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Sun Z, Chu X, Adams C, Ilina TV, Guerrero M, Lin G, Chen C, Jelev D, Ishima R, Li W, Mellors JW, Calero G, Dimitrov DS. Preclinical assessment of a novel human antibody VH domain targeting mesothelin as an antibody-drug conjugate. Mol Ther Oncolytics 2023; 31:100726. [PMID: 37771390 PMCID: PMC10522976 DOI: 10.1016/j.omto.2023.09.002] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 09/08/2023] [Indexed: 09/30/2023] Open
Abstract
Mesothelin (MSLN) has been a validated tumor-associated antigen target for several solid tumors for over a decade, making it an attractive option for therapeutic interventions. Novel antibodies with high affinity and better therapeutic properties are needed. In the current study, we have isolated and characterized a novel heavy chain variable (VH) domain 3C9 from a large-size human immunoglobulin VH domain library. 3C9 exhibited high affinity (KD [dissociation constant] <3 nM) and binding specificity in a membrane proteome array (MPA). In a mouse xenograft model, 3C9 fused to human IgG1 Fc was detected at tumor sites as early as 8 h post-infusion and remained at the site for over 10 days. Furthermore, 3C9 fused to a human Fc domain drug conjugate effectively inhibited MSLN-positive tumor growth in a mouse xenograft model. The X-ray crystal structure of full-length MSLN in complex with 3C9 reveals interaction of the 3C9 domains with two distinctive residue patches on the MSLN surface. This newly discovered VH antibody domain has a high potential as a therapeutic candidate for MSLN-expressing cancers.
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Affiliation(s)
- Zehua Sun
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Street, Pittsburgh, PA 15261, USA
| | - Xiaojie Chu
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Street, Pittsburgh, PA 15261, USA
| | - Cynthia Adams
- Abound Bio, 1401 Forbes Avenue, Pittsburgh, PA 15219, USA
| | - Tatiana V. Ilina
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Michel Guerrero
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Guowu Lin
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Chuan Chen
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Street, Pittsburgh, PA 15261, USA
| | - Dontcho Jelev
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Street, Pittsburgh, PA 15261, USA
| | - Rieko Ishima
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Wei Li
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Street, Pittsburgh, PA 15261, USA
| | - John W. Mellors
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Street, Pittsburgh, PA 15261, USA
- Abound Bio, 1401 Forbes Avenue, Pittsburgh, PA 15219, USA
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Dimiter S. Dimitrov
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, 3550 Terrace Street, Pittsburgh, PA 15261, USA
- Abound Bio, 1401 Forbes Avenue, Pittsburgh, PA 15219, USA
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2
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Vergara S, Zhou X, Santiago U, Conway JF, Sluis-Cremer N, Calero G. Structures of kinetic intermediate states of HIV-1 reverse transcriptase DNA synthesis. bioRxiv 2023:2023.12.18.572243. [PMID: 38187617 PMCID: PMC10769260 DOI: 10.1101/2023.12.18.572243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Reverse transcription of the retroviral single-stranded RNA into double-stranded DNA is an integral step during HIV-1 replication, and reverse transcriptase (RT) is a primary target for antiviral therapy. Despite a wealth of structural information on RT, we lack critical insight into the intermediate kinetic states of DNA synthesis. Using catalytically active substrates, and a novel blot/diffusion cryo-electron microscopy approach, we captured 11 structures that define the substrate binding, reactant, transition and product states of dATP addition by RT at 1.9 to 2.4 Å resolution in the active site. Initial dATP binding to RT-template/primer complex involves a single Mg 2+ (site B), and promotes partial closure of the active site pocket by a large conformational change in the β3-β4 loop in the Fingers domain, and formation of a negatively charged pocket where a second "drifting" Mg 2+ can bind (site A). During the transition state, the α-phosphate oxygen from a previously unobserved dATP conformer aligns with the site A Mg 2+ and the primer 3'-OH for nucleophilic attack. In the product state, we captured two substrate conformations in the active site: 1) dATP that had yet to be incorporated into the nascent DNA, and 2) an incorporated dAMP with the pyrophosphate leaving group coordinated by metal B and stabilized through H- bonds in the active site of RT. This study provides insights into a fundamental chemical reaction that impacts polymerase fidelity, nucleoside inhibitor drug design, and mechanisms of drug resistance.
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Lin G, Barnes CO, Weiss S, Dutagaci B, Qiu C, Feig M, Song J, Lyubimov A, Cohen AE, Kaplan CD, Calero G. Structural basis of transcription: RNA Polymerase II substrate binding and metal coordination at 3.0 Å using a free-electron laser. bioRxiv 2023:2023.09.22.559052. [PMID: 37790421 PMCID: PMC10543002 DOI: 10.1101/2023.09.22.559052] [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] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Catalysis and translocation of multi-subunit DNA-directed RNA polymerases underlie all cellular mRNA synthesis. RNA polymerase II (Pol II) synthesizes eukaryotic pre-mRNAs from a DNA template strand buried in its active site. Structural details of catalysis at near atomic resolution and precise arrangement of key active site components have been elusive. Here we present the free electron laser (FEL) structure of a matched ATP-bound Pol II, revealing the full active site interaction network at the highest resolution to date, including the trigger loop (TL) in the closed conformation, bonafide occupancy of both site A and B Mg2+, and a putative third (site C) Mg2+ analogous to that described for some DNA polymerases but not observed previously for cellular RNA polymerases. Molecular dynamics (MD) simulations of the structure indicate that the third Mg2+ is coordinated and stabilized at its observed position. TL residues provide half of the substrate binding pocket while multiple TL/bridge helix (BH) interactions induce conformational changes that could propel translocation upon substrate hydrolysis. Consistent with TL/BH communication, a FEL structure and MD simulations of the hyperactive Rpb1 T834P bridge helix mutant reveals rearrangement of some active site interactions supporting potential plasticity in active site function and long-distance effects on both the width of the central channel and TL conformation, likely underlying its increased elongation rate at the expense of fidelity.
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Affiliation(s)
- Guowu Lin
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh PA 15261 USA
| | - Christopher O Barnes
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena CA 91125 USA
| | - Simon Weiss
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh PA 15261 USA
| | - Bercem Dutagaci
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing MI 48824 USA
| | - Chenxi Qiu
- Department of Genetics, Harvard Medical School, Boston MA 02115 USA
| | - Michael Feig
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing MI 48824 USA
| | - Jihnu Song
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Artem Lyubimov
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Aina E Cohen
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Craig D Kaplan
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh PA 15260 USA
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh PA 15261 USA
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4
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Sarkar S, Runge B, Russell RW, Movellan KT, Calero D, Zeinalilathori S, Quinn CM, Lu M, Calero G, Gronenborn AM, Polenova T. Atomic-Resolution Structure of SARS-CoV-2 Nucleocapsid Protein N-Terminal Domain. J Am Chem Soc 2022; 144:10543-10555. [PMID: 35638584 PMCID: PMC9173677 DOI: 10.1021/jacs.2c03320] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Indexed: 11/28/2022]
Abstract
The nucleocapsid (N) protein is one of the four structural proteins of the SARS-CoV-2 virus and plays a crucial role in viral genome organization and, hence, replication and pathogenicity. The N-terminal domain (NNTD) binds to the genomic RNA and thus comprises a potential target for inhibitor and vaccine development. We determined the atomic-resolution structure of crystalline NNTD by integrating solid-state magic angle spinning (MAS) NMR and X-ray diffraction. Our combined approach provides atomic details of protein packing interfaces as well as information about flexible regions as the N- and C-termini and the functionally important RNA binding, β-hairpin loop. In addition, ultrafast (100 kHz) MAS 1H-detected experiments permitted the assignment of side-chain proton chemical shifts not available by other means. The present structure offers guidance for designing therapeutic interventions against the SARS-CoV-2 infection.
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Affiliation(s)
- Sucharita Sarkar
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Brent Runge
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Ryan W. Russell
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Kumar Tekwani Movellan
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
| | - Daniel Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Somayeh Zeinalilathori
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
| | - Caitlin M. Quinn
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
| | - Manman Lu
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Guillermo Calero
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Angela M. Gronenborn
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, 1051 Biomedical Science Tower 3, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Ave., Pittsburgh, PA 15261, United States
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5
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Baek DS, Kim YJ, Vergara S, Conard A, Adams C, Calero G, Ishima R, Mellors JW, Dimitrov DS. A highly-specific fully-human antibody and CAR-T cells targeting CD66e/CEACAM5 are cytotoxic for CD66e-expressing cancer cells in vitro and in vivo. Cancer Lett 2021; 525:97-107. [PMID: 34740610 DOI: 10.1016/j.canlet.2021.10.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 09/20/2021] [Accepted: 10/27/2021] [Indexed: 11/02/2022]
Abstract
Neuro-endocrine prostate cancer (NEPC) accounts for about 20% of lethal metastatic castration-resistant prostate cancer (CRPC). NEPC has the most aggressive biologic behavior of all prostate cancers and is associated with poor patient outcome. Effective treatment for NEPC is not available because NEPC exhibit distinct cell-surface expression profiles compared to other types of prostate cancer. Recently, the carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) (known as CEA or CD66e) was suggested to be a specific surface protein marker for NEPC. Therefore, we identified a new, fully-human anti-CEACAM5 monoclonal antibody, 1G9, which bound to the most proximal membrane domains, A3 and B3, of CEACAM5 with high affinity and specificity. It shows no off-target binding to other CEACAM family members, membrane distal domains of CEACAM5, or 5800 human membrane proteins. IgG1 1G9 exhibited CEACAM5-specific ADCC activity toward CEACAM5-positive prostate cancer cells in vitro and in vivo. Chimeric antigen receptor T cells (CAR-T) based on scFv 1G9 induced specific and strong antitumor activity in a mouse model of prostate cancer. Our results suggest that IgG1 and CAR-T cells based on 1G9 are promising candidate therapeutics for CEACAM5-positive NEPC and other cancers.
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Affiliation(s)
- Du-San Baek
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Ye-Jin Kim
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sandra Vergara
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Alex Conard
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Abound Bio, Pittsburgh, PA, USA
| | - Cynthia Adams
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Rieko Ishima
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - John W Mellors
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Abound Bio, Pittsburgh, PA, USA
| | - Dimiter S Dimitrov
- Center for Antibody Therapeutics, Division of Infectious Diseases, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Abound Bio, Pittsburgh, PA, USA.
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6
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Shen Z, Xiang Y, Vergara S, Chen A, Xiao Z, Santiago U, Jin C, Sang Z, Luo J, Chen K, Schneidman-Duhovny D, Camacho C, Calero G, Hu B, Shi Y. A resource of high-quality and versatile nanobodies for drug delivery. iScience 2021; 24:103014. [PMID: 34522857 PMCID: PMC8426283 DOI: 10.1016/j.isci.2021.103014] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [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: 02/16/2021] [Revised: 06/09/2021] [Accepted: 08/18/2021] [Indexed: 01/08/2023] Open
Abstract
Therapeutic and diagnostic efficacies of small biomolecules and chemical compounds are hampered by suboptimal pharmacokinetics. Here, we developed a repertoire of robust and high-affinity antihuman serum albumin nanobodies (NbHSA) that can be readily fused to small biologics for half-life extension. We characterized the thermostability, binding kinetics, and cross-species reactivity of NbHSAs, mapped their epitopes, and structurally resolved a tetrameric HSA-Nb complex. We parallelly determined the half-lives of a cohort of selected NbHSAs in an HSA mouse model by quantitative proteomics. Compared to short-lived control nanobodies, the half-lives of NbHSAs were drastically prolonged by 771-fold. NbHSAs have distinct and diverse pharmacokinetics, positively correlating with their albumin binding affinities at the endosomal pH. We then generated stable and highly bioactive NbHSA-cytokine fusion constructs “Duraleukin” and demonstrated Duraleukin's high preclinical efficacy for cancer treatment in a melanoma model. This high-quality and versatile Nb toolkit will help tailor drug half-life to specific medical needs. We provide a resource of high-affinity and versatile albumin nanobodies for drug delivery We systematically map albumin nanobody epitopes by hybrid structural approaches We parallelly measure the pharmacokinetics of nanobodies in a humanized mouse model We develop nanobody-cytokine conjugates “Duraleukin” for cancer immunotherapy
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Affiliation(s)
- Zhuolun Shen
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA.,School of Medicine, Tsinghua University, Beijing, China
| | - Yufei Xiang
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sandra Vergara
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Apeng Chen
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA.,Pediatric Neurosurgery, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA
| | - Zhengyun Xiao
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ulises Santiago
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Changzhong Jin
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zhe Sang
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA.,University of Pittsburgh-Carnegie Mellon University Joint Program for Computational Biology, Pittsburgh, PA, USA
| | - Jiadi Luo
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kong Chen
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Dina Schneidman-Duhovny
- School of Computer Science and Engineering, Institute of Life Sciences, University of Jerusalem, Tambaram, Israel
| | - Carlos Camacho
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Baoli Hu
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, USA.,Pediatric Neurosurgery, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.,Molecular and Cellular Cancer Biology Program, UPMC Hillman Cancer Center, Pittsburgh, PA, USA
| | - Yi Shi
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA.,University of Pittsburgh-Carnegie Mellon University Joint Program for Computational Biology, Pittsburgh, PA, USA
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Weiss S, Vergara S, Lin G, Calero G. Detection of Microcrystals for CryoEM. Methods Mol Biol 2020; 2215:299-307. [PMID: 33368010 DOI: 10.1007/978-1-0716-0966-8_14] [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] [Indexed: 05/09/2023]
Abstract
Here, we present a strategy to identify microcrystals from initial protein crystallization screen experiments and to optimize diffraction quality of those crystals using negative stain transmission electron microscopy (TEM) as a guiding technique. The use of negative stain TEM allows visualization along the process and thus enables optimization of crystal diffraction by monitoring the lattice quality of crystallization conditions. Nanocrystals bearing perfect lattices are seeded and can be used for MicroED as well as growing larger crystals for X-ray and free electron laser (FEL) data collection.
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Affiliation(s)
- Simon Weiss
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sandra Vergara
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Guowu Lin
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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Lin G, Weiss SC, Vergara S, Camacho C, Calero G. Transcription with a laser: Radiation-damage-free diffraction of RNA Polymerase II crystals. Methods 2019; 159-160:23-28. [PMID: 31029767 DOI: 10.1016/j.ymeth.2019.04.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [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: 01/29/2019] [Revised: 03/04/2019] [Accepted: 04/21/2019] [Indexed: 12/27/2022] Open
Abstract
Well-diffracting crystals are essential to obtain relevant structural data that will lead to understanding of RNA Polymerase II (Pol II) transcriptional processes at a molecular level. Here we present a strategy to study Pol II crystals using negative stain transmission electron microscopy (TEM) and a methodology to optimize radiation damage free data collection using free electron laser (FEL) at the Linac Coherent Light Source (LCLS). The use of negative stain TEM allowed visualization and optimization of crystal diffraction by monitoring the lattice quality of crystallization conditions. Nano crystals bearing perfect lattices were seeded and used to grow larger crystals for FEL data collection. Moreover, the use of in house designed crystal loops together with ultra-violet (UV) microscopy for crystal detection facilitated data collection. Such strategy permitted collection of multiple crystals of radiation-free-damage data, resulting in the highest resolution of wild type (WT) Pol II crystals ever observed.
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Affiliation(s)
- Guowu Lin
- Department of Structural Biology, University of Pittsburgh School of Medicine, United States
| | - Simon C Weiss
- Department of Structural Biology, University of Pittsburgh School of Medicine, United States
| | - Sandra Vergara
- Department of Structural Biology, University of Pittsburgh School of Medicine, United States
| | - Carlos Camacho
- Department of Computanional and Systems Biology, University of Pittsburgh School of Medicine, United States
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, United States.
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López-Lozano X, Plascencia-Villa G, Calero G, Whetten RL, Weissker HC. Is the largest aqueous gold cluster a superatom complex? Electronic structure & optical response of the structurally determined Au 146(p-MBA) 57. Nanoscale 2017; 9:18629-18634. [PMID: 29182699 DOI: 10.1039/c7nr04764a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The new water-soluble gold cluster Au146(p-MBA)57, the structure of which has been recently determined at sub-atomic resolution by Vergara et al., is the largest aqueous gold cluster ever structurally determined and likewise the smallest cluster with a stacking fault. The core presents a twinned truncated octahedron, while additional peripheral gold atoms follow a C2 rotational symmetry. According to the usual counting rules of the superatom complex (SAC) model, the compound attains a number of 92 SAC electrons if the overall net charge is 3- (three additional electrons). As this is the number of electrons required for a major shell closing, the question arises of whether Au146(p-MBA)57 should be regarded as a superatom complex. Starting from the experimental coordinates we have analyzed the structure using density-functional theory. The optimized (relaxed) structure retains all the connectivity of the experimental coordinates, while removing much of its irregularities in interatomic distances, thereby enhancing the C2-symmetry feature. On analyzing the angular-momentum-projected states, we show that, despite a small gap, the electronic structure does not exhibit SAC model character. In addition, optical absorption spectra are found to be relatively smooth compared to the example of the Au144(SR)60 cluster. The Au146(SR)57 does not derive its stability from SAC character; it cannot be considered as a superatom complex.
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Affiliation(s)
- Xóchitl López-Lozano
- Department of Physics & Astronomy, The University of Texas at San Antonio, One UTSA circle, 78249-0697 San Antonio, TX, USA.
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10
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Vergara S, Lukes DA, Martynowycz MW, Santiago U, Plascencia-Villa G, Weiss SC, de la Cruz MJ, Black DM, Alvarez MM, Lopez-Lozano X, Barnes CO, Lin G, Weissker HC, Whetten RL, Gonen T, Jose-Yacaman M, Calero G. MicroED Structure of Au 146(p-MBA) 57 at Subatomic Resolution Reveals a Twinned FCC Cluster. J Phys Chem Lett 2017; 8:5523-5530. [PMID: 29072840 PMCID: PMC5769702 DOI: 10.1021/acs.jpclett.7b02621] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [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] [Indexed: 05/29/2023]
Abstract
Solving the atomic structure of metallic clusters is fundamental to understanding their optical, electronic, and chemical properties. Herein we present the structure of the largest aqueous gold cluster, Au146(p-MBA)57 (p-MBA: para-mercaptobenzoic acid), solved by electron micro-diffraction (MicroED) to subatomic resolution (0.85 Å) and by X-ray diffraction at atomic resolution (1.3 Å). The 146 gold atoms may be decomposed into two constituent sets consisting of 119 core and 27 peripheral atoms. The core atoms are organized in a twinned FCC structure, whereas the surface gold atoms follow a C2 rotational symmetry about an axis bisecting the twinning plane. The protective layer of 57 p-MBAs fully encloses the cluster and comprises bridging, monomeric, and dimeric staple motifs. Au146(p-MBA)57 is the largest cluster observed exhibiting a bulk-like FCC structure as well as the smallest gold particle exhibiting a stacking fault.
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Affiliation(s)
- Sandra Vergara
- Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Dylan A. Lukes
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Ulises Santiago
- Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, TX, USA
| | - German Plascencia-Villa
- Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Simon C. Weiss
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - David M. Black
- Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Marcos M. Alvarez
- Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Xochitl Lopez-Lozano
- Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, TX, USA
| | | | - Guowu Lin
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Robert L. Whetten
- Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Tamir Gonen
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
- Howard Hughes Medical Institute, Departments of Biological Chemistry and Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Miguel Jose-Yacaman
- Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, TX, USA
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, PA, USA
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11
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Kim SK, Barron L, Hinck CS, Petrunak EM, Cano KE, Thangirala A, Iskra B, Brothers M, Vonberg M, Leal B, Richter B, Kodali R, Taylor AB, Du S, Barnes CO, Sulea T, Calero G, Hart PJ, Hart MJ, Demeler B, Hinck AP. An engineered transforming growth factor β (TGF-β) monomer that functions as a dominant negative to block TGF-β signaling. J Biol Chem 2017; 292:7173-7188. [PMID: 28228478 PMCID: PMC5409485 DOI: 10.1074/jbc.m116.768754] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [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: 11/22/2016] [Revised: 02/12/2017] [Indexed: 11/06/2022] Open
Abstract
The transforming growth factor β isoforms, TGF-β1, -β2, and -β3, are small secreted homodimeric signaling proteins with essential roles in regulating the adaptive immune system and maintaining the extracellular matrix. However, dysregulation of the TGF-β pathway is responsible for promoting the progression of several human diseases, including cancer and fibrosis. Despite the known importance of TGF-βs in promoting disease progression, no inhibitors have been approved for use in humans. Herein, we describe an engineered TGF-β monomer, lacking the heel helix, a structural motif essential for binding the TGF-β type I receptor (TβRI) but dispensable for binding the other receptor required for TGF-β signaling, the TGF-β type II receptor (TβRII), as an alternative therapeutic modality for blocking TGF-β signaling in humans. As shown through binding studies and crystallography, the engineered monomer retained the same overall structure of native TGF-β monomers and bound TβRII in an identical manner. Cell-based luciferase assays showed that the engineered monomer functioned as a dominant negative to inhibit TGF-β signaling with a Ki of 20-70 nm Investigation of the mechanism showed that the high affinity of the engineered monomer for TβRII, coupled with its reduced ability to non-covalently dimerize and its inability to bind and recruit TβRI, enabled it to bind endogenous TβRII but prevented it from binding and recruiting TβRI to form a signaling complex. Such engineered monomers provide a new avenue to probe and manipulate TGF-β signaling and may inform similar modifications of other TGF-β family members.
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Affiliation(s)
- Sun Kyung Kim
- the Departments of Biochemistry and Structural Biology and
| | | | - Cynthia S Hinck
- From the Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Elyse M Petrunak
- From the Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Kristin E Cano
- the Departments of Biochemistry and Structural Biology and
| | | | - Brian Iskra
- the Departments of Biochemistry and Structural Biology and
| | - Molly Brothers
- the Departments of Biochemistry and Structural Biology and
| | | | - Belinda Leal
- the Departments of Biochemistry and Structural Biology and
| | - Blair Richter
- the Departments of Biochemistry and Structural Biology and
| | - Ravindra Kodali
- From the Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | | | - Shoucheng Du
- From the Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Christopher O Barnes
- From the Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Traian Sulea
- the National Research Council, Human Health Therapeutics Portfolio, Montréal, Quebec H4P 2R2, Canada
| | - Guillermo Calero
- From the Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - P John Hart
- the Departments of Biochemistry and Structural Biology and
| | - Matthew J Hart
- Center for Innovative Drug Discovery, University of Texas Health Science Center, San Antonio, Texas 78229-3900, and
| | | | - Andrew P Hinck
- From the Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260,
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12
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Wu Y, Zhou X, Barnes CO, DeLucia M, Cohen AE, Gronenborn AM, Ahn J, Calero G. The DDB1-DCAF1-Vpr-UNG2 crystal structure reveals how HIV-1 Vpr steers human UNG2 toward destruction. Nat Struct Mol Biol 2016; 23:933-940. [PMID: 27571178 DOI: 10.1038/nsmb.3284] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 08/03/2016] [Indexed: 01/04/2023]
Abstract
The HIV-1 accessory protein Vpr is required for efficient viral infection of macrophages and promotion of viral replication in T cells. Vpr's biological activities are closely linked to the interaction with human DCAF1, a cellular substrate receptor of the Cullin4-RING E3 ubiquitin ligase (CRL4) of the host ubiquitin-proteasome-mediated protein degradation pathway. The molecular details of how Vpr usurps the protein degradation pathway have not been delineated. Here we present the crystal structure of the DDB1-DCAF1-HIV-1-Vpr-uracil-DNA glycosylase (UNG2) complex. The structure reveals how Vpr engages with DCAF1, creating a binding interface for UNG2 recruitment in a manner distinct from the recruitment of SAMHD1 by Vpx proteins. Vpr and Vpx use similar N-terminal and helical regions to bind the substrate receptor, whereas different regions target the specific cellular substrates. Furthermore, Vpr uses molecular mimicry of DNA by a variable loop for specific recruitment of the UNG2 substrate.
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Affiliation(s)
- Ying Wu
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Xiaohong Zhou
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Christopher O Barnes
- Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Maria DeLucia
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Aina E Cohen
- Stanford Synchrotron Radiation Lightsource, Stanford University, Menlo Park, California, USA
| | - Angela M Gronenborn
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jinwoo Ahn
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Guillermo Calero
- Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Structural Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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13
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Stevenson HP, Lin G, Barnes CO, Sutkeviciute I, Krzysiak T, Weiss SC, Reynolds S, Wu Y, Nagarajan V, Makhov AM, Lawrence R, Lamm E, Clark L, Gardella TJ, Hogue BG, Ogata CM, Ahn J, Gronenborn AM, Conway JF, Vilardaga JP, Cohen AE, Calero G. Transmission electron microscopy for the evaluation and optimization of crystal growth. Acta Crystallogr D Struct Biol 2016; 72:603-15. [PMID: 27139624 PMCID: PMC4854312 DOI: 10.1107/s2059798316001546] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [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: 09/18/2015] [Accepted: 01/25/2016] [Indexed: 11/10/2022] Open
Abstract
The crystallization of protein samples remains the most significant challenge in structure determination by X-ray crystallography. Here, the effectiveness of transmission electron microscopy (TEM) analysis to aid in the crystallization of biological macromolecules is demonstrated. It was found that the presence of well ordered lattices with higher order Bragg spots, revealed by Fourier analysis of TEM images, is a good predictor of diffraction-quality crystals. Moreover, the use of TEM allowed (i) comparison of lattice quality among crystals from different conditions in crystallization screens; (ii) the detection of crystal pathologies that could contribute to poor X-ray diffraction, including crystal lattice defects, anisotropic diffraction and crystal contamination by heavy protein aggregates and nanocrystal nuclei; (iii) the qualitative estimation of crystal solvent content to explore the effect of lattice dehydration on diffraction and (iv) the selection of high-quality crystal fragments for microseeding experiments to generate reproducibly larger sized crystals. Applications to X-ray free-electron laser (XFEL) and micro-electron diffraction (microED) experiments are also discussed.
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Affiliation(s)
- Hilary P Stevenson
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Guowu Lin
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Christopher O Barnes
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Ieva Sutkeviciute
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, M240 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA 15261, USA
| | - Troy Krzysiak
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Simon C Weiss
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Shelley Reynolds
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Ying Wu
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | | | - Alexander M Makhov
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Robert Lawrence
- School of Life Sciences, Arizona State University, PO Box 874501, Tempe, AZ 85287, USA
| | - Emily Lamm
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Lisa Clark
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Timothy J Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Brenda G Hogue
- School of Life Sciences, Arizona State University, PO Box 874501, Tempe, AZ 85287, USA
| | - Craig M Ogata
- Biosciences Division, Argonne National Laboratory, 9700 South Cass Ave, Lemont, IL 60439, USA
| | - Jinwoo Ahn
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Angela M Gronenborn
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - James F Conway
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
| | - Jean Pierre Vilardaga
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, M240 Scaife Hall, 3550 Terrace Street, Pittsburgh, PA 15261, USA
| | - Aina E Cohen
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, 3501 Fifth Avenue, Pittsburgh, PA 15260, USA
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14
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Shi D, Nannenga BL, de la Cruz MJ, Liu J, Sawtelle S, Calero G, Reyes FE, Hattne J, Gonen T. The collection of MicroED data for macromolecular crystallography. Nat Protoc 2016; 11:895-904. [PMID: 27077331 PMCID: PMC5357465 DOI: 10.1038/nprot.2016.046] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The formation of large, well-ordered crystals for crystallographic experiments remains a crucial bottleneck to the structural understanding of many important biological systems. To help alleviate this problem in crystallography, we have developed the MicroED method for the collection of electron diffraction data from 3D microcrystals and nanocrystals of radiation-sensitive biological material. In this approach, liquid solutions containing protein microcrystals are deposited on carbon-coated electron microscopy grids and are vitrified by plunging them into liquid ethane. MicroED data are collected for each selected crystal using cryo-electron microscopy, in which the crystal is diffracted using very few electrons as the stage is continuously rotated. This protocol gives advice on how to identify microcrystals by light microscopy or by negative-stain electron microscopy in samples obtained from standard protein crystallization experiments. The protocol also includes information about custom-designed equipment for controlling crystal rotation and software for recording experimental parameters in diffraction image metadata. Identifying microcrystals, preparing samples and setting up the microscope for diffraction data collection take approximately half an hour for each step. Screening microcrystals for quality diffraction takes roughly an hour, and the collection of a single data set is ∼10 min in duration. Complete data sets and resulting high-resolution structures can be obtained from a single crystal or by merging data from multiple crystals.
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Affiliation(s)
- Dan Shi
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Brent L Nannenga
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - M Jason de la Cruz
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Jinyang Liu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Steven Sawtelle
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Francis E Reyes
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Johan Hattne
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
| | - Tamir Gonen
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, USA
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15
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Barnes CO, Kovaleva EG, Fu X, Stevenson HP, Brewster AS, DePonte DP, Baxter EL, Cohen AE, Calero G. Assessment of microcrystal quality by transmission electron microscopy for efficient serial femtosecond crystallography. Arch Biochem Biophys 2016; 602:61-68. [PMID: 26944553 DOI: 10.1016/j.abb.2016.02.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [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: 12/10/2015] [Revised: 02/04/2016] [Accepted: 02/06/2016] [Indexed: 12/13/2022]
Abstract
Serial femtosecond crystallography (SFX) employing high-intensity X-ray free-electron laser (XFEL) sources has enabled structural studies on microcrystalline protein samples at non-cryogenic temperatures. However, the identification and optimization of conditions that produce well diffracting microcrystals remains an experimental challenge. Here, we report parallel SFX and transmission electron microscopy (TEM) experiments using fragmented microcrystals of wild type (WT) homoprotocatechuate 2,3-dioxygenase (HPCD) and an active site variant (H200Q). Despite identical crystallization conditions and morphology, as well as similar crystal size and density, the indexing efficiency of the diffraction data collected using the H200Q variant sample was over 7-fold higher compared to the diffraction results obtained using the WT sample. TEM analysis revealed an abundance of protein aggregates, crystal conglomerates and a smaller population of highly ordered lattices in the WT sample as compared to the H200Q variant sample. While not reported herein, the 1.75 Å resolution structure of the H200Q variant was determined from ∼16 min of beam time, demonstrating the utility of TEM analysis in evaluating sample monodispersity and lattice quality, parameters critical to the efficiency of SFX experiments.
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Affiliation(s)
- Christopher O Barnes
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA.,Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Elena G Kovaleva
- Stanford Synchrotron Radiation Lightsource, Menlo Park, CA 94025, USA
| | - Xiaofeng Fu
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Hilary P Stevenson
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
| | - Aaron S Brewster
- Molecular Biophysics & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | | | - Aina E Cohen
- Stanford Synchrotron Radiation Lightsource, Menlo Park, CA 94025, USA
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15260, USA
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16
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Baxter EL, Aguila L, Alonso-Mori R, Barnes CO, Bonagura CA, Brehmer W, Brunger AT, Calero G, Caradoc-Davies TT, Chatterjee R, Degrado WF, Fraser JS, Ibrahim M, Kern J, Kobilka BK, Kruse AC, Larsson KM, Lemke HT, Lyubimov AY, Manglik A, McPhillips SE, Norgren E, Pang SS, Soltis SM, Song J, Thomaston J, Tsai Y, Weis WI, Woldeyes RA, Yachandra V, Yano J, Zouni A, Cohen AE. High-density grids for efficient data collection from multiple crystals. Acta Crystallogr D Struct Biol 2016; 72:2-11. [PMID: 26894529 PMCID: PMC4756618 DOI: 10.1107/s2059798315020847] [Citation(s) in RCA: 56] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 11/03/2015] [Indexed: 03/01/2023] Open
Abstract
Higher throughput methods to mount and collect data from multiple small and radiation-sensitive crystals are important to support challenging structural investigations using microfocus synchrotron beamlines. Furthermore, efficient sample-delivery methods are essential to carry out productive femtosecond crystallography experiments at X-ray free-electron laser (XFEL) sources such as the Linac Coherent Light Source (LCLS). To address these needs, a high-density sample grid useful as a scaffold for both crystal growth and diffraction data collection has been developed and utilized for efficient goniometer-based sample delivery at synchrotron and XFEL sources. A single grid contains 75 mounting ports and fits inside an SSRL cassette or uni-puck storage container. The use of grids with an SSRL cassette expands the cassette capacity up to 7200 samples. Grids may also be covered with a polymer film or sleeve for efficient room-temperature data collection from multiple samples. New automated routines have been incorporated into the Blu-Ice/DCSS experimental control system to support grids, including semi-automated grid alignment, fully automated positioning of grid ports, rastering and automated data collection. Specialized tools have been developed to support crystallization experiments on grids, including a universal adaptor, which allows grids to be filled by commercial liquid-handling robots, as well as incubation chambers, which support vapor-diffusion and lipidic cubic phase crystallization experiments. Experiments in which crystals were loaded into grids or grown on grids using liquid-handling robots and incubation chambers are described. Crystals were screened at LCLS-XPP and SSRL BL12-2 at room temperature and cryogenic temperatures.
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Affiliation(s)
- Elizabeth L. Baxter
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Laura Aguila
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Roberto Alonso-Mori
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Christopher O. Barnes
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | | | - Winnie Brehmer
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Axel T. Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Tom T. Caradoc-Davies
- The ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Melbourne, Victoria 3800, Australia
- Australian Synchrotron, 800 Blackburn Road, Clayton, Melbourne, Victoria 3168, Australia
| | - Ruchira Chatterjee
- Physical Bioscences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - William F. Degrado
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | - James S. Fraser
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94158, USA
| | - Mohamed Ibrahim
- Institut für Biologie, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - Jan Kern
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
- Physical Bioscences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Brian K. Kobilka
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Andrew C. Kruse
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Karl M. Larsson
- Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Heinrik T. Lemke
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Artem Y. Lyubimov
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Aashish Manglik
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
| | - Scott E. McPhillips
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Erik Norgren
- Art Robbins Instruments, Sunnyvale, CA 94089, USA
| | - Siew S. Pang
- The ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Melbourne, Victoria 3800, Australia
| | - S. M. Soltis
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Jinhu Song
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Jessica Thomaston
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | - Yingssu Tsai
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - William I. Weis
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA 94305, USA
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
| | - Rahel A. Woldeyes
- Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA 94158, USA
| | - Vittal Yachandra
- Physical Bioscences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Junko Yano
- Physical Bioscences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Athina Zouni
- Institut für Biologie, Humboldt-Universität zu Berlin, 10099 Berlin, Germany
| | - Aina E. Cohen
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
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17
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Abdallah BG, Zatsepin NA, Roy-Chowdhury S, Coe J, Conrad CE, Dörner K, Sierra RG, Stevenson HP, Camacho-Alanis F, Grant TD, Nelson G, James D, Calero G, Wachter RM, Spence JCH, Weierstall U, Fromme P, Ros A. Microfluidic sorting of protein nanocrystals by size for X-ray free-electron laser diffraction. Struct Dyn 2015; 2:041719. [PMID: 26798818 PMCID: PMC4711642 DOI: 10.1063/1.4928688] [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] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 08/05/2015] [Indexed: 05/23/2023]
Abstract
The advent and application of the X-ray free-electron laser (XFEL) has uncovered the structures of proteins that could not previously be solved using traditional crystallography. While this new technology is powerful, optimization of the process is still needed to improve data quality and analysis efficiency. One area is sample heterogeneity, where variations in crystal size (among other factors) lead to the requirement of large data sets (and thus 10-100 mg of protein) for determining accurate structure factors. To decrease sample dispersity, we developed a high-throughput microfluidic sorter operating on the principle of dielectrophoresis, whereby polydisperse particles can be transported into various fluid streams for size fractionation. Using this microsorter, we isolated several milliliters of photosystem I nanocrystal fractions ranging from 200 to 600 nm in size as characterized by dynamic light scattering, nanoparticle tracking, and electron microscopy. Sorted nanocrystals were delivered in a liquid jet via the gas dynamic virtual nozzle into the path of the XFEL at the Linac Coherent Light Source. We obtained diffraction to ∼4 Å resolution, indicating that the small crystals were not damaged by the sorting process. We also observed the shape transforms of photosystem I nanocrystals, demonstrating that our device can optimize data collection for the shape transform-based phasing method. Using simulations, we show that narrow crystal size distributions can significantly improve merged data quality in serial crystallography. From this proof-of-concept work, we expect that the automated size-sorting of protein crystals will become an important step for sample production by reducing the amount of protein needed for a high quality final structure and the development of novel phasing methods that exploit inter-Bragg reflection intensities or use variations in beam intensity for radiation damage-induced phasing. This method will also permit an analysis of the dependence of crystal quality on crystal size.
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Affiliation(s)
| | | | | | | | | | | | - Raymond G Sierra
- Stanford PULSE Institute, SLAC National Accelerator Laboratory , Menlo Park, California 94025, USA
| | - Hilary P Stevenson
- Department of Structural Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15261, USA
| | - Fernanda Camacho-Alanis
- Department of Chemistry and Biochemistry, Arizona State University , Tempe, Arizona 85287, USA
| | - Thomas D Grant
- Hauptman-Woodward Medical Research Institute, University at Buffalo , Buffalo, New York 14203, USA
| | | | | | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania 15261, USA
| | - Rebekka M Wachter
- Department of Chemistry and Biochemistry, Arizona State University , Tempe, Arizona 85287, USA
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18
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Yang J, Cusimano A, Monga JK, Preziosi ME, Pullara F, Calero G, Lang R, Yamaguchi TP, Nejak-Bowen KN, Monga SP. WNT5A inhibits hepatocyte proliferation and concludes β-catenin signaling in liver regeneration. Am J Pathol 2015; 185:2194-205. [PMID: 26100214 DOI: 10.1016/j.ajpath.2015.04.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 03/09/2015] [Accepted: 04/07/2015] [Indexed: 02/08/2023]
Abstract
Activation of Wnt/β-catenin signaling during liver regeneration (LR) after partial hepatectomy (PH) is observed in several species. However, how this pathway is turned off when hepatocyte proliferation is no longer required is unknown. We assessed LR in liver-specific knockouts of Wntless (Wls-LKO), a protein required for Wnt secretion from a cell. When subjected to PH, Wls-LKO showed prolongation of hepatocyte proliferation for up to 4 days compared with littermate controls. This coincided with increased β-catenin-T-cell factor 4 interaction and cyclin-D1 expression. Wls-LKO showed decreased expression and secretion of inhibitory Wnt5a during LR. Wnt5a expression increased between 24 and 48 hours, and Frizzled-2 between 24 and 72 hours, after PH in normal mice. Treatment of primary mouse hepatocytes and liver tumor cells with Wnt5a led to a notable decrease in β-catenin-T-cell factor activity, cyclin-D1 expression, and cell proliferation. Intriguingly, Wnt5a-LKO did not display any prolongation of LR because of compensation by other cells. In addition, Wnt5a-LKO hepatocytes failed to respond to exogenous Wnt5a treatment in culture because of a compensatory decrease in Frizzled-2 expression. In conclusion, we demonstrate Wnt5a to be, by default, a negative regulator of β-catenin signaling and hepatocyte proliferation, both in vitro and in vivo. We also provide evidence that the Wnt5a/Frizzled-2 axis suppresses β-catenin signaling in hepatocytes in an autocrine manner, thereby contributing to timely conclusion of the LR process.
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Affiliation(s)
- Jing Yang
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Antonella Cusimano
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Ri.MED Foundation, Palermo, Italy; Institute of Biomedicine and Molecular Immunology Alberto Monroy, National Research Council, Palermo, Italy
| | - Jappmann K Monga
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Morgan E Preziosi
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Filippo Pullara
- Ri.MED Foundation, Palermo, Italy; Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Richard Lang
- Visual Systems Group, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Terry P Yamaguchi
- Cancer and Developmental Biology Laboratory, Center for Cancer Research, National Cancer Institute-Frederick, NIH, Frederick, Maryland
| | - Kari N Nejak-Bowen
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Satdarshan P Monga
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
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19
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Wu Y, Koharudin LMI, Mehrens J, DeLucia M, Byeon CH, Byeon IJL, Calero G, Ahn J, Gronenborn AM. Structural Basis of Clade-specific Engagement of SAMHD1 (Sterile α Motif and Histidine/Aspartate-containing Protein 1) Restriction Factors by Lentiviral Viral Protein X (Vpx) Virulence Factors. J Biol Chem 2015; 290:17935-17945. [PMID: 26045556 DOI: 10.1074/jbc.m115.665513] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [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: 05/15/2015] [Indexed: 11/06/2022] Open
Abstract
Sterile α motif (SAM) and histidine/aspartate (HD)-containing protein 1 (SAMHD1) restricts human/simian immunodeficiency virus infection in certain cell types and is counteracted by the virulence factor Vpx. Current evidence indicates that Vpx recruits SAMHD1 to the Cullin4-Ring Finger E3 ubiquitin ligase (CRL4) by facilitating an interaction between SAMHD1 and the substrate receptor DDB1- and Cullin4-associated factor 1 (DCAF1), thereby targeting SAMHD1 for proteasome-dependent down-regulation. Host-pathogen co-evolution and positive selection at the interfaces of host-pathogen complexes are associated with sequence divergence and varying functional consequences. Two alternative interaction interfaces are used by SAMHD1 and Vpx: the SAMHD1 N-terminal tail and the adjacent SAM domain or the C-terminal tail proceeding the HD domain are targeted by different Vpx variants in a unique fashion. In contrast, the C-terminal WD40 domain of DCAF1 interfaces similarly with the two above complexes. Comprehensive biochemical and structural biology approaches permitted us to delineate details of clade-specific recognition of SAMHD1 by lentiviral Vpx proteins. We show that not only the SAM domain but also the N-terminal tail engages in the DCAF1-Vpx interaction. Furthermore, we show that changing the single Ser-52 in human SAMHD1 to Phe, the residue found in SAMHD1 of Red-capped monkey and Mandrill, allows it to be recognized by Vpx proteins of simian viruses infecting those primate species, which normally does not target wild type human SAMHD1 for degradation.
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Affiliation(s)
- Ying Wu
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Leonardus M I Koharudin
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Jennifer Mehrens
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Maria DeLucia
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Chang-Hyeok Byeon
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - In-Ja L Byeon
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Guillermo Calero
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Jinwoo Ahn
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260.
| | - Angela M Gronenborn
- Department of Structural Biology and Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260.
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20
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Stevenson HP, DePonte DP, Makhov AM, Conway JF, Zeldin OB, Boutet S, Calero G, Cohen AE. Transmission electron microscopy as a tool for nanocrystal characterization pre- and post-injector. Philos Trans R Soc Lond B Biol Sci 2015; 369:20130322. [PMID: 24914151 DOI: 10.1098/rstb.2013.0322] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [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: 12/29/2022] Open
Abstract
Recent advancements at the Linac Coherent Light Source X-ray free-electron laser (XFEL) enabling successful serial femtosecond diffraction experiments using nanometre-sized crystals (NCs) have opened up the possibility of X-ray structure determination of proteins that produce only submicrometre crystals such as many membrane proteins. Careful crystal pre-characterization including compatibility testing of the sample delivery method is essential to ensure efficient use of the limited beamtime available at XFEL sources. This work demonstrates the utility of transmission electron microscopy for detecting and evaluating NCs within the carrier solutions of liquid injectors. The diffraction quality of these crystals may be assessed by examining the crystal lattice and by calculating the fast Fourier transform of the image. Injector reservoir solutions, as well as solutions collected post-injection, were evaluated for three types of protein NCs (i) the membrane protein PTHR1, (ii) the multi-protein complex Pol II-GFP and (iii) the soluble protein lysozyme. Our results indicate that the concentration and diffraction quality of NCs, particularly those with high solvent content and sensitivity to mechanical manipulation may be affected by the delivery process.
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Affiliation(s)
- H P Stevenson
- Department of Structural Biology, University of Pittsburgh School of Medicine, 1040 Biomedical Science Tower 3, Pittsburgh, PA 15260, USA
| | - D P DePonte
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - A M Makhov
- Department of Structural Biology, University of Pittsburgh School of Medicine, 1040 Biomedical Science Tower 3, Pittsburgh, PA 15260, USA
| | - James F Conway
- Department of Structural Biology, University of Pittsburgh School of Medicine, 1040 Biomedical Science Tower 3, Pittsburgh, PA 15260, USA
| | - O B Zeldin
- Department of Structural Biology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - S Boutet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - G Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, 1040 Biomedical Science Tower 3, Pittsburgh, PA 15260, USA
| | - A E Cohen
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
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21
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Cohen AE, Soltis SM, González A, Aguila L, Alonso-Mori R, Barnes CO, Baxter EL, Brehmer W, Brewster AS, Brunger AT, Calero G, Chang JF, Chollet M, Ehrensberger P, Eriksson TL, Feng Y, Hattne J, Hedman B, Hollenbeck M, Holton JM, Keable S, Kobilka BK, Kovaleva EG, Kruse AC, Lemke HT, Lin G, Lyubimov AY, Manglik A, Mathews II, McPhillips SE, Nelson S, Peters JW, Sauter NK, Smith CA, Song J, Stevenson HP, Tsai Y, Uervirojnangkoorn M, Vinetsky V, Wakatsuki S, Weis WI, Zadvornyy OA, Zeldin OB, Zhu D, Hodgson KO. Goniometer-based femtosecond crystallography with X-ray free electron lasers. Proc Natl Acad Sci U S A 2014; 111:17122-7. [PMID: 25362050 PMCID: PMC4260607 DOI: 10.1073/pnas.1418733111] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [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: 11/18/2022] Open
Abstract
The emerging method of femtosecond crystallography (FX) may extend the diffraction resolution accessible from small radiation-sensitive crystals and provides a means to determine catalytically accurate structures of acutely radiation-sensitive metalloenzymes. Automated goniometer-based instrumentation developed for use at the Linac Coherent Light Source enabled efficient and flexible FX experiments to be performed on a variety of sample types. In the case of rod-shaped Cpl hydrogenase crystals, only five crystals and about 30 min of beam time were used to obtain the 125 still diffraction patterns used to produce a 1.6-Å resolution electron density map. For smaller crystals, high-density grids were used to increase sample throughput; 930 myoglobin crystals mounted at random orientation inside 32 grids were exposed, demonstrating the utility of this approach. Screening results from cryocooled crystals of β2-adrenoreceptor and an RNA polymerase II complex indicate the potential to extend the diffraction resolution obtainable from very radiation-sensitive samples beyond that possible with undulator-based synchrotron sources.
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Affiliation(s)
| | | | | | | | | | - Christopher O Barnes
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | | | | | - Aaron S Brewster
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Axel T Brunger
- Molecular and Cellular Physiology, and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Guillermo Calero
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | | | | | | | | | | | - Johan Hattne
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | | | | | - James M Holton
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158; and
| | - Stephen Keable
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59715
| | | | | | | | | | - Guowu Lin
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Artem Y Lyubimov
- Molecular and Cellular Physiology, and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | | | | | | | | | - John W Peters
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59715
| | - Nicholas K Sauter
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | | | - Jinhu Song
- Stanford Synchrotron Radiation Lightsource
| | - Hilary P Stevenson
- Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Yingssu Tsai
- Stanford Synchrotron Radiation Lightsource, Departments of Chemistry
| | - Monarin Uervirojnangkoorn
- Molecular and Cellular Physiology, and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | | | - Soichi Wakatsuki
- Photon Science, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025; Structural Biology, and
| | - William I Weis
- Molecular and Cellular Physiology, and Structural Biology, and
| | - Oleg A Zadvornyy
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59715
| | - Oliver B Zeldin
- Molecular and Cellular Physiology, and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | | | - Keith O Hodgson
- Stanford Synchrotron Radiation Lightsource, Departments of Chemistry,
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22
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Arjunan P, Wang J, Nemeria NS, Reynolds S, Brown I, Chandrasekhar K, Calero G, Jordan F, Furey W. Novel binding motif and new flexibility revealed by structural analyses of a pyruvate dehydrogenase-dihydrolipoyl acetyltransferase subcomplex from the Escherichia coli pyruvate dehydrogenase multienzyme complex. J Biol Chem 2014; 289:30161-76. [PMID: 25210042 DOI: 10.1074/jbc.m114.592915] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [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: 11/06/2022] Open
Abstract
The Escherichia coli pyruvate dehydrogenase multienzyme complex contains multiple copies of three enzymatic components, E1p, E2p, and E3, that sequentially carry out distinct steps in the overall reaction converting pyruvate to acetyl-CoA. Efficient functioning requires the enzymatic components to assemble into a large complex, the integrity of which is maintained by tethering of the displaced, peripheral E1p and E3 components to the E2p core through non-covalent binding. We here report the crystal structure of a subcomplex between E1p and an E2p didomain containing a hybrid lipoyl domain along with the peripheral subunit-binding domain responsible for tethering to the core. In the structure, a region at the N terminus of each subunit in the E1p homodimer previously unseen due to crystallographic disorder was observed, revealing a new folding motif involved in E1p-E2p didomain interactions, and an additional, unexpected, flexibility was discovered in the E1p-E2p didomain subcomplex, both of which probably have consequences in the overall multienzyme complex assembly. This represents the first structure of an E1p-E2p didomain subcomplex involving a homodimeric E1p, and the results may be applicable to a large range of complexes with homodimeric E1 components. Results of HD exchange mass spectrometric experiments using the intact, wild type 3-lipoyl E2p and E1p are consistent with the crystallographic data obtained from the E1p-E2p didomain subcomplex as well as with other biochemical and NMR data reported from our groups, confirming that our findings are applicable to the entire E1p-E2p assembly.
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Affiliation(s)
| | - Junjie Wang
- the Department of Chemistry, Rutgers University, Newark, New Jersey 07102, and
| | - Natalia S Nemeria
- the Department of Chemistry, Rutgers University, Newark, New Jersey 07102, and
| | - Shelley Reynolds
- Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Ian Brown
- Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | | | - Guillermo Calero
- Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Frank Jordan
- the Department of Chemistry, Rutgers University, Newark, New Jersey 07102, and
| | - William Furey
- From the Departments of Pharmacology and Chemical Biology and the Veterans Affairs Medical Center, Pittsburgh, Pennsylvania 15240
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23
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Calero G, Cohen AE, Luft JR, Newman J, Snell EH. Identifying, studying and making good use of macromolecular crystals. Acta Crystallogr F Struct Biol Commun 2014; 70:993-1008. [PMID: 25084371 PMCID: PMC4118793 DOI: 10.1107/s2053230x14016574] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 07/16/2014] [Indexed: 11/30/2022]
Abstract
As technology advances, the crystal volume that can be used to collect useful X-ray diffraction data decreases. The technologies available to detect and study growing crystals beyond the optical resolution limit and methods to successfully place the crystal into the X-ray beam are discussed. Structural biology has contributed tremendous knowledge to the understanding of life on the molecular scale. The Protein Data Bank, a depository of this structural knowledge, currently contains over 100 000 protein structures, with the majority stemming from X-ray crystallography. As the name might suggest, crystallography requires crystals. As detectors become more sensitive and X-ray sources more intense, the notion of a crystal is gradually changing from one large enough to embellish expensive jewellery to objects that have external dimensions of the order of the wavelength of visible light. Identifying these crystals is a prerequisite to their study. This paper discusses developments in identifying these crystals during crystallization screening and distinguishing them from other potential outcomes. The practical aspects of ensuring that once a crystal is identified it can then be positioned in the X-ray beam for data collection are also addressed.
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Affiliation(s)
- Guillermo Calero
- Department of Structural Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261, USA
| | - Aina E Cohen
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Stanford University, Menlo Park, CA 94025, USA
| | - Joseph R Luft
- Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA
| | - Janet Newman
- CSIRO Collaborative Crystallisation Centre, 343 Royal Parade, Parkville, Victoria 3052, Australia
| | - Edward H Snell
- Hauptman-Woodward Medical Research Institute, 700 Ellicott Street, Buffalo, NY 14203, USA
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24
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Wang J, Nemeria NS, Chandrasekhar K, Kumaran S, Arjunan P, Reynolds S, Calero G, Brukh R, Kakalis L, Furey W, Jordan F. Structure and function of the catalytic domain of the dihydrolipoyl acetyltransferase component in Escherichia coli pyruvate dehydrogenase complex. J Biol Chem 2014; 289:15215-30. [PMID: 24742683 DOI: 10.1074/jbc.m113.544080] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The Escherichia coli pyruvate dehydrogenase complex (PDHc) catalyzing conversion of pyruvate to acetyl-CoA comprises three components: E1p, E2p, and E3. The E2p is the five-domain core component, consisting of three tandem lipoyl domains (LDs), a peripheral subunit binding domain (PSBD), and a catalytic domain (E2pCD). Herein are reported the following. 1) The x-ray structure of E2pCD revealed both intra- and intertrimer interactions, similar to those reported for other E2pCDs. 2) Reconstitution of recombinant LD and E2pCD with E1p and E3p into PDHc could maintain at least 6.4% activity (NADH production), confirming the functional competence of the E2pCD and active center coupling among E1p, LD, E2pCD, and E3 even in the absence of PSBD and of a covalent link between domains within E2p. 3) Direct acetyl transfer between LD and coenzyme A catalyzed by E2pCD was observed with a rate constant of 199 s(-1), comparable with the rate of NADH production in the PDHc reaction. Hence, neither reductive acetylation of E2p nor acetyl transfer within E2p is rate-limiting. 4) An unprecedented finding is that although no interaction could be detected between E1p and E2pCD by itself, a domain-induced interaction was identified on E1p active centers upon assembly with E2p and C-terminally truncated E2p proteins by hydrogen/deuterium exchange mass spectrometry. The inclusion of each additional domain of E2p strengthened the interaction with E1p, and the interaction was strongest with intact E2p. E2p domain-induced changes at the E1p active site were also manifested by the appearance of a circular dichroism band characteristic of the canonical 4'-aminopyrimidine tautomer of bound thiamin diphosphate (AP).
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Affiliation(s)
- Junjie Wang
- From the Department of Chemistry, Rutgers University, Newark, New Jersey 07102
| | - Natalia S Nemeria
- From the Department of Chemistry, Rutgers University, Newark, New Jersey 07102
| | - Krishnamoorthy Chandrasekhar
- the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Sowmini Kumaran
- From the Department of Chemistry, Rutgers University, Newark, New Jersey 07102
| | - Palaniappa Arjunan
- the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Shelley Reynolds
- the Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Guillermo Calero
- the Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Roman Brukh
- From the Department of Chemistry, Rutgers University, Newark, New Jersey 07102
| | - Lazaros Kakalis
- From the Department of Chemistry, Rutgers University, Newark, New Jersey 07102
| | - William Furey
- the Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, the Veterans Affairs Medical Center, Pittsburgh, Pennsylvania 15240, and
| | - Frank Jordan
- From the Department of Chemistry, Rutgers University, Newark, New Jersey 07102,
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25
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Murakami K, Calero G, Brown CR, Liu X, Davis RE, Boeger H, Kornberg RD. Formation and fate of a complete 31-protein RNA polymerase II transcription preinitiation complex. J Biol Chem 2013; 288:6325-32. [PMID: 23303183 DOI: 10.1074/jbc.m112.433623] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Whereas individual RNA polymerase II (pol II)-general transcription factor (GTF) complexes are unstable, an assembly of pol II with six GTFs and promoter DNA could be isolated in abundant homogeneous form. The resulting complete pol II transcription preinitiation complex (PIC) contained equimolar amounts of all 31 protein components. An intermediate in assembly, consisting of four GTFs and promoter DNA, could be isolated and supplemented with the remaining components for formation of the PIC. Nuclease digestion and psoralen cross-linking mapped the PIC between positions -70 and -9, centered on the TATA box. Addition of ATP to the PIC resulted in quantitative conversion to an open complex, which retained all 31 proteins, contrary to expectation from previous studies. Addition of the remaining NTPs resulted in run-off transcription, with an efficiency that was promoter-dependent and was as great as 17.5% with the promoters tested.
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Affiliation(s)
- Kenji Murakami
- Department of Structural Biology, Stanford University, Stanford, California 94305, USA
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26
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Cai G, Chaban YL, Imasaki T, Kovacs JA, Calero G, Penczek PA, Takagi Y, Asturias FJ. Interaction of the mediator head module with RNA polymerase II. Structure 2012; 20:899-910. [PMID: 22579255 DOI: 10.1016/j.str.2012.02.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Revised: 02/24/2012] [Accepted: 02/28/2012] [Indexed: 02/09/2023]
Abstract
Mediator, a large (21 polypeptides, MW ∼1 MDa) complex conserved throughout eukaryotes, plays an essential role in control of gene expression by conveying regulatory signals that influence the activity of the preinitiation complex. However, the precise mode of interaction between Mediator and RNA polymerase II (RNAPII), and the mechanism of regulation by Mediator remain elusive. We used cryo-electron microscopy and reconstituted in vitro transcription assays to characterize a transcriptionally-active complex including the Mediator Head module and components of a minimum preinitiation complex (RNAPII, TFIIF, TFIIB, TBP, and promoter DNA). Our results reveal how the Head interacts with RNAPII, affecting its conformation and function.
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Affiliation(s)
- Gang Cai
- Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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27
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Wehbi VL, Stevenson HP, Feinstein TN, Romero G, Calero G, Vilardaga JP. Dynamic Formation of a Ternary PTH receptor−Arrestin−Gβγ Complex required for sustained Signaling. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.665.3] [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)
| | | | | | - Guillermo Romero
- Pharmacology and Chemical biologyUniversity of PittsburghPittsburghPA
| | - Guillermo Calero
- Department of Structural BiologyUniversity of PittsburghPittsburghPA
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28
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Stevenson HP, Zhang Q, Pullara F, Calero G. Structure-Function Studies of Detergent Solubilized PTH1R-GαSβγ. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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29
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Wehbi VL, Stevenson HP, Feinstein TN, Romero G, Calero G, Vilardaga JP. Dynamic Formation of a Ternary PTH Receptor-Arrestin-GS Complex: Consequences for Cell Signaling. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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30
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Calero M, Guerrero J, Pullara F, Zhang Q, Stevenson H, Calero G. A novel high-throughput approach for purification and reconstitution of large multi-protein complexes. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311079402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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31
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Imasaki T, Calero G, Cai G, Tsai KL, Yamada K, Cardelli F, Erdjument-Bromage H, Tempst P, Berger I, Kornberg GL, Asturias FJ, Kornberg RD, Takagi Y. Architecture of the Mediator head module. Nature 2011; 475:240-3. [PMID: 21725323 DOI: 10.1038/nature10162] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 04/28/2011] [Indexed: 01/14/2023]
Abstract
Mediator is a key regulator of eukaryotic transcription, connecting activators and repressors bound to regulatory DNA elements with RNA polymerase II (Pol II). In the yeast Saccharomyces cerevisiae, Mediator comprises 25 subunits with a total mass of more than one megadalton (refs 5, 6) and is organized into three modules, called head, middle/arm and tail. Our understanding of Mediator assembly and its role in regulating transcription has been impeded so far by limited structural information. Here we report the crystal structure of the essential Mediator head module (seven subunits, with a mass of 223 kilodaltons) at a resolution of 4.3 ångströms. Our structure reveals three distinct domains, with the integrity of the complex centred on a bundle of ten helices from five different head subunits. An intricate pattern of interactions within this helical bundle ensures the stable assembly of the head subunits and provides the binding sites for general transcription factors and Pol II. Our structural and functional data suggest that the head module juxtaposes transcription factor IIH and the carboxy-terminal domain of the largest subunit of Pol II, thereby facilitating phosphorylation of the carboxy-terminal domain of Pol II. Our results reveal architectural principles underlying the role of Mediator in the regulation of gene expression.
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Affiliation(s)
- Tsuyoshi Imasaki
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, Indiana 46202, USA
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32
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Abstract
Previous x-ray crystal structures have given insight into the mechanism of transcription and the role of general transcription factors in the initiation of the process. A structure of an RNA polymerase II-general transcription factor TFIIB complex at 4.5 angstrom resolution revealed the amino-terminal region of TFIIB, including a loop termed the "B finger," reaching into the active center of the polymerase where it may interact with both DNA and RNA, but this structure showed little of the carboxyl-terminal region. A new crystal structure of the same complex at 3.8 angstrom resolution obtained under different solution conditions is complementary with the previous one, revealing the carboxyl-terminal region of TFIIB, located above the polymerase active center cleft, but showing none of the B finger. In the new structure, the linker between the amino- and carboxyl-terminal regions can also be seen, snaking down from above the cleft toward the active center. The two structures, taken together with others previously obtained, dispel long-standing mysteries of the transcription initiation process.
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Affiliation(s)
- Xin Liu
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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33
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Kornberg R, Calero G, Takagi Y, Spahr H, Imasaki T. Structures of RNA polymerase II ‐ TFIIF and Mediator complexes. FASEB J 2009. [DOI: 10.1096/fasebj.23.1_supplement.79.3] [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)
| | | | - Yuichiro Takagi
- Biochemistry and Molecular BiologyIndiana UniversityIndianapolisIN
| | - Henrik Spahr
- Laboratory MedicineKarolinska InstitutetStockholmSweden
| | - Tsuyoshi Imasaki
- Biochemistry and Molecular BiologyIndiana UniversityIndianapolisIN
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Walter M, Akola J, Lopez-Acevedo O, Jadzinsky PD, Calero G, Ackerson CJ, Whetten RL, Grönbeck H, Häkkinen H. A unified view of ligand-protected gold clusters as superatom complexes. Proc Natl Acad Sci U S A 2008; 105:9157-62. [PMID: 18599443 PMCID: PMC2442568 DOI: 10.1073/pnas.0801001105] [Citation(s) in RCA: 1075] [Impact Index Per Article: 67.2] [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: 01/31/2008] [Indexed: 11/18/2022] Open
Abstract
Synthesis, characterization, and functionalization of self-assembled, ligand-stabilized gold nanoparticles are long-standing issues in the chemistry of nanomaterials. Factors driving the thermodynamic stability of well documented discrete sizes are largely unknown. Herein, we provide a unified view of principles that underlie the stability of particles protected by thiolate (SR) or phosphine and halide (PR(3), X) ligands. The picture has emerged from analysis of large-scale density functional theory calculations of structurally characterized compounds, namely Au(102)(SR)(44), Au(39)(PR(3))(14)X(6)(-), Au(11)(PR(3))(7)X(3), and Au(13)(PR(3))(10)X(2)(3+), where X is either a halogen or a thiolate. Attributable to a compact, symmetric core and complete steric protection, each compound has a filled spherical electronic shell and a major energy gap to unoccupied states. Consequently, the exceptional stability is best described by a "noble-gas superatom" analogy. The explanatory power of this concept is shown by its application to many monomeric and oligomeric compounds of precisely known composition and structure, and its predictive power is indicated through suggestions offered for a series of anomalously stable cluster compositions which are still awaiting a precise structure determination.
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Affiliation(s)
| | - Jaakko Akola
- Departments of Physics and
- Institut für Festkörperforschung, Forschungszentrum Jülich, D-52425 Jülich, Germany
| | | | - Pablo D. Jadzinsky
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Applied Physics, Stanford University, Stanford, CA 94305
| | - Guillermo Calero
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Christopher J. Ackerson
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Robert L. Whetten
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332; and
| | - Henrik Grönbeck
- Competence Centre for Catalysis and Department of Applied Physics, Chalmers University of Technology, SE-41296, Göteborg, Sweden
| | - Hannu Häkkinen
- Departments of Physics and
- Chemistry, Nanoscience Center, University of Jyväskylä, FI-40014 Jyväskylä, Finland
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Phillips MJ, Calero G, Chan B, Ramachandran S, Cerione RA. Effector proteins exert an important influence on the signaling-active state of the small GTPase Cdc42. J Biol Chem 2008; 283:14153-64. [PMID: 18348980 PMCID: PMC2376242 DOI: 10.1074/jbc.m706271200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [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: 07/30/2007] [Revised: 02/25/2008] [Indexed: 11/06/2022] Open
Abstract
GTP-binding (G) proteins regulate the flow of information in cellular signaling pathways by alternating between a GTP-bound "active" state and a GDP-bound "inactive" state. Cdc42, a member of the Rho family of Ras-related small G-proteins, plays key roles in the regulation of cell shape, motility, and growth. Here we describe the high resolution x-ray crystal structure for Cdc42 bound to the GTP analog guanylyl beta,gamma-methylene-diphosphonate (GMP-PCP) (i.e. the presumed signaling-active state) and show that it is virtually identical to the structures for the signaling-inactive, GDP-bound form of the protein, contrary to what has been reported for Ras and other G-proteins. Especially surprising was that the GMP-PCP- and GDP-bound forms of Cdc42 did not show detectable differences in their Switch I and Switch II loops. Fluorescence studies using a Cdc42 mutant in which a tryptophan residue was introduced at position 32 of Switch I also showed that there was little difference in the Switch I conformation between the GDP- and GMP-PCP-bound states (i.e. <10%), which again differed from Ras where much larger changes in Trp-32 fluorescence were observed when comparing these two nucleotide-bound states (>30%). However, the binding of an effector protein induced significant changes in the Trp-32 emission specifically from GMP-PCP-bound Cdc42, as well as in the phosphate resonances for GTP bound to this G-protein as indicated in NMR studies. An examination of the available structures for Cdc42 complexed to different effector proteins, versus the x-ray crystal structure for GMP-PCP-bound Cdc42, provides a possible explanation for how effectors can distinguish between the GTP- and GDP-bound forms of this G-protein and ensure that the necessary conformational changes for signal propagation occur.
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Affiliation(s)
- Matthew J Phillips
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, USA
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36
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Abstract
Structural information on nanometer-sized gold particles has been limited, due in part to the problem of preparing homogeneous material. Here we report the crystallization and x-ray structure determination of a p-mercaptobenzoic acid (p-MBA)-protected gold nanoparticle, which comprises 102 gold atoms and 44 p-MBAs. The central gold atoms are packed in a Marks decahedron, surrounded by additional layers of gold atoms in unanticipated geometries. The p-MBAs interact not only with the gold but also with one another, forming a rigid surface layer. The particles are chiral, with the two enantiomers alternating in the crystal lattice. The discrete nature of the particle may be explained by the closing of a 58-electron shell.
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Affiliation(s)
- Pablo D Jadzinsky
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
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37
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Takagi Y, Calero G, Komori H, Brown JA, Ehrensberger AH, Hudmon A, Asturias F, Kornberg RD. Head module control of mediator interactions. Mol Cell 2006; 23:355-64. [PMID: 16885025 DOI: 10.1016/j.molcel.2006.06.007] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [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: 04/08/2006] [Revised: 05/22/2006] [Accepted: 06/07/2006] [Indexed: 10/24/2022]
Abstract
Yeast Mediator proteins interacting with Med17(Srb4) have been expressed at a high level with the use of recombinant baculoviruses and recovered in homogeneous form as a seven subunit, 223 kDa complex. Electron microscopy and single-particle analysis identify this complex as the Mediator head module. The recombinant head module complements "headless" Mediator for the initiation of transcription in vitro. The module interacts with an RNA polymerase II-TFIIF complex, but not with the polymerase or TFIIF alone. This interaction is lost in the presence of a DNA template and associated RNA transcript, recapitulating the release of Mediator that occurs upon the initiation of transcription. Disruption of the head module in a temperature-sensitive mutant in vivo leads to the release of middle and tail modules from a transcriptionally active promoter. The head module evidently controls Mediator-RNA polymerase II and Mediator-promoter interactions.
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Affiliation(s)
- Yuichiro Takagi
- Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305, USA
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38
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Calero G, Gupta P, Nonato MC, Tandel S, Biehl ER, Hofmann SL, Clardy J. The crystal structure of palmitoyl protein thioesterase-2 (PPT2) reveals the basis for divergent substrate specificities of the two lysosomal thioesterases, PPT1 and PPT2. J Biol Chem 2003; 278:37957-64. [PMID: 12855696 DOI: 10.1074/jbc.m301225200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [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: 11/06/2022] Open
Abstract
Mutations in palmitoyl protein thioesterase-1 (PPT1) have been found to cause the infantile form of neuronal ceroid lipofuscinosis, which is a lysosomal storage disorder characterized by impaired degradation of fatty acid-modified proteins with accumulation of amorphous granular deposits in cortical neurons, leading to mental retardation and death. Palmitoyl protein thioesterase-2 (PPT2) is a second lysosomal hydrolase that shares a 26% identity with PPT1. A previous study had suggested that palmitoyl-CoA was the preferred substrate of PPT2. Furthermore, PPT2 did not hydrolyze palmitate from the several S-palmitoylated protein substrates. Interestingly, PPT2 deficiency in a recent transgenic mouse model is associated with a form of neuronal ceroid lipofuscinosis, suggesting that PPT1 and -2 perform non-redundant roles in lysosomal thioester catabolism. In the current paper, we present the crystal structure of PPT2 at a resolution of 2.7 A. Comparisons of the structures of PPT1 and -2 show very similar architectural features; however, conformational differences in helix alpha4 lead to a solvent-exposed lipid-binding groove in PPT1. The limited space between two parallel loops (beta3-alphaA and beta8-alphaF) located immediately above the lipid-binding groove in PPT2 restricts the binding of fatty acids with bulky head groups, and this binding groove is significantly larger in PPT1. This structural difference accounts for the ability of PPT2 to hydrolyze an unbranched structure such as palmitoyl-CoA but not palmitoylcysteine or palmitoylated proteins. Furthermore, differences in fatty acid chain length specificity of PPT1 and -2, also reported here, are explained by the structure and may provide a biochemical basis for their non-redundant roles.
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Affiliation(s)
- Guillermo Calero
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA
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Calero G, Wilson KF, Ly T, Rios-Steiner JL, Clardy JC, Cerione RA. Structural basis of m7GpppG binding to the nuclear cap-binding protein complex. Nat Struct Biol 2002; 9:912-7. [PMID: 12434151 DOI: 10.1038/nsb874] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2002] [Accepted: 10/21/2002] [Indexed: 11/09/2022]
Abstract
The 7-methyl guanosine cap structure of RNA is essential for key aspects of RNA processing, including pre-mRNA splicing, 3' end formation, U snRNA transport, nonsense-mediated decay and translation. Two cap-binding proteins mediate these effects: cytosolic eIF-4E and nuclear cap-binding protein complex (CBC). The latter consists of a CBP20 subunit, which binds the cap, and a CBP80 subunit, which ensures high-affinity cap binding. Here we report the 2.1 A resolution structure of human CBC with the cap analog m7GpppG, as well as the structure of unliganded CBC. Comparisons between these structures indicate that the cap induces substantial conformational changes within the N-terminal loop of CBP20, enabling Tyr 20 to join Tyr 43 in pi-pi stacking interactions with the methylated guanosine base. CBP80 stabilizes the movement of the N-terminal loop of CBP20 and locks the CBC into a high affinity cap-binding state. The structure for the CBC bound to m7GpppG highlights interesting similarities and differences between CBC and eIF-4E, and provides insights into the regulatory mechanisms used by growth factors and other extracellular stimuli to influence the cap-binding state of the CBC.
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Affiliation(s)
- Guillermo Calero
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, USA
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Abstract
We describe a 63-year-old man who presented with painful malodorous lesions in the perianal, perineal and scrotal regions. Following definitive diagnosis of paracoccidioidomycosis, he was treated initially with trimethoprim/sulphamethoxazole, but there was no clinical improvement. He then received terbinafine (Lamisil) 250 mg twice daily for 6 months. There was rapid resolution of all lesions and complete relief of symptoms, without any associated side-effects. The patient remains clinically well and without any evidence of infection 2 years after discontinuation of terbinafine treatment.
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Affiliation(s)
- J M Ollague
- Department of Dermatology, Venereology and Allergy, IESS University of Guayaquil, PO Box 09-01-8611, Guayaquil, Ecuador.
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Abstract
Structure/function analysis shows that the carboxyl terminal (CT) domain of connexin43 (Cx43) is essential for the chemical regulation of cell-cell communication. Of particular interest is the region between amino acids 260 and 300. Structural preservation of this region is essential for acidification-induced uncoupling (ie, pH gating). In this study, we report data showing that a 17mer peptide of the same sequence as amino acids 271 to 287 of Cx43 (CSSPTAPLSPMSPPGYK) can prevent pH gating of Cx43-expressing oocytes. Experiments were carried out in pairs of Xenopus oocytes previously injected with connexin38 antisense and expressing wild-type Cx43. Junctional conductance was measured electrophysiologically. pHi was determined from the light emission of the proton-sensitive dye dextran-seminaphthorhodafluor. Intracellular acidification was induced by superfusion with a bicarbonate-buffered solution gassed with a progressively increasing concentration of CO2. Injection of water alone into both oocytes of a Cx43-expressing pair or injection of a peptide from region 321 to 337 of Cx43 did not modify pH sensitivity. However, injection of a polypeptide corresponding to amino acids 241 to 382 of Cx43 interfered with the ability of gap junctions to close on acidification. Similar results were obtained when a 17mer peptide (region 271 to 287) was injected into both oocytes of the pair. Normal Cx43 pH gating was observed if (1) the amino acid sequence of the 17mer peptide was scrambled or (2) the N and the C ends of the 17mer peptide were not included in the sequence. This is the first demonstration of a molecule that can interfere with the chemical regulation of connexin channels in a cell pair. The data may lead to the development of small molecules that can be used in Cx43-expressing multicellular preparations to study the role of gap junction regulation in normal as well as diseased states.
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Affiliation(s)
- G Calero
- SUNY/Health Science Center, Syracuse, NY 13210, USA
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42
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Abstract
Gap junction channels allow for the passage of ions and small molecules between neighboring cells. These channels are formed by multimers of an integral membrane protein named connexin. In the heart and other tissues, the most abundant connexin is a 43-kDa, 382-amino acid protein termed connexin43 (Cx43). A characteristic property of connexin channels is that they close upon acidification of the intracellular space. Previous studies have shown that truncation of the carboxyl terminal of Cx43 impairs pH sensitivity. In the present study, we have used a combination of optical, electrophysiological, and molecular biological techniques and the oocyte expression system to further localize the regions of the carboxyl terminal that are involved in pH regulation of Cx43 channels. Our results show that regions 261-300 and 374-382 are essential components of a pH-dependent "gating particle," which is responsible for acidification-induced uncoupling of Cx43-expressing cells. Regions 261-300 and 374-382 seem to be interdependent. The function of region 261-300 may be related to the presence of a poly-proline repeat between amino acids 274 and 285. Furthermore, site-directed mutagenesis studies show that the function of region 374-382 is not directly related to its net balance of charges, although mutation of only one amino acid (aspartate 379) for asparagine impairs pH sensitivity to the same extent as truncation of the carboxyl terminal domain (from amino acid 257). The mutation in which serine 364 is substituted for proline, which has been associated with some cases of cardiac congenital malformations in humans, also disrupts the pH gating of Cx43, although deletion of amino acids 364-373 has no effect on acidification-induced uncoupling. These results provide new insight into the molecular mechanisms responsible for acidification-induced uncoupling of gap junction channels in the heart and in other Cx43-expressing structures.
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Affiliation(s)
- J F Ek-Vitorín
- Department of Pharmacology, SUNY/Health Science Center at Syracuse 13210, USA
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43
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Pérez Alva S, Valenzuela R, Tamanaha B, Bustinza F, Vadillo B, Calero G. [Presence of the parasite Bartonella bacilliformis in the blood and its recovery in thymectomized mice. Strains: 049, 35, 12 and 15]. Rev Latinoam Microbiol 1977; 19:1-6. [PMID: 279054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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