1
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Garg P, Hsueh SCC, Plotkin SS. Testing the feasibility of targeting a conserved region on the S2 domain of the SARS-CoV-2 spike protein. Biophys J 2024; 123:992-1005. [PMID: 38491772 PMCID: PMC11052916 DOI: 10.1016/j.bpj.2024.03.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 10/02/2023] [Accepted: 03/11/2024] [Indexed: 03/18/2024] Open
Abstract
The efficacy of vaccines against the SARS-CoV-2 virus significantly declines with the emergence of mutant strains, prompting investigation into the feasibility of targeting highly conserved but often cryptic regions on the S2 domain of spike protein. Using tools from molecular dynamics, we find that exposure of a conserved S2 epitope located in the central helices below the receptor binding domains would require large-scale motion beyond receptor binding domain up-down motion, but, along the reaction coordinates we explored, it is unlikely to be exposed by such large-scale dynamic fluctuations of the S1 domain without any external facilitating factors, despite some previous computational evidence suggesting transient exposure of this region. Furthermore, glycans, particularly those on N165 and N234, hinder S2-exposing opening dynamics, and thus stabilize spike in addition to immunologically shielding the protein surface. Although the S2 epitope region examined here is central to large-scale conformational changes during viral entry, free energy landscape analysis obtained using the path coordinate formalism reveals no inherent "loaded spring" effect, suggesting that a vaccine immunogen would tend to present the epitope in a prefusion-like conformation and may be effective in neutralization. These findings contribute to a deeper understanding of the dynamic origins of the function of the spike protein, as well as further characterizing the feasibility of the S2 epitope as a therapeutic target.
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Affiliation(s)
- Pranav Garg
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - Shawn C C Hsueh
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - Steven S Plotkin
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada; Genome Sciences and Technology Program, University of British Columbia, Vancouver, British Columbia, Canada.
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2
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Su R, Zeng J, Marcink TC, Porotto M, Moscona A, O’Shaughnessy B. Host Cell Membrane Capture by the SARS-CoV-2 Spike Protein Fusion Intermediate. ACS CENTRAL SCIENCE 2023; 9:1213-1228. [PMID: 37396856 PMCID: PMC10255576 DOI: 10.1021/acscentsci.3c00158] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Indexed: 07/04/2023]
Abstract
Cell entry by SARS-CoV-2 is accomplished by the S2 subunit of the spike S protein on the virion surface by capture of the host cell membrane and fusion with the viral envelope. Capture and fusion require the prefusion S2 to transit to its potent fusogenic form, the fusion intermediate (FI). However, the FI structure is unknown, detailed computational models of the FI are unavailable, and the mechanisms and timing of membrane capture and fusion are not established. Here, we constructed a full-length model of the SARS-CoV-2 FI by extrapolating from known SARS-CoV-2 pre- and postfusion structures. In atomistic and coarse-grained molecular dynamics simulations the FI was remarkably flexible and executed giant bending and extensional fluctuations due to three hinges in the C-terminal base. The simulated configurations and their giant fluctuations are quantitatively consistent with SARS-CoV-2 FI configurations measured recently using cryo-electron tomography. Simulations suggested a host cell membrane capture time of ∼2 ms. Isolated fusion peptide simulations identified an N-terminal helix that directed and maintained binding to the membrane but grossly underestimated the binding time, showing that the fusion peptide environment is radically altered when attached to its host fusion protein. The large configurational fluctuations of the FI generated a substantial exploration volume that aided capture of the target membrane, and may set the waiting time for fluctuation-triggered refolding of the FI that draws the viral envelope and host cell membrane together for fusion. These results describe the FI as machinery that uses massive configurational fluctuations for efficient membrane capture and suggest novel potential drug targets.
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Affiliation(s)
- Rui Su
- Department
of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Jin Zeng
- Department
of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - Tara C. Marcink
- Department
of Pediatrics, Columbia University Vagelos
College of Physicians & Surgeons, New York, New York 10032, United States
- Center
for Host−Pathogen Interaction, Columbia
University Vagelos College of Physicians & Surgeons, New York, New York 10032, United States
| | - Matteo Porotto
- Department
of Pediatrics, Columbia University Vagelos
College of Physicians & Surgeons, New York, New York 10032, United States
- Center
for Host−Pathogen Interaction, Columbia
University Vagelos College of Physicians & Surgeons, New York, New York 10032, United States
- Department
of Experimental Medicine, University of
Campania “Luigi Vanvitelli”, 81100 Caserta, Italy
| | - Anne Moscona
- Department
of Pediatrics, Columbia University Vagelos
College of Physicians & Surgeons, New York, New York 10032, United States
- Center
for Host−Pathogen Interaction, Columbia
University Vagelos College of Physicians & Surgeons, New York, New York 10032, United States
- Department
of Microbiology & Immunology, Columbia
University Vagelos College of Physicians & Surgeons, New York, New York 10032, United States
- Department
of Physiology, Columbia University Vagelos
College of Physicians & Surgeons, New York, New York 10032, United States
| | - Ben O’Shaughnessy
- Department
of Chemical Engineering, Columbia University, New York, New York 10027, United States
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3
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Pushan SS, Samantaray M, Rajagopalan M, Ramaswamy A. Evolution of Indian Influenza A (H1N1) Hemagglutinin Strains: A Comparative Analysis of the Pandemic Californian HA Strain. Front Mol Biosci 2023; 10:1111869. [PMID: 37006623 PMCID: PMC10061220 DOI: 10.3389/fmolb.2023.1111869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/20/2023] [Indexed: 03/18/2023] Open
Abstract
The need for a vaccine/inhibitor design has become inevitable concerning the emerging epidemic and pandemic viral infections, and the recent outbreak of the influenza A (H1N1) virus is one such example. From 2009 to 2018, India faced severe fatalities due to the outbreak of the influenza A (H1N1) virus. In this study, the potential features of reported Indian H1N1 strains are analyzed in comparison with their evolutionarily closest pandemic strain, A/California/04/2009. The focus is laid on one of its surface proteins, hemagglutinin (HA), which imparts a significant role in attacking the host cell surface and its entry. The extensive analysis performed, in comparison with the A/California/04/2009 strain, revealed significant point mutations in all Indian strains reported from 2009 to 2018. Due to these mutations, all Indian strains disclosed altered features at the sequence and structural levels, which are further presumed to be associated with their functional diversity as well. The mutations observed with the 2018 HA sequence such as S91R, S181T, S200P, I312V, K319T, I419M, and E523D might improve the fitness of the virus in a new host and environment. The higher fitness and decreased sequence similarity of mutated strains may compromise therapeutic efficacy. In particular, the mutations observed commonly, such as serine-to-threonine, alanine-to-threonine, and lysine-to-glutamine at various regions, alter the physico-chemical features of receptor-binding domains, N-glycosylation, and epitope-binding sites when compared with the reference strain. Such mutations render diversity among all Indian strains, and the structural and functional characterization of these strains becomes inevitable. In this study, we observed that mutational drift results in the alteration of the receptor-binding domain, the generation of new variant N-glycosylation along with novel epitope-binding sites, and modifications at the structural level. Eventually, the pressing need to develop potentially distinct next-generation therapeutic inhibitors against the HA strains of the Indian influenza A (H1N1) virus is also highlighted here.
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Affiliation(s)
- Shilpa Sri Pushan
- Department of Bioinformatics, Pondicherry University, Puducherry, India
| | - Mahesh Samantaray
- Department of Bioinformatics, Pondicherry University, Puducherry, India
| | - Muthukumaran Rajagopalan
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur, India
| | - Amutha Ramaswamy
- Department of Bioinformatics, Pondicherry University, Puducherry, India
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4
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Li Z, Li T, Liu M, Ivanovic T. Hemagglutinin Stability Determines Influenza A Virus Susceptibility to a Broad-Spectrum Fusion Inhibitor Arbidol. ACS Infect Dis 2022; 8:1543-1552. [PMID: 35819162 PMCID: PMC9810120 DOI: 10.1021/acsinfecdis.2c00178] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Understanding mechanisms of resistance to antiviral inhibitors can reveal nuanced features of targeted viral mechanisms and, in turn, lead to improved strategies for inhibitor design. Arbidol is a broad-spectrum antiviral that binds to and prevents the fusion-associated conformational changes in the trimeric influenza A virus (IAV) hemagglutinin (HA). The rate-limiting step during the HA-mediated membrane fusion is the release of the hydrophobic fusion peptides from a conserved pocket on HA. Here, we investigated how destabilizing or stabilizing mutations in or near the fusion peptide affect viral sensitivity to Arbidol. The degree of sensitivity was proportional to the extent of fusion-peptide stability on the prefusion HA: stabilized mutants were more sensitive, and destabilized ones were resistant to Arbidol. Single-virion membrane fusion experiments for representative wild-type (WT) and mutant viruses demonstrated that resistance is a direct consequence of fusion-peptide destabilization not requiring reduced Arbidol binding to HA. Our results support the model whereby the probability of individual HAs extending to engage the target membrane is determined by the composite of two critical forces: a "tug" on the fusion peptide by HA rearrangements near the Arbidol binding site and the key interactions stabilizing the fusion peptide in the prefusion pocket. Arbidol increases and destabilizing mutations decrease the free-energy cost for fusion-peptide release, accounting for the observed resistance. Our findings have broad implications for fusion inhibitor design, viral mechanisms of resistance, and our basic understanding of HA-mediated membrane fusion.
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5
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Michalski M, Setny P. Membrane-Bound Configuration and Lipid Perturbing Effects of Hemagglutinin Subunit 2 N-Terminus Investigated by Computer Simulations. Front Mol Biosci 2022; 9:826366. [PMID: 35155580 PMCID: PMC8830744 DOI: 10.3389/fmolb.2022.826366] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/04/2022] [Indexed: 01/08/2023] Open
Abstract
Hemagglutinin (HA) mediated fusion of influenza virus envelope with host lipid membrane is a critical step warrantying virus entry to the cell. Despite tremendous advances in structural biology methods, the knowledge concerning the details of HA2 subunit insertion into the target membrane and its subsequent bilayer perturbing effect is still rather limited. Herein, based on a set of molecular dynamics simulations, we investigate the structure and interaction with lipid membrane of the N-terminal HA2 region comprising a trimer of fusion peptides (HAfps) tethered by flexible linkers to a fragment of coiled-coil stem structure. We find that, prior to insertion into the membrane, HAfps within the trimers do not sample space individually but rather associate into a compact hydrophobic aggregate. Once within the membrane, they fold into tight helical hairpins, which remain at the lipid-water interface. However, they can also assume stable, membrane-spanning configurations of significantly increased membrane-perturbing potential. In this latter case, HAfps trimers centre around the well-hydrated transmembrane channel-forming distinct, symmetric assemblies, whose wedge-like shape may play a role in promoting membrane curvature. We also demonstrate that, following HAfps insertion, the coiled-coil stem spontaneously tilts to almost membrane-parallel orientation, reflecting experimentally observed configuration adopted in the course of membrane fusion by complete HA2 units at the rim of membrane contact zones.
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Jones PE, Pérez-Segura C, Bryer AJ, Perilla JR, Hadden-Perilla JA. Molecular dynamics of the viral life cycle: progress and prospects. Curr Opin Virol 2021; 50:128-138. [PMID: 34464843 PMCID: PMC8651149 DOI: 10.1016/j.coviro.2021.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/09/2021] [Accepted: 08/09/2021] [Indexed: 01/29/2023]
Abstract
Molecular dynamics (MD) simulations across spatiotemporal resolutions are widely applied to study viruses and represent the central technique uniting the field of computational virology. We discuss the progress of MD in elucidating the dynamics of the viral life cycle, including the status of modeling intact extracellular virions and leveraging advanced simulations to mimic active life cycle processes. We further remark on the prospects of MD for continued contributions to the basic science characterization of viruses, especially given the increasing availability of high-quality experimental data and supercomputing power. Overall, integrative computational methods that are closely guided by experiments are unmatched in the level of detail they provide, enabling-now and in the future-new discoveries relevant to thwarting viral infection.
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Affiliation(s)
- Peter Eugene Jones
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
| | - Carolina Pérez-Segura
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
| | - Alexander J Bryer
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
| | - Juan R Perilla
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States
| | - Jodi A Hadden-Perilla
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, United States.
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7
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Eller MW, Siaw HMH, Dyer RB. Stability of HA2 Prefusion Structure and pH-Induced Conformational Changes in the HA2 Domain of H3N2 Hemagglutinin. Biochemistry 2021; 60:2623-2636. [PMID: 34435771 PMCID: PMC8485334 DOI: 10.1021/acs.biochem.1c00551] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Influenza hemagglutinin is the fusion protein that mediates fusion of the viral and host membranes through a large conformational change upon acidification in the developing endosome. The "spring-loaded" model has long been used to describe the mechanism of hemagglutinin and other type 1 viral glycoproteins. This model postulates a metastable conformation of the HA2 subunit, caged from adopting a lower-free energy conformation by the HA1 subunit. Here, using a combination of biochemical and spectroscopic methods, we study a truncated construct of HA2 (HA2*, lacking the transmembrane domain) recombinantly expressed in Escherichia coli as a model for HA2 without the influence of HA1. Our data show that HA2* folds into a conformation like that of HA2 in full length HA and forms trimers. Upon acidification, HA2* undergoes a conformational change that is consistent with the change from pre- to postfusion HA2 in HA. This conformational change is fast and occurs on a time scale that is not consistent with aggregation. These results suggest that the prefusion conformation of HA2 is stable and the change to the postfusion conformation is due to protonation of HA2 itself and not merely uncaging by HA1.
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Affiliation(s)
- Micah W Eller
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Hew Ming Helen Siaw
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - R Brian Dyer
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
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8
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Borisevich SS, Gureev MA, Yarovaya ОI, Zarubaev VV, Kostin GA, Porozov YB, Salakhutdinov NF. Can molecular dynamics explain decreased pathogenicity in mutant camphecene-resistant influenza virus? J Biomol Struct Dyn 2021; 40:5481-5492. [PMID: 33480324 DOI: 10.1080/07391102.2020.1871414] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
ABSTARCTThe development of new anti-influenza drugs remains an active area, and efforts in this direction will likely continue far into the future. In this paper, we present the results of a theoretical study explaining the mechanisms behind the antiviral activity of camphor derivatives. These include camphecene and a number of its analogues. The compounds tested can inhibit hemagglutinin (HA) by binding to it at two possible sites. Moreover, the binding site located at the site of proteolysis is the most important. Serial passaging of influenza in the presence of camphecene leads to the formation of mutation-associated resistance. Specifically, camphecene causes a significant mutation in HA (V615L). This substitution likely reduces the affinity of the compound for the binding site due to steric restriction of the positioning of camphecene in the binding cavity. Molecular dynamics (MD) simulation results show that the mutant HA is a more stable structure in terms of thermodynamics. In other words, launching conformational rearrangements preceding the transition from pre- to post-fusion requires more energy than in wild type HA. This may well explain the lower virulence seen with the camphecene-resistant strain.
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Affiliation(s)
- Sophia S Borisevich
- Laboratory of Physical Chemistry, Ufa Institute of Chemistry UFRS RAS, Ufa, Russia
| | - Maxim A Gureev
- Laboratory of Bioinformatics, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Оlga I Yarovaya
- Department of Medicinal Chemistry, N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch RAS, Novosibirsk, Russia
| | - Vladimir V Zarubaev
- Department of Virology, Saint Petersburg Pasteur Institute, St. Petersburg, Russia
| | - Gennadiy A Kostin
- Nikolaev Institute of Inorganic Chemistry SB RAS, Novosibirsk, Russia
| | - Yuriy B Porozov
- Laboratory of Bioinformatics, I.M. Sechenov First Moscow State Medical University, Moscow, Russia.,Department of Food Biotechnology and Engineering, ITMO University, St. Petersburg, Russia.,Department of Computational Biology, Sirius University of Science and Technology, Sochi, Russia
| | - Nariman F Salakhutdinov
- Department of Medicinal Chemistry, N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch RAS, Novosibirsk, Russia
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9
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Ginex T, Luque FJ. Searching for effective antiviral small molecules against influenza A virus: A patent review. Expert Opin Ther Pat 2020; 31:53-66. [PMID: 33012213 DOI: 10.1080/13543776.2020.1831471] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Introduction: Despite the current interest caused by SARS-Cov-2, influenza continues to be one of the most serious health concerns, with an estimated 1 billion cases across the globe, including 3-5 million severe cases and 290,000-650,000 deaths worldwide. Areas covered: This manuscript reviews the efforts made in the development of small molecules for the treatment of influenza virus, primarily focused on patent applications in the last 5 years. Attention is paid to compounds targeting key functional viral proteins, such as the M2 channel, neuraminidase, and hemagglutinin, highlighting the evolution toward new ligands and scaffolds motivated by the emergence of resistant strains. Finally, the discovery of compounds against novel viral targets, such as the RNA-dependent RNA polymerase, is discussed. Expert opinion: The therapeutic potential of antiviral agents is limited by the increasing presence of resistant strains. This should encourage research on novel strategies for therapeutic intervention. In this context, the discovery of arbidol and JNJ7918 against hemagglutinin, and current efforts on RNA-dependent RNA polymerase have disclosed novel opportunities for therapeutic treatment. Studies should attempt to expand the therapeutic arsenal of anti-flu agents, often in combined therapies, to prevent future health challenges caused by influenza virus. Abbreviations: AlphaLISA: amplified luminescent proximity homogeneous assay; HA: hemagglutinin; NA: neuraminidase; RBD: receptor binding domain; RdRp: RNA-dependent RNA polymerase; SA: sialic Acid; TBHQ: tert-butyl hydroquinone; TEVC: two-electrode voltage clamp.
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Affiliation(s)
- Tiziana Ginex
- Translational Medicinal and Biological Chemistry Group, Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Biológicas (CIB-CSIC) , Madrid, Spain
| | - F Javier Luque
- Department of Nutrition, Food Science and Gastronomy, Faculty of Pharmacy and Food Sciences, Institute of Biomedicine (IBUB), and Institute of Theoretical and Computational Chemistry (IQTCUB), University of Barcelona , Santa Coloma de Gramanet, Spain
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10
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Burke DF, Mantell RG, Pitt CE, Wales DJ. Energy Landscape for the Membrane Fusion Pathway in Influenza A Hemagglutinin From Discrete Path Sampling. Front Chem 2020; 8:575195. [PMID: 33102445 PMCID: PMC7546250 DOI: 10.3389/fchem.2020.575195] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/19/2020] [Indexed: 11/22/2022] Open
Abstract
The conformational change associated with membrane fusion for Influenza A Hemagglutinin is investigated with a model based upon pre- and post-fusion structures of the HA2 component. We employ computational methods based on the potential energy landscape framework to obtain an initial path connecting these two end points, which provides the starting point for refinement of a kinetic transition network. Here we employ discrete path sampling, which provides access to the experimental time and length scales via geometry optimization techniques to identify local minima and the transition states that connect them. We then analyse the distinct phases of the predicted pathway in terms of structure and energetics, and compare with available experimental data and previous simulations. Our results provide the foundations for future work, which will address the effect of mutations, changes in pH, and incorporation of additional components, especially the HA1 chain and the fusion peptide.
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Affiliation(s)
- David F. Burke
- EMBL-EBI, Wellcome Genome Campus, Hinxton, United Kingdom
- David F. Burke
| | | | - Catherine E. Pitt
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - David J. Wales
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
- *Correspondence: David J. Wales
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11
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Benhaim MA, Mangala Prasad V, Garcia NK, Guttman M, Lee KK. Structural monitoring of a transient intermediate in the hemagglutinin fusion machinery on influenza virions. SCIENCE ADVANCES 2020; 6:eaaz8822. [PMID: 32494683 PMCID: PMC7190341 DOI: 10.1126/sciadv.aaz8822] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 02/05/2020] [Indexed: 05/16/2023]
Abstract
The influenza virus hemagglutinin (HA) fusion protein has long been viewed as a "spring-loaded" fusion machine whereby activation at low pH initiates a rapid and irreversible cascade of conformational changes that drives the membrane fusion reaction. This mechanism has shaped our understanding of how type 1 viral fusion proteins function as a whole. Experimental limitations have hindered efforts to expand our mechanistic and structural understanding of viral membrane fusion. Here, we used pulse-labeling hydrogen/deuterium exchange mass spectrometry and cryo-electron tomography to monitor and characterize the structural dynamics of HA during fusion activation on intact virions. Our data reveal how concurrent reorganizations at the HA1 receptor binding domain interface and HA2 fusion subunit produce a dynamic fusion intermediate ensemble in full-length HA. The soluble HA ectodomain transitions directly to the postfusion state with no observable intermediate.
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Affiliation(s)
- M. A. Benhaim
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - V. Mangala Prasad
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - N. K. Garcia
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - M. Guttman
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
| | - K. K. Lee
- Department of Medicinal Chemistry, University of Washington, Seattle, WA, USA
- Biological Physics, Structure and Design Graduate Program, University of Washington, Seattle, WA, USA
- Department of Microbiology, University of Washington, Seattle, WA, USA
- Corresponding author.
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12
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Benhaim MA, Lee KK. New Biophysical Approaches Reveal the Dynamics and Mechanics of Type I Viral Fusion Machinery and Their Interplay with Membranes. Viruses 2020; 12:E413. [PMID: 32276357 PMCID: PMC7232462 DOI: 10.3390/v12040413] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/04/2020] [Accepted: 04/04/2020] [Indexed: 12/27/2022] Open
Abstract
Protein-mediated membrane fusion is a highly regulated biological process essential for cellular and organismal functions and infection by enveloped viruses. During viral entry the membrane fusion reaction is catalyzed by specialized protein machinery on the viral surface. These viral fusion proteins undergo a series of dramatic structural changes during membrane fusion where they engage, remodel, and ultimately fuse with the host membrane. The structural and dynamic nature of these conformational changes and their impact on the membranes have long-eluded characterization. Recent advances in structural and biophysical methodologies have enabled researchers to directly observe viral fusion proteins as they carry out their functions during membrane fusion. Here we review the structure and function of type I viral fusion proteins and mechanisms of protein-mediated membrane fusion. We highlight how recent technological advances and new biophysical approaches are providing unprecedented new insight into the membrane fusion reaction.
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Affiliation(s)
- Mark A. Benhaim
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195-7610, USA;
| | - Kelly K. Lee
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195-7610, USA;
- Biological Physics Structure and Design Program, University of Washington, Seattle, WA 98195-7610, USA
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13
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