1
|
López CA, Alam SM, Derdeyn CA, Haynes BF, Gnanakaran S. Influence of membrane on the antigen presentation of the HIV-1 envelope membrane proximal external region (MPER). Curr Opin Struct Biol 2024; 88:102897. [PMID: 39173417 DOI: 10.1016/j.sbi.2024.102897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 07/18/2024] [Accepted: 07/19/2024] [Indexed: 08/24/2024]
Abstract
The membrane proximal external region (MPER) of the HIV envelope glycoproteins has generated renewed interest after a recent phase I vaccine trial that presented MPER lipid-peptide epitopes demonstrated promise to elicit a broad neutralization response. The antigenicity of MPER is intimately associated with the membrane, and its presentation relies significantly on the lipid composition. This review brings together recent findings on the influence of membranes on the conformation of MPER and its recognition by broadly neutralizing antibodies. Specifically, the review highlights the importance of properly accounting for the balance between protein-protein and membrane-protein interactions in vaccine design.
Collapse
Affiliation(s)
- Cesar A López
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - S Munir Alam
- Department of Medicine, Duke University School of Medicine, Durham, NC, 27710, USA; Department of Pathology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Cynthia A Derdeyn
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | - Barton F Haynes
- Department of Medicine, Duke University School of Medicine, Durham, NC, 27710, USA; Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, USA; Department of Immunology, Duke University of School of Medicine, Durham, NC, USA.
| | - Sandrasegaram Gnanakaran
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
| |
Collapse
|
2
|
Nyembe PL, Ntombela T, Makatini MM. Review: Structure-Activity Relationship of Antimicrobial Peptoids. Pharmaceutics 2023; 15:pharmaceutics15051506. [PMID: 37242748 DOI: 10.3390/pharmaceutics15051506] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/06/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
Due to their broad-spectrum activity against Gram-negative and Gram-positive bacteria, natural antimicrobial peptides (AMPs) and their synthetic analogs have emerged as prospective therapies for treating illnesses brought on by multi-drug resistant pathogens. To overcome the limitations of AMPs, such as protease degradation, oligo-N-substituted glycines (peptoids) are a promising alternative. Despite having the same backbone atom sequence as natural peptides, peptoid structures are more stable because, unlike AMP, their functional side chains are attached to the backbone nitrogen (N)-atom rather than the alpha carbon atom. As a result, peptoid structures are less susceptible to proteolysis and enzymatic degradation. The advantages of AMPs, such as hydrophobicity, cationic character, and amphipathicity, are mimicked by peptoids. Furthermore, structure-activity relationship studies (SAR) have shown that tuning the structure of peptoids is a crucial step in developing effective antimicrobials.
Collapse
Affiliation(s)
- Priscilla L Nyembe
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Thandokuhle Ntombela
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa
| | - Maya M Makatini
- Molecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg 2050, South Africa
| |
Collapse
|
3
|
Wang SF, Hung YH, Tsao CH, Chiang CY, Teoh PG, Chiang ML, Lin WH, Hsu DK, Jan HM, Lin HC, Lin CH, Liu FT, Chen HY. Galectin-3 facilitates cell-to-cell HIV-1 transmission by altering the composition of membrane lipid rafts in CD4 T cells. Glycobiology 2022; 32:760-777. [PMID: 35789267 DOI: 10.1093/glycob/cwac040] [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: 09/09/2021] [Revised: 05/28/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Galectin-3 (GAL3) is a β-galactoside-binding lectin expressed in CD4 T cells infected with human immunodeficiency virus-1 (HIV-1). GAL3 promotes HIV-1 budding by associating with ALIX and Gag p6. GAL3 has been shown to localize in membrane lipid rafts in dendritic cells and positively regulate cell migration. HIV-1 spreads between T cells by forming supramolecular structures (virological synapses [VSs]), whose integrity depends on lipid rafts. Here, we addressed the potential role of GAL3 in cell-to-cell transmission of HIV-1 in CD4 T cells. GAL3 expressed in donor cells was more important for facilitating HIV-1 cell-to-cell transfer than GAL3 expressed in target cells. GAL3 was found to be co-transferred with Gag from HIV-1-positive donor to HIV-1-negative target T cells. HIV-1 infection induced translocation of GAL3 together with Gag to the cell-cell interfaces and colocalize with GM1, where GAL3 facilitated VS formation. GAL3 regulated the coordinated transfer of Gag and flotillin-1 into plasma membrane fractions. Finally, depletion of GAL3 reduced the cholesterol levels in membrane lipid rafts in CD4 T cells. These findings provide evidence that endogenous GAL3 stimulates lipid raft components and facilitates intercellular HIV-1 transfer among CD4 T cells, offering another pathway by which GAL3 regulates HIV-1 infection. These findings may inform the treatment of HIV-1 infection based on targeting GAL3 to modulate lipid rafts.
Collapse
Affiliation(s)
- Sheng-Fan Wang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yu-Hsien Hung
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Ching-Han Tsao
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Ph.D. Program in Translational Medicine, Kaohsiung Medical University and Academia Sinica, Taiwan
| | - Cho-Ying Chiang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Pak-Guan Teoh
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Meng-Lin Chiang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Wei-Han Lin
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Daniel K Hsu
- Department of Dermatology, University of California Davis, California, USA
| | - Hau-Ming Jan
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Hsiu-Chu Lin
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chun-Hung Lin
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Fu-Tong Liu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Department of Dermatology, University of California Davis, California, USA
| | - Huan-Yuan Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.,Department of Dermatology, University of California Davis, California, USA
| |
Collapse
|
4
|
Parajuli B, Acharya K, Nangarlia A, Zhang S, Parajuli B, Dick A, Ngo B, Abrams CF, Chaiken I. Identification of a glycan cluster in gp120 essential for irreversible HIV-1 lytic inactivation by a lectin-based recombinantly engineered protein conjugate. Biochem J 2020; 477:4263-4280. [PMID: 33057580 DOI: 10.1042/bcj20200495] [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: 06/23/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 11/17/2022]
Abstract
We previously discovered a class of recombinant lectin conjugates, denoted lectin DLIs ('dual-acting lytic inhibitors') that bind to the HIV-1 envelope (Env) protein trimer and cause both lytic inactivation of HIV-1 virions and cytotoxicity of Env-expressing cells. To facilitate mechanistic investigation of DLI function, we derived the simplified prototype microvirin (MVN)-DLI, containing an MVN domain that binds high-mannose glycans in Env, connected to a DKWASLWNW sequence (denoted 'Trp3') derived from the membrane-associated region of gp41. The relatively much stronger affinity of the lectin component than Trp3 argues that the lectin functions to capture Env to enable Trp3 engagement and consequent Env membrane disruption and virolysis. The relatively simplified engagement pattern of MVN with Env opened up the opportunity, pursued here, to use recombinant glycan knockout gp120 variants to identify the precise Env binding site for MVN that drives DLI engagement and lysis. Using mutagenesis combined with a series of biophysical and virological experiments, we identified a restricted set of residues, N262, N332 and N448, all localized in a cluster on the outer domain of gp120, as the essential epitope for MVN binding. By generating these mutations in the corresponding HIV-1 virus, we established that the engagement of this glycan cluster with the lectin domain of MVN*-DLI is the trigger for DLI-derived virus and cell inactivation. Beyond defining the initial encounter step for lytic inactivation, this study provides a guide to further elucidate DLI mechanism, including the stoichiometry of Env trimer required for function, and downstream DLI optimization.
Collapse
Affiliation(s)
- Bibek Parajuli
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Kriti Acharya
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Aakansha Nangarlia
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Shiyu Zhang
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Bijay Parajuli
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Alexej Dick
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Brendon Ngo
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Cameron F Abrams
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA 19104, U.S.A
| | - Irwin Chaiken
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| |
Collapse
|
5
|
Munusamy S, Conde R, Bertrand B, Munoz-Garay C. Biophysical approaches for exploring lipopeptide-lipid interactions. Biochimie 2020; 170:173-202. [PMID: 31978418 PMCID: PMC7116911 DOI: 10.1016/j.biochi.2020.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 01/19/2020] [Indexed: 02/07/2023]
Abstract
In recent years, lipopeptides (LPs) have attracted a lot of attention in the pharmaceutical industry due to their broad-spectrum of antimicrobial activity against a variety of pathogens and their unique mode of action. This class of compounds has enormous potential for application as an alternative to conventional antibiotics and for pest control. Understanding how LPs work from a structural and biophysical standpoint through investigating their interaction with cell membranes is crucial for the rational design of these biomolecules. Various analytical techniques have been developed for studying intramolecular interactions with high resolution. However, these tools have been barely exploited in lipopeptide-lipid interactions studies. These biophysical approaches would give precise insight on these interactions. Here, we reviewed these state-of-the-art analytical techniques. Knowledge at this level is indispensable for understanding LPs activity and particularly their potential specificity, which is relevant information for safe application. Additionally, the principle of each analytical technique is presented and the information acquired is discussed. The key challenges, such as the selection of the membrane model are also been briefly reviewed. A brief overview of topics to understand the generalities of lipopeptide (LP) science. Main analytical techniques used to reveal the interaction and the distorting effect of LP on artificial membranes. Guidelines for selecting of the most adequate membrane models for the given analytical technique.
Collapse
Affiliation(s)
- Sathishkumar Munusamy
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210, Cuernavaca, Mexico
| | - Renaud Conde
- Centro de Investigación Sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico
| | - Brandt Bertrand
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210, Cuernavaca, Mexico
| | - Carlos Munoz-Garay
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, 62210, Cuernavaca, Mexico.
| |
Collapse
|
6
|
Andreev K, Martynowycz MW, Gidalevitz D. Peptoid drug discovery and optimization via surface X-ray scattering. Biopolymers 2019; 110:e23274. [PMID: 30892696 PMCID: PMC6661014 DOI: 10.1002/bip.23274] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 03/01/2019] [Accepted: 03/04/2019] [Indexed: 12/31/2022]
Abstract
Synthetic polymers mimicking antimicrobial peptides have drawn considerable interest as potential therapeutics. N-substituted glycines, or peptoids, are recognized by their in vivo stability and ease of synthesis. Peptoids are thought to act primarily on the negatively charged lipids that are abundant in bacterial cell membranes. A mechanistic understanding of lipid-peptoid interaction at the molecular level will provide insights for rational design and optimization of peptoids. Here, we highlight recent studies that utilize synchrotron liquid surface X-ray scattering to characterize the underlying peptoid interactions with bacterial and eukaryotic membranes. Cellular membranes are highly complex, and difficult to characterize at the molecular level. Model systems including Langmuir monolayers, are used in these studies to reduce system complexity. The general workflow of these systems and the corresponding data analysis techniques are presented alongside recent findings. These studies investigate the role of peptoid physicochemical characteristics on membrane activity. Specifically, the roles of cationic charge, conformational constraint via macrocyclization, and hydrophobicity are shown to correlate their membrane interactions to biological activities in vitro. These structure-activity relationships have led to new insights into the mechanism of action by peptoid antimicrobials, and suggest optimization strategies for future therapeutics based on peptoids.
Collapse
Affiliation(s)
- Konstantin Andreev
- Howard Hughes Medical Institute, Northwestern University, Evanston, Illinois
| | | | - David Gidalevitz
- Center for the Molecular Study of Condensed Soft Matter and Department of Physics, Illinois Institute of Technology, Chicago, Illinois
| |
Collapse
|
7
|
Andreev K, Martynowycz MW, Huang ML, Kuzmenko I, Bu W, Kirshenbaum K, Gidalevitz D. Hydrophobic interactions modulate antimicrobial peptoid selectivity towards anionic lipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1414-1423. [PMID: 29621496 DOI: 10.1016/j.bbamem.2018.03.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 03/15/2018] [Accepted: 03/26/2018] [Indexed: 12/21/2022]
Abstract
Hydrophobic interactions govern specificity for natural antimicrobial peptides. No such relationship has been established for synthetic peptoids that mimic antimicrobial peptides. Peptoid macrocycles synthesized with five different aromatic groups are investigated by minimum inhibitory and hemolytic concentration assays, epifluorescence microscopy, atomic force microscopy, and X-ray reflectivity. Peptoid hydrophobicity is determined using high performance liquid chromatography. Disruption of bacterial but not eukaryotic lipid membranes is demonstrated on the solid supported lipid bilayers and Langmuir monolayers. X-ray reflectivity studies demonstrate that intercalation of peptoids with zwitterionic or negatively charged lipid membranes is found to be regulated by hydrophobicity. Critical levels of peptoid selectivity are demonstrated and found to be modulated by their hydrophobic groups. It is suggested that peptoids may follow different optimization schemes as compared to their natural analogues.
Collapse
Affiliation(s)
- Konstantin Andreev
- Department of Physics, Center for Molecular Study of Condensed Soft Matter (μCoSM), Pritzker Institute of Biomedical Science and Engineering, Illinois Institute of Technology, 3440 South Dearborn Street, Chicago, IL 60616, United States
| | - Michael W Martynowycz
- Department of Physics, Center for Molecular Study of Condensed Soft Matter (μCoSM), Pritzker Institute of Biomedical Science and Engineering, Illinois Institute of Technology, 3440 South Dearborn Street, Chicago, IL 60616, United States; Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439, United States
| | - Mia L Huang
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003, United States
| | - Ivan Kuzmenko
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439, United States
| | - Wei Bu
- The Center for Advanced Radiation Sources (CARS), University of Chicago, Chicago, IL 60637, United States
| | - Kent Kirshenbaum
- Department of Chemistry, New York University, 100 Washington Square East, New York, NY 10003, United States
| | - David Gidalevitz
- Department of Physics, Center for Molecular Study of Condensed Soft Matter (μCoSM), Pritzker Institute of Biomedical Science and Engineering, Illinois Institute of Technology, 3440 South Dearborn Street, Chicago, IL 60616, United States.
| |
Collapse
|
8
|
Klug YA, Rotem E, Schwarzer R, Shai Y. Mapping out the intricate relationship of the HIV envelope protein and the membrane environment. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1859:550-560. [PMID: 27793589 DOI: 10.1016/j.bbamem.2016.10.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/20/2016] [Accepted: 10/24/2016] [Indexed: 01/08/2023]
Abstract
The HIV gp160 envelope fusion protein is situated in the viral membrane and mediates virus entry into its host cell. Increasing evidence suggests that virtually all parts of the HIV envelope are structurally and functionally dependent on membranes. Protein-lipid interactions and membrane properties influence the dynamics of a manifold of gp160 biological activities such as membrane fusion, immune suppression and gp160 incorporation into virions during HIV budding and assembly. In the following we will summarize our current understanding of this interdependence between membrane interaction, structural conformation and functionality of the different gp160 domains. This article is part of a Special Issue entitled: Lipid order/lipid defects and lipid-control of protein activity edited by Dirk Schneider.
Collapse
Affiliation(s)
- Yoel A Klug
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Etai Rotem
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Roland Schwarzer
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Yechiel Shai
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| |
Collapse
|
9
|
Oliva R, Emendato A, Vitiello G, De Santis A, Grimaldi M, D'Ursi AM, Busi E, Del Vecchio P, Petraccone L, D'Errico G. On the microscopic and mesoscopic perturbations of lipid bilayers upon interaction with the MPER domain of the HIV glycoprotein gp41. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1904-13. [DOI: 10.1016/j.bbamem.2016.05.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/04/2016] [Accepted: 05/09/2016] [Indexed: 12/15/2022]
|
10
|
Kessans SA, Linhart MD, Meador LR, Kilbourne J, Hogue BG, Fromme P, Matoba N, Mor TS. Immunological Characterization of Plant-Based HIV-1 Gag/Dgp41 Virus-Like Particles. PLoS One 2016; 11:e0151842. [PMID: 26986483 PMCID: PMC4795674 DOI: 10.1371/journal.pone.0151842] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/04/2016] [Indexed: 02/08/2023] Open
Abstract
It is widely anticipated that a prophylactic vaccine may be needed to control the HIV/AIDS epidemic worldwide. Despite over two decades of research, a vaccine against HIV-1 remains elusive, although a recent clinical trial has shown promising results. Recent studies have focused on highly conserved domains within HIV-1 such as the membrane proximal external region (MPER) of the envelope glycoprotein, gp41. MPER has been shown to play critical roles in mucosal transmission of HIV-1, though this peptide is poorly immunogenic on its own. Here we provide evidence that plant-produced HIV-1 enveloped virus-like particles (VLPs) consisting of Gag and a deconstructed form of gp41 comprising the MPER, transmembrane, and cytoplasmic domains (Dgp41) provides an effective platform to display MPER for use as an HIV vaccine candidate. Prime-boost strategies combining systemic and mucosal priming with systemic boosting using two different vaccine candidates (VLPs and CTB-MPR--a fusion of MPER and the B-subunit of cholera toxin) were investigated in BALB/c mice. Serum antibody responses against both the Gag and gp41 antigens were elicited when systemically primed with VLPs. These responses could be recalled following systemic boosting with VLPs. In addition, mucosal priming with VLPs allowed for a boosting response against Gag and gp41 when boosted with either candidate. Importantly, the VLPs also induced Gag-specific CD4 and CD8 T-cell responses. This report on the immunogenicity of plant-based Gag/Dgp41 VLPs may represent an important milestone on the road towards a broadly efficacious and inexpensive subunit vaccine against HIV-1.
Collapse
Affiliation(s)
- Sarah A. Kessans
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Mark D. Linhart
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Lydia R. Meador
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Jacquelyn Kilbourne
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Brenda G. Hogue
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Petra Fromme
- Center for Applied Structural Discovery, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, United States of America
| | - Nobuyuki Matoba
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - Tsafrir S. Mor
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| |
Collapse
|
11
|
Apellániz B, Nieva JL. The Use of Liposomes to Shape Epitope Structure and Modulate Immunogenic Responses of Peptide Vaccines Against HIV MPER. PEPTIDE AND PROTEIN VACCINES 2015; 99:15-54. [DOI: 10.1016/bs.apcsb.2015.03.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
|
12
|
Kyrychenko A, Freites JA, He J, Tobias DJ, Wimley WC, Ladokhin AS. Structural plasticity in the topology of the membrane-interacting domain of HIV-1 gp41. Biophys J 2014; 106:610-20. [PMID: 24507601 DOI: 10.1016/j.bpj.2013.12.032] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 12/17/2013] [Accepted: 12/23/2013] [Indexed: 11/27/2022] Open
Abstract
We use a number of computational and experimental approaches to investigate the membrane topology of the membrane-interacting C-terminal domain of the HIV-1 gp41 fusion protein. Several putative transmembrane regions are identified using hydrophobicity analysis based on the Wimley-White scales, including the membrane-proximal external region (MPER). The MPER region is an important target for neutralizing anti-HIV monoclonal antibodies and is believed to have an interfacial topology in the membrane. To assess the possibility of a transmembrane topology of MPER, we examined the membrane interactions of a peptide corresponding to a 22-residue stretch of the MPER sequence (residues 662-683) using fluorescence spectroscopy and oriented circular dichroism. In addition to the previously reported interfacial location, we identify a stable transmembrane conformation of the peptide in synthetic lipid bilayers. All-atom molecular dynamics simulations of the MPER-derived peptide in a lipid bilayer demonstrate a stable helical structure with an average tilt of 24 degrees, with the five tryptophan residues sampling different environments inside the hydrocarbon core of the lipid bilayer, consistent with the observed spectral properties of intrinsic fluorescence. The degree of lipid bilayer penetration obtained by computer simulation was verified using depth-dependent fluorescence quenching of a selectively attached fluorescence probe. Overall, our data indicate that the MPER sequence can have at least two stable conformations in the lipid bilayer, interfacial and transmembrane, and suggest a possibility that external perturbations can switch the topology during physiological functioning.
Collapse
Affiliation(s)
- Alexander Kyrychenko
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, Kansas
| | - J Alfredo Freites
- Department of Chemistry, University of California, Irvine, California
| | - Jing He
- Department of Biochemistry, Tulane University School of Medicine, New Orleans, Louisiana
| | - Douglas J Tobias
- Department of Chemistry, University of California, Irvine, California
| | - William C Wimley
- Department of Biochemistry, Tulane University School of Medicine, New Orleans, Louisiana
| | - Alexey S Ladokhin
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, Kansas.
| |
Collapse
|
13
|
Cholesterol-dependent membrane fusion induced by the gp41 membrane-proximal external region-transmembrane domain connection suggests a mechanism for broad HIV-1 neutralization. J Virol 2014; 88:13367-77. [PMID: 25210180 DOI: 10.1128/jvi.02151-14] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The HIV-1 glycoprotein 41 promotes fusion of the viral membrane with that of the target cell. Structural, biochemical, and biophysical studies suggest that its membrane-proximal external region (MPER) may interact with the HIV-1 membrane and induce its disruption and/or deformation during the process. However, the high cholesterol content of the envelope (ca. 40 to 50 mol%) imparts high rigidity, thereby acting against lipid bilayer restructuring. Here, based on the outcome of vesicle stability assays, all-atom molecular dynamics simulations, and atomic force microscopy observations, we propose that the conserved sequence connecting the MPER with the N-terminal residues of the transmembrane domain (TMD) is involved in HIV-1 fusion. This junction would function by inducing phospholipid protrusion and acyl-chain splay in the cholesterol-enriched rigid envelope. Supporting the functional relevance of such a mechanism, membrane fusion was inhibited by the broadly neutralizing 4E10 antibody but not by a nonneutralizing variant with the CDR-H3 loop deleted. We conclude that the MPER-TMD junction embodies an envelope-disrupting C-terminal fusion peptide that can be targeted by broadly neutralizing antibodies. IMPORTANCE Fusion of the cholesterol-enriched viral envelope with the cell membrane marks the beginning of the infectious HIV-1 replicative cycle. Consequently, the Env glycoprotein-mediated fusion function constitutes an important clinical target for inhibitors and preventive vaccines. Antibodies 4E10 and 10E8 bind to one Env vulnerability site located at the gp41 membrane-proximal external region (MPER)-transmembrane domain (TMD) junction and block infection. These antibodies display broad viral neutralization, which underscores the conservation and functionality of the MPER-TMD region. In this work, we combined biochemical assays with molecular dynamics simulations and microscopy observations to characterize the unprecedented fusogenic activity of the MPER-TMD junction. The fact that such activity is dependent on cholesterol and inhibited by the broadly neutralizing 4E10 antibody emphasizes its physiological relevance. Discovery of this functional element adds to our understanding of the mechanisms underlying HIV-1 infection and its blocking by antibodies.
Collapse
|
14
|
Andreev K, Bianchi C, Laursen JS, Citterio L, Hein-Kristensen L, Gram L, Kuzmenko I, Olsen CA, Gidalevitz D. Guanidino groups greatly enhance the action of antimicrobial peptidomimetics against bacterial cytoplasmic membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2492-2502. [PMID: 24878450 DOI: 10.1016/j.bbamem.2014.05.022] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 05/11/2014] [Accepted: 05/19/2014] [Indexed: 11/18/2022]
Abstract
Antimicrobial peptides or their synthetic mimics are a promising class of potential new antibiotics. Herein we assess the effect of the type of cationic side chain (i.e., guanidino vs. amino groups) on the membrane perturbing mechanism of antimicrobial α-peptide-β-peptoid chimeras. Langmuir monolayers composed of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylglycerol (DPPG) were used to model cytoplasmic membranes of both Gram-positive and Gram-negative bacteria, while lipopolysaccharide Kdo2-lipid A monolayers were mimicking the outer membrane of Gram-negative species. We report the results of the measurements using an array of techniques, including high-resolution synchrotron surface X-ray scattering, epifluorescence microscopy, and in vitro antimicrobial activity to study the molecular mechanisms of peptidomimetic interaction with bacterial membranes. We found guanidino group-containing chimeras to exhibit greater disruptive activity on DPPG monolayers than the amino group-containing analogues. However, this effect was not observed for lipopolysaccharide monolayers where the difference was negligible. Furthermore, the addition of the nitrobenzoxadiazole fluorophore did not reduce the insertion activity of these antimicrobials into both model membrane systems examined, which may be useful for future cellular localization studies.
Collapse
Affiliation(s)
- Konstantin Andreev
- Center for Molecular Study of Condensed Soft Matter (μCoSM), Pritzker Institute of Biomedical Science and Engineering and Department of Physics, Illinois Institute of Technology, 3440 S. Dearborn St., Chicago, IL 60616 (USA)
| | - Christopher Bianchi
- Center for Molecular Study of Condensed Soft Matter (μCoSM), Pritzker Institute of Biomedical Science and Engineering and Department of Physics, Illinois Institute of Technology, 3440 S. Dearborn St., Chicago, IL 60616 (USA)
| | - Jonas S Laursen
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kgs. Lyngby (Denmark)
| | - Linda Citterio
- Department of Systems Biology, Technical University of Denmark, Matematiktorvet 301, DK-2800 Kgs. Lyngby (Denmark)
| | - Line Hein-Kristensen
- , National Food Institute, Technical University of Denmark, Søltofts Plads 221, DK-2800, Kgs Lyngby (Denmark)
| | - Lone Gram
- Department of Systems Biology, Technical University of Denmark, Matematiktorvet 301, DK-2800 Kgs. Lyngby (Denmark)
| | - Ivan Kuzmenko
- Advanced Photon Source, Argonne National Laboratory, 9700 S. Cass Ave., Lemont, IL 60439 (USA)
| | - Christian A Olsen
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, DK-2800 Kgs. Lyngby (Denmark)
| | - David Gidalevitz
- Center for Molecular Study of Condensed Soft Matter (μCoSM), Pritzker Institute of Biomedical Science and Engineering and Department of Physics, Illinois Institute of Technology, 3440 S. Dearborn St., Chicago, IL 60616 (USA)
| |
Collapse
|
15
|
Koller D, Lohner K. The role of spontaneous lipid curvature in the interaction of interfacially active peptides with membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2250-9. [PMID: 24853655 DOI: 10.1016/j.bbamem.2014.05.013] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Revised: 05/07/2014] [Accepted: 05/08/2014] [Indexed: 01/28/2023]
Abstract
Research on antimicrobial peptides is in part driven by urgent medical needs such as the steady increase in pathogens being resistant to antibiotics. Despite the wealth of information compelling structure-function relationships are still scarce and thus the interfacial activity model has been proposed to bridge this gap. This model also applies to other interfacially active (membrane active) peptides such as cytolytic, cell penetrating or antitumor peptides. One parameter that is strongly linked to interfacial activity is the spontaneous lipid curvature, which is experimentally directly accessible. We discuss different parameters such as H-bonding, electrostatic repulsion, changes in monolayer surface area and lateral pressure that affect induction of membrane curvature, but also vice versa how membrane curvature triggers peptide response. In addition, the impact of membrane lipid composition on the formation of curved membrane structures and its relevance for diverse mode of action of interfacially active peptides and in turn biological activity are described. This article is part of a Special Issue entitled: Interfacially Active Peptides and Proteins. Guest Editors: William C. Wimley and Kalina Hristova.
Collapse
Affiliation(s)
- Daniel Koller
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Schmiedlstraße 6, A-8042 Graz, Austria.
| | - Karl Lohner
- Institute of Molecular Biosciences, Biophysics Division, University of Graz, Schmiedlstraße 6, A-8042 Graz, Austria.
| |
Collapse
|
16
|
Apellániz B, Huarte N, Largo E, Nieva JL. The three lives of viral fusion peptides. Chem Phys Lipids 2014; 181:40-55. [PMID: 24704587 PMCID: PMC4061400 DOI: 10.1016/j.chemphyslip.2014.03.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/19/2014] [Accepted: 03/20/2014] [Indexed: 02/07/2023]
Abstract
The presence of a fusion peptide (FP) is a hallmark of viral fusion glycoproteins. Structure–function relationships underlying FP conservation remain greatly unknown. FPs establish interactions satisfying their folding within pre-fusion glycoproteins. Upon fusion activation FPs insert into and restructure target membranes. FPs can finally combine with transmembrane domains to form integral membrane bundles.
Fusion peptides comprise conserved hydrophobic domains absolutely required for the fusogenic activity of glycoproteins from divergent virus families. After 30 years of intensive research efforts, the structures and functions underlying their high degree of sequence conservation are not fully elucidated. The long-hydrophobic viral fusion peptide (VFP) sequences are structurally constrained to access three successive states after biogenesis. Firstly, the VFP sequence must fulfill the set of native interactions required for (meta) stable folding within the globular ectodomains of glycoprotein complexes. Secondly, at the onset of the fusion process, they get transferred into the target cell membrane and adopt specific conformations therein. According to commonly accepted mechanistic models, membrane-bound states of the VFP might promote the lipid bilayer remodeling required for virus-cell membrane merger. Finally, at least in some instances, several VFPs co-assemble with transmembrane anchors into membrane integral helical bundles, following a locking movement hypothetically coupled to fusion-pore expansion. Here we review different aspects of the three major states of the VFPs, including the functional assistance by other membrane-transferring glycoprotein regions, and discuss briefly their potential as targets for clinical intervention.
Collapse
Affiliation(s)
- Beatriz Apellániz
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Nerea Huarte
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - Eneko Largo
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain
| | - José L Nieva
- Biophysics Unit (CSIC-UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), P.O. Box 644, 48080 Bilbao, Spain.
| |
Collapse
|
17
|
Key T, Duncan R. A compact, multifunctional fusion module directs cholesterol-dependent homomultimerization and syncytiogenic efficiency of reovirus p10 FAST proteins. PLoS Pathog 2014; 10:e1004023. [PMID: 24651689 PMCID: PMC3961370 DOI: 10.1371/journal.ppat.1004023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 02/05/2014] [Indexed: 12/11/2022] Open
Abstract
The homologous p10 fusion-associated small transmembrane (FAST) proteins of the avian (ARV) and Nelson Bay (NBV) reoviruses are the smallest known viral membrane fusion proteins, and are virulence determinants of the fusogenic reoviruses. The small size of FAST proteins is incompatible with the paradigmatic membrane fusion pathway proposed for enveloped viral fusion proteins. Understanding how these diminutive viral fusogens mediate the complex process of membrane fusion is therefore of considerable interest, from both the pathogenesis and mechanism-of-action perspectives. Using chimeric ARV/NBV p10 constructs, the 36–40-residue ectodomain was identified as the major determinant of the differing fusion efficiencies of these homologous p10 proteins. Extensive mutagenic analysis determined the ectodomain comprises two distinct, essential functional motifs. Syncytiogenesis assays, thiol-specific surface biotinylation, and liposome lipid mixing assays identified an ∼25-residue, N-terminal motif that dictates formation of a cystine loop fusion peptide in both ARV and NBV p10. Surface immunofluorescence staining, FRET analysis and cholesterol depletion/repletion studies determined the cystine loop motif is connected through a two-residue linker to a 13-residue membrane-proximal ectodomain region (MPER). The MPER constitutes a second, independent motif governing reversible, cholesterol-dependent assembly of p10 multimers in the plasma membrane. Results further indicate that: (1) ARV and NBV homomultimers segregate to distinct, cholesterol-dependent microdomains in the plasma membrane; (2) p10 homomultimerization and cholesterol-dependent microdomain localization are co-dependent; and (3) the four juxtamembrane MPER residues present in the multimerization motif dictate species-specific microdomain association and homomultimerization. The p10 ectodomain therefore constitutes a remarkably compact, multifunctional fusion module that directs syncytiogenic efficiency and species-specific assembly of p10 homomultimers into cholesterol-dependent fusion platforms in the plasma membrane. Natural infections by fusogenic orthoreoviruses can result in severe afflictions ranging from neuropathogenicity to pneumonia and death. The fusogenic capacity of these viruses, attributable to a unique family of fusion-associated small transmembrane (FAST) proteins, is a correlate of virulence. The FAST proteins are the only known examples of nonenveloped virus membrane fusion proteins, and they are the smallest known viral fusogens whose structural and functional attributes are incompatible with current models of protein-mediated membrane fusion. Exploiting the sequence divergence and distinct syncytiogenic rates of representative p10 FAST proteins from avian and bat reovirus isolates, we determined the p10 ectodomain is a compact, complex fusion module comprising two independent functional motifs. One motif determines species-specific p10 fusion efficiency by governing formation of a cystine loop fusion peptide, while the other directs reversible clustering and multimerization of p10 in cholesterol-dependent membrane microdomains. Remarkably, a juxtamembrane tetra-peptide is solely responsible for co-dependent clustering and multimerization of p10 in distinct, species-specific fusion platforms. This is the first example of a viral fusogen utilizing a membrane-proximal ectodomain region (MPER) to direct cholesterol-dependent multimerization and assembly into fusion platforms.
Collapse
Affiliation(s)
- Tim Key
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Roy Duncan
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada
- * E-mail:
| |
Collapse
|
18
|
Sun ZYJ, Cheng Y, Kim M, Song L, Choi J, Kudahl UJ, Brusic V, Chowdhury B, Yu L, Seaman MS, Bellot G, Shih WM, Wagner G, Reinherz EL. Disruption of helix-capping residues 671 and 674 reveals a role in HIV-1 entry for a specialized hinge segment of the membrane proximal external region of gp41. J Mol Biol 2013; 426:1095-108. [PMID: 24075869 DOI: 10.1016/j.jmb.2013.09.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 09/18/2013] [Accepted: 09/20/2013] [Indexed: 11/30/2022]
Abstract
HIV-1 (human immunodeficiency virus type 1) uses its trimeric gp160 envelope (Env) protein consisting of non-covalently associated gp120 and gp41 subunits to mediate entry into human T lymphocytes. A facile virus fusion mechanism compensates for the sparse Env copy number observed on viral particles and includes a 22-amino-acid, lentivirus-specific adaptation at the gp41 base (amino acid residues 662-683), termed the membrane proximal external region (MPER). We show by NMR and EPR that the MPER consists of a structurally conserved pair of viral lipid-immersed helices separated by a hinge with tandem joints that can be locked by capping residues between helices. This design fosters efficient HIV-1 fusion via interconverting structures while, at the same time, affording immune escape. Disruption of both joints by double alanine mutations at Env positions 671 and 674 (AA) results in attenuation of Env-mediated cell-cell fusion and hemifusion, as well as viral infectivity mediated by both CD4-dependent and CD4-independent viruses. The potential mechanism of disruption was revealed by structural analysis of MPER conformational changes induced by AA mutation. A deeper acyl chain-buried MPER middle section and the elimination of cross-hinge rigid-body motion almost certainly impede requisite structural rearrangements during the fusion process, explaining the absence of MPER AA variants among all known naturally occurring HIV-1 viral sequences. Furthermore, those broadly neutralization antibodies directed against the HIV-1 MPER exploit the tandem joint architecture involving helix capping, thereby disrupting hinge function.
Collapse
Affiliation(s)
- Zhen-Yu J Sun
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Yuxing Cheng
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Mikyung Kim
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Likai Song
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Jaewon Choi
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Ulrich J Kudahl
- Cancer Vaccine Center and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Vladimir Brusic
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA; Cancer Vaccine Center and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Barnali Chowdhury
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Lu Yu
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Michael S Seaman
- Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA
| | - Gaëtan Bellot
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Wyss Institute for Biologically Inspired Engineering at Harvard, Boston, MA 02115, USA
| | - William M Shih
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Wyss Institute for Biologically Inspired Engineering at Harvard, Boston, MA 02115, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Ellis L Reinherz
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.
| |
Collapse
|
19
|
Cholesterol induces uneven curvature of asymmetric lipid bilayers. ScientificWorldJournal 2013; 2013:965230. [PMID: 23766730 PMCID: PMC3671548 DOI: 10.1155/2013/965230] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 04/28/2013] [Indexed: 01/07/2023] Open
Abstract
A remarkable flexibility is observed in biological membranes, which allows them to form the structures of different curvatures. We addressed the question of intrinsic ability of phospholipid membranes to form highly curved structures and the role of cholesterol in this process. The distribution of cholesterol in the highly curved asymmetric DOPC/DOPS lipid bilayer was investigated by the coarse-grained molecular dynamics simulations in the membrane patches with large aspect ratio. It is shown that cholesterol induces uneven membrane curvature promoting the formation of extended flattened regions of the membrane interleaved by sharp bends. It is shown that the affinity of cholesterol to anionic DOPS or neutral DOPC lipids is curvature dependent. The cholesterol prefers DOPS to DOPC in either planar or highly curved parts of the membrane. In contrast, in the narrow interval of moderate membrane curvatures this preference is inverted. Our data suggest that there is a complex self-consistent interplay between the membrane curvature and cholesterol distribution in the asymmetric lipid bilayers. The suggested new function of cholesterol may have a biological relevance.
Collapse
|