1
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Desautels TA, Arrildt KT, Zemla AT, Lau EY, Zhu F, Ricci D, Cronin S, Zost SJ, Binshtein E, Scheaffer SM, Dadonaite B, Petersen BK, Engdahl TB, Chen E, Handal LS, Hall L, Goforth JW, Vashchenko D, Nguyen S, Weilhammer DR, Lo JKY, Rubinfeld B, Saada EA, Weisenberger T, Lee TH, Whitener B, Case JB, Ladd A, Silva MS, Haluska RM, Grzesiak EA, Earnhart CG, Hopkins S, Bates TW, Thackray LB, Segelke BW, Lillo AM, Sundaram S, Bloom JD, Diamond MS, Crowe JE, Carnahan RH, Faissol DM. Computationally restoring the potency of a clinical antibody against Omicron. Nature 2024; 629:878-885. [PMID: 38720086 PMCID: PMC11111397 DOI: 10.1038/s41586-024-07385-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 04/04/2024] [Indexed: 05/21/2024]
Abstract
The COVID-19 pandemic underscored the promise of monoclonal antibody-based prophylactic and therapeutic drugs1-3 and revealed how quickly viral escape can curtail effective options4,5. When the SARS-CoV-2 Omicron variant emerged in 2021, many antibody drug products lost potency, including Evusheld and its constituent, cilgavimab4-6. Cilgavimab, like its progenitor COV2-2130, is a class 3 antibody that is compatible with other antibodies in combination4 and is challenging to replace with existing approaches. Rapidly modifying such high-value antibodies to restore efficacy against emerging variants is a compelling mitigation strategy. We sought to redesign and renew the efficacy of COV2-2130 against Omicron BA.1 and BA.1.1 strains while maintaining efficacy against the dominant Delta variant. Here we show that our computationally redesigned antibody, 2130-1-0114-112, achieves this objective, simultaneously increases neutralization potency against Delta and subsequent variants of concern, and provides protection in vivo against the strains tested: WA1/2020, BA.1.1 and BA.5. Deep mutational scanning of tens of thousands of pseudovirus variants reveals that 2130-1-0114-112 improves broad potency without increasing escape liabilities. Our results suggest that computational approaches can optimize an antibody to target multiple escape variants, while simultaneously enriching potency. Our computational approach does not require experimental iterations or pre-existing binding data, thus enabling rapid response strategies to address escape variants or lessen escape vulnerabilities.
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Affiliation(s)
- Thomas A Desautels
- Computational Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Kathryn T Arrildt
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Adam T Zemla
- Global Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Edmond Y Lau
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Fangqiang Zhu
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Dante Ricci
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Stephanie Cronin
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Seth J Zost
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Elad Binshtein
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Suzanne M Scheaffer
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Bernadeta Dadonaite
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Brenden K Petersen
- Computational Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Taylor B Engdahl
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Elaine Chen
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Laura S Handal
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lynn Hall
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John W Goforth
- Global Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Denis Vashchenko
- Applications Simulations and Quality Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Sam Nguyen
- Computational Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
- Google, Alphabet Inc., Mountain View, CA, USA
| | - Dina R Weilhammer
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Jacky Kai-Yin Lo
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Bonnee Rubinfeld
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Edwin A Saada
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Tracy Weisenberger
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Tek-Hyung Lee
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Bradley Whitener
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Vir Biotechnology, San Francisco, CA, USA
| | - James B Case
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Alexander Ladd
- Computational Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Mary S Silva
- Global Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Rebecca M Haluska
- Applications Simulations and Quality Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Emilia A Grzesiak
- Global Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Christopher G Earnhart
- Joint Program Executive Office for Chemical, Biological, Radiological, and Nuclear Defense, US Department of Defense, Frederick, MD, USA
| | | | - Thomas W Bates
- Computational Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Larissa B Thackray
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Brent W Segelke
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | | | - Shivshankar Sundaram
- Center for Bioengineering, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Jesse D Bloom
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Howard Hughes Medical Institute, Seattle, WA, USA
| | - Michael S Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
- Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
| | - James E Crowe
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Robert H Carnahan
- Vanderbilt Vaccine Center, Vanderbilt University Medical Center, Nashville, TN, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Daniel M Faissol
- Computational Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA, USA.
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2
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Stevenson GA, Kirshner D, Bennion BJ, Yang Y, Zhang X, Zemla A, Torres MW, Epstein A, Jones D, Kim H, Bennett WFD, Wong SE, Allen JE, Lightstone FC. Clustering Protein Binding Pockets and Identifying Potential Drug Interactions: A Novel Ligand-Based Featurization Method. J Chem Inf Model 2023; 63:6655-6666. [PMID: 37847557 PMCID: PMC10647021 DOI: 10.1021/acs.jcim.3c00722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Indexed: 10/18/2023]
Abstract
Protein-ligand interactions are essential to drug discovery and drug development efforts. Desirable on-target or multitarget interactions are the first step in finding an effective therapeutic, while undesirable off-target interactions are the first step in assessing safety. In this work, we introduce a novel ligand-based featurization and mapping of human protein pockets to identify closely related protein targets and to project novel drugs into a hybrid protein-ligand feature space to identify their likely protein interactions. Using structure-based template matches from PDB, protein pockets are featured by the ligands that bind to their best co-complex template matches. The simplicity and interpretability of this approach provide a granular characterization of the human proteome at the protein-pocket level instead of the traditional protein-level characterization by family, function, or pathway. We demonstrate the power of this featurization method by clustering a subset of the human proteome and evaluating the predicted cluster associations of over 7000 compounds.
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Affiliation(s)
- Garrett A. Stevenson
- Computational
Engineering Division, Lawrence Livermore
National Laboratory, Livermore, California 94550, United States
| | - Dan Kirshner
- Biosciences
and Biotechnology Division, Lawrence Livermore
National Laboratory, Livermore, California 94550, United States
| | - Brian J. Bennion
- Biosciences
and Biotechnology Division, Lawrence Livermore
National Laboratory, Livermore, California 94550, United States
| | - Yue Yang
- Biosciences
and Biotechnology Division, Lawrence Livermore
National Laboratory, Livermore, California 94550, United States
| | - Xiaohua Zhang
- Biosciences
and Biotechnology Division, Lawrence Livermore
National Laboratory, Livermore, California 94550, United States
| | - Adam Zemla
- Global
Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Marisa W. Torres
- Global
Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Aidan Epstein
- Global
Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Derek Jones
- Global
Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
- Department
of Computer Science and Engineering, University
of California, San Diego, La Jolla, California 92093, United States
| | - Hyojin Kim
- Center
for Applied Scientific Computing, Lawrence
Livermore National Laboratory, Livermore, California 94550, United States
| | - W. F. Drew Bennett
- Biosciences
and Biotechnology Division, Lawrence Livermore
National Laboratory, Livermore, California 94550, United States
| | - Sergio E. Wong
- Biosciences
and Biotechnology Division, Lawrence Livermore
National Laboratory, Livermore, California 94550, United States
| | - Jonathan E. Allen
- Global
Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Felice C. Lightstone
- Biosciences
and Biotechnology Division, Lawrence Livermore
National Laboratory, Livermore, California 94550, United States
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3
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Đaković S, Zeelen JP, Gkeka A, Chandra M, van Straaten M, Foti K, Zhong J, Vlachou EP, Aresta-Branco F, Verdi JP, Papavasiliou FN, Stebbins CE. A structural classification of the variant surface glycoproteins of the African trypanosome. PLoS Negl Trop Dis 2023; 17:e0011621. [PMID: 37656766 PMCID: PMC10501684 DOI: 10.1371/journal.pntd.0011621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 09/14/2023] [Accepted: 08/23/2023] [Indexed: 09/03/2023] Open
Abstract
Long-term immune evasion by the African trypanosome is achieved through repetitive cycles of surface protein replacement with antigenically distinct versions of the dense Variant Surface Glycoprotein (VSG) coat. Thousands of VSG genes and pseudo-genes exist in the parasite genome that, together with genetic recombination mechanisms, allow for essentially unlimited immune escape from the adaptive immune system of the host. The diversity space of the "VSGnome" at the protein level was thought to be limited to a few related folds whose structures were determined more than 30 years ago. However, recent progress has shown that the VSGs possess significantly more architectural variation than had been appreciated. Here we combine experimental X-ray crystallography (presenting structures of N-terminal domains of coat proteins VSG11, VSG21, VSG545, VSG558, and VSG615) with deep-learning prediction using Alphafold to produce models of hundreds of VSG proteins. We classify the VSGnome into groups based on protein architecture and oligomerization state, contextualize recent bioinformatics clustering schemes, and extensively map VSG-diversity space. We demonstrate that in addition to the structural variability and post-translational modifications observed thus far, VSGs are also characterized by variations in oligomerization state and possess inherent flexibility and alternative conformations, lending additional variability to what is exposed to the immune system. Finally, these additional experimental structures and the hundreds of Alphafold predictions confirm that the molecular surfaces of the VSGs remain distinct from variant to variant, supporting the hypothesis that protein surface diversity is central to the process of antigenic variation used by this organism during infection.
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Affiliation(s)
- Sara Đaković
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Johan P. Zeelen
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Anastasia Gkeka
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - Monica Chandra
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - Monique van Straaten
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Konstantina Foti
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Janet Zhong
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Evi P. Vlachou
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - Francisco Aresta-Branco
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - Joseph P. Verdi
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - F. Nina Papavasiliou
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - C. Erec Stebbins
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
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4
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New J, Barsky D, Uhde-Stone C. ROS Consumers or Producers? Interpreting Transcriptomic Data by AlphaFold Modeling Provides Insights into Class III Peroxidase Functions in Response to Biotic and Abiotic Stresses. Int J Mol Sci 2023; 24:ijms24098297. [PMID: 37176003 PMCID: PMC10179425 DOI: 10.3390/ijms24098297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 05/02/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
Participating in both biotic and abiotic stress responses, plant-specific class III peroxidases (PERs) show promise as candidates for crop improvement. The multigenic PER family is known to take part in diverse functions, such as lignin formation and defense against pathogens. Traditionally linked to hydrogen peroxide (H2O2) consumption, PERs can also produce reactive oxygen species (ROS), essential in tissue development, pathogen defense and stress signaling. The amino acid sequences of both orthologues and paralogues of PERs are highly conserved, but discovering correlations between sequence differences and their functional diversity has proven difficult. By combining meta-analysis of transcriptomic data and sequence alignments, we discovered a correlation between three key amino acid positions and gene expression in response to biotic and abiotic stresses. Phylogenetic analysis revealed evolutionary pressure on these amino acids toward stress responsiveness. Using AlphaFold modeling, we found unique interdomain and protein-heme interactions involving those key amino acids in stress-induced PERs. Plausibly, these structural interactions may act as "gate keepers" by preventing larger substrates from accessing the heme and thereby shifting PER function from consumption to the production of ROS.
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Affiliation(s)
- James New
- Department of Biological Sciences, California State University, East Bay, Hayward, CA 94542, USA
| | - Daniel Barsky
- Department of Physics, California State University, East Bay, Hayward, CA 94542, USA
| | - Claudia Uhde-Stone
- Department of Biological Sciences, California State University, East Bay, Hayward, CA 94542, USA
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5
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Desautels TA, Arrildt KT, Zemla AT, Lau EY, Zhu F, Ricci D, Cronin S, Zost SJ, Binshtein E, Scheaffer SM, Dadonaite B, Petersen BK, Engdahl TB, Chen E, Handal LS, Hall L, Goforth JW, Vashchenko D, Nguyen S, Weilhammer DR, Lo JKY, Rubinfeld B, Saada EA, Weisenberger T, Lee TH, Whitener B, Case JB, Ladd A, Silva MS, Haluska RM, Grzesiak EA, Earnhart CG, Hopkins S, Bates TW, Thackray LB, Segelke BW, Lillo AM, Sundaram S, Bloom J, Diamond MS, Crowe JE, Carnahan RH, Faissol DM. Computationally restoring the potency of a clinical antibody against SARS-CoV-2 Omicron subvariants. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2022.10.21.513237. [PMID: 36324800 PMCID: PMC9628197 DOI: 10.1101/2022.10.21.513237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The COVID-19 pandemic underscored the promise of monoclonal antibody-based prophylactic and therapeutic drugs1-3, but also revealed how quickly viral escape can curtail effective options4,5. With the emergence of the SARS-CoV-2 Omicron variant in late 2021, many clinically used antibody drug products lost potency, including Evusheld™ and its constituent, cilgavimab4,6. Cilgavimab, like its progenitor COV2-2130, is a class 3 antibody that is compatible with other antibodies in combination4 and is challenging to replace with existing approaches. Rapidly modifying such high-value antibodies with a known clinical profile to restore efficacy against emerging variants is a compelling mitigation strategy. We sought to redesign COV2-2130 to rescue in vivo efficacy against Omicron BA.1 and BA.1.1 strains while maintaining efficacy against the contemporaneously dominant Delta variant. Here we show that our computationally redesigned antibody, 2130-1-0114-112, achieves this objective, simultaneously increases neutralization potency against Delta and many variants of concern that subsequently emerged, and provides protection in vivo against the strains tested, WA1/2020, BA.1.1, and BA.5. Deep mutational scanning of tens of thousands pseudovirus variants reveals 2130-1-0114-112 improves broad potency without incurring additional escape liabilities. Our results suggest that computational approaches can optimize an antibody to target multiple escape variants, while simultaneously enriching potency. Because our approach is computationally driven, not requiring experimental iterations or pre-existing binding data, it could enable rapid response strategies to address escape variants or pre-emptively mitigate escape vulnerabilities.
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Affiliation(s)
- Thomas A Desautels
- Computational Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Kathryn T Arrildt
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Adam T Zemla
- Global Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Edmond Y Lau
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Fangqiang Zhu
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Dante Ricci
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | | | - Seth J Zost
- Vanderbilt Vaccine Center, Nashville, TN 37232, USA
| | | | - Suzanne M Scheaffer
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Bernadeta Dadonaite
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
| | - Brenden K Petersen
- Computational Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | | | - Elaine Chen
- Vanderbilt Vaccine Center, Nashville, TN 37232, USA
| | | | - Lynn Hall
- Vanderbilt Vaccine Center, Nashville, TN 37232, USA
| | - John W Goforth
- Global Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Denis Vashchenko
- Applications Simulations and Quality Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Sam Nguyen
- Computational Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Dina R Weilhammer
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Jacky Kai-Yin Lo
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Bonnee Rubinfeld
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Edwin A Saada
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Tracy Weisenberger
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Tek-Hyung Lee
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Bradley Whitener
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - James B Case
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Alexander Ladd
- Computational Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Mary S Silva
- Global Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Rebecca M Haluska
- Applications Simulations and Quality Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Emilia A Grzesiak
- Global Security Computing Applications Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Christopher G Earnhart
- Joint Program Executive Office for Chemical, Biological, Radiological, and Nuclear Defense, US, Department of Defense, Frederick, MD 21703, USA
| | | | - Thomas W Bates
- Global Security Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Larissa B Thackray
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Brent W Segelke
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | | | - Shivshankar Sundaram
- Center for Bioengineering, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
| | - Jesse Bloom
- Basic Sciences Division and Computational Biology Program, Fred Hutchinson Cancer Center, Seattle, WA 98109, USA
- Howard Hughes Medical Institute, Seattle, WA 98195, USA
| | - Michael S Diamond
- Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Pathology & Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - James E Crowe
- Vanderbilt Vaccine Center, Nashville, TN 37232, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robert H Carnahan
- Vanderbilt Vaccine Center, Nashville, TN 37232, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Daniel M Faissol
- Computational Engineering Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
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6
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Sharma A, Zhang X, Dejnirattisai W, Dai X, Gong D, Wongwiwat W, Duquerroy S, Rouvinski A, Vaney MC, Guardado-Calvo P, Haouz A, England P, Sun R, Zhou ZH, Mongkolsapaya J, Screaton GR, Rey FA. The epitope arrangement on flavivirus particles contributes to Mab C10's extraordinary neutralization breadth across Zika and dengue viruses. Cell 2021; 184:6052-6066.e18. [PMID: 34852239 PMCID: PMC8724787 DOI: 10.1016/j.cell.2021.11.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 09/06/2021] [Accepted: 11/08/2021] [Indexed: 10/26/2022]
Abstract
The human monoclonal antibody C10 exhibits extraordinary cross-reactivity, potently neutralizing Zika virus (ZIKV) and the four serotypes of dengue virus (DENV1-DENV4). Here we describe a comparative structure-function analysis of C10 bound to the envelope (E) protein dimers of the five viruses it neutralizes. We demonstrate that the C10 Fab has high affinity for ZIKV and DENV1 but not for DENV2, DENV3, and DENV4. We further show that the C10 interaction with the latter viruses requires an E protein conformational landscape that limits binding to only one of the three independent epitopes per virion. This limited affinity is nevertheless counterbalanced by the particle's icosahedral organization, which allows two different dimers to be reached by both Fab arms of a C10 immunoglobulin. The epitopes' geometric distribution thus confers C10 its exceptional neutralization breadth. Our results highlight the importance not only of paratope/epitope complementarity but also the topological distribution for epitope-focused vaccine design.
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Affiliation(s)
- Arvind Sharma
- Institut Pasteur, Université de Paris, CNRS UMR3569, Unité de Virologie Structurale, 75015 Paris, France
| | - Xiaokang Zhang
- Institut Pasteur, Université de Paris, CNRS UMR3569, Unité de Virologie Structurale, 75015 Paris, France; Interdisciplinary Center for Brain Information, the Brain Cognition and Brain Disease Institute, Faculty of Life and Health Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, Guangdong 518055, China
| | - Wanwisa Dejnirattisai
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Xinghong Dai
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Danyang Gong
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Wiyada Wongwiwat
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Stéphane Duquerroy
- Institut Pasteur, Université de Paris, CNRS UMR3569, Unité de Virologie Structurale, 75015 Paris, France; Université Paris-Saclay, Faculté des Sciences, F-91405 Orsay, France
| | - Alexander Rouvinski
- Institut Pasteur, Université de Paris, CNRS UMR3569, Unité de Virologie Structurale, 75015 Paris, France
| | - Marie-Christine Vaney
- Institut Pasteur, Université de Paris, CNRS UMR3569, Unité de Virologie Structurale, 75015 Paris, France
| | - Pablo Guardado-Calvo
- Institut Pasteur, Université de Paris, CNRS UMR3569, Unité de Virologie Structurale, 75015 Paris, France
| | - Ahmed Haouz
- Institut Pasteur, Université de Paris, CNRS UMR 3528, Center for Technological Resources and Research, 75015 Paris, France
| | - Patrick England
- Institut Pasteur, Université de Paris, CNRS UMR 3528, Center for Technological Resources and Research, 75015 Paris, France
| | - Ren Sun
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Z Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Juthathip Mongkolsapaya
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Dengue Hemorrhagic Fever Research Unit, Office for Research and Development, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | | | - Felix A Rey
- Institut Pasteur, Université de Paris, CNRS UMR3569, Unité de Virologie Structurale, 75015 Paris, France.
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7
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Borucki MK, Collette NM, Coffey LL, Van Rompay KKA, Hwang MH, Thissen JB, Allen JE, Zemla AT. Multiscale analysis for patterns of Zika virus genotype emergence, spread, and consequence. PLoS One 2019; 14:e0225699. [PMID: 31809512 PMCID: PMC6897431 DOI: 10.1371/journal.pone.0225699] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 11/11/2019] [Indexed: 11/19/2022] Open
Abstract
The question of how Zika virus (ZIKV) changed from a seemingly mild virus to a human pathogen capable of microcephaly and sexual transmission remains unanswered. The unexpected emergence of ZIKV's pathogenicity and capacity for sexual transmission may be due to genetic changes, and future changes in phenotype may continue to occur as the virus expands its geographic range. Alternatively, the sheer size of the 2015-16 epidemic may have brought attention to a pre-existing virulent ZIKV phenotype in a highly susceptible population. Thus, it is important to identify patterns of genetic change that may yield a better understanding of ZIKV emergence and evolution. However, because ZIKV has an RNA genome and a polymerase incapable of proofreading, it undergoes rapid mutation which makes it difficult to identify combinations of mutations associated with viral emergence. As next generation sequencing technology has allowed whole genome consensus and variant sequence data to be generated for numerous virus samples, the task of analyzing these genomes for patterns of mutation has become more complex. However, understanding which combinations of mutations spread widely and become established in new geographic regions versus those that disappear relatively quickly is essential for defining the trajectory of an ongoing epidemic. In this study, multiscale analysis of the wealth of genomic data generated over the course of the epidemic combined with in vivo laboratory data allowed trends in mutations and outbreak trajectory to be assessed. Mutations were detected throughout the genome via deep sequencing, and many variants appeared in multiple samples and in some cases become consensus. Similarly, amino acids that were previously consensus in pre-outbreak samples were detected as low frequency variants in epidemic strains. Protein structural models indicate that most of the mutations associated with the epidemic transmission occur on the exposed surface of viral proteins. At the macroscale level, consensus data was organized into large and interactive databases to allow the spread of individual mutations and combinations of mutations to be visualized and assessed for temporal and geographical patterns. Thus, the use of multiscale modeling for identifying mutations or combinations of mutations that impact epidemic transmission and phenotypic impact can aid the formation of hypotheses which can then be tested using reverse genetics.
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Affiliation(s)
- Monica K. Borucki
- Physical Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Nicole M. Collette
- Physical Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Lark L. Coffey
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Koen K. A. Van Rompay
- Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
- California National Primate Research Center, University of California Davis, Davis, California, United States of America
| | - Mona H. Hwang
- Physical Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - James B. Thissen
- Physical Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Jonathan E. Allen
- Computations Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Adam T. Zemla
- Computations Directorate, Lawrence Livermore National Laboratory, Livermore, California, United States of America
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8
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Navid A, Jiao Y, Wong SE, Pett-Ridge J. System-level analysis of metabolic trade-offs during anaerobic photoheterotrophic growth in Rhodopseudomonas palustris. BMC Bioinformatics 2019; 20:233. [PMID: 31072303 PMCID: PMC6509789 DOI: 10.1186/s12859-019-2844-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 04/24/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Living organisms need to allocate their limited resources in a manner that optimizes their overall fitness by simultaneously achieving several different biological objectives. Examination of these biological trade-offs can provide invaluable information regarding the biophysical and biochemical bases behind observed cellular phenotypes. A quantitative knowledge of a cell system's critical objectives is also needed for engineering of cellular metabolism, where there is interest in mitigating the fitness costs that may result from human manipulation. RESULTS To study metabolism in photoheterotrophs, we developed and validated a genome-scale model of metabolism in Rhodopseudomonas palustris, a metabolically versatile gram-negative purple non-sulfur bacterium capable of growing phototrophically on various carbon sources, including inorganic carbon and aromatic compounds. To quantitatively assess trade-offs among a set of important biological objectives during different metabolic growth modes, we used our new model to conduct an 8-dimensional multi-objective flux analysis of metabolism in R. palustris. Our results revealed that phototrophic metabolism in R. palustris is light-limited under anaerobic conditions, regardless of the available carbon source. Under photoheterotrophic conditions, R. palustris prioritizes the optimization of carbon efficiency, followed by ATP production and biomass production rate, in a Pareto-optimal manner. To achieve maximum carbon fixation, cells appear to divert limited energy resources away from growth and toward CO2 fixation, even in the presence of excess reduced carbon. We also found that to achieve the theoretical maximum rate of biomass production, anaerobic metabolism requires import of additional compounds (such as protons) to serve as electron acceptors. Finally, we found that production of hydrogen gas, of potential interest as a candidate biofuel, lowers the cellular growth rates under all circumstances. CONCLUSIONS Photoheterotrophic metabolism of R. palustris is primarily regulated by the amount of light it can absorb and not the availability of carbon. However, despite carbon's secondary role as a regulating factor, R. palustris' metabolism strives for maximum carbon efficiency, even when this increased efficiency leads to slightly lower growth rates.
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Affiliation(s)
- Ali Navid
- Physics and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 USA
| | - Yongqin Jiao
- Physics and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 USA
| | - Sergio Ernesto Wong
- Physics and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 USA
| | - Jennifer Pett-Ridge
- Physics and Life Sciences Directorate, Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 USA
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9
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Michalak P, Kang L. Unique divergence of the breast cancer 2 ( BRCA2) gene in Neanderthals. Hereditas 2018; 155:34. [PMID: 30410429 PMCID: PMC6215347 DOI: 10.1186/s41065-018-0073-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 10/23/2018] [Indexed: 11/10/2022] Open
Abstract
Unique divergence of the BRCA2, a tumor suppressor gene, in Neanderthals relative to other primates, including modern humans, is highlighted. This divergence with potentially pathogenic consequences raises a question about cancer susceptibility in the archaic species that was replaced by modern humans about 40,000 years ago.
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Affiliation(s)
- Pawel Michalak
- 1One Health Research Center, Virginia-Maryland College of Veterinary Medicine, 1410 Prices Fork Rd, Blacksburg, VA 24060 USA.,2Edward Via College of Osteopathic Medicine, Blacksburg, VA 24060 USA.,3Institute of Evolution, University of Haifa, Abba Khoushy Ave 199, 3498838 Haifa, Israel
| | - Lin Kang
- 2Edward Via College of Osteopathic Medicine, Blacksburg, VA 24060 USA
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10
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Jaing CJ, McLoughlin KS, Thissen JB, Zemla A, Gardner SN, Vergez LM, Bourguet F, Mabery S, Fofanov VY, Koshinsky H, Jackson PJ. Identification of Genome-Wide Mutations in Ciprofloxacin-Resistant F. tularensis LVS Using Whole Genome Tiling Arrays and Next Generation Sequencing. PLoS One 2016; 11:e0163458. [PMID: 27668749 PMCID: PMC5036845 DOI: 10.1371/journal.pone.0163458] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 09/08/2016] [Indexed: 11/19/2022] Open
Abstract
Francisella tularensis is classified as a Class A bioterrorism agent by the U.S. government due to its high virulence and the ease with which it can be spread as an aerosol. It is a facultative intracellular pathogen and the causative agent of tularemia. Ciprofloxacin (Cipro) is a broad spectrum antibiotic effective against Gram-positive and Gram-negative bacteria. Increased Cipro resistance in pathogenic microbes is of serious concern when considering options for medical treatment of bacterial infections. Identification of genes and loci that are associated with Ciprofloxacin resistance will help advance the understanding of resistance mechanisms and may, in the future, provide better treatment options for patients. It may also provide information for development of assays that can rapidly identify Cipro-resistant isolates of this pathogen. In this study, we selected a large number of F. tularensis live vaccine strain (LVS) isolates that survived in progressively higher Ciprofloxacin concentrations, screened the isolates using a whole genome F. tularensis LVS tiling microarray and Illumina sequencing, and identified both known and novel mutations associated with resistance. Genes containing mutations encode DNA gyrase subunit A, a hypothetical protein, an asparagine synthase, a sugar transamine/perosamine synthetase and others. Structural modeling performed on these proteins provides insights into the potential function of these proteins and how they might contribute to Cipro resistance mechanisms.
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Affiliation(s)
- Crystal J. Jaing
- Physical Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States of America
- * E-mail:
| | - Kevin S. McLoughlin
- Computations Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States of America
| | - James B. Thissen
- Physical Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States of America
| | - Adam Zemla
- Computations Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States of America
| | - Shea N. Gardner
- Computations Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States of America
| | - Lisa M. Vergez
- Physical Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States of America
| | - Feliza Bourguet
- Physical Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States of America
| | - Shalini Mabery
- Physical Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States of America
| | | | | | - Paul J. Jackson
- Physical Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, 94550, United States of America
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11
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Gionfriddo CM, Tate MT, Wick RR, Schultz MB, Zemla A, Thelen MP, Schofield R, Krabbenhoft DP, Holt KE, Moreau JW. Microbial mercury methylation in Antarctic sea ice. Nat Microbiol 2016; 1:16127. [PMID: 27670112 DOI: 10.1038/nmicrobiol.2016.127] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 06/29/2016] [Indexed: 11/09/2022]
Abstract
Atmospheric deposition of mercury onto sea ice and circumpolar sea water provides mercury for microbial methylation, and contributes to the bioaccumulation of the potent neurotoxin methylmercury in the marine food web. Little is known about the abiotic and biotic controls on microbial mercury methylation in polar marine systems. However, mercury methylation is known to occur alongside photochemical and microbial mercury reduction and subsequent volatilization. Here, we combine mercury speciation measurements of total and methylated mercury with metagenomic analysis of whole-community microbial DNA from Antarctic snow, brine, sea ice and sea water to elucidate potential microbially mediated mercury methylation and volatilization pathways in polar marine environments. Our results identify the marine microaerophilic bacterium Nitrospina as a potential mercury methylator within sea ice. Anaerobic bacteria known to methylate mercury were notably absent from sea-ice metagenomes. We propose that Antarctic sea ice can harbour a microbial source of methylmercury in the Southern Ocean.
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Affiliation(s)
- Caitlin M Gionfriddo
- School of Earth Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Michael T Tate
- Wisconsin Water Science Center, US Geological Survey, Middleton, Wisconsin 53562, USA
| | - Ryan R Wick
- Centre for Systems Genomics, University of Melbourne, Victoria 3010, Australia.,Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - Mark B Schultz
- Centre for Systems Genomics, University of Melbourne, Victoria 3010, Australia.,Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - Adam Zemla
- Computation Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 USA
| | - Michael P Thelen
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Robyn Schofield
- School of Earth Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
| | - David P Krabbenhoft
- Wisconsin Water Science Center, US Geological Survey, Middleton, Wisconsin 53562, USA
| | - Kathryn E Holt
- Centre for Systems Genomics, University of Melbourne, Victoria 3010, Australia.,Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Victoria 3010, Australia
| | - John W Moreau
- School of Earth Sciences, University of Melbourne, Parkville, Victoria 3010, Australia
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12
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Peña J, Chen-Harris H, Allen JE, Hwang M, Elsheikh M, Mabery S, Bielefeldt-Ohmann H, Zemla AT, Bowen RA, Borucki MK. Sendai virus intra-host population dynamics and host immunocompetence influence viral virulence during in vivo passage. Virus Evol 2016; 2:vew008. [PMID: 27774301 PMCID: PMC4989884 DOI: 10.1093/ve/vew008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
In vivo serial passage of non-pathogenic viruses has been shown to lead to increased viral virulence, and although the precise mechanism(s) are not clear, it is known that both host and viral factors are associated with increased pathogenicity. Under- or overnutrition leads to a decreased or dysregulated immune response and can increase viral mutant spectrum diversity and virulence. The objective of this study was to identify the role of viral mutant spectra dynamics and host immunocompetence in the development of pathogenicity during in vivo passage. Because the nutritional status of the host has been shown to affect the development of viral virulence, the diet of animal model reflected two extremes of diets which exist in the global population, malnutrition and obesity. Sendai virus was serially passaged in groups of mice with differing nutritional status followed by transmission of the passaged virus to a second host species, guinea pigs. Viral population dynamics were characterized using deep sequence analysis and computational modeling. Histopathology, viral titer and cytokine assays were used to characterize viral virulence. Viral virulence increased with passage and the virulent phenotype persisted upon passage to a second host species. Additionally, nutritional status of mice during passage influenced the phenotype. Sequencing revealed the presence of several non-synonymous changes in the consensus sequence associated with passage, a majority of which occurred in the hemagglutinin-neuraminidase and polymerase genes, as well as the presence of persistent high frequency variants in the viral population. In particular, an N1124D change in the consensus sequences of the polymerase gene was detected by passage 10 in a majority of the animals. In vivo comparison of an 1124D plaque isolate to a clone with 1124N genotype indicated that 1124D was associated with increased virulence.
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Affiliation(s)
- José Peña
- Lawrence Livermore National Laboratory, Livermore, CA, USA
| | | | | | - Mona Hwang
- Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Maher Elsheikh
- Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Shalini Mabery
- Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Helle Bielefeldt-Ohmann
- Australian Infectious Diseases Research Centre, University of Queensland , Brisbane, Australia; and
| | - Adam T Zemla
- Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Richard A Bowen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
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13
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Wiech EM, Cheng HP, Singh SM. Molecular modeling and computational analyses suggests that the Sinorhizobium meliloti periplasmic regulator protein ExoR adopts a superhelical fold and is controlled by a unique mechanism of proteolysis. Protein Sci 2015; 24:319-27. [PMID: 25492513 PMCID: PMC4353358 DOI: 10.1002/pro.2616] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 11/26/2014] [Accepted: 12/01/2014] [Indexed: 12/12/2022]
Abstract
The Sinorhizobium meliloti periplasmic ExoR protein and the ExoS/ChvI two-component system form a regulatory mechanism that directly controls the transformation of free-living to host-invading cells. In the absence of crystal structures, understanding the molecular mechanism of interaction between ExoR and the ExoS sensor, which is believed to drive the key regulatory step in the invasion process, remains a major challenge. In this study, we present a theoretical structural model of the active form of ExoR protein, ExoRm , generated using computational methods. Our model suggests that ExoR possesses a super-helical fold comprising 12 α-helices forming six Sel1-like repeats, including two that were unidentified in previous studies. This fold is highly conducive to mediating protein-protein interactions and this is corroborated by the identification of putative protein binding sites on the surface of the ExoRm protein. Our studies reveal two novel insights: (a) an extended conformation of the third Sel1-like repeat that might be important for ExoR regulatory function and (b) a buried proteolytic site that implies a unique proteolytic mechanism. This study provides new and interesting insights into the structure of S. meliloti ExoR, lays the groundwork for elaborating the molecular mechanism of ExoRm cleavage, ExoRm -ExoS interactions, and studies of ExoR homologs in other bacterial host interactions.
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Affiliation(s)
- Eliza M Wiech
- Department of Biology, The Graduate Center of the City University of New YorkNew York, New York, 10016
- Department of Biology, Brooklyn College, The City University of New YorkBrooklyn, New York, 11210
| | - Hai-Ping Cheng
- Department of Biology, The Graduate Center of the City University of New YorkNew York, New York, 10016
- Biological Sciences Department, Lehman College, The City University of New YorkBronx, New York, 10468
| | - Shaneen M Singh
- Department of Biology, The Graduate Center of the City University of New YorkNew York, New York, 10016
- Department of Biology, Brooklyn College, The City University of New YorkBrooklyn, New York, 11210
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14
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Al Olaby RR, Cocquerel L, Zemla A, Saas L, Dubuisson J, Vielmetter J, Marcotrigiano J, Khan AG, Catalan FV, Perryman AL, Freundlich JS, Forli S, Levy S, Balhorn R, Azzazy HM. Identification of a novel drug lead that inhibits HCV infection and cell-to-cell transmission by targeting the HCV E2 glycoprotein. PLoS One 2014; 9:e111333. [PMID: 25357246 PMCID: PMC4214736 DOI: 10.1371/journal.pone.0111333] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 09/23/2014] [Indexed: 12/17/2022] Open
Abstract
Hepatitis C Virus (HCV) infects 200 million individuals worldwide. Although several FDA approved drugs targeting the HCV serine protease and polymerase have shown promising results, there is a need for better drugs that are effective in treating a broader range of HCV genotypes and subtypes without being used in combination with interferon and/or ribavirin. Recently, two crystal structures of the core of the HCV E2 protein (E2c) have been determined, providing structural information that can now be used to target the E2 protein and develop drugs that disrupt the early stages of HCV infection by blocking E2’s interaction with different host factors. Using the E2c structure as a template, we have created a structural model of the E2 protein core (residues 421–645) that contains the three amino acid segments that are not present in either structure. Computational docking of a diverse library of 1,715 small molecules to this model led to the identification of a set of 34 ligands predicted to bind near conserved amino acid residues involved in the HCV E2: CD81 interaction. Surface plasmon resonance detection was used to screen the ligand set for binding to recombinant E2 protein, and the best binders were subsequently tested to identify compounds that inhibit the infection of Huh-7 cells by HCV. One compound, 281816, blocked E2 binding to CD81 and inhibited HCV infection in a genotype-independent manner with IC50’s ranging from 2.2 µM to 4.6 µM. 281816 blocked the early and late steps of cell-free HCV entry and also abrogated the cell-to-cell transmission of HCV. Collectively the results obtained with this new structural model of E2c suggest the development of small molecule inhibitors such as 281816 that target E2 and disrupt its interaction with CD81 may provide a new paradigm for HCV treatment.
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Affiliation(s)
- Reem R. Al Olaby
- Department of Chemistry, The American University in Cairo, New Cairo, Egypt
| | - Laurence Cocquerel
- Center for Infection and Immunity of Lille, CNRS-UMR8204/Inserm-U1019, Pasteur Institute of Lille, University of Lille North of France, Lille, France
| | - Adam Zemla
- Pathogen Bioinformatics, Lawrence Livermore National Laboratory, Livermore, CA, United States of America
| | - Laure Saas
- Center for Infection and Immunity of Lille, CNRS-UMR8204/Inserm-U1019, Pasteur Institute of Lille, University of Lille North of France, Lille, France
| | - Jean Dubuisson
- Center for Infection and Immunity of Lille, CNRS-UMR8204/Inserm-U1019, Pasteur Institute of Lille, University of Lille North of France, Lille, France
| | - Jost Vielmetter
- Protein Expression Center, Beckman Institute, California Institute of Technology, Pasadena, CA, United States of America
| | - Joseph Marcotrigiano
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, United States of America
| | - Abdul Ghafoor Khan
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, United States of America
| | - Felipe Vences Catalan
- Department of Medicine, Stanford University Medical Center, Stanford, CA, United States of America
| | - Alexander L. Perryman
- Department of Medicine, Division of Infectious Diseases, Center for Emerging & Re-emerging Pathogens, Rutgers University-New Jersey Medical School, Newark, NJ, United States of America
| | - Joel S. Freundlich
- Department of Medicine, Division of Infectious Diseases, Center for Emerging & Re-emerging Pathogens, Rutgers University-New Jersey Medical School, Newark, NJ, United States of America
- Department of Pharmacology and Physiology, Rutgers University-New Jersey Medical School, Newark, NJ, United States of America
| | - Stefano Forli
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, United States of America
| | - Shoshana Levy
- Department of Medicine, Stanford University Medical Center, Stanford, CA, United States of America
| | - Rod Balhorn
- Department of Applied Science, University of California Davis, Davis, CA, United States of America
- * E-mail:
| | - Hassan M. Azzazy
- Department of Chemistry, The American University in Cairo, New Cairo, Egypt
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15
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Spindler N, Diestel U, Stump JD, Wiegers AK, Winkler TH, Sticht H, Mach M, Muller YA. Structural basis for the recognition of human cytomegalovirus glycoprotein B by a neutralizing human antibody. PLoS Pathog 2014; 10:e1004377. [PMID: 25299639 PMCID: PMC4192593 DOI: 10.1371/journal.ppat.1004377] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 07/29/2014] [Indexed: 11/23/2022] Open
Abstract
Human cytomegalovirus (HCMV) infections are life-threating to people with a compromised or immature immune system. Upon adhesion, fusion of the virus envelope with the host cell is initiated. In this step, the viral glycoprotein gB is considered to represent the major fusogen. Here, we present for the first time structural data on the binding of an anti-herpes virus antibody and describe the atomic interactions between the antigenic domain Dom-II of HCMV gB and the Fab fragment of the human antibody SM5-1. The crystal structure shows that SM5-1 binds Dom-II almost exclusively via only two CDRs, namely light chain CDR L1 and a 22-residue-long heavy chain CDR H3. Two contiguous segments of Dom-II are targeted by SM5-1, and the combining site includes a hydrophobic pocket on the Dom-II surface that is only partially filled by CDR H3 residues. SM5-1 belongs to a series of sequence-homologous anti-HCMV gB monoclonal antibodies that were isolated from the same donor at a single time point and that represent different maturation states. Analysis of amino acid substitutions in these antibodies in combination with molecular dynamics simulations show that key contributors to the picomolar affinity of SM5-1 do not directly interact with the antigen but significantly reduce the flexibility of CDR H3 in the bound and unbound state of SM5-1 through intramolecular side chain interactions. Thus, these residues most likely alleviate unfavorable binding entropies associated with extra-long CDR H3s, and this might represent a common strategy during antibody maturation. Models of entire HCMV gB in different conformational states hint that SM5-1 neutralizes HCMV either by blocking the pre- to postfusion transition of gB or by precluding the interaction with additional effectors such as the gH/gL complex. Human cytomegalovirus (HCMV) belongs to the family of β-herpes viruses. HCMV infections are not only life threatening to people with a compromised immune system but also the most common viral cause of congenital defects in newborns. Hence, the development of HCMV vaccines was ranked top priority by the US Institute of Medicine in 1999. Virtually all infected individuals develop antibodies against the envelope protein gB, which plays a crucial role in the infection process. Here, we describe the crystal structure of a fragment of the virus neutralizing antibody SM5-1 in complex with an antigenic determinant of gB, namely Dom-II. The structure shows that antigen antibody interactions are concentrated within two CDRs of SM5-1. Computational methods and an analysis of additional antibody sequences from the same lineage reveal that additional key contributions to high affinity binding are provided by residues that stiffen the extra-long CDR H3 loop without directly contacting the antigen. We suggest that the optimization of such indirect contributions represents a common and yet undervalued principle of the antibody maturation process. Furthermore our data suggest that the neutralizing effect of SM5-1 either originates from blocking membrane fusion or from preventing interaction of gB with other envelope proteins.
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Affiliation(s)
- Nadja Spindler
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Uschi Diestel
- Lehrstuhl für Biotechnik, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Joachim D. Stump
- Institut für Biochemie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Anna-Katharina Wiegers
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Thomas H. Winkler
- Nikolaus-Fiebiger-Zentrum für Molekulare Medizin, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Heinrich Sticht
- Institut für Biochemie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Michael Mach
- Institut für Klinische und Molekulare Virologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
- * E-mail: . (MM); . (YAM)
| | - Yves A. Muller
- Lehrstuhl für Biotechnik, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
- * E-mail: . (MM); . (YAM)
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16
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Zemla A, Kostova T, Gorchakov R, Volkova E, Beasley DWC, Cardosa J, Weaver SC, Vasilakis N, Naraghi-Arani P. GeneSV - an Approach to Help Characterize Possible Variations in Genomic and Protein Sequences. Bioinform Biol Insights 2014; 8:1-16. [PMID: 24453480 PMCID: PMC3893053 DOI: 10.4137/bbi.s13076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 10/31/2013] [Accepted: 10/31/2013] [Indexed: 01/13/2023] Open
Abstract
A computational approach for identification and assessment of genomic sequence variability (GeneSV) is described. For a given nucleotide sequence, GeneSV collects information about the permissible nucleotide variability (changes that potentially preserve function) observed in corresponding regions in genomic sequences, and combines it with conservation/variability results from protein sequence and structure-based analyses of evaluated protein coding regions. GeneSV was used to predict effects (functional vs. non-functional) of 37 amino acid substitutions on the NS5 polymerase (RdRp) of dengue virus type 2 (DENV-2), 36 of which are not observed in any publicly available DENV-2 sequence. 32 novel mutants with single amino acid substitutions in the RdRp were generated using a DENV-2 reverse genetics system. In 81% (26 of 32) of predictions tested, GeneSV correctly predicted viability of introduced mutations. In 4 of 5 (80%) mutants with double amino acid substitutions proximal in structure to one another GeneSV was also correct in its predictions. Predictive capabilities of the developed system were illustrated on dengue RNA virus, but described in the manuscript a general approach to characterize real or theoretically possible variations in genomic and protein sequences can be applied to any organism.
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Affiliation(s)
- Adam Zemla
- Computing Application and Research Department, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Tanya Kostova
- Center for Applied Scientific Computing, Lawrence Livermore National Laboratory
| | - Rodion Gorchakov
- Department of Pathology and Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, USA. ; Center for Tropical Diseases, University of Texas Medical Branch, Galveston, TX 77555-0609. ; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - Evgeniya Volkova
- Department of Pathology and Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, USA. ; Center for Tropical Diseases, University of Texas Medical Branch, Galveston, TX 77555-0609. ; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - David W C Beasley
- Department of Pathology and Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, USA. ; Center for Tropical Diseases, University of Texas Medical Branch, Galveston, TX 77555-0609. ; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA. ; Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston
| | - Jane Cardosa
- Sentinext Therapeutics Sdn Bhd, Penang, Malaysia
| | - Scott C Weaver
- Department of Pathology and Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, USA. ; Center for Tropical Diseases, University of Texas Medical Branch, Galveston, TX 77555-0609. ; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - Nikos Vasilakis
- Department of Pathology and Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch, Galveston, TX, USA. ; Center for Tropical Diseases, University of Texas Medical Branch, Galveston, TX 77555-0609. ; Institute for Human Infections and Immunity, University of Texas Medical Branch, Galveston, TX, USA
| | - Pejman Naraghi-Arani
- Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, CA, USA
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17
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Chaudhury S, Abdulhameed MDM, Singh N, Tawa GJ, D’haeseleer PM, Zemla AT, Navid A, Zhou CE, Franklin MC, Cheung J, Rudolph MJ, Love J, Graf JF, Rozak DA, Dankmeyer JL, Amemiya K, Daefler S, Wallqvist A. Rapid countermeasure discovery against Francisella tularensis based on a metabolic network reconstruction. PLoS One 2013; 8:e63369. [PMID: 23704901 PMCID: PMC3660459 DOI: 10.1371/journal.pone.0063369] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Accepted: 03/30/2013] [Indexed: 11/29/2022] Open
Abstract
In the future, we may be faced with the need to provide treatment for an emergent biological threat against which existing vaccines and drugs have limited efficacy or availability. To prepare for this eventuality, our objective was to use a metabolic network-based approach to rapidly identify potential drug targets and prospectively screen and validate novel small-molecule antimicrobials. Our target organism was the fully virulent Francisella tularensis subspecies tularensis Schu S4 strain, a highly infectious intracellular pathogen that is the causative agent of tularemia and is classified as a category A biological agent by the Centers for Disease Control and Prevention. We proceeded with a staggered computational and experimental workflow that used a strain-specific metabolic network model, homology modeling and X-ray crystallography of protein targets, and ligand- and structure-based drug design. Selected compounds were subsequently filtered based on physiological-based pharmacokinetic modeling, and we selected a final set of 40 compounds for experimental validation of antimicrobial activity. We began screening these compounds in whole bacterial cell-based assays in biosafety level 3 facilities in the 20th week of the study and completed the screens within 12 weeks. Six compounds showed significant growth inhibition of F. tularensis, and we determined their respective minimum inhibitory concentrations and mammalian cell cytotoxicities. The most promising compound had a low molecular weight, was non-toxic, and abolished bacterial growth at 13 µM, with putative activity against pantetheine-phosphate adenylyltransferase, an enzyme involved in the biosynthesis of coenzyme A, encoded by gene coaD. The novel antimicrobial compounds identified in this study serve as starting points for lead optimization, animal testing, and drug development against tularemia. Our integrated in silico/in vitro approach had an overall 15% success rate in terms of active versus tested compounds over an elapsed time period of 32 weeks, from pathogen strain identification to selection and validation of novel antimicrobial compounds.
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Affiliation(s)
- Sidhartha Chaudhury
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
| | - Mohamed Diwan M. Abdulhameed
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
| | - Narender Singh
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
| | - Gregory J. Tawa
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
| | - Patrik M. D’haeseleer
- Pathogen Bioinformatics, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Adam T. Zemla
- Pathogen Bioinformatics, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Ali Navid
- Pathogen Bioinformatics, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Carol E. Zhou
- Pathogen Bioinformatics, Lawrence Livermore National Laboratory, Livermore, California, United States of America
| | - Matthew C. Franklin
- New York Structural Biology Center, New York, New York, United States of America
| | - Jonah Cheung
- New York Structural Biology Center, New York, New York, United States of America
| | - Michael J. Rudolph
- New York Structural Biology Center, New York, New York, United States of America
| | - James Love
- New York Structural Biology Center, New York, New York, United States of America
| | - John F. Graf
- Computational Biology and Biostatistics Laboratory, Diagnostics and Biomedical Technologies, GE Global Research, General Electric Company, Niskayuna, New York, United States of America
| | - David A. Rozak
- Bacteriology Division, U.S. Army Medical Research Institute for Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Jennifer L. Dankmeyer
- Bacteriology Division, U.S. Army Medical Research Institute for Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Kei Amemiya
- Bacteriology Division, U.S. Army Medical Research Institute for Infectious Diseases, Fort Detrick, Maryland, United States of America
| | - Simon Daefler
- Mount Sinai School of Medicine, New York, New York, United States of America
| | - Anders Wallqvist
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Materiel Command, Fort Detrick, Maryland, United States of America
- * E-mail:
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18
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Kirshner DA, Nilmeier JP, Lightstone FC. Catalytic site identification--a web server to identify catalytic site structural matches throughout PDB. Nucleic Acids Res 2013; 41:W256-65. [PMID: 23680785 PMCID: PMC3692059 DOI: 10.1093/nar/gkt403] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The catalytic site identification web server provides the innovative capability to find structural matches to a user-specified catalytic site among all Protein Data Bank proteins rapidly (in less than a minute). The server also can examine a user-specified protein structure or model to identify structural matches to a library of catalytic sites. Finally, the server provides a database of pre-calculated matches between all Protein Data Bank proteins and the library of catalytic sites. The database has been used to derive a set of hypothesized novel enzymatic function annotations. In all cases, matches and putative binding sites (protein structure and surfaces) can be visualized interactively online. The website can be accessed at http://catsid.llnl.gov.
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Affiliation(s)
| | | | - Felice C. Lightstone
- *To whom correspondence should be addressed. Tel: +1 925 423 8657; Fax: +1 925 423 0785;
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19
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Borucki MK, Allen JE, Chen-Harris H, Zemla A, Vanier G, Mabery S, Torres C, Hullinger P, Slezak T. The role of viral population diversity in adaptation of bovine coronavirus to new host environments. PLoS One 2013; 8:e52752. [PMID: 23308119 PMCID: PMC3538757 DOI: 10.1371/journal.pone.0052752] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 11/21/2012] [Indexed: 12/04/2022] Open
Abstract
The high mutation rate of RNA viruses enables a diverse genetic population of viral genotypes to exist within a single infected host. In-host genetic diversity could better position the virus population to respond and adapt to a diverse array of selective pressures such as host-switching events. Multiple new coronaviruses, including SARS, have been identified in human samples just within the last ten years, demonstrating the potential of coronaviruses as emergent human pathogens. Deep sequencing was used to characterize genomic changes in coronavirus quasispecies during simulated host-switching. Three bovine nasal samples infected with bovine coronavirus were used to infect human and bovine macrophage and lung cell lines. The virus reproduced relatively well in macrophages, but the lung cell lines were not infected efficiently enough to allow passage of non lab-adapted samples. Approximately 12 kb of the genome was amplified before and after passage and sequenced at average coverages of nearly 950×(454 sequencing) and 38,000×(Illumina). The consensus sequence of many of the passaged samples had a 12 nucleotide insert in the consensus sequence of the spike gene, and multiple point mutations were associated with the presence of the insert. Deep sequencing revealed that the insert was present but very rare in the unpassaged samples and could quickly shift to dominate the population when placed in a different environment. The insert coded for three arginine residues, occurred in a region associated with fusion entry into host cells, and may allow infection of new cell types via heparin sulfate binding. Analysis of the deep sequencing data indicated that two distinct genotypes circulated at different frequency levels in each sample, and support the hypothesis that the mutations present in passaged strains were “selected” from a pre-existing pool rather than through de novo mutation and subsequent population fixation.
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20
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Dougherty MJ, D'haeseleer P, Hazen TC, Simmons BA, Adams PD, Hadi MZ. Glycoside hydrolases from a targeted compost metagenome, activity-screening and functional characterization. BMC Biotechnol 2012; 12:38. [PMID: 22759983 PMCID: PMC3477009 DOI: 10.1186/1472-6750-12-38] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 07/03/2012] [Indexed: 11/29/2022] Open
Abstract
Background Metagenomics approaches provide access to environmental genetic diversity for biotechnology applications, enabling the discovery of new enzymes and pathways for numerous catalytic processes. Discovery of new glycoside hydrolases with improved biocatalytic properties for the efficient conversion of lignocellulosic material to biofuels is a critical challenge in the development of economically viable routes from biomass to fuels and chemicals. Results Twenty-two putative ORFs (open reading frames) were identified from a switchgrass-adapted compost community based on sequence homology to related gene families. These ORFs were expressed in E. coli and assayed for predicted activities. Seven of the ORFs were demonstrated to encode active enzymes, encompassing five classes of hemicellulases. Four enzymes were over expressed in vivo, purified to homogeneity and subjected to detailed biochemical characterization. Their pH optima ranged between 5.5 - 7.5 and they exhibit moderate thermostability up to ~60-70°C. Conclusions Seven active enzymes were identified from this set of ORFs comprising five different hemicellulose activities. These enzymes have been shown to have useful properties, such as moderate thermal stability and broad pH optima, and may serve as the starting points for future protein engineering towards the goal of developing efficient enzyme cocktails for biomass degradation under diverse process conditions.
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21
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Carpenter TS, Lau EY, Lightstone FC. A role for loop F in modulating GABA binding affinity in the GABA(A) receptor. J Mol Biol 2012; 422:310-23. [PMID: 22659322 DOI: 10.1016/j.jmb.2012.05.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 05/08/2012] [Accepted: 05/17/2012] [Indexed: 10/28/2022]
Abstract
The brain's major inhibitory neuroreceptor is the ligand-gated ion channel γ-aminobutyric acid (GABA) type A receptor (GABAR). GABARs exist in a variety of different subunit combinations that act to modulate the physiological behavior of GABAR by altering its pharmacological profile, as well as its affinity for GABA. While the α(1)β(2)γ(2) subtype is one of the most prevalent GABARs, the less populous α(6)β(3)δ subtype has much higher GABA sensitivity. Previous studies identified residues crucial for GABA binding; however, the specific molecular differences responsible for this diverse sensitivity are not known. Furthermore, the role of loop F is a divisive subject, with conflicting evidence for ligand binding function. Using homology modeling, ligand docking, and molecular dynamics simulations, we investigated the GABA binding sites of the two receptor subtypes. Simulations identified seven residues that consistently interacted with GABA in both subtypes: αF65, αR132, βL99, βE155, βR/K196, βY205, and βR207. Residue substitution at position β196 (arginine in α(6)β(3)δ, lysine in α(1)β(2)γ(2)) resulted in a shift in GABA binding. However, the major difference between the two binding sites was the magnitude of loop F involvement, with a greater contribution in the α(6)β(3)δ receptor. Free energy calculations confirm that the α(6)β(3)δ binding pocket has an increased affinity for GABA. Thus, the possible role for loop F across the GABAR family is to modulate GABA affinity.
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Affiliation(s)
- Timothy S Carpenter
- Biosciences and Biotechnology Division, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
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22
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Promiscuity, stability and cold adaptation of a newly isolated acylaminoacyl peptidase. Biochimie 2011; 93:1543-54. [DOI: 10.1016/j.biochi.2011.05.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Accepted: 05/13/2011] [Indexed: 11/21/2022]
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23
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Uchtenhagen H, Friemann R, Raszewski G, Spetz AL, Nilsson L, Achour A. Crystal structure of the HIV-2 neutralizing Fab fragment 7C8 with high specificity to the V3 region of gp125. PLoS One 2011; 6:e18767. [PMID: 21541316 PMCID: PMC3082531 DOI: 10.1371/journal.pone.0018767] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 03/18/2011] [Indexed: 02/05/2023] Open
Abstract
7C8 is a mouse monoclonal antibody specific for the third hypervariable region (V3) of the human immunodeficiency virus type 2 (HIV-2)-associated protein gp125. The three-dimensional crystal structure of the Fab fragment of 7C8, determined to 2.7 Å resolution, reveals a deep and narrow antigen-binding cleft with architecture appropriate for an elongated epitope. The highly hydrophobic cleft is bordered on one side by the negatively charged second complementarity determining region (CDR2) and the unusually long positively charged CDR3 of the heavy chain and, on the other side, by the CDR1 of the light chain. Analysis of 7C8 in complex with molecular models of monomeric and trimeric gp125 highlights the importance of a conserved stretch of residues FHSQ that is localized centrally on the V3 region of gp125. Furthermore, modeling also indicates that the Fab fragment neutralizes the virus by sterically impairing subsequent engagement of the gp125 trimer with the co-receptor on the target cell.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/chemistry
- Antibodies, Monoclonal/immunology
- Antibodies, Neutralizing/chemistry
- Antibodies, Neutralizing/immunology
- Antibody Specificity/immunology
- Binding Sites
- Complementarity Determining Regions/chemistry
- Complementarity Determining Regions/immunology
- Computer Simulation
- Crystallography, X-Ray
- Epitopes/chemistry
- Epitopes/immunology
- HIV-2/immunology
- Humans
- Hydrophobic and Hydrophilic Interactions
- Immunoglobulin Fab Fragments/chemistry
- Immunoglobulin Fab Fragments/immunology
- Mice
- Models, Molecular
- Molecular Sequence Data
- Protein Multimerization
- Protein Structure, Secondary
- Protein Structure, Tertiary
- env Gene Products, Human Immunodeficiency Virus/chemistry
- env Gene Products, Human Immunodeficiency Virus/immunology
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Affiliation(s)
- Hannes Uchtenhagen
- F59 Department of Medicine, Center for Infectious Medicine (CIM), Karolinska University Hospital Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Rosmarie Friemann
- Department of Cell and Molecular Biology, Molecular Biophysics, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Grzegorz Raszewski
- Department of Biosciences and Nutrition, Center for Biosciences, Karolinska Institutet, Huddinge, Sweden
| | - Anna-Lena Spetz
- F59 Department of Medicine, Center for Infectious Medicine (CIM), Karolinska University Hospital Huddinge, Karolinska Institutet, Stockholm, Sweden
| | - Lennart Nilsson
- Department of Biosciences and Nutrition, Center for Biosciences, Karolinska Institutet, Huddinge, Sweden
| | - Adnane Achour
- F59 Department of Medicine, Center for Infectious Medicine (CIM), Karolinska University Hospital Huddinge, Karolinska Institutet, Stockholm, Sweden
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Janganan TK, Zhang L, Bavro VN, Matak-Vinkovic D, Barrera NP, Burton MF, Steel PG, Robinson CV, Borges-Walmsley MI, Walmsley AR. Opening of the outer membrane protein channel in tripartite efflux pumps is induced by interaction with the membrane fusion partner. J Biol Chem 2010; 286:5484-93. [PMID: 21115481 PMCID: PMC3037662 DOI: 10.1074/jbc.m110.187658] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The multiple transferable resistance (MTR) pump, from Neisseria gonorrhoeae, is typical of the specialized machinery used to translocate drugs across the inner and outer membranes of Gram-negative bacteria. It consists of a tripartite complex composed of an inner-membrane transporter, MtrD, a periplasmic membrane fusion protein, MtrC, and an outer-membrane channel, MtrE. We have expressed the components of the pump in Escherichia coli and used the antibiotic vancomycin, which is too large to cross the outer-membrane by passive diffusion, to test for opening of the MtrE channel. Cells expressing MtrCDE are not susceptible to vancomycin, indicating that the channel is closed; but become susceptible to vancomycin in the presence of transported substrates, consistent with drug-induced opening of the MtrE channel. A mutational analysis identified residues Asn-198, Glu-434, and Gln-441, lining an intraprotomer groove on the surface of MtrE, to be important for pump function; mutation of these residues yielded cells that were sensitive to vancomycin. Pull-down assays and micro-calorimetry measurements indicated that this functional impairment is not due to the inability of MtrC to interact with the MtrE mutants; nor was it due to the MtrE mutants adopting an open conformation, because cells expressing these MtrE mutants alone are relatively insensitive to vancomycin. However, cells expressing the MtrE mutants with MtrC are sensitive to vancomycin, indicating that residues lining the intra-protomer groove control opening of the MtrE channel in response to binding of MtrC.
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Affiliation(s)
- Thamarai K Janganan
- School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, United Kingdom
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Integrating ion mobility mass spectrometry with molecular modelling to determine the architecture of multiprotein complexes. PLoS One 2010; 5:e12080. [PMID: 20711472 PMCID: PMC2919415 DOI: 10.1371/journal.pone.0012080] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 07/09/2010] [Indexed: 11/21/2022] Open
Abstract
Current challenges in the field of structural genomics point to the need for new tools and technologies for obtaining structures of macromolecular protein complexes. Here, we present an integrative computational method that uses molecular modelling, ion mobility-mass spectrometry (IM-MS) and incomplete atomic structures, usually from X-ray crystallography, to generate models of the subunit architecture of protein complexes. We begin by analyzing protein complexes using IM-MS, and by taking measurements of both intact complexes and sub-complexes that are generated in solution. We then examine available high resolution structural data and use a suite of computational methods to account for missing residues at the subunit and/or domain level. High-order complexes and sub-complexes are then constructed that conform to distance and connectivity constraints imposed by IM-MS data. We illustrate our method by applying it to multimeric protein complexes within the Escherichia coli replisome: the sliding clamp, (β2), the γ complex (γ3δδ′), the DnaB helicase (DnaB6) and the Single-Stranded Binding Protein (SSB4).
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Paquette SM, Jensen K, Bak S. A web-based resource for the Arabidopsis P450, cytochromes b5, NADPH-cytochrome P450 reductases, and family 1 glycosyltransferases (http://www.P450.kvl.dk). PHYTOCHEMISTRY 2009; 70:1940-7. [PMID: 19818975 DOI: 10.1016/j.phytochem.2009.08.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Accepted: 08/12/2009] [Indexed: 05/18/2023]
Abstract
Gene and genome duplication is a key driving force in evolution of plant diversity. This has resulted in a number of large multi-gene families. Two of the largest multi-gene families in plants are the cytochromes P450 (P450s) and family 1 glycosyltransferases (UGTs). These two families are key players in evolution, especially of plant secondary metabolism, and in adaption to abiotic and biotic stress. In the model plant Arabidopsis thaliana there are 246 and 112 cytochromes P450 and UGTs, respectively. The Arabidopsis P450, cytochromes b(5), NADPH-cytochrome P450 reductases, and family 1 glycosyltransferases website (http://www.P450.kvl.dk) is a sequence repository of manually curated sequences, multiple sequence alignments, phylogenetic trees, sequence motif logos, 3D structures, intron-exon maps, and customized BLAST datasets.
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Affiliation(s)
- Suzanne M Paquette
- Department of Biological Structure, University of Washington, HSB G-520/Box 357420, Seattle, WA 98195-7420, USA
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27
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Amino acid and structural variability of Yersinia pestis LcrV protein. INFECTION GENETICS AND EVOLUTION 2009; 10:137-45. [PMID: 19835996 DOI: 10.1016/j.meegid.2009.10.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 10/05/2009] [Accepted: 10/07/2009] [Indexed: 01/09/2023]
Abstract
The LcrV protein is a multifunctional virulence factor and protective antigen of the plague bacterium and is generally conserved between the epidemic strains of Yersinia pestis. We investigated the diversity in the LcrV sequences among non-epidemic Y. pestis strains which have a limited virulence in selected animal models and for humans. Sequencing of lcrV genes from 19 Y. pestis strains belonging to different phylogenetic groups (subspecies) showed that the LcrV proteins possess four major variable hotspots at positions 18, 72, 273, and 324-326. These major variations, together with other minor substitutions in amino acid sequences, allowed us to classify the LcrV alleles into five sequence types (A-E). We observed that the strains of different Y. pestis "subspecies" can have the same type of LcrV, including that conserved in epidemic strains, and different types of LcrV can exist within the same natural plague focus. Therefore, the phenomenon of "selective virulence" characteristic of the strains of the microtus biovar is unlikely to be the result of polymorphism of the V antigen. The LcrV polymorphisms were structurally analyzed by comparing the modeled structures of LcrV from all available strains. All changes except one occurred either in flexible regions or on the surface of the protein, but local chemical properties (i.e. those of a hydrophobic, hydrophilic, amphipathic, or charged nature) were conserved across all of the strains. Polymorphisms in flexible and surface regions are likely subject to less selective pressure, and have a limited impact on the structure. In contrast, the substitution of tryptophan at position 113 with either glutamic acid or glycine likely has a serious influence on the regional structure of the protein, and these mutations might have an effect on the function of LcrV. The polymorphisms at positions 18, 72 and 273 were accountable for differences in the oligomerization of LcrV.
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28
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Chakicherla A, Ecale Zhou CL, Dang ML, Rodriguez V, Hansen JN, Zemla A. SpaK/SpaR two-component system characterized by a structure-driven domain-fusion method and in vitro phosphorylation studies. PLoS Comput Biol 2009; 5:e1000401. [PMID: 19503843 PMCID: PMC2686270 DOI: 10.1371/journal.pcbi.1000401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Accepted: 05/04/2009] [Indexed: 12/23/2022] Open
Abstract
Here we introduce a quantitative structure-driven computational domain-fusion
method, which we used to predict the structures of proteins believed to be
involved in regulation of the subtilin pathway in Bacillus
subtilis, and used to predict a protein-protein complex formed by
interaction between the proteins. Homology modeling of SpaK and SpaR yielded
preliminary structural models based on a best template for SpaK comprising a
dimer of a histidine kinase, and for SpaR a response regulator protein. Our LGA
code was used to identify multi-domain proteins with structure homology to both
modeled structures, yielding a set of domain-fusion templates then used to model
a hypothetical SpaK/SpaR complex. The models were used to identify putative
functional residues and residues at the protein-protein interface, and
bioinformatics was used to compare functionally and structurally relevant
residues in corresponding positions among proteins with structural homology to
the templates. Models of the complex were evaluated in light of known properties
of the functional residues within two-component systems involving His-Asp
phosphorelays. Based on this analysis, a phosphotransferase complexed with a
beryllofluoride was selected as the optimal template for modeling a SpaK/SpaR
complex conformation. In vitro phosphorylation studies
performed using wild type and site-directed SpaK mutant proteins validated the
predictions derived from application of the structure-driven domain-fusion
method: SpaK was phosphorylated in the presence of 32P-ATP and the
phosphate moiety was subsequently transferred to SpaR, supporting the hypothesis
that SpaK and SpaR function as sensor and response regulator, respectively, in a
two-component signal transduction system, and furthermore suggesting that the
structure-driven domain-fusion approach correctly predicted a physical
interaction between SpaK and SpaR. Our domain-fusion algorithm leverages
quantitative structure information and provides a tool for generation of
hypotheses regarding protein function, which can then be tested using empirical
methods. Because proteins so frequently function in coordination with other proteins,
identification and characterization of the interactions among proteins are
essential for understanding how proteins work. Computational methods for
identification of protein-protein interactions have been limited by the degree
to which proteins are similar in sequence. However, methods that leverage
structure information can overcome this limitation of sequence-based methods;
the three-dimensional information provided by structure enables identification
of related proteins even when their sequences are dissimilar. In this work we
present a quantitative method for identification of protein interacting
partners, and we demonstrate its use in modeling the structure of a hypothetical
complex between two proteins that function in a bacterial signaling system. This
quantitative approach comprises a tool for generation of hypotheses regarding
protein function, which can then be tested using empirical methods, and provides
a basis for high-throughput prediction of protein-protein interactions, which
could be applied on a whole-genome scale.
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Affiliation(s)
- Anu Chakicherla
- Computing Applications and Research Department, Lawrence Livermore
National Laboratory, Livermore, California, United States of America
| | - Carol L. Ecale Zhou
- Computing Applications and Research Department, Lawrence Livermore
National Laboratory, Livermore, California, United States of America
- * E-mail:
| | | | - Virginia Rodriguez
- Genome Technology Branch, National Human Genome Research Institute,
National Institutes of Health, Bethesda, Maryland, United States of
America
| | - J. Norman Hansen
- Department of Chemistry and Biochemistry, University of Maryland, College
Park, Maryland, United States of America
| | - Adam Zemla
- Computing Applications and Research Department, Lawrence Livermore
National Laboratory, Livermore, California, United States of America
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29
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Community genomic and proteomic analyses of chemoautotrophic iron-oxidizing "Leptospirillum rubarum" (Group II) and "Leptospirillum ferrodiazotrophum" (Group III) bacteria in acid mine drainage biofilms. Appl Environ Microbiol 2009; 75:4599-615. [PMID: 19429552 DOI: 10.1128/aem.02943-08] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We analyzed near-complete population (composite) genomic sequences for coexisting acidophilic iron-oxidizing Leptospirillum group II and III bacteria (phylum Nitrospirae) and an extrachromosomal plasmid from a Richmond Mine, Iron Mountain, CA, acid mine drainage biofilm. Community proteomic analysis of the genomically characterized sample and two other biofilms identified 64.6% and 44.9% of the predicted proteins of Leptospirillum groups II and III, respectively, and 20% of the predicted plasmid proteins. The bacteria share 92% 16S rRNA gene sequence identity and >60% of their genes, including integrated plasmid-like regions. The extrachromosomal plasmid carries conjugation genes with detectable sequence similarity to genes in the integrated conjugative plasmid, but only those on the extrachromosomal element were identified by proteomics. Both bacterial groups have genes for community-essential functions, including carbon fixation and biosynthesis of vitamins, fatty acids, and biopolymers (including cellulose); proteomic analyses reveal these activities. Both Leptospirillum types have multiple pathways for osmotic protection. Although both are motile, signal transduction and methyl-accepting chemotaxis proteins are more abundant in Leptospirillum group III, consistent with its distribution in gradients within biofilms. Interestingly, Leptospirillum group II uses a methyl-dependent and Leptospirillum group III a methyl-independent response pathway. Although only Leptospirillum group III can fix nitrogen, these proteins were not identified by proteomics. The abundances of core proteins are similar in all communities, but the abundance levels of unique and shared proteins of unknown function vary. Some proteins unique to one organism were highly expressed and may be key to the functional and ecological differentiation of Leptospirillum groups II and III.
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30
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Xu J, Zhou X, Ge H, Xu H, He J, Hao Z, Jiang X. Endothelial cells anchoring by functionalized yeast polypeptide. J Biomed Mater Res A 2009; 87:819-24. [PMID: 18228253 DOI: 10.1002/jbm.a.31826] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The immobilization and proliferation of endothelial cells on the surface of engineered tissues requires the development of new biomaterials that can mimic the anchoring and signaling functions of basement membrane. Here, we report a modified polypeptide from yeast translation termination factor protein that can self-assembly into nanofibers and improve endothelial cell adhesion by its functional motif. The polypeptide (YNNNLQGYQAGFQ) is a beta sheet forming sequence, but it is noninfectious in mammalian tissue because of the absence of substrate protein for propagation. The prion-derived polypeptide was extended at the amino terminal with a short sequence motif from laminin I (YIGSR), and the resultant polypeptide retained self-assembly propensity. Both circular dichroism (CD) measurement and molecular dynamics simulation suggest the assembled nanofibers consists mainly beta sheet structure. The 3D porous hydrogel formed by the modified polypeptide was evaluated as a coating material for vascular tissue engineering. In static culture system, the polypeptide scaffold improved the morphology of endothelial cells and confluency of cell monolayer. In the dynamic bioreactor (pulsatile vascular deformation at 5%), the polypeptide scaffold anchored 3-fold higher number of endothelial cells, which exhibited normal nitric oxide release function. These results suggest that prion-derived polypeptides have high self-assembling and motif integrating capacities. These unique properties can be utilized to build up biomaterials with robust porous structure as well as functionalized motifs for cell enrichment.
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Affiliation(s)
- Jie Xu
- Department of General Surgery, Shanghai No.10 People's Hospital, Tongji University, Shanghai, China
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31
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Singer SW, Chan CS, Zemla A, VerBerkmoes NC, Hwang M, Hettich RL, Banfield JF, Thelen MP. Characterization of cytochrome 579, an unusual cytochrome isolated from an iron-oxidizing microbial community. Appl Environ Microbiol 2008; 74:4454-62. [PMID: 18469132 PMCID: PMC2493166 DOI: 10.1128/aem.02799-07] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Accepted: 03/26/2008] [Indexed: 11/20/2022] Open
Abstract
A novel, soluble cytochrome with an unusual visible spectral signature at 579 nm (Cyt(579)) has been characterized after isolation from several different microbial biofilms collected in an extremely acidic ecosystem. Previous proteogenomic studies of an Fe(II)-oxidizing community indicated that this abundant red cytochrome could be extracted from the biofilms with dilute sulfuric acid. Here, we found that the Fe(II)-dependent reduction of Cyt(579) was thermodynamically favorable at a pH of >3, raising the possibility that Cyt(579) acts as an accessory protein for electron transfer. The results of transmission electron microscopy of immunogold-labeled biofilm indicated that Cyt(579) is localized near the bacterial cell surface, consistent with periplasmic localization. The results of further protein analysis of Cyt(579), using preparative chromatofocusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, revealed three forms of the protein that correspond to different N-terminal truncations of the amino acid sequence. The results of intact-protein analysis corroborated the posttranslational modifications of these forms and identified a genomically uncharacterized Cyt(579) variant. Homology modeling was used to predict the overall cytochrome structure and heme binding site; the positions of nine amino acid substitutions found in three Cyt(579) variants all map to the surface of the protein and away from the heme group. Based on this detailed characterization of Cyt(579), we propose that Cyt(579) acts as an electron transfer protein, shuttling electrons derived from Fe(II) oxidation to support critical metabolic functions in the acidophilic microbial community.
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Affiliation(s)
- Steven W Singer
- Chemistry Directorate, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
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32
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Zemla AT, Zhou CLE. Structural Re-Alignment in an Immunogenic Surface Region of Ricin a Chain. Bioinform Biol Insights 2008; 2:5-13. [PMID: 19812763 PMCID: PMC2735970 DOI: 10.4137/bbi.s437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
We compared structure alignments generated by several protein structure comparison programs to determine whether existing methods would satisfactorily align residues at a highly conserved position within an immunogenic loop in ribosome inactivating proteins (RIPs). Using default settings, structure alignments generated by several programs (CE, DaliLite, FATCAT, LGA, MAMMOTH, MATRAS, SHEBA, SSM) failed to align the respective conserved residues, although LGA reported correct residue-residue (R-R) correspondences when the beta-carbon (Cb) position was used as the point of reference in the alignment calculations. Further tests using variable points of reference indicated that points distal from the beta carbon along a vector connecting the alpha and beta carbons yielded rigid structural alignments in which residues known to be highly conserved in RIPs were reported as corresponding residues in structural comparisons between ricin A chain, abrin-A, and other RIPs. Results suggest that approaches to structure alignment employing alternate point representations corresponding to side chain position may yield structure alignments that are more consistent with observed conservation of functional surface residues than do standard alignment programs, which apply uniform criteria for alignment (i.e. alpha carbon (Ca) as point of reference) along the entirety of the peptide chain. We present the results of tests that suggest the utility of allowing user-specified points of reference in generating alternate structural alignments, and we present a web server for automatically generating such alignments: http://as2ts.llnl.gov/AS2TS/LGA/lga_pdblist_plots.html.
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Affiliation(s)
- Adam T. Zemla
- Computational Biology for Countermeasures Group, Lawrence Livermore National Laboratory, Livermore, CA, U.S.A. 94550
| | - Carol L. Ecale Zhou
- Computational Biology for Countermeasures Group, Lawrence Livermore National Laboratory, Livermore, CA, U.S.A. 94550
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33
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Zemla A, Geisbrecht B, Smith J, Lam M, Kirkpatrick B, Wagner M, Slezak T, Zhou CE. STRALCP--structure alignment-based clustering of proteins. Nucleic Acids Res 2007; 35:e150. [PMID: 18039711 PMCID: PMC2190701 DOI: 10.1093/nar/gkm1049] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Protein structural annotation and classification is an important and challenging problem in bioinformatics. Research towards analysis of sequence–structure correspondences is critical for better understanding of a protein's structure, function, and its interaction with other molecules. Clustering of protein domains based on their structural similarities provides valuable information for protein classification schemes. In this article, we attempt to determine whether structure information alone is sufficient to adequately classify protein structures. We present an algorithm that identifies regions of structural similarity within a given set of protein structures, and uses those regions for clustering. In our approach, called STRALCP (STRucture ALignment-based Clustering of Proteins), we generate detailed information about global and local similarities between pairs of protein structures, identify fragments (spans) that are structurally conserved among proteins, and use these spans to group the structures accordingly. We also provide a web server at http://as2ts.llnl.gov/AS2TS/STRALCP/ for selecting protein structures, calculating structurally conserved regions and performing automated clustering.
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Affiliation(s)
- Adam Zemla
- Computing Applications and Research, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
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34
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Raimondo D, Giorgetti A, Giorgetti A, Bosi S, Tramontano A. Automatic procedure for using models of proteins in molecular replacement. Proteins 2006; 66:689-96. [PMID: 17109404 DOI: 10.1002/prot.21225] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In a crystallography experiment, a crystal is irradiated with X-rays whose diffracted waves are collected and measured. The reconstruction of the structure of the molecule in the crystal requires knowledge of the phase of the diffracted waves, information that is lost in the passage from the three-dimensional structure of the molecule to its diffraction pattern. It can be recovered using experimental methods such as heavy-atom isomorphous replacement and anomalous scattering or by molecular replacement, which relies on the availability of an atomic model of the target structure. This can be the structure of the target protein itself, if a previous structure determination is available, or a computational model or, in some cases, the structure of a homologous protein. It is not straightforward to predict beforehand whether or not a computational model will work in a molecular replacement experiment, although some rules of thumb exist. The consensus is that even minor differences in the quality of the model, which are rather difficult to estimate a priori, can have a significant effect on the outcome of the procedure. We describe here a method for quickly assessing whether a protein structure can be solved by molecular replacement. The procedure consists in submitting the sequence of the target protein to a selected list of freely available structure prediction servers, cluster the resulting models, select the representative structures of each cluster and use them as search models in an automatic phasing procedure. We tested the procedure using the structure factors of newly released proteins of known structure downloaded from the Protein Data Bank as soon as they were made available. Using our automatic procedure we were able to obtain an interpretable electron density map in more than half the cases.
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Affiliation(s)
- Domenico Raimondo
- Department of Biochemical Sciences, University of Rome La Sapienza, P.le Aldo Moro, 5-00185 Rome, Italy
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35
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Beuning PJ, Sawicka D, Barsky D, Walker GC. Two processivity clamp interactions differentially alter the dual activities of UmuC. Mol Microbiol 2006; 59:460-74. [PMID: 16390442 DOI: 10.1111/j.1365-2958.2005.04959.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
DNA polymerases of the Y family promote survival by their ability to synthesize past lesions in the DNA template. One Escherichia coli member of this family, DNA pol V (UmuC), which is primarily responsible for UV-induced and chemically induced mutagenesis, possesses a canonical beta processivity clamp-binding motif. A detailed analysis of this motif in DNA pol V (UmuC) showed that mutation of only two residues in UmuC is sufficient to result in a loss of UV-induced mutagenesis. Increased levels of wild-type beta can partially rescue this loss of mutagenesis. Alterations in this motif of UmuC also cause loss of the cold-sensitive and beta-dependent synthetic lethal phenotypes associated with increased levels of UmuD and UmuC that are thought to represent an exaggeration of a DNA damage checkpoint. By designing compensatory mutations in the cleft between domains II and III in beta, we restored UV-induced mutagenesis by a UmuC beta-binding motif variant. A recent co-crystal structure of the 'little finger' domain of E. coli pol IV (DinB) with beta suggests that, in addition to the canonical beta-binding motif, a second site of pol IV ((303)VWP(305)) interacts with beta at the outer rim of the dimer interface. Mutational analysis of the corresponding motif in UmuC showed that it is dispensable for induced mutagenesis, but that alterations in this motif result in loss of the cold-sensitive phenotype. These two beta interaction sites of UmuC affect the dual functions of UmuC differentially and indicate subtle and sophisticated polymerase management by the beta clamp.
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Affiliation(s)
- Penny J Beuning
- Department of Biology, Massachusetts Institute of Technology, Cambridge, 02139, USA
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36
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Beuning PJ, Simon SM, Zemla A, Barsky D, Walker GC. A non-cleavable UmuD variant that acts as a UmuD' mimic. J Biol Chem 2006; 281:9633-40. [PMID: 16464848 DOI: 10.1074/jbc.m511101200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
UmuD(2) cleaves and removes its N-terminal 24 amino acids to form UmuD'(2), which activates UmuC for its role in UV-induced mutagenesis in Escherichia coli. Cells with a non-cleavable UmuD exhibit essentially no UV-induced mutagenesis and are hypersensitive to killing by UV light. UmuD binds to the beta processivity clamp ("beta") of the replicative DNA polymerase, pol III. A possible beta-binding motif has been predicted in the same region of UmuD shown to be important for its interaction with beta. We performed alanine-scanning mutagenesis of this motif ((14)TFPLF(18)) in UmuD and found that it has a moderate influence on UV-induced mutagenesis but is required for the cold-sensitive phenotype caused by elevated levels of wild-type UmuD and UmuC. Surprisingly, the wild-type and the beta-binding motif variant bind to beta with similar K(d) values as determined by changes in tryptophan fluorescence. However, these data also imply that the single tryptophan in beta is in strikingly different environments in the presence of the wild-type versus the variant UmuD proteins, suggesting a distinct change in some aspect of the interaction with little change in its strength. Despite the fact that this novel UmuD variant is non-cleavable, we find that cells harboring it display phenotypes more consistent with the cleaved form UmuD', such as resistance to killing by UV light and failure to exhibit the cold-sensitive phenotype. Cross-linking and chemical modification experiments indicate that the N-terminal arms of the UmuD variant are less likely to be bound to the globular domain than those of the wild-type, which may be the mechanism by which this UmuD variant acts as a UmuD' mimic.
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Affiliation(s)
- Penny J Beuning
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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