1
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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] [MESH Headings] [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.
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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.
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2
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Guo Y, Li L, Huang S, Sun H, Shao Y, Li Z, Song F. Exploring Linker-Group-Guided Self-Assembly of Ultrathin 2D Supramolecular Nanosheets in Water for Synergistic Cancer Phototherapy. ACS APPLIED MATERIALS & INTERFACES 2023; 15:54851-54862. [PMID: 37968254 DOI: 10.1021/acsami.3c13640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
Water is ubiquitous in natural systems where it builds an essential environment supporting biological supramolecular polymers to function, transport, and exchange. However, this extreme polar environment becomes a hindrance for the superhydrophobic functional π-conjugated molecules, causing significant negative impacts on regulating their aggregation pathways, structures, and properties of the subsequently assembled nanomaterials. It especially makes the self-assembly of ultrathin two-dimensional (2D) functional nanomaterials by π-conjugated molecules a grand challenge in water, although ultrathin 2D functional nanomaterials have exhibited unique and superior properties. Herein, we demonstrate the organic solvent-free self-assembly of one-molecule-thick 2D nanosheets based on exploring how side chain modifications rule the aggregation behaviors of π-conjugated macrocycles in water. Through an in-depth understanding of the roles of linking groups for side chains on affecting the aggregation behaviors of porphyrins in water, the regulation of molecular arrangement in the aggregated state (H- or J-type aggregation) was attained. Moreover, by arranging ionic porphyrins into 2D single layers through J-aggregation, the ultrathin nanosheets (thickness ≈ 2 nm) with excellent solubility and stability were self-assembled in pure water, which demonstrated both outstanding 1O2 generation and photothermal capability. The ultrathin nanosheets were further investigated as metal- and carrier-free nanodrugs for synergetic phototherapies of cancers both in vitro and in vivo, which are highly desirable by combining the advantages and avoiding the disadvantages of the single use of PDT or PTT.
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Affiliation(s)
- Yanhui Guo
- Institute of Molecular Science and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, Shandong 266237, P. R. China
| | - Lukun Li
- Institute of Molecular Science and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, Shandong 266237, P. R. China
| | - Shuheng Huang
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, Hainan University, Haikou 570228, P. R. China
| | - Han Sun
- Institute of Molecular Science and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, Shandong 266237, P. R. China
| | - Yutong Shao
- Institute of Molecular Science and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, Shandong 266237, P. R. China
| | - Zhiliang Li
- Institute of Molecular Science and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, Shandong 266237, P. R. China
| | - Fengling Song
- Institute of Molecular Science and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao, Shandong 266237, P. R. China
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3
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Rokonujjaman M, Sahyouni A, Wolfe R, Jia L, Ghosh U, Weliky DP. A large HIV gp41 construct with trimer-of-hairpins structure exhibits V2E mutation-dominant attenuation of vesicle fusion and helicity very similar to V2E attenuation of HIV fusion and infection and supports: (1) hairpin stabilization of membrane apposition with larger distance for V2E; and (2) V2E dominance by an antiparallel β sheet with interleaved fusion peptide strands from two gp41 trimers. Biophys Chem 2023; 293:106933. [PMID: 36508984 PMCID: PMC9879285 DOI: 10.1016/j.bpc.2022.106933] [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: 09/29/2022] [Revised: 11/13/2022] [Accepted: 11/14/2022] [Indexed: 11/27/2022]
Abstract
There is complete attenuation of fusion and infection mediated by HIV gp160 with gp41 subunit with V2E mutation, and also V2E dominance with WT/V2E mixtures. V2E is at the N-terminus of the ∼25-residue fusion peptide (Fp) which likely binds the target membrane. In this study, large V2E attenuation and dominance were observed for vesicle fusion induced by FP_HM, a large gp41 ectodomain construct with Fp followed by hyperthermostable hairpin with N- and C-helices, and membrane-proximal external region (Mper). FP_HM is a trimer-of-hairpins, the final gp41 structure during fusion. Vesicle fusion and helicity were measured for FP_HM using trimers with different fractions (f's) of WT and V2E proteins. Reductions in FP_HM fusion and helicity vs. fV2E were quantitatively-similar to those for gp160-mediated fusion and infection. Global fitting of all V2E data supports 6 WT gp41 (2 trimers) required for fusion. These data are understood by a model in which the ∼25 kcal/mol free energy for initial membrane apposition is compensated by the thermostable hairpin between the Fp in target membrane and Mper/transmembrane domain in virus membrane. The data support a structural model for V2E dominance with a membrane-bound Fp with antiparallel β sheet and interleaved strands from the two trimers. Relative to fV2E = 0, a longer Fp sheet is stabilized with small fV2E because of salt-bridge and/or hydrogen bonds between E2 on one strand and C-terminal Fp residues on adjacent strands, like R22. A longer Fp sheet results in shorter N- and C-helices, and larger separation during membrane apposition which hinders fusion.
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Affiliation(s)
- Md Rokonujjaman
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Abdulrazak Sahyouni
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Robert Wolfe
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Lihui Jia
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - Ujjayini Ghosh
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
| | - David P Weliky
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA.
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4
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Torralba J, de la Arada I, Partida-Hanon A, Rujas E, Arribas M, Insausti S, Valotteau C, Valle J, Andreu D, Caaveiro JMM, Jiménez MA, Apellániz B, Redondo-Morata L, Nieva JL. Molecular recognition of a membrane-anchored HIV-1 pan-neutralizing epitope. Commun Biol 2022; 5:1265. [DOI: 10.1038/s42003-022-04219-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 11/03/2022] [Indexed: 11/19/2022] Open
Abstract
AbstractAntibodies against the carboxy-terminal section of the membrane-proximal external region (C-MPER) of the HIV-1 envelope glycoprotein (Env) are considered as nearly pan-neutralizing. Development of vaccines capable of producing analogous broadly neutralizing antibodies requires deep understanding of the mechanism that underlies C-MPER recognition in membranes. Here, we use the archetypic 10E8 antibody and a variety of biophysical techniques including single-molecule approaches to study the molecular recognition of C-MPER in membrane mimetics. In contrast to the assumption that an interfacial MPER helix embodies the entire C-MPER epitope recognized by 10E8, our data indicate that transmembrane domain (TMD) residues contribute to binding affinity and specificity. Moreover, anchoring to membrane the helical C-MPER epitope through the TMD augments antibody binding affinity and relieves the effects exerted by the interfacial MPER helix on the mechanical stability of the lipid bilayer. These observations support that addition of TMD residues may result in more efficient and stable anti-MPER vaccines.
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5
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Miao Q, Nitsche C, Orton H, Overhand M, Otting G, Ubbink M. Paramagnetic Chemical Probes for Studying Biological Macromolecules. Chem Rev 2022; 122:9571-9642. [PMID: 35084831 PMCID: PMC9136935 DOI: 10.1021/acs.chemrev.1c00708] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Indexed: 12/11/2022]
Abstract
Paramagnetic chemical probes have been used in electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopy for more than four decades. Recent years witnessed a great increase in the variety of probes for the study of biological macromolecules (proteins, nucleic acids, and oligosaccharides). This Review aims to provide a comprehensive overview of the existing paramagnetic chemical probes, including chemical synthetic approaches, functional properties, and selected applications. Recent developments have seen, in particular, a rapid expansion of the range of lanthanoid probes with anisotropic magnetic susceptibilities for the generation of structural restraints based on residual dipolar couplings and pseudocontact shifts in solution and solid state NMR spectroscopy, mostly for protein studies. Also many new isotropic paramagnetic probes, suitable for NMR measurements of paramagnetic relaxation enhancements, as well as EPR spectroscopic studies (in particular double resonance techniques) have been developed and employed to investigate biological macromolecules. Notwithstanding the large number of reported probes, only few have found broad application and further development of probes for dedicated applications is foreseen.
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Affiliation(s)
- Qing Miao
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
- School
of Chemistry &Chemical Engineering, Shaanxi University of Science & Technology, Xi’an710021, China
| | - Christoph Nitsche
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Henry Orton
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
- ARC
Centre of Excellence for Innovations in Peptide & Protein Science,
Research School of Chemistry, Australian
National University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Mark Overhand
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Gottfried Otting
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
- ARC
Centre of Excellence for Innovations in Peptide & Protein Science,
Research School of Chemistry, Australian
National University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Marcellus Ubbink
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
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6
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Tran N, Oh Y, Sutherland M, Cui Q, Hong M. Cholesterol-Mediated Clustering of the HIV Fusion Protein gp41 in Lipid Bilayers. J Mol Biol 2021; 434:167345. [PMID: 34762895 DOI: 10.1016/j.jmb.2021.167345] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 10/26/2021] [Accepted: 10/31/2021] [Indexed: 11/16/2022]
Abstract
The envelope glycoprotein (Env) of the human immunodeficient virus (HIV-1) is known to cluster on the viral membrane surface to attach to target cells and cause membrane fusion for HIV-1 infection. However, the molecular structural mechanisms that drive Env clustering remain opaque. Here, we use solid-state NMR spectroscopy and molecular dynamics (MD) simulations to investigate nanometer-scale clustering of the membrane-proximal external region (MPER) and transmembrane domain (TMD) of gp41, the fusion protein component of Env. Using 19F solid-state NMR experiments of mixed fluorinated peptides, we show that MPER-TMD trimers form clusters with interdigitated MPER helices in cholesterol-containing membranes. Inter-trimer 19F-19F cross peaks, which are indicative of spatial contacts within ∼2 nm, are observed in cholesterol-rich virus-mimetic membranes but are suppressed in cholesterol-free model membranes. Water-peptide and lipid-peptide cross peaks in 2D 1H-19F correlation spectra indicate that the MPER is well embedded in model phosphocholine membranes but is more exposed to the surface of the virus-mimetic membrane. These experimental results are reproduced in coarse-grained and atomistic molecular dynamics simulations, which suggest that the effects of cholesterol on gp41 clustering is likely via indirect modulation of the MPER orientation. Cholesterol binding to the helix-turn-helix region of the MPER-TMD causes a parallel orientation of the MPER with the membrane surface, thus allowing MPERs of neighboring trimers to interact with each other to cause clustering. These solid-state NMR data and molecular dynamics simulations suggest that MPER and cholesterol cooperatively govern the clustering of gp41 trimers during virus-cell membrane fusion.
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Affiliation(s)
- Nhi Tran
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States
| | - Younghoon Oh
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, United States
| | - Madeleine Sutherland
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States
| | - Qiang Cui
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, United States; Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, United States; Department of Biomedical Engineering, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, United States.
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States. https://twitter.com/MeiHongLab
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7
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Shcherbakov AA, Medeiros-Silva J, Tran N, Gelenter MD, Hong M. From Angstroms to Nanometers: Measuring Interatomic Distances by Solid-State NMR. Chem Rev 2021; 122:9848-9879. [PMID: 34694769 DOI: 10.1021/acs.chemrev.1c00662] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Internuclear distances represent one of the main structural constraints in molecular structure determination using solid-state NMR spectroscopy, complementing chemical shifts and orientational restraints. Although a large number of magic-angle-spinning (MAS) NMR techniques have been available for distance measurements, traditional 13C and 15N NMR experiments are inherently limited to distances of a few angstroms due to the low gyromagnetic ratios of these nuclei. Recent development of fast MAS triple-resonance 19F and 1H NMR probes has stimulated the design of MAS NMR experiments that measure distances in the 1-2 nm range with high sensitivity. This review describes the principles and applications of these multiplexed multidimensional correlation distance NMR experiments, with an emphasis on 19F- and 1H-based distance experiments. Representative applications of these long-distance NMR methods to biological macromolecules as well as small molecules are reviewed.
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Affiliation(s)
- Alexander A Shcherbakov
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States
| | - João Medeiros-Silva
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States
| | - Nhi Tran
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States
| | - Martin D Gelenter
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, Massachusetts 02139, United States
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8
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Bozdaganyan ME, Orekhov PS, Litvinov DS, Novoseletsky VN. Molecular Modeling of the HR2 and Transmembrane Domains of the SARS-CoV-2 S Protein in the Prefusion State. MOSCOW UNIVERSITY BIOLOGICAL SCIENCES BULLETIN 2021; 76:130-136. [PMID: 34667336 PMCID: PMC8517943 DOI: 10.3103/s0096392521030044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/22/2021] [Accepted: 06/24/2021] [Indexed: 11/30/2022]
Abstract
SARS-CoV-2, the causative agent of COVID-19, remains the focus of research worldwide. SARS-CoV-2 entry into the cell starts with its S protein binding to the angiotensin-converting enzyme-2 (ACE2) expressed on the cell surface. The knowledge of the S protein’s spatial structure is indispensable for understanding the molecular principles of its work. The S protein structure has been almost fully described using experimental approaches with the only exception for the protein’s endodomain, the transmembrane domain, and the ectodomain parts adjacent to the latter. The paper reports molecular modelling of the S protein fragment corresponding to its coiled coil HR2 domain and fully palmitoylated transmembrane domain. Model stability in lipid bilayer was confirmed by all-atom and coarse-grained molecular dynamics simulations. It has been demonstrated that palmitoylation leads to a significant decrease in transmembrane domain mobility and local bilayer thickening, which may be relevant for protein trimerization.
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Affiliation(s)
- M E Bozdaganyan
- Biology Department, Moscow State University, 119234 Moscow, Russia.,Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences, 119991 Moscow, Russia
| | - P S Orekhov
- Biology Department, Moscow State University, 119234 Moscow, Russia.,Institute of Personalized Medicine, Sechenov University, 119435 Moscow, Russia
| | - D S Litvinov
- Biology Department, Moscow State University, 119234 Moscow, Russia
| | - V N Novoseletsky
- Biology Department, Moscow State University, 119234 Moscow, Russia
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9
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Mkrtchyan S, Jakubczyk M, Lanka S, Yar M, Ayub K, Shkoor M, Pittelkow M, Iaroshenko VO. Mechanochemical Transformation of CF
3
Group: Synthesis of Amides and Schiff Bases. Adv Synth Catal 2021. [DOI: 10.1002/adsc.202100538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Satenik Mkrtchyan
- Laboratory of Homogeneous Catalysis and Molecular Design at the Center of Molecular and Macromolecular Studies Polish Academy of Sciences Sienkiewicza 112 PL-90-363 Łodź Poland
| | - Michał Jakubczyk
- Laboratory of Homogeneous Catalysis and Molecular Design at the Center of Molecular and Macromolecular Studies Polish Academy of Sciences Sienkiewicza 112 PL-90-363 Łodź Poland
- Institute of Bioorganic Chemistry Polish Academy of Sciences Noskowskiego 12/14 61-704 Poznań Poland
| | - Suneel Lanka
- Laboratory of Homogeneous Catalysis and Molecular Design at the Center of Molecular and Macromolecular Studies Polish Academy of Sciences Sienkiewicza 112 PL-90-363 Łodź Poland
- Lodz University of Technology Żeromskiego str. 116 90-924 Lodz Poland
| | - Muhammad Yar
- COMSATS University Department of Chemistry Abbottabad Campus Abbottabad, KPK 22060 Pakistan
| | - Khurshid Ayub
- COMSATS University Department of Chemistry Abbottabad Campus Abbottabad, KPK 22060 Pakistan
| | - Mohanad Shkoor
- Department of Chemistry and Earth Sciences Qatar University P.O. Box 2713 Doha Qatar
| | - Michael Pittelkow
- University of Copenhagen Department of Chemistry Universitetsparken 5 2100 Copenhagen Denmark
| | - Viktor O. Iaroshenko
- Laboratory of Homogeneous Catalysis and Molecular Design at the Center of Molecular and Macromolecular Studies Polish Academy of Sciences Sienkiewicza 112 PL-90-363 Łodź Poland
- Department of Chemistry University of Helsinki A.I. Virtasen aukio 1 00014 Helsinki Finland
- Department of Chemistry, Faculty of Natural Sciences Matej Bel University Tajovkého 40 97401 Banska Bystrica Slovakia
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10
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Chiliveri SC, Louis JM, Ghirlando R, Bax A. Transient lipid-bound states of spike protein heptad repeats provide insights into SARS-CoV-2 membrane fusion. SCIENCE ADVANCES 2021; 7:eabk2226. [PMID: 34623907 PMCID: PMC8500521 DOI: 10.1126/sciadv.abk2226] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Entry of SARS-CoV-2 into a host cell is mediated by spike, a class I viral fusion protein responsible for merging the viral and host cell membranes. Recent studies have revealed atomic-resolution models for both the postfusion 6-helix bundle (6HB) and the prefusion state of spike. However, a mechanistic understanding of the molecular basis for the intervening structural transition, important for the design of fusion inhibitors, has remained elusive. Using nuclear magnetic resonance spectroscopy and other biophysical methods, we demonstrate the presence of α-helical, membrane-bound, intermediate states of spike’s heptad repeat (HR1 and HR2) domains that are embedded at the lipid-water interface while in a slow dynamic equilibrium with the postfusion 6HB state. These results support a model where the HR domains lower the large energy barrier associated with membrane fusion by destabilizing the host and viral membranes, while 6HB formation actively drives their fusion by forcing physical proximity.
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Affiliation(s)
- Sai Chaitanya Chiliveri
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
- Corresponding author. (S.C.C.); (A.B.)
| | - John M. Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
- Corresponding author. (S.C.C.); (A.B.)
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11
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Sutherland M, Kwon B, Hong M. Interactions of HIV gp41's membrane-proximal external region and transmembrane domain with phospholipid membranes from 31P NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183723. [PMID: 34352242 DOI: 10.1016/j.bbamem.2021.183723] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/22/2021] [Accepted: 07/30/2021] [Indexed: 11/30/2022]
Abstract
HIV-1 entry into cells requires coordinated changes of the conformation and dynamics of both the fusion protein, gp41, and the lipids in the cell membrane and virus envelope. Commonly proposed features of membrane deformation during fusion include high membrane curvature, lipid disorder, and membrane surface dehydration. The virus envelope and target cell membrane contain a diverse set of phospholipids and cholesterol. To dissect how different lipids interact with gp41 to contribute to membrane fusion, here we use 31P solid-state NMR spectroscopy to investigate the curvature, dynamics, and hydration of POPE, POPC and POPS membranes, with and without cholesterol, in the presence of a peptide comprising the membrane proximal external region (MPER) and transmembrane domain (TMD) of gp41. Static 31P NMR spectra indicate that the MPER-TMD induces strong negative Gaussian curvature (NGC) to the POPE membrane but little curvature to POPC and POPC:POPS membranes. The NGC manifests as an isotropic peak in the static NMR spectra, whose intensity increases with the peptide concentration. Cholesterol inhibits the NGC formation and stabilizes the lamellar phase. Relative intensities of magic-angle spinning 31P cross-polarization and direct-polarization spectra indicate that all three phospholipids become more mobile upon peptide binding. Finally, 2D 1H-31P correlation spectra show that the MPER-TMD enhances water 1H polarization transfer to the lipids, indicating that the membrane surfaces become more hydrated. These results suggest that POPE is an essential component of the high-curvature fusion site, and lipid dynamic disorder is a general feature of membrane restructuring during fusion.
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Affiliation(s)
- Madeleine Sutherland
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Byungsu Kwon
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.
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12
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Caillat C, Guilligay D, Torralba J, Friedrich N, Nieva JL, Trkola A, Chipot CJ, Dehez FL, Weissenhorn W. Structure of HIV-1 gp41 with its membrane anchors targeted by neutralizing antibodies. eLife 2021; 10:65005. [PMID: 33871352 PMCID: PMC8084527 DOI: 10.7554/elife.65005] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 04/18/2021] [Indexed: 12/19/2022] Open
Abstract
The HIV-1 gp120/gp41 trimer undergoes a series of conformational changes in order to catalyze gp41-induced fusion of viral and cellular membranes. Here, we present the crystal structure of gp41 locked in a fusion intermediate state by an MPER-specific neutralizing antibody. The structure illustrates the conformational plasticity of the six membrane anchors arranged asymmetrically with the fusion peptides and the transmembrane regions pointing into different directions. Hinge regions located adjacent to the fusion peptide and the transmembrane region facilitate the conformational flexibility that allows high-affinity binding of broadly neutralizing anti-MPER antibodies. Molecular dynamics simulation of the MPER Ab-stabilized gp41 conformation reveals a possible transition pathway into the final post-fusion conformation with the central fusion peptides forming a hydrophobic core with flanking transmembrane regions. This suggests that MPER-specific broadly neutralizing antibodies can block final steps of refolding of the fusion peptide and the transmembrane region, which is required for completing membrane fusion.
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Affiliation(s)
- Christophe Caillat
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Delphine Guilligay
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), Grenoble, France
| | - Johana Torralba
- Instituto Biofisika (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Nikolas Friedrich
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Jose L Nieva
- Instituto Biofisika (CSIC, UPV/EHU) and Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), Bilbao, Spain
| | - Alexandra Trkola
- Institute of Medical Virology, University of Zurich, Zurich, Switzerland
| | - Christophe J Chipot
- Laboratoire de Physique et Chimie Théoriques (LPCT), University of Lorraine, Vandoeuvre-lès-Nancy, France.,Laboratoire International Associé, CNRS and University of Illinois at Urbana-Champaign, Vandoeuvre-lès-Nancy, France.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
| | - François L Dehez
- Laboratoire de Physique et Chimie Théoriques (LPCT), University of Lorraine, Vandoeuvre-lès-Nancy, France.,Laboratoire International Associé, CNRS and University of Illinois at Urbana-Champaign, Vandoeuvre-lès-Nancy, France
| | - Winfried Weissenhorn
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), Grenoble, France
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13
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de la Arada I, Torralba J, Tascón I, Colom A, Ubarretxena-Belandia I, Arrondo JLR, Apellániz B, Nieva JL. Conformational plasticity underlies membrane fusion induced by an HIV sequence juxtaposed to the lipid envelope. Sci Rep 2021; 11:1278. [PMID: 33446748 PMCID: PMC7809034 DOI: 10.1038/s41598-020-80156-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/13/2020] [Indexed: 01/05/2023] Open
Abstract
Envelope glycoproteins from genetically-divergent virus families comprise fusion peptides (FPs) that have been posited to insert and perturb the membranes of target cells upon activation of the virus-cell fusion reaction. Conserved sequences rich in aromatic residues juxtaposed to the external leaflet of the virion-wrapping membranes are also frequently found in viral fusion glycoproteins. These membrane-proximal external regions (MPERs) have been implicated in the promotion of the viral membrane restructuring event required for fusion to proceed, hence, proposed to comprise supplementary FPs. However, it remains unknown whether the structure–function relationships governing canonical FPs also operate in the mirroring MPER sequences. Here, we combine infrared spectroscopy-based approaches with cryo-electron microscopy to analyze the alternating conformations adopted, and perturbations generated in membranes by CpreTM, a peptide derived from the MPER of the HIV-1 Env glycoprotein. Altogether, our structural and morphological data support a cholesterol-dependent conformational plasticity for this HIV-1 sequence, which could assist cell-virus fusion by destabilizing the viral membrane at the initial stages of the process.
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Affiliation(s)
- Igor de la Arada
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080, Bilbao, Spain
| | - Johana Torralba
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080, Bilbao, Spain.,Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080, Bilbao, Spain
| | - Igor Tascón
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080, Bilbao, Spain.,Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain
| | - Adai Colom
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080, Bilbao, Spain.,Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080, Bilbao, Spain.,Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain
| | - Iban Ubarretxena-Belandia
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080, Bilbao, Spain.,Ikerbasque, Basque Foundation for Science, 48013, Bilbao, Spain
| | - José L R Arrondo
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080, Bilbao, Spain.,Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080, Bilbao, Spain
| | - Beatriz Apellániz
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country (UPV/EHU), Paseo de la Universidad, 7, 01006, Vitoria-Gasteiz, Spain
| | - José L Nieva
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080, Bilbao, Spain. .,Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080, Bilbao, Spain.
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14
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Fake It 'Till You Make It-The Pursuit of Suitable Membrane Mimetics for Membrane Protein Biophysics. Int J Mol Sci 2020; 22:ijms22010050. [PMID: 33374526 PMCID: PMC7793082 DOI: 10.3390/ijms22010050] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/17/2020] [Accepted: 12/19/2020] [Indexed: 12/13/2022] Open
Abstract
Membrane proteins evolved to reside in the hydrophobic lipid bilayers of cellular membranes. Therefore, membrane proteins bridge the different aqueous compartments separated by the membrane, and furthermore, dynamically interact with their surrounding lipid environment. The latter not only stabilizes membrane proteins, but directly impacts their folding, structure and function. In order to be characterized with biophysical and structural biological methods, membrane proteins are typically extracted and subsequently purified from their native lipid environment. This approach requires that lipid membranes are replaced by suitable surrogates, which ideally closely mimic the native bilayer, in order to maintain the membrane proteins structural and functional integrity. In this review, we survey the currently available membrane mimetic environments ranging from detergent micelles to bicelles, nanodiscs, lipidic-cubic phase (LCP), liposomes, and polymersomes. We discuss their respective advantages and disadvantages as well as their suitability for downstream biophysical and structural characterization. Finally, we take a look at ongoing methodological developments, which aim for direct in-situ characterization of membrane proteins within native membranes instead of relying on membrane mimetics.
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15
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Ding WQ, Liu H, Qin SY, Jiang Y, Lei X, Zhang AQ. A Lyotropic Liquid Crystal from a Flexible Oligopeptide Amphiphile in Dimethyl Sulfoxide. ACS APPLIED BIO MATERIALS 2020; 3:8989-8996. [PMID: 35019575 DOI: 10.1021/acsabm.0c01231] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Despite the rapid progress in peptide liquid crystals (LCs) due to their prominent properties, our investigation on flexible peptide-based LCs is incomplete, mainly resulted from their unclear formation mechanisms and unexploited applications in organic solvents. Here, we develop a lyotropic LC based on a flexible oligopeptide amphiphile, which aggregates into aligned cylinder-like nanostructures in dimethyl sulfoxide (DMSO). The formation mechanism of lyotropic LC in DMSO was probed by the experimental investigation and molecular dynamics simulation, indicating that the hydrogen bonding and hydrophobic and electrostatic interactions contribute to the formation of ordered nanostructures in the organic solvent. Arising from the orientational order and suitable fluidity, we exploit the application of lyotropic LC as an aligned medium to measure the residual dipolar couplings of bioactive molecules. This study not only offers the understanding of the mechanism to create LC systems without rigid aromatic groups but also expands the applications of ordered bottom-up nanomaterials in organic solvents.
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Affiliation(s)
- Wen-Qiang Ding
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science, South-Central University for Nationalities, Wuhan 430074, China
| | - Han Liu
- School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, China
| | - Si-Yong Qin
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science, South-Central University for Nationalities, Wuhan 430074, China
| | - Yan Jiang
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science, South-Central University for Nationalities, Wuhan 430074, China
| | - Xinxiang Lei
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science, South-Central University for Nationalities, Wuhan 430074, China.,School of Pharmaceutical Sciences, South-Central University for Nationalities, Wuhan 430074, China
| | - Ai-Qing Zhang
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science, South-Central University for Nationalities, Wuhan 430074, China
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16
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Aisenbrey C, Rifi O, Bechinger B. Structure, membrane topology and influence of cholesterol of the membrane proximal region: transmembrane helical anchor sequence of gp41 from HIV. Sci Rep 2020; 10:22278. [PMID: 33335248 PMCID: PMC7746737 DOI: 10.1038/s41598-020-79327-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 11/30/2020] [Indexed: 11/13/2022] Open
Abstract
During the first steps of HIV infection the Env subunit gp41 is thought to establish contact between the membranes and to be the main driver of fusion. Here we investigated in liquid crystalline membranes the structure and cholesterol recognition of constructs made of a gp41 external region carrying a cholesterol recognition amino acid consensus (CRAC) motif and a hydrophobic membrane anchoring sequence. CD- und ATR-FTIR spectroscopies indicate that the constructs adopt a high degree of helical secondary structure in membrane environments. Furthermore, 15N and 2H solid-state NMR spectra of gp41 polypeptides reconstituted into uniaxially oriented bilayers agree with the CRAC domain being an extension of the transmembrane helix. Upon addition of cholesterol the CRAC NMR spectra remain largely unaffected when being associated with the native gp41 transmembrane sequence but its topology changes when anchored in the membrane by a hydrophobic model sequence. The 2H solid-state NMR spectra of deuterated cholesterol are indicative of a stronger influence of the model sequence on this lipid when compared to the native gp41 sequence. These observations are suggestive of a strong coupling between the transmembrane and the membrane proximal region of gp41 possibly enforced by oligomerization of the transmembrane helical region.
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Affiliation(s)
- Christopher Aisenbrey
- Institut de chimie de Strasbourg, UMR7177, University of Strasbourg/CNRS, 4, Rue Blaise Pascal, 67070, Strasbourg, France
| | - Omar Rifi
- Institut de chimie de Strasbourg, UMR7177, University of Strasbourg/CNRS, 4, Rue Blaise Pascal, 67070, Strasbourg, France
| | - Burkhard Bechinger
- Institut de chimie de Strasbourg, UMR7177, University of Strasbourg/CNRS, 4, Rue Blaise Pascal, 67070, Strasbourg, France.
- Institut Universitaire de France, Paris, France.
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17
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Caillat C, Guilligay D, Sulbaran G, Weissenhorn W. Neutralizing Antibodies Targeting HIV-1 gp41. Viruses 2020; 12:E1210. [PMID: 33114242 PMCID: PMC7690876 DOI: 10.3390/v12111210] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/20/2020] [Accepted: 10/20/2020] [Indexed: 12/21/2022] Open
Abstract
HIV-1 vaccine research has obtained an enormous boost since the discovery of many broadly neutralizing antibodies (bnAbs) targeting all accessible sites on the HIV-1 envelope glycoprotein (Env). This in turn facilitated high-resolution structures of the Env glycoprotein in complex with bnAbs. Here we focus on gp41, its highly conserved heptad repeat region 1 (HR1), the fusion peptide (FP) and the membrane-proximal external region (MPER). Notably, the broadest neutralizing antibodies target MPER. Both gp41 HR1 and MPER are only fully accessible once receptor-induced conformational changes have taken place, although some studies suggest access to MPER in the close to native Env conformation. We summarize the data on the structure and function of neutralizing antibodies targeting gp41 HR1, FP and MPER and we review their access to Env and their complex formation with gp41 HR1, MPER peptides and FP within native Env. We further discuss MPER bnAb binding to lipids and the role of somatic mutations in recognizing a bipartite epitope composed of the conserved MPER sequence and membrane components. The problematic of gp41 HR1 access and MPER bnAb auto- and polyreactivity is developed in the light of inducing such antibodies by vaccination.
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Affiliation(s)
- Christophe Caillat
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, Commissariat à L'énergie Atomique et Aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), 38000 Grenoble, France
| | - Delphine Guilligay
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, Commissariat à L'énergie Atomique et Aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), 38000 Grenoble, France
| | - Guidenn Sulbaran
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, Commissariat à L'énergie Atomique et Aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), 38000 Grenoble, France
| | - Winfried Weissenhorn
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, Commissariat à L'énergie Atomique et Aux Énergies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), 38000 Grenoble, France
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18
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Torralba J, de la Arada I, Carravilla P, Insausti S, Rujas E, Largo E, Eggeling C, Arrondo JLR, Apellániz B, Nieva JL. Cholesterol Constrains the Antigenic Configuration of the Membrane-Proximal Neutralizing HIV-1 Epitope. ACS Infect Dis 2020; 6:2155-2168. [PMID: 32584020 DOI: 10.1021/acsinfecdis.0c00243] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The envelope glycoprotein (Env) enables HIV-1 cell entry through fusion of host-cell and viral membranes induced by the transmembrane subunit gp41. Antibodies targeting the C-terminal sequence of the membrane-proximal external region (C-MPER) block the fusogenic activity of gp41 and achieve neutralization of divergent HIV-1 strains and isolates. Thus, recreating the structure that generates broadly neutralizing C-MPER antibodies during infection is a major goal in HIV vaccine development. Here, we have reconstituted a peptide termed CpreTM-TMD in a membrane environment. This peptide contains the C-MPER epitope and the minimum TMD residues required for the anchorage of the Env glycoprotein to the viral membrane. In addition, we have used antibody 10E8 variants to gauge the antigenic configuration attained by CpreTM-TMD as a function of the membrane cholesterol content, a functional determinant of the HIV envelope and liposome-based vaccines. Differential binding of the 10E8 variants and the trend of the IgG responses recovered from rabbits immunized with liposome-peptide formulations, suggested that cholesterol may restrict 10E8 accessibility to the C-MPER epitope. Our data ruled out the destabilization of the lipid bilayer architecture in CpreTM-TMD-containing membranes, and pointed to the perturbation of the helical conformation by lipid packing as the cause of the antigenic configuration loss induced by cholesterol. Overall, our results provide additional insights into the structural basis of the Env complex anchoring to membranes, and suggest new approaches to the design of effective immunogens directed against the near pan-neutralizing HIV-1 epitope C-MPER.
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Affiliation(s)
- Johana Torralba
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Igor de la Arada
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Pablo Carravilla
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743 Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Sara Insausti
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Edurne Rujas
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Eneko Largo
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Immunology, Microbiology and Parasitology, Medicine and Odontology Faculty, University of Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Christian Eggeling
- Institute of Applied Optics and Biophysics, Friedrich-Schiller-University Jena, Max-Wien Platz 1, 07743 Jena, Germany
- Leibniz Institute of Photonic Technology e.V., Albert-Einstein-Straße 9, 07745 Jena, Germany
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Headley Way, OX3 9DS Oxford, U.K
| | - José L R Arrondo
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - Beatriz Apellániz
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country (UPV/EHU), Paseo de la Universidad, 7, 01006 Vitoria-Gasteiz, Spain
| | - José L Nieva
- Biofisika Institute (CSIC, UPV/EHU), University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
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19
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Kwon B, Mandal T, Elkins MR, Oh Y, Cui Q, Hong M. Cholesterol Interaction with the Trimeric HIV Fusion Protein gp41 in Lipid Bilayers Investigated by Solid-State NMR Spectroscopy and Molecular Dynamics Simulations. J Mol Biol 2020; 432:4705-4721. [PMID: 32592698 PMCID: PMC7781112 DOI: 10.1016/j.jmb.2020.06.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/07/2020] [Accepted: 06/18/2020] [Indexed: 12/13/2022]
Abstract
HIV-1 entry into cells is mediated by the fusion protein gp41. Cholesterol plays an important role in this virus-cell fusion, but molecular structural information about cholesterol-gp41 interaction is so far absent. Here, we present experimental and computational data about cholesterol complexation with gp41 in lipid bilayers. We focus on the C-terminal region of the protein, which comprises a membrane-proximal external region (MPER) and the transmembrane domain (TMD). We measured peptide-cholesterol contacts in virus-mimetic lipid bilayers using solid-state NMR spectroscopy, and augmented these experimental data with all-atom molecular dynamics simulations. 2D 19F NMR spectra show correlation peaks between MPER residues and the cholesterol isooctyl tail, indicating that cholesterol is in molecular contact with the MPER-TMD trimer. 19F-13C distance measurements between the peptide and 13C-labeled cholesterol show that C17 on the D ring and C9 at the intersection of B and C rings are ~7.0 Å from the F673 side-chain 4-19F. At high peptide concentrations in the membrane, the 19F-13C distance data indicate three cholesterol molecules bound near F673 in each trimer. Mutation of a cholesterol recognition amino acid consensus motif did not change these distances, indicating that cholesterol binding does not require this sequence motif. Molecular dynamics simulations further identify two hotspots for cholesterol interactions. Taken together, these experimental data and simulations indicate that the helix-turn-helix conformation of the MPER-TMD is responsible for sequestering cholesterol. We propose that this gp41-cholesterol interaction mediates virus-cell fusion by recruiting gp41 to the boundary of the liquid-disordered and liquid-ordered phases to incur membrane curvature.
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Affiliation(s)
- Byungsu Kwon
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, USA
| | - Taraknath Mandal
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA
| | - Matthew R Elkins
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, USA
| | - Younghoon Oh
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA
| | - Qiang Cui
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA; Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA; Department of Biomedical Engineering, Boston University, 590 Commonwealth Avenue, Boston, MA 02215, USA
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, USA.
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20
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Structure, interactions and membrane topology of HIV gp41 ectodomain sequences. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183274. [DOI: 10.1016/j.bbamem.2020.183274] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/06/2020] [Accepted: 03/10/2020] [Indexed: 11/21/2022]
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21
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Schmidt T, Jeon J, Okuno Y, Chiliveri SC, Clore GM. Submillisecond Freezing Permits Cryoprotectant-Free EPR Double Electron-Electron Resonance Spectroscopy. Chemphyschem 2020; 21:1224-1229. [PMID: 32383308 DOI: 10.1002/cphc.202000312] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/06/2020] [Indexed: 01/22/2023]
Abstract
Double electron-electron resonance (DEER) EPR spectroscopy is a powerful method for obtaining distance distributions between pairs of engineered nitroxide spin-labels in proteins and other biological macromolecules. These measurements require the use of cryogenic temperatures (77 K or less) to prolong the phase memory relaxation time (Tm ) sufficiently to enable detection of a DEER echo curve. Generally, a cryoprotectant such as glycerol is added to protein samples to facilitate glass formation and avoid protein clustering (which can result in a large decrease in Tm ) during relatively slow flash freezing in liquid N2 . However, cryoprotectants are osmolytes and can influence protein folding/unfolding equilibria, as well as species populations in weak multimeric systems. Here we show that submillisecond rapid freezing, achieved by high velocity spraying of the sample onto a rapidly spinning, liquid nitrogen cooled copper disc obviates the requirement for cryoprotectants and permits high quality DEER data to be obtained in absence of glycerol. We demonstrate this approach on five different protein systems: protein A, the metastable drkN SH3 domain, urea-unfolded drkN SH3, HIV-1 reverse transcriptase, and the transmembrane domain of HIV-1 gp41 in lipid bicelles.
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Affiliation(s)
- Thomas Schmidt
- Laboratory of Chemical Physics, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - Jaekyun Jeon
- Laboratory of Chemical Physics, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - Yusuke Okuno
- Laboratory of Chemical Physics, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - Sai C Chiliveri
- Laboratory of Chemical Physics, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - G Marius Clore
- Laboratory of Chemical Physics, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
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22
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Murphy RE, Saad JS. The Interplay between HIV-1 Gag Binding to the Plasma Membrane and Env Incorporation. Viruses 2020; 12:E548. [PMID: 32429351 PMCID: PMC7291237 DOI: 10.3390/v12050548] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/14/2020] [Accepted: 05/14/2020] [Indexed: 12/21/2022] Open
Abstract
Advancement in drug therapies and patient care have drastically improved the mortality rates of HIV-1 infected individuals. Many of these therapies were developed or improved upon by using structure-based techniques, which underscore the importance of understanding essential mechanisms in the replication cycle of HIV-1 at the structural level. One such process which remains poorly understood is the incorporation of the envelope glycoprotein (Env) into budding virus particles. Assembly of HIV particles is initiated by targeting of the Gag polyproteins to the inner leaflet of the plasma membrane (PM), a process mediated by the N-terminally myristoylated matrix (MA) domain and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). There is strong evidence that formation of the Gag lattice on the PM is a prerequisite for the incorporation of Env into budding particles. It is also suggested that Env incorporation is mediated by an interaction between its cytoplasmic tail (gp41CT) and the MA domain of Gag. In this review, we highlight the latest developments and current efforts to understand the interplay between gp41CT, MA, and the membrane during assembly. Elucidation of the molecular determinants of Gag-Env-membrane interactions may help in the development of new antiviral therapeutic agents that inhibit particle assembly, Env incorporation and ultimately virus production.
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Affiliation(s)
| | - Jamil S. Saad
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
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23
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Rantalainen K, Berndsen ZT, Antanasijevic A, Schiffner T, Zhang X, Lee WH, Torres JL, Zhang L, Irimia A, Copps J, Zhou KH, Kwon YD, Law WH, Schramm CA, Verardi R, Krebs SJ, Kwong PD, Doria-Rose NA, Wilson IA, Zwick MB, Yates JR, Schief WR, Ward AB. HIV-1 Envelope and MPER Antibody Structures in Lipid Assemblies. Cell Rep 2020; 31:107583. [PMID: 32348769 PMCID: PMC7196886 DOI: 10.1016/j.celrep.2020.107583] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 03/05/2020] [Accepted: 04/07/2020] [Indexed: 11/25/2022] Open
Abstract
Structural and functional studies of HIV envelope glycoprotein (Env) as a transmembrane protein have long been complicated by challenges associated with inherent flexibility of the molecule and the membrane-embedded hydrophobic regions. Here, we present approaches for incorporating full-length, wild-type HIV-1 Env, as well as C-terminally truncated and stabilized versions, into lipid assemblies, providing a modular platform for Env structural studies by single particle electron microscopy. We reconstitute a full-length Env clone into a nanodisc, complex it with a membrane-proximal external region (MPER) targeting antibody 10E8, and structurally define the full quaternary epitope of 10E8 consisting of lipid, MPER, and ectodomain contacts. By aligning this and other Env-MPER antibody complex reconstructions with the lipid bilayer, we observe evidence of Env tilting as part of the neutralization mechanism for MPER-targeting antibodies. We also adapt the platform toward vaccine design purposes by introducing stabilizing mutations that allow purification of unliganded Env with a peptidisc scaffold.
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Affiliation(s)
- Kimmo Rantalainen
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Zachary T Berndsen
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Aleksandar Antanasijevic
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Torben Schiffner
- Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, CA 92037, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Xi Zhang
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
| | - Wen-Hsin Lee
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jonathan L Torres
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Lei Zhang
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Adriana Irimia
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA; Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jeffrey Copps
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Kenneth H Zhou
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Young D Kwon
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - William H Law
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Chaim A Schramm
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Raffaello Verardi
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Shelly J Krebs
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA
| | - Peter D Kwong
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Nicole A Doria-Rose
- Vaccine Research Center, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, MD 20892, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA; Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, CA 92037, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Michael B Zwick
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - John R Yates
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA, USA
| | - William R Schief
- International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA; Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, CA 92037, USA; Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, USA; Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02129, USA
| | - Andrew B Ward
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA; International AIDS Vaccine Initiative Neutralizing Antibody Center, The Scripps Research Institute, La Jolla, CA 92037, USA; Center for HIV/AIDS Vaccine Development, The Scripps Research Institute, La Jolla, CA 92037, USA.
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24
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Pinto D, Fenwick C, Caillat C, Silacci C, Guseva S, Dehez F, Chipot C, Barbieri S, Minola A, Jarrossay D, Tomaras GD, Shen X, Riva A, Tarkowski M, Schwartz O, Bruel T, Dufloo J, Seaman MS, Montefiori DC, Lanzavecchia A, Corti D, Pantaleo G, Weissenhorn W. Structural Basis for Broad HIV-1 Neutralization by the MPER-Specific Human Broadly Neutralizing Antibody LN01. Cell Host Microbe 2019; 26:623-637.e8. [PMID: 31653484 PMCID: PMC6854463 DOI: 10.1016/j.chom.2019.09.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/29/2019] [Accepted: 09/27/2019] [Indexed: 11/24/2022]
Abstract
Potent and broadly neutralizing antibodies (bnAbs) are the hallmark of HIV-1 protection by vaccination. The membrane-proximal external region (MPER) of the HIV-1 gp41 fusion protein is targeted by the most broadly reactive HIV-1 neutralizing antibodies. Here, we examine the structural and molecular mechansims of neutralization by anti-MPER bnAb, LN01, which was isolated from lymph-node-derived germinal center B cells of an elite controller and exhibits broad neutralization breadth. LN01 engages both MPER and the transmembrane (TM) region, which together form a continuous helix in complex with LN01. The tilted TM orientation allows LN01 to interact simultaneously with the peptidic component of the MPER epitope and membrane via two specific lipid binding sites of the antibody paratope. Although LN01 carries a high load of somatic mutations, most key residues interacting with the MPER epitope and lipids are germline encoded, lending support for the LN01 epitope as a candidate for lineage-based vaccine development. bNAb LN01 neutralizes 92% of a 118-strain virus panel LN01 targets the HIV-1 gp41 MPER, the TM region, and lipids LN01-complexed MPER forms a continuous helix with TM Most LN01 paratope residues interacting with MPER-TM and lipids are germline encoded
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Affiliation(s)
- Dora Pinto
- Institute for Research in Biomedicine, Bellinzona 6500, Ticino, Switzerland
| | - Craig Fenwick
- Swiss Vaccine Research Institute, Lausanne University Hospital, University of Lausanne, 1011 Lausanne, Switzerland
| | - Christophe Caillat
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38000 Grenoble, France
| | - Chiara Silacci
- Institute for Research in Biomedicine, Bellinzona 6500, Ticino, Switzerland
| | - Serafima Guseva
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38000 Grenoble, France
| | - François Dehez
- LPCT, UMR 7019 Université de Lorraine CNRS, 54500 Vandœuvre-lès-Nancy, France; Laboratoire International Associé CNRS and University of Illinois at Urbana-Champaign, LPCT, UMR 7019 Universiteé de Lorraine CNRS, Vandœuvre-lès-Nancy 54500, France
| | - Christophe Chipot
- LPCT, UMR 7019 Université de Lorraine CNRS, 54500 Vandœuvre-lès-Nancy, France; Laboratoire International Associé CNRS and University of Illinois at Urbana-Champaign, LPCT, UMR 7019 Universiteé de Lorraine CNRS, Vandœuvre-lès-Nancy 54500, France; Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Sonia Barbieri
- Institute for Research in Biomedicine, Bellinzona 6500, Ticino, Switzerland
| | - Andrea Minola
- Humabs Biomed SA, Vir Biotechnology, 6500 Bellinzona, Ticino, Switzerland
| | - David Jarrossay
- Institute for Research in Biomedicine, Bellinzona 6500, Ticino, Switzerland
| | - Georgia D Tomaras
- Duke Human Vaccine Institute, Durham, NC 27710, USA; Paris Diderot University, Sorbonne Paris Cité, Paris 75013, France
| | | | - Agostino Riva
- Department of Biomedical and Clinical Sciences, Luigi Sacco University Hospital, Università di Milano, 20157 Milan, Italy; III Division of Infectious Diseases, ASST Fatebenefratelli-Sacco, 20157 Milan, Italy
| | - Maciej Tarkowski
- Department of Biomedical and Clinical Sciences, Luigi Sacco University Hospital, Università di Milano, 20157 Milan, Italy
| | - Olivier Schwartz
- Institut Pasteur, Virus & Immunity Unit, CNRS UMR 3569, Paris 75015, France; Vaccine Research Institute, 94000 Créteil, France
| | - Timothée Bruel
- Institut Pasteur, Virus & Immunity Unit, CNRS UMR 3569, Paris 75015, France; Vaccine Research Institute, 94000 Créteil, France
| | - Jérémy Dufloo
- Institut Pasteur, Virus & Immunity Unit, CNRS UMR 3569, Paris 75015, France; Vaccine Research Institute, 94000 Créteil, France; Paris Diderot University, Sorbonne Paris Cité, Paris 75013, France
| | - Michael S Seaman
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - David C Montefiori
- Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA
| | | | - Davide Corti
- Humabs Biomed SA, Vir Biotechnology, 6500 Bellinzona, Ticino, Switzerland.
| | - Giuseppe Pantaleo
- Swiss Vaccine Research Institute, Lausanne University Hospital, University of Lausanne, 1011 Lausanne, Switzerland; Service of Immunology and Allergy, Lausanne University Hospital, University of Lausanne, 1011 Lausanne, Switzerland.
| | - Winfried Weissenhorn
- Institut de Biologie Structurale (IBS), University Grenoble Alpes, CEA, CNRS, 38000 Grenoble, France.
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25
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Topological analysis of the gp41 MPER on lipid bilayers relevant to the metastable HIV-1 envelope prefusion state. Proc Natl Acad Sci U S A 2019; 116:22556-22566. [PMID: 31624123 DOI: 10.1073/pnas.1912427116] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The membrane proximal external region (MPER) of HIV-1 envelope glycoprotein (gp) 41 is an attractive vaccine target for elicitation of broadly neutralizing antibodies (bNAbs) by vaccination. However, current details regarding the quaternary structural organization of the MPER within the native prefusion trimer [(gp120/41)3] are elusive and even contradictory, hindering rational MPER immunogen design. To better understand the structural topology of the MPER on the lipid bilayer, the adjacent transmembrane domain (TMD) was appended (MPER-TMD) and studied. Membrane insertion of the MPER-TMD was sensitive both to the TMD sequence and cytoplasmic residues. Antigen binding of MPER-specific bNAbs, in particular 10E8 and DH511.2_K3, was significantly impacted by the presence of the TMD. Furthermore, MPER-TMD assembly into 10-nm diameter nanodiscs revealed a heterogeneous membrane array comprised largely of monomers and dimers, as enumerated by bNAb Fab binding using single-particle electron microscopy analysis, arguing against preferential trimeric association of native MPER and TMD protein segments. Moreover, introduction of isoleucine mutations in the C-terminal heptad repeat to induce an extended MPER α-helical bundle structure yielded an antigenicity profile of cell surface-arrayed Env variants inconsistent with that found in the native prefusion state. In line with these observations, electron paramagnetic resonance analysis suggested that 10E8 inhibits viral membrane fusion by lifting the MPER N-terminal region out of the viral membrane, mandating the exposure of residues that would be occluded by MPER trimerization. Collectively, our data suggest that the MPER is not a stable trimer, but rather a dynamic segment adapted for structural changes accompanying fusion.
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26
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Joss D, Häussinger D. Design and applications of lanthanide chelating tags for pseudocontact shift NMR spectroscopy with biomacromolecules. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:284-312. [PMID: 31779884 DOI: 10.1016/j.pnmrs.2019.08.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/21/2019] [Accepted: 08/24/2019] [Indexed: 05/14/2023]
Abstract
In this review, lanthanide chelating tags and their applications to pseudocontact shift NMR spectroscopy as well as analysis of residual dipolar couplings are covered. A complete overview is presented of DOTA-derived and non-DOTA-derived lanthanide chelating tags, critical points in the design of lanthanide chelating tags as appropriate linker moieties, their stability under reductive conditions, e.g., for in-cell applications, the magnitude of the anisotropy transferred from the lanthanide chelating tag to the biomacromolecule under investigation and structural properties, as well as conformational bias of the lanthanide chelating tags are discussed. Furthermore, all DOTA-derived lanthanide chelating tags used for PCS NMR spectroscopy published to date are displayed in tabular form, including their anisotropy parameters, with all employed lanthanide ions, CB-Ln distances and tagging reaction conditions, i.e., the stoichiometry of lanthanide chelating tags, pH, buffer composition, temperature and reaction time. Additionally, applications of lanthanide chelating tags for pseudocontact shifts and residual dipolar couplings that have been reported for proteins, protein-protein and protein-ligand complexes, carbohydrates, carbohydrate-protein complexes, nucleic acids and nucleic acid-protein complexes are presented and critically reviewed. The vast and impressive range of applications of lanthanide chelating tags to structural investigations of biomacromolecules in solution clearly illustrates the significance of this particular field of research. The extension of the repertoire of lanthanide chelating tags from proteins to nucleic acids holds great promise for the determination of valuable structural parameters and further developments in characterizing intermolecular interactions.
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Affiliation(s)
- Daniel Joss
- University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland.
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27
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Puthenveetil R, Vinogradova O. Solution NMR: A powerful tool for structural and functional studies of membrane proteins in reconstituted environments. J Biol Chem 2019; 294:15914-15931. [PMID: 31551353 DOI: 10.1074/jbc.rev119.009178] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A third of the genes in prokaryotic and eukaryotic genomes encode membrane proteins that are either essential for signal transduction and solute transport or function as scaffold structures. Unlike many of their soluble counterparts, the overall structural and functional organization of membrane proteins is sparingly understood. Recent advances in X-ray crystallography, cryo-EM, and nuclear magnetic resonance (NMR) are closing this gap by enabling an in-depth view of these ever-elusive proteins at atomic resolution. Despite substantial technological advancements, however, the overall proportion of membrane protein entries in the Protein Data Bank (PDB) remains <4%. This paucity is mainly attributed to difficulties associated with their expression and purification, propensity to form large multisubunit complexes, and challenges pertinent to identification of an ideal detergent, lipid, or detergent/lipid mixture that closely mimic their native environment. NMR is a powerful technique to obtain atomic-resolution and dynamic details of a protein in solution. This is accomplished through an assortment of isotopic labeling schemes designed to acquire multiple spectra that facilitate deduction of the final protein structure. In this review, we discuss current approaches and technological developments in the determination of membrane protein structures by solution NMR and highlight recent structural and mechanistic insights gained with this technique. We also discuss strategies for overcoming size limitations in NMR applications, and we explore a plethora of membrane mimetics available for the structural and mechanistic understanding of these essential cellular proteins.
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Affiliation(s)
- Robbins Puthenveetil
- Department of Molecular and Cell Biology, college of liberal arts and sciences, University of Connecticut at Storrs, Storrs, Connecticut 06269
| | - Olga Vinogradova
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut at Storrs, Storrs, Connecticut 06269
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28
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Hollingsworth LR, Lemkul JA, Bevan DR, Brown AM. HIV-1 Env gp41 Transmembrane Domain Dynamics Are Modulated by Lipid, Water, and Ion Interactions. Biophys J 2019; 115:84-94. [PMID: 29972814 DOI: 10.1016/j.bpj.2018.05.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/04/2018] [Accepted: 05/21/2018] [Indexed: 12/20/2022] Open
Abstract
The gp41 transmembrane domain (TMD) of the envelope glycoprotein of the human immunodeficiency virus modulates the conformation of the viral envelope spike, the only druggable target on the surface of the virion. Targeting the envelope glycoprotein with small-molecule and antibody therapies requires an understanding of gp41 TMD dynamics, which is often challenging given the difficulties in describing native membrane properties. Here, atomistic molecular dynamics simulations of a trimeric, prefusion gp41 TMD in a model, asymmetric viral membrane that mimics the native viral envelope were performed. Water and chloride ions were observed to permeate the membrane and interact with the highly conserved arginine bundle, (R696)3, at the center of the membrane and influenced TMD stability by creating a network of hydrogen bonds and electrostatic interactions. We propose that this (R696)3 - water - anion network plays an important role in viral fusion with the host cell by modulating protein conformational changes within the membrane. Additionally, R683 and R707 at the exofacial and cytofacial membrane-water interfaces, respectively, are anchored in the lipid headgroup region and serve as a junction point for stabilization of the termini. The membrane thins as a result of the tilting of the gp41 trimer with nearby lipids increasing in volume, leading to an entropic driving force for TMD conformational change. These results provide additional detail and perspective on the influence of certain lipid types on TMD dynamics and a rationale for targeting key residues of the TMD for therapeutic design. These insights into the molecular details of TMD membrane anchoring will build toward a greater understanding of the dynamics that lead to viral fusion with the host cell.
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Affiliation(s)
| | - Justin A Lemkul
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia; Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia
| | - David R Bevan
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia; Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia
| | - Anne M Brown
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia; Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia; University Libraries, Virginia Tech, Blacksburg, Virginia.
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29
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Lee M, Morgan CA, Hong M. Fully hydrophobic HIV gp41 adopts a hemifusion-like conformation in phospholipid bilayers. J Biol Chem 2019; 294:14732-14744. [PMID: 31409642 DOI: 10.1074/jbc.ra119.009542] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 08/04/2019] [Indexed: 11/06/2022] Open
Abstract
The HIV envelope glycoprotein mediates virus entry into target cells by fusing the virus lipid envelope with the cell membrane. This process requires large-scale conformational changes of the fusion protein gp41. Current understanding of the mechanisms with which gp41 induces membrane merger is limited by the fact that the hydrophobic N-terminal fusion peptide (FP) and C-terminal transmembrane domain (TMD) of the protein are challenging to characterize structurally in the lipid bilayer. Here we have expressed a gp41 construct that contains both termini, including the FP, the fusion peptide-proximal region (FPPR), the membrane-proximal external region (MPER), and the TMD. These hydrophobic domains are linked together by a shortened water-soluble ectodomain. We reconstituted this "short NC" gp41 into a virus-mimetic lipid membrane and conducted solid-state NMR experiments to probe the membrane-bound conformation and topology of the protein. 13C chemical shifts indicate that the C-terminal MPER-TMD is predominantly α-helical, whereas the N-terminal FP-FPPR exhibits β-sheet character. Water and lipid 1H polarization transfer to the protein revealed that the TMD is well-inserted into the lipid bilayer, whereas the FPPR and MPER are exposed to the membrane surface. Importantly, correlation signals between the FP-FPPR and the MPER are observed, providing evidence that the ectodomain is sufficiently collapsed to bring the N- and C-terminal hydrophobic domains into close proximity. These results support a hemifusion-like model of the short NC gp41 in which the ectodomain forms a partially folded hairpin that places the FPPR and MPER on the opposing surfaces of two lipid membranes.
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Affiliation(s)
- Myungwoon Lee
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Chloe A Morgan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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30
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Elkins MR, Hong M. Elucidating ligand-bound structures of membrane proteins using solid-state NMR spectroscopy. Curr Opin Struct Biol 2019; 57:103-109. [PMID: 30903830 PMCID: PMC6697555 DOI: 10.1016/j.sbi.2019.02.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 02/05/2019] [Accepted: 02/08/2019] [Indexed: 01/08/2023]
Abstract
Magic-angle-spinning (MAS) solid-state NMR spectroscopy is a versatile technique to elucidate functionally important protein-ligand interactions in lipid membranes. Here, we review recent solid-state NMR studies of membrane protein interactions with cholesterol, lipids, transported substrates, and peptide ligands. These studies are conducted in synthetic or native lipid bilayers to provide an accurate environment for ligand binding. The solid-state NMR approaches include multinuclear detection to gain comprehensive structural information, distance measurements to locate ligand-binding sites, and dynamic nuclear polarization and 1H detection to enhance spectral sensitivity. These studies provide novel insights into the mechanisms of virus budding, virus entry into cells, transmembrane signaling, substrate transport, antibacterial action, and many other biological processes.
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Affiliation(s)
- Matthew R Elkins
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, United States.
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31
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Benton DJ, Nans A, Calder LJ, Turner J, Neu U, Lin YP, Ketelaars E, Kallewaard NL, Corti D, Lanzavecchia A, Gamblin SJ, Rosenthal PB, Skehel JJ. Influenza hemagglutinin membrane anchor. Proc Natl Acad Sci U S A 2018; 115:10112-10117. [PMID: 30224494 PMCID: PMC6176637 DOI: 10.1073/pnas.1810927115] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Viruses with membranes fuse them with cellular membranes, to transfer their genomes into cells at the beginning of infection. For Influenza virus, the membrane glycoprotein involved in fusion is the hemagglutinin (HA), the 3D structure of which is known from X-ray crystallographic studies. The soluble ectodomain fragments used in these studies lacked the "membrane anchor" portion of the molecule. Since this region has a role in membrane fusion, we have determined its structure by analyzing the intact, full-length molecule in a detergent micelle, using cryo-EM. We have also compared the structures of full-length HA-detergent micelles with full-length HA-Fab complex detergent micelles, to describe an infectivity-neutralizing monoclonal Fab that binds near the ectodomain membrane anchor junction. We determine a high-resolution HA structure which compares favorably in detail with the structure of the ectodomain seen by X-ray crystallography; we detect, clearly, all five carbohydrate side chains of HA; and we find that the ectodomain is joined to the membrane anchor by flexible, eight-residue-long, linkers. The linkers extend into the detergent micelle to join a central triple-helical structure that is a major component of the membrane anchor.
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Affiliation(s)
- Donald J Benton
- Structural Biology of Disease Processes Laboratory, Francis Crick Institute, NW1 1AT London, United Kingdom;
| | - Andrea Nans
- Structural Biology of Cells and Viruses Laboratory, Francis Crick Institute, NW1 1AT London, United Kingdom
- Structural Biology Science Technology Platform, Francis Crick Institute, NW1 1AT London, United Kingdom
| | - Lesley J Calder
- Structural Biology of Cells and Viruses Laboratory, Francis Crick Institute, NW1 1AT London, United Kingdom
| | - Jack Turner
- Structural Biology of Cells and Viruses Laboratory, Francis Crick Institute, NW1 1AT London, United Kingdom
| | - Ursula Neu
- Structural Biology of Disease Processes Laboratory, Francis Crick Institute, NW1 1AT London, United Kingdom
| | - Yi Pu Lin
- Worldwide Influenza Centre, Francis Crick Institute, NW1 1AT London, United Kingdom
| | - Esther Ketelaars
- Institute for Research in Biomedicine, 6500 Bellinzona, Switzerland
| | | | | | | | - Steven J Gamblin
- Structural Biology of Disease Processes Laboratory, Francis Crick Institute, NW1 1AT London, United Kingdom
| | - Peter B Rosenthal
- Structural Biology of Cells and Viruses Laboratory, Francis Crick Institute, NW1 1AT London, United Kingdom;
| | - John J Skehel
- Structural Biology of Disease Processes Laboratory, Francis Crick Institute, NW1 1AT London, United Kingdom;
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32
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Structure of the membrane proximal external region of HIV-1 envelope glycoprotein. Proc Natl Acad Sci U S A 2018; 115:E8892-E8899. [PMID: 30185554 DOI: 10.1073/pnas.1807259115] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The membrane-proximal external region (MPER) of the HIV-1 envelope glycoprotein (Env) bears epitopes of broadly neutralizing antibodies (bnAbs) from infected individuals; it is thus a potential vaccine target. We report an NMR structure of the MPER and its adjacent transmembrane domain in bicelles that mimic a lipid-bilayer membrane. The MPER lies largely outside the lipid bilayer. It folds into a threefold cluster, stabilized mainly by conserved hydrophobic residues and potentially by interaction with phospholipid headgroups. Antigenic analysis and comparison with published images from electron cryotomography of HIV-1 Env on the virion surface suggest that the structure may represent a prefusion conformation of the MPER, distinct from the fusion-intermediate state targeted by several well-studied bnAbs. Very slow bnAb binding indicates that infrequent fluctuations of the MPER structure give these antibodies occasional access to alternative conformations of MPER epitopes. Mutations in the MPER not only impede membrane fusion but also influence presentation of bnAb epitopes in other regions. These results suggest strategies for developing MPER-based vaccine candidates.
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33
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Ranaweera A, Ratnayake PU, Weliky DP. The Stabilities of the Soluble Ectodomain and Fusion Peptide Hairpins of the Influenza Virus Hemagglutinin Subunit II Protein Are Positively Correlated with Membrane Fusion. Biochemistry 2018; 57:5480-5493. [PMID: 30141905 DOI: 10.1021/acs.biochem.8b00764] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cellular entry of influenza virus is mediated by the viral protein hemagglutinin (HA), which forms an initial complex of three HA1 and three HA2 subunits. Each HA2 includes a fusion peptide (FP), a soluble ectodomain (SE), and a transmembrane domain. HA1 binds to cellular sialic acids, followed by virus endocytosis, pH reduction, dissociation of HA1, and structural rearrangement of HA2 into a final trimer-of-SE hairpins. A decrease in pH also triggers HA2-mediated virus/endosome membrane fusion. SE hairpins have an interior parallel helical bundle and C-terminal strands in the grooves of the exterior of the bundle. FPs are separate helical hairpins. This study compares wild-type HA2 (WT-HA2) with G1E(FP) and I173E(SE strand) mutants. WT-HA2 induces vesicle fusion at pH 5.0, whereas the extent of fusion is greatly reduced for both mutants. Circular dichroism for HA2 and FHA2≡FP+SE constructs shows dramatic losses of stability for the mutants, including a Tm reduced by 40 °C for I173E-FHA2. This is evidence of destabilization of SE hairpins via dissociation of strands from the helical bundle, which is also supported by larger monomer fractions for mutant versus WT proteins. The G1E mutant may have disrupted FP hairpins, with consequent non-native FP binding to dissociated SE strands. It is commonly proposed that free energy released by the HA2 structural rearrangement catalyzes HA-mediated fusion. This study supports an alternate mechanistic model in which fusion is preceded by FP insertion in the target membrane and formation of the final SE hairpin. Less fusion by the mutants is due to the loss of hairpin stability and consequent reduced level of membrane apposition of the virus and target membranes.
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Affiliation(s)
- Ahinsa Ranaweera
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Punsisi U Ratnayake
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
| | - David P Weliky
- Department of Chemistry , Michigan State University , East Lansing , Michigan 48824 , United States
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34
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Kwon B, Lee M, Waring AJ, Hong M. Oligomeric Structure and Three-Dimensional Fold of the HIV gp41 Membrane-Proximal External Region and Transmembrane Domain in Phospholipid Bilayers. J Am Chem Soc 2018; 140:8246-8259. [PMID: 29888593 DOI: 10.1021/jacs.8b04010] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The HIV-1 glycoprotein, gp41, mediates fusion of the virus lipid envelope with the target cell membrane during virus entry into cells. Despite extensive studies of this protein, inconsistent and contradictory structural information abounds in the literature about the C-terminal membrane-interacting region of gp41. This C-terminal region contains the membrane-proximal external region (MPER), which harbors the epitopes for four broadly neutralizing antibodies, and the transmembrane domain (TMD), which anchors the protein to the virus lipid envelope. Due to the difficulty of crystallizing and solubilizing the MPER-TMD, most structural studies of this functionally important domain were carried out using truncated peptides either in the absence of membrane-mimetic solvents or bound to detergents and lipid bicelles. To determine the structural architecture of the MPER-TMD in the native environment of lipid membranes, we have now carried out a solid-state NMR study of the full MPER-TMD segment bound to cholesterol-containing phospholipid bilayers. 13C chemical shifts indicate that the majority of the peptide is α-helical, except for the C-terminus of the TMD, which has moderate β-sheet character. Intermolecular 19F-19F distance measurements of singly fluorinated peptides indicate that the MPER-TMD is trimerized in the virus-envelope mimetic lipid membrane. Intramolecular 13C-19F distance measurements indicate the presence of a turn between the MPER helix and the TMD helix. This is supported by lipid-peptide and water-peptide 2D 1H-13C correlation spectra, which indicate that the MPER binds to the membrane surface whereas the TMD spans the bilayer. Together, these data indicate that full-length MPER-TMD assembles into a trimeric helix-turn-helix structure in lipid membranes. We propose that the turn between the MPER and TMD may be important for inducing membrane defects in concert with negative-curvature lipid components such as cholesterol and phosphatidylethanolamine, while the surface-bound MPER helix may interact with N-terminal segments of the protein during late stages of membrane fusion.
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Affiliation(s)
- Byungsu Kwon
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
| | - Myungwoon Lee
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
| | - Alan J Waring
- Department of Medicine , Harbor-UCLA Medical Center , 1000 West Carson Street, Building RB2 , Torrance , California 90502 , United States
| | - Mei Hong
- Department of Chemistry , Massachusetts Institute of Technology , 170 Albany Street , Cambridge , Massachusetts 02139 , United States
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35
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Chipot C, Dehez F, Schnell JR, Zitzmann N, Pebay-Peyroula E, Catoire LJ, Miroux B, Kunji ERS, Veglia G, Cross TA, Schanda P. Perturbations of Native Membrane Protein Structure in Alkyl Phosphocholine Detergents: A Critical Assessment of NMR and Biophysical Studies. Chem Rev 2018; 118:3559-3607. [PMID: 29488756 PMCID: PMC5896743 DOI: 10.1021/acs.chemrev.7b00570] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Indexed: 12/25/2022]
Abstract
Membrane proteins perform a host of vital cellular functions. Deciphering the molecular mechanisms whereby they fulfill these functions requires detailed biophysical and structural investigations. Detergents have proven pivotal to extract the protein from its native surroundings. Yet, they provide a milieu that departs significantly from that of the biological membrane, to the extent that the structure, the dynamics, and the interactions of membrane proteins in detergents may considerably vary, as compared to the native environment. Understanding the impact of detergents on membrane proteins is, therefore, crucial to assess the biological relevance of results obtained in detergents. Here, we review the strengths and weaknesses of alkyl phosphocholines (or foscholines), the most widely used detergent in solution-NMR studies of membrane proteins. While this class of detergents is often successful for membrane protein solubilization, a growing list of examples points to destabilizing and denaturing properties, in particular for α-helical membrane proteins. Our comprehensive analysis stresses the importance of stringent controls when working with this class of detergents and when analyzing the structure and dynamics of membrane proteins in alkyl phosphocholine detergents.
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Affiliation(s)
- Christophe Chipot
- SRSMC, UMR 7019 Université de Lorraine CNRS, Vandoeuvre-les-Nancy F-54500, France
- Laboratoire
International Associé CNRS and University of Illinois at Urbana−Champaign, Vandoeuvre-les-Nancy F-54506, France
- Department
of Physics, University of Illinois at Urbana−Champaign, 1110 West Green Street, Urbana, Illinois 61801, United States
| | - François Dehez
- SRSMC, UMR 7019 Université de Lorraine CNRS, Vandoeuvre-les-Nancy F-54500, France
- Laboratoire
International Associé CNRS and University of Illinois at Urbana−Champaign, Vandoeuvre-les-Nancy F-54506, France
| | - Jason R. Schnell
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Nicole Zitzmann
- Department
of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | | | - Laurent J. Catoire
- Laboratory
of Biology and Physico-Chemistry of Membrane Proteins, Institut de Biologie Physico-Chimique (IBPC), UMR
7099 CNRS, Paris 75005, France
- University
Paris Diderot, Paris 75005, France
- PSL
Research University, Paris 75005, France
| | - Bruno Miroux
- Laboratory
of Biology and Physico-Chemistry of Membrane Proteins, Institut de Biologie Physico-Chimique (IBPC), UMR
7099 CNRS, Paris 75005, France
- University
Paris Diderot, Paris 75005, France
- PSL
Research University, Paris 75005, France
| | - Edmund R. S. Kunji
- Medical
Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Gianluigi Veglia
- Department
of Biochemistry, Molecular Biology, and Biophysics, and Department
of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Timothy A. Cross
- National
High Magnetic Field Laboratory, Florida
State University, Tallahassee, Florida 32310, United States
| | - Paul Schanda
- Université
Grenoble Alpes, CEA, CNRS, IBS, Grenoble F-38000, France
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36
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Schroeder S, Kaufman JD, Grunwald M, Walla PJ, Lakomek NA, Wingfield PT. HIV-1 gp41 transmembrane oligomerization monitored by FRET and FCS. FEBS Lett 2018; 592:939-948. [PMID: 29453892 DOI: 10.1002/1873-3468.13010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/21/2018] [Accepted: 02/11/2018] [Indexed: 11/08/2022]
Abstract
The HIV-1 envelope gp120/gp41 trimer mediates viral membrane fusion. After cluster of differentiation-4 recognition, gp120 detaches from the virus, exposing gp41 which triggers fusion. During the fusion process, gp41 may not remain trimeric, which could have functional importance. Here, we probe the reversible association of full length gp41 (minus the cytoplasmic domain) in detergent micelles (with probes attached to transmembrane domain) by fluorescence resonance energy transfer (FRET) with a μm dissociation constant. This is compared with other methods. A gp41-targeted fusion inhibitor must interfere with this transition, and monomeric, partially monomeric or trimeric states all present potential binding epitopes. The gp41 self-association is a valid drug target model and FRET, a potential high-throughput assay system, could be used to screen drug libraries.
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Affiliation(s)
| | - Joshua D Kaufman
- Protein Expression Laboratory, NIAMS, National Institutes of Health, Bethesda, MD, USA
| | | | - Peter J Walla
- Institute for Physical and Theoretical Chemistry, Technical University Braunschweig, Germany
| | - Nils-Alexander Lakomek
- Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany.,Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences (D-CHAB), ETH Zurich, Switzerland
| | - Paul T Wingfield
- Protein Expression Laboratory, NIAMS, National Institutes of Health, Bethesda, MD, USA
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