Phosphatase 1 Using 193 nm Ultraviolet Photodissociation Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:1330-1341. [PMID: 38662915 PMCID: PMC11384422 DOI: 10.1021/jasms.4c00098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Working in tandem with kinases via a dynamic interplay of phosphorylation and dephosphorylation of proteins, phosphatases regulate many cellular processes and thus represent compelling therapeutic targets. Here we leverage ultraviolet photodissociation to shed light on the binding characteristics of two covalent phosphatase inhibitors, T65 and rabeprazole, and their respective interactions with the human small C-terminal domain phosphatase 1 (SCP1) and its single-point mutant C181A, in which a nonreactive alanine replaces one key reactive cysteine. Top-down MS/MS analysis is used to localize the binding of T65 and rabeprazole on the two proteins and estimate the relative reactivities of each cysteine residue.
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Affiliation(s)
| | | | | | | | | | - Dionicio Siegel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive 0741, La Jolla, California 92093, United States
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2
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Zhu Y, Liu Z, Liu J, Zhao H, Feng R, Shu K, Wang F, Chang C. Panda-UV Unlocks Deeper Protein Characterization with Internal Fragments in Ultraviolet Photodissociation Mass Spectrometry. Anal Chem 2024; 96:8474-8483. [PMID: 38739687 PMCID: PMC11140674 DOI: 10.1021/acs.analchem.4c00253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 05/06/2024] [Accepted: 05/06/2024] [Indexed: 05/16/2024]
Abstract
Ultraviolet photodissociation (UVPD) mass spectrometry unlocks insights into the protein structure and sequence through fragmentation patterns. While N- and C-terminal fragments are traditionally relied upon, this work highlights the critical role of internal fragments in achieving near-complete sequencing of protein. Previous limitations of internal fragment utilization, owing to their abundance and potential for random matching, are addressed here with the development of Panda-UV, a novel software tool combining spectral calibration, and Pearson correlation coefficient scoring for confident fragment assignment. Panda-UV showcases its power through comprehensive benchmarks on three model proteins. The inclusion of internal fragments boosts identified fragment numbers by 26% and enhances average protein sequence coverage to a remarkable 93% for intact proteins, unlocking the hidden region of the largest protein carbonic anhydrase II in model proteins. Notably, an average of 65% of internal fragments can be identified in multiple replicates, demonstrating the high confidence of the fragments Panda-UV provided. Finally, the sequence coverages of mAb subunits can be increased up to 86% and the complementary determining regions (CDRs) are nearly completely sequenced in a single experiment. The source codes of Panda-UV are available at https://github.com/PHOENIXcenter/Panda-UV.
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Affiliation(s)
- Yinlong Zhu
- Chongqing
Key Laboratory on Big Data for Bio Intelligence, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
- State
Key Laboratory of Medical Proteomics, Beijing
Proteome Research Center, National Center for Protein Sciences (Beijing),
Beijing Institute of Lifeomics, Beijing 102206, China
- CAS
Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian
Institute of Chemical Physics, Chinese Academy
of Sciences, Dalian 116023, China
| | - Zheyi Liu
- CAS
Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian
Institute of Chemical Physics, Chinese Academy
of Sciences, Dalian 116023, China
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
| | - Jialiang Liu
- CAS
Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian
Institute of Chemical Physics, Chinese Academy
of Sciences, Dalian 116023, China
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- School of
Pharmacy, China Medical University, Shenyang 110122, China
| | - Heng Zhao
- CAS
Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian
Institute of Chemical Physics, Chinese Academy
of Sciences, Dalian 116023, China
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Rui Feng
- State
Key Laboratory of Medical Proteomics, Beijing
Proteome Research Center, National Center for Protein Sciences (Beijing),
Beijing Institute of Lifeomics, Beijing 102206, China
| | - Kunxian Shu
- Chongqing
Key Laboratory on Big Data for Bio Intelligence, Chongqing University of Posts and Telecommunications, Chongqing 400065, China
| | - Fangjun Wang
- CAS
Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian
Institute of Chemical Physics, Chinese Academy
of Sciences, Dalian 116023, China
- State
Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of
Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
- University
of Chinese Academy of Sciences, Beijing 100049, China
| | - Cheng Chang
- State
Key Laboratory of Medical Proteomics, Beijing
Proteome Research Center, National Center for Protein Sciences (Beijing),
Beijing Institute of Lifeomics, Beijing 102206, China
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3
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Martínez-Fernández L, Ranković ML, Canon F, Nahon L, Giuliani A, Milosavljević AR, Martin-Somer A. Photodissociation of leucine-enkephalin protonated peptide: an experimental and theoretical perspective. RSC Adv 2024; 14:16809-16820. [PMID: 38784408 PMCID: PMC11112675 DOI: 10.1039/d4ra01690d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024] Open
Abstract
Understanding the competing processes that govern far ultraviolet photodissociation (FUV-PD) of biopolymers such as proteins is a challenge. Here, we report a combined experimental and theoretical investigation of FUV-PD of protonated leucine-enkephalin pentapeptide ([YGGFL + H]+) in the gas-phase. Time-dependent density functional theory (TD-DFT) calculations in combination with experiments and previous results for amino acids and shorter peptides help in rationalizing the evolution of the excited states. The results confirm that fragmentation of [YGGFL + H]+ results mainly from vibrationally excited species in the ground electronic state, populated after internal conversion. We also propose fragmentation mechanisms for specific photo-fragments such as tyrosine side chain loss (with an extra hydrogen) or hydrogen loss. In general, we observe the same mechanisms as for smaller peptides or protonated Tyr and Phe, that are not quenched by the presence of other amino acids. Nevertheless, we also found some differences, as for H loss, in part due to the fact that the charge is solvated by the peptide chain and not only by the COOH terminal group.
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Affiliation(s)
- Lara Martínez-Fernández
- Departamento de Química Física de Materiales, Instituto de Química Física de Materiales, Instituto de Química Física Blas Cabrera, CSIC 28006 Madrid Spain
| | - Miloš Lj Ranković
- Institute of Physics Belgrade, University of Belgrade Pregrevica 118 11080 Belgrade Serbia
| | - Francis Canon
- SOLEIL l'Orme des Merisiers, St Aubin, BP48, F-91192 Gif sur Yvette Cedex France
| | - Laurent Nahon
- SOLEIL l'Orme des Merisiers, St Aubin, BP48, F-91192 Gif sur Yvette Cedex France
| | - Alexandre Giuliani
- SOLEIL l'Orme des Merisiers, St Aubin, BP48, F-91192 Gif sur Yvette Cedex France
- INRAE, Dpet. Transform UAR1008, Rue de la Géraudière, BP 71627 F-44316 Nantes France
| | | | - Ana Martin-Somer
- Departamento de Química Física Aplicada, Universidad Autónoma de Madrid Módulo 14 28049 Spain
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4
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Juliano BR, Keating JW, Ruotolo BT. Infrared Photoactivation Enables Improved Native Top-Down Mass Spectrometry of Transmembrane Proteins. Anal Chem 2023; 95:13361-13367. [PMID: 37610409 PMCID: PMC11081007 DOI: 10.1021/acs.analchem.3c02788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Membrane proteins are often challenging targets for native top-down mass spectrometry experimentation. The requisite use of membrane mimetics to solubilize such proteins necessitates the application of supplementary activation methods to liberate protein ions prior to sequencing, which typically limits the sequence coverage achieved. Recently, infrared photoactivation has emerged as an alternative to collisional activation for the liberation of membrane proteins from surfactant micelles. However, much remains unknown regarding the mechanism by which IR activation liberates membrane protein ions from such micelles, the extent to which such methods can improve membrane protein sequence coverage, and the degree to which such approaches can be extended to support native proteomics. Here, we describe experiments designed to evaluate and probe infrared photoactivation for membrane protein sequencing, proteoform identification, and native proteomics applications. Our data reveal that infrared photoactivation can dissociate micelles composed of a variety of detergent classes, without the need for a strong IR chromophore by leveraging the relatively weak association energies of such detergent clusters in the gas phase. Additionally, our data illustrate how IR photoactivation can be extended to include membrane mimetics beyond micelles and liberate proteins from nanodiscs, liposomes, and bicelles. Finally, our data quantify the improvements in membrane protein sequence coverage produced through the use of IR photoactivation, which typically leads to membrane protein sequence coverage values ranging from 40 to 60%.
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Affiliation(s)
- Brock R Juliano
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Joseph W Keating
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Brandon T Ruotolo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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5
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Macias LA, Garcia SP, Back KM, Wu Y, Johnson GH, Kathiresan S, Bellinger AM, Rohde E, Freitas MA, Madsen JA. Spacer Fidelity Assessments of Guide RNA by Top-Down Mass Spectrometry. ACS CENTRAL SCIENCE 2023; 9:1437-1452. [PMID: 37521788 PMCID: PMC10375574 DOI: 10.1021/acscentsci.3c00289] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Indexed: 08/01/2023]
Abstract
The advancement of CRISPR-based gene editing tools into biotherapeutics offers the potential for cures to genetic disorders and for new treatment paradigms for even common diseases. Arguably, the most important component of a CRISPR-based medicine is the guide RNA, which is generally large (>100-mer) synthetic RNA composed of a "tracr" and "spacer" region, the latter of which dictates the on-target editing site as well as potential undesired off-target edits. Aiming to advance contemporary capabilities for gRNA characterization to ensure the spacer region is of high fidelity, top-down mass spectrometry was herein implemented to provide direct and quantitative assessments of highly modified gRNA. In addition to sequencing the spacer region and pinpointing modifications, top-down mass spectra were utilized to quantify single-base spacer substitution impurities down to <1% and to decipher highly dissimilar spacers. To accomplish these results in an automated fashion, we devised custom software capable of sequencing and quantifying impurities in gRNA spacers. Notably, we developed automated tools that enabled the quantification of single-base substitutions, including advanced isotopic pattern matching for C > U and U > C substitutions, and created a de novo sequencing strategy to facilitate the identification and quantification of gRNA impurities with highly dissimilar spacer regions.
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Affiliation(s)
- Luis A. Macias
- Verve
Therapeutics, 201 Brookline Avenue, Suite 601, Boston, Massachusetts 02215, United States
| | - Sara P. Garcia
- Verve
Therapeutics, 201 Brookline Avenue, Suite 601, Boston, Massachusetts 02215, United States
| | - Kayla M. Back
- Verve
Therapeutics, 201 Brookline Avenue, Suite 601, Boston, Massachusetts 02215, United States
| | - Yue Wu
- Verve
Therapeutics, 201 Brookline Avenue, Suite 601, Boston, Massachusetts 02215, United States
| | - G. Hall Johnson
- MassMatrix,
Inc., 600 Teteridge Road, Columbus, Ohio 43214, United States
| | - Sekar Kathiresan
- Verve
Therapeutics, 201 Brookline Avenue, Suite 601, Boston, Massachusetts 02215, United States
| | - Andrew M. Bellinger
- Verve
Therapeutics, 201 Brookline Avenue, Suite 601, Boston, Massachusetts 02215, United States
| | - Ellen Rohde
- Verve
Therapeutics, 201 Brookline Avenue, Suite 601, Boston, Massachusetts 02215, United States
| | - Michael A. Freitas
- MassMatrix,
Inc., 600 Teteridge Road, Columbus, Ohio 43214, United States
- The
Ohio State University, 281 West Lane Avenue, Columbus, Ohio 43210, United States
| | - James A. Madsen
- Verve
Therapeutics, 201 Brookline Avenue, Suite 601, Boston, Massachusetts 02215, United States
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6
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Shoff TA, Julian RR. Fragment Ion Abundance Reveals Information about Structure and Charge Localization in Highly Charged Proteins. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023. [PMID: 37477985 PMCID: PMC10401701 DOI: 10.1021/jasms.3c00196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/23/2023]
Abstract
Top-down mass spectrometry (MS) is a versatile tool that has been employed to investigate both protein sequence and structure. Although a variety of different fragmentation methods are available in top-down MS that can potentially yield structural information, quantifying differences between spectra remains challenging. Herein, we show that subtle differences in spectra produced by a variety of fragmentation methods are surprisingly sensitive to protein structure and/or charge localization, even in highly unfolded proteins observed in high charge states. In addition to exposing information about the protein structure, differences in fragmentation also reveal insight into the mechanisms underlying the dissociation methods themselves. The results further reveal that small changes in experimental parameters (such as the addition of methanol instead of acetonitrile) lead to changes in structure that are reflected in statistically reproducible differences in dissociation. Collisional annealing of structurally dissimilar ions in the gas phase eventually leads to dissociation spectra that are indistinguishable, suggesting that structural differences can be erased by sufficient thermal activation. Additional experiments illustrate that identical charge states of the same protein can be distinguished if those produced directly by electrospray are compared to ions manipulated by in vacuo proton-transfer charge reduction. Overall, the results show that subtle differences in both three-dimensional structure and charge-site localization can influence the abundance of fragment ions produced by top-down MS, including dissociation methods not typically thought to be structurally sensitive.
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Affiliation(s)
- Thomas A Shoff
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Ryan R Julian
- Department of Chemistry, University of California, Riverside, California 92521, United States
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7
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Zemaitis KJ, Zhou M, Kew W, Paša-Tolić L. 193 nm Ultraviolet Photodissociation for the Characterization of Singly Charged Proteoforms Generated by MALDI. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:328-332. [PMID: 36622763 PMCID: PMC10084724 DOI: 10.1021/jasms.2c00302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
MALDI imaging allows for the near-cellular profiling of proteoforms directly from microbial, plant, and mammalian samples. Despite detecting hundreds of proteoforms, identification of unknowns with only intact mass information remains a distinct challenge, even with high mass resolving power and mass accuracy. To this end, many supplementary methods have been used to create experimental databases for accurate mass matching, including bulk or spatially resolved bottom-up and/or top-down proteomics. Herein, we describe the application of 193 nm ultraviolet photodissociation (UVPD) for fragmentation of quadrupole isolated singly charged ubiquitin (m/z 8565) by MALDI-UVPD on a UHMR HF Orbitrap. This platform permitted the high-resolution accurate mass measurement of not just terminal fragments but also large internal fragments. The outlined workflow demonstrates the feasibility of top-down analyses of isolated MALDI protein ions and the potential toward more comprehensive characterization of proteoforms in MALDI imaging applications.
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Affiliation(s)
- Kevin J Zemaitis
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Mowei Zhou
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - William Kew
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Ljiljana Paša-Tolić
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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8
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Theisen A, Wootton CA, Haris A, Morgan TE, Lam YPY, Barrow MP, O’Connor PB. Enhancing Biomolecule Analysis and 2DMS Experiments by Implementation of (Activated Ion) 193 nm UVPD on a FT-ICR Mass Spectrometer. Anal Chem 2022; 94:15631-15638. [DOI: 10.1021/acs.analchem.2c02354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Alina Theisen
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | | | - Anisha Haris
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Tomos E. Morgan
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Yuko P. Y. Lam
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Mark P. Barrow
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
| | - Peter B. O’Connor
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K
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9
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Sipe SN, Lancaster EB, Butalewicz JP, Whitman CP, Brodbelt JS. Symmetry of 4-Oxalocrotonate Tautomerase Trimers Influences Unfolding and Fragmentation in the Gas Phase. J Am Chem Soc 2022; 144:12299-12309. [PMID: 35767842 DOI: 10.1021/jacs.2c03564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The recent discovery of asymmetric arrangements of trimers in the tautomerase superfamily (TSF) adds structural diversity to this already mechanistically diverse superfamily. Classification of asymmetric trimers has previously been determined using X-ray crystallography. Here, native mass spectrometry (MS) and ultraviolet photodissociation (UVPD) are employed as an integrated strategy for more rapid and sensitive differentiation of symmetric and asymmetric trimers. Specifically, the unfolding of symmetric and asymmetric trimers initiated by collisional heating was probed using UVPD, which revealed unique gas-phase unfolding pathways. Variations in UVPD patterns from native-like, compact trimeric structures to unfolded, extended conformations indicate a rearrangement of higher-order structure in the asymmetric trimers that are believed to be stabilized by salt-bridge triads, which are absent from the symmetric trimers. Consequently, the symmetric trimers were found to be less stable in the gas phase, resulting in enhanced UVPD fragmentation overall and a notable difference in higher-order re-structuring based on the extent of hydrogen migration of protein fragments. The increased stability of the asymmetric trimers may justify their evolution and concomitant diversification of the TSF. Facilitating the classification of TSF members as symmetric or asymmetric trimers assists in delineating the evolutionary history of the TSF.
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Affiliation(s)
- Sarah N Sipe
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
| | - Emily B Lancaster
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, Texas 78712, United States
| | - Jamie P Butalewicz
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
| | - Christian P Whitman
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, University of Texas, Austin, Texas 78712, United States.,Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas, Austin, Texas 78712, United States
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10
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Liu R, Xia S, Li H. Native top-down mass spectrometry for higher-order structural characterization of proteins and complexes. MASS SPECTROMETRY REVIEWS 2022:e21793. [PMID: 35757976 DOI: 10.1002/mas.21793] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Progress in structural biology research has led to a high demand for powerful and yet complementary analytical tools for structural characterization of proteins and protein complexes. This demand has significantly increased interest in native mass spectrometry (nMS), particularly native top-down mass spectrometry (nTDMS) in the past decade. This review highlights recent advances in nTDMS for structural research of biological assemblies, with a particular focus on the extra multi-layers of information enabled by TDMS. We include a short introduction of sample preparation and ionization to nMS, tandem fragmentation techniques as well as mass analyzers and software/analysis pipelines used for nTDMS. We highlight unique structural information offered by nTDMS and examples of its broad range of applications in proteins, protein-ligand interactions (metal, cofactor/drug, DNA/RNA, and protein), therapeutic antibodies and antigen-antibody complexes, membrane proteins, macromolecular machineries (ribosome, nucleosome, proteosome, and viruses), to endogenous protein complexes. The challenges, potential, along with perspectives of nTDMS methods for the analysis of proteins and protein assemblies in recombinant and biological samples are discussed.
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Affiliation(s)
- Ruijie Liu
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Shujun Xia
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Huilin Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
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11
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Macias LA, Wang X, Davies BW, Brodbelt JS. Mapping paratopes of nanobodies using native mass spectrometry and ultraviolet photodissociation. Chem Sci 2022; 13:6610-6618. [PMID: 35756525 PMCID: PMC9172568 DOI: 10.1039/d2sc01536f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 05/16/2022] [Indexed: 11/21/2022] Open
Abstract
Following immense growth and maturity of the field in the past decade, native mass spectrometry has garnered widespread adoption for the structural characterization of macromolecular complexes. Routine analysis of biotherapeutics by this technique has become commonplace to assist in the development and quality control of immunoglobulin antibodies. Concurrently, 193 nm ultraviolet photodissociation (UVPD) has been developed as a structurally sensitive ion activation technique capable of interrogating protein conformational changes. Here, UVPD was applied to probe the paratopes of nanobodies, a class of single-domain antibodies with an expansive set of applications spanning affinity reagents, molecular imaging, and biotherapeutics. Comparing UVPD sequence fragments for the free nanobodies versus nanobody·antigen complexes empowered assignment of nanobody paratopes and intermolecular salt-bridges, elevating the capabilities of UVPD as a new strategy for characterization of nanobodies. Ultraviolet photodissociation mass spectrometry is used to probe the paratopes of nanobodies, a class of single-domain antibodies, and to determine intersubunit salt-bridges and explore the nanobody·antigen interfaces.![]()
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Affiliation(s)
- Luis A Macias
- Department of Chemistry, University of Texas at Austin Austin TX 78712 USA
| | - Xun Wang
- Department of Molecular Biosciences, University of Texas at Austin Austin TX 78712 USA
| | - Bryan W Davies
- Department of Molecular Biosciences, University of Texas at Austin Austin TX 78712 USA
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12
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Zhou M, Jiao L, Xu S, Xu Y, Du M, Zhang X, Kong X. A novel method for photon unfolding spectroscopy of protein ions in the gas phase. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:043003. [PMID: 35489914 DOI: 10.1063/5.0080040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 03/18/2022] [Indexed: 06/14/2023]
Abstract
In this study, a new experimental method for photon unfolding spectroscopy of protein ions based on a Fourier transform ion cyclotron resonance (FT ICR) mass spectrometer was developed. The method of short-time Fourier transform has been applied here to obtain decay curves of target ions trapped in the cell of the FT ICR mass spectrometer. Based on the decay constants, the collision cross sections (CCSs) of target ions were calculated using the energetic hard-sphere model. By combining a tunable laser to the FT ICR mass spectrometer, the changes of CCSs of the target ions were recorded as a function of the wavelengths; thus, the photon isomerization spectrum was obtained. As one example, the photon isomerization spectrum of [Cyt c + 13H]13+ was recorded as the decay constants relative to the applied wavelengths of the laser in the 410-480 nm range. The spectrum shows a maximum at 426 nm, where an unfolded structure induced by a 4 s irradiation can be deduced. The strong peak at 426 nm was also observed for another ion of [Cyt c + 15H]15+, although some difference at 410 nm between the two spectra was found at the same time. This novel method can be expanded to ultraviolet or infrared region, making the experimental study of wavelength-dependent photon-induced structural variation of a variety of organic or biological molecules possible.
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Affiliation(s)
- Min Zhou
- State Key Laboratory of Elemento-organic Chemistry, Collage of Chemistry, Nankai University, Tianjin 300071, China
| | - Luyang Jiao
- State Key Laboratory of Elemento-organic Chemistry, Collage of Chemistry, Nankai University, Tianjin 300071, China
| | - Shiyin Xu
- State Key Laboratory of Elemento-organic Chemistry, Collage of Chemistry, Nankai University, Tianjin 300071, China
| | - Yicheng Xu
- State Key Laboratory of Elemento-organic Chemistry, Collage of Chemistry, Nankai University, Tianjin 300071, China
| | - Mengying Du
- State Key Laboratory of Elemento-organic Chemistry, Collage of Chemistry, Nankai University, Tianjin 300071, China
| | - Xianyi Zhang
- School of Physics and Electronic Information, Anhui Normal University, Wuhu 241000, China
| | - Xianglei Kong
- State Key Laboratory of Elemento-organic Chemistry, Collage of Chemistry, Nankai University, Tianjin 300071, China
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