1
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Santoro A, Buonocore M, Firoznezhad M, Grimaldi M, D'Ursi AM. Conformational analysis of a new peptide derived from feline immunodeficiency virus gp36 in SDS micelles: An NMR-MD based investigation. J Pept Sci 2024:e3645. [PMID: 39030892 DOI: 10.1002/psc.3645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 07/22/2024]
Abstract
Feline immunodeficiency virus (FIV) shares structural similarities with human immunodeficiency virus (HIV): the surface glycoprotein gp36 corresponds to the HIV gp41, which drives virus-host cell interactions and is targeted by the peptide entry inhibitor enfuvirtide. Following a similar drug design strategy for the development of an anti-FIV therapy, the present study investigates 627-646gp36 NHR, a peptide sequence derived from a region of gp36 that was previously found to interfere with the antiviral activity of the peptide C8, which instead derives from the gp36 MPER. CD, NMR, and MD simulations were employed to probe the conformational characteristics of 627-646gp36 NHR in the membrane-mimicking environment of SDS micelles. Our data show that 627-646gp36 NHR is characterized by three dynamic helix structures. MD simulations involving 627-646gp36 NHR, C8, and a larger protein, including the CHR and MPER regions, suggest that the interaction of C8 with the MPER region, the origin of the antiviral activity of C8, is disfavored in the presence of 627-646gp36 NHR in the simulation. This evidence can be useful for interpreting the molecular mechanism that leads to interference with the activity of C8, providing information on the folding/unfolding mechanism of the viral glycoprotein to design new strategies to inhibit viral entry.
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Affiliation(s)
- Angelo Santoro
- Department of Pharmacy, University of Salerno, Fisciano, Italy
- Department of Pharmacy, Scuola di Specializzazione in Farmacia Ospedaliera, University of Salerno, Italy
| | - Michela Buonocore
- Department of Chemical Sciences and Research Centre on Bioactive Peptides (CIRPeB), University of Naples Federico II, Naples, Italy
| | - Mohammad Firoznezhad
- Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Trento, Italy
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2
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Rujas E, Apellániz B, Torralba J, Andreu D, Caaveiro JMM, Wang S, Lu S, Nieva JL. Liposome-based peptide vaccines to elicit immune responses against the membrane active domains of the HIV-1 Env glycoprotein. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184235. [PMID: 37793559 DOI: 10.1016/j.bbamem.2023.184235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 09/12/2023] [Accepted: 09/27/2023] [Indexed: 10/06/2023]
Abstract
The fusion peptide (FP) and the Trp-rich membrane proximal external region (MPER) display membrane activity during HIV-1 fusion. These domains are highly conserved in the envelope glycoprotein (Env) and, consequently, antibodies targeting these regions block entry of divergent HIV strains and isolates into target cells. With the aim of recovering concurrent responses against the membrane-active Env domains, we have produced hybrid peptides that connect FP and MPER sequences via flexible aminohexanoic acid tethers, and tested their potential as immunogens. We demonstrate that liposome-based formulations containing FP-MPER hybrid peptides could elicit in rabbits, antibodies with the binding sequence specificity of neutralizing antibodies that engage with the N-terminal MPER sub-region. Determination of the thermodynamic parameters of binding using the Fab 2F5 as an N-terminal MPER antibody model, revealed that the hydrophobic interaction surface for epitope engagement appears to be optimal in the FP-MPER hybrid. In general, our data support: i) the use of liposomes as carriers for membrane active peptides; ii) the capacity of these liposome-based vaccines to focus humoral responses to N-terminal MPER epitopes; and iii) the need to include lipid membranes in immunogens to elicit such specific responses.
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Affiliation(s)
- Edurne Rujas
- Instituto Biofisika (CSIC, UPV/EHU) and Biochemistry and Molecular Biology Department, 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; Bioaraba, Microbiology, Infectious Disease, Antimicrobial Agents, and Gene Therapy, 01006 Vitoria-Gasteiz, Spain
| | - Johana Torralba
- Instituto Biofisika (CSIC, UPV/EHU) and Biochemistry and Molecular Biology Department, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain
| | - David Andreu
- Laboratory of Proteomics and Protein Chemistry, Department of Medicine and Life Sciences, Pompeu Fabra University, Barcelona Biomedical Research Park, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Jose M M Caaveiro
- Laboratory of Global Healthcare, School of Pharmaceutical Sciences, Kyushu University, Fukuoka 819-0395, Japan
| | - Shixia Wang
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, United States of America
| | - Shan Lu
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA 01605, United States of America
| | - Jose L Nieva
- Instituto Biofisika (CSIC, UPV/EHU) and Biochemistry and Molecular Biology Department, University of the Basque Country (UPV/EHU), PO Box 644, 48080 Bilbao, Spain.
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3
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Abstract
There are at least 21 families of enveloped viruses that infect mammals, and many contain members of high concern for global human health. All enveloped viruses have a dedicated fusion protein or fusion complex that enacts the critical genome-releasing membrane fusion event that is essential before viral replication within the host cell interior can begin. Because all enveloped viruses enter cells by fusion, it behooves us to know how viral fusion proteins function. Viral fusion proteins are also major targets of neutralizing antibodies, and hence they serve as key vaccine immunogens. Here we review current concepts about viral membrane fusion proteins focusing on how they are triggered, structural intermediates between pre- and postfusion forms, and their interplay with the lipid bilayers they engage. We also discuss cellular and therapeutic interventions that thwart virus-cell membrane fusion.
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Affiliation(s)
- Judith M White
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia, USA;
| | - Amanda E Ward
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Laura Odongo
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Lukas K Tamm
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
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4
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Toke O. Three Decades of REDOR in Protein Science: A Solid-State NMR Technique for Distance Measurement and Spectral Editing. Int J Mol Sci 2023; 24:13637. [PMID: 37686450 PMCID: PMC10487747 DOI: 10.3390/ijms241713637] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 08/30/2023] [Accepted: 09/01/2023] [Indexed: 09/10/2023] Open
Abstract
Solid-state NMR (ss-NMR) is a powerful tool to investigate noncrystallizable, poorly soluble molecular systems, such as membrane proteins, amyloids, and cell walls, in environments that closely resemble their physical sites of action. Rotational-echo double resonance (REDOR) is an ss-NMR methodology, which by reintroducing heteronuclear dipolar coupling under magic angle spinning conditions provides intramolecular and intermolecular distance restraints at the atomic level. In addition, REDOR can be exploited as a selection tool to filter spectra based on dipolar couplings. Used extensively as a spectroscopic ruler between isolated spins in site-specifically labeled systems and more recently as a building block in multidimensional ss-NMR pulse sequences allowing the simultaneous measurement of multiple distances, REDOR yields atomic-scale information on the structure and interaction of proteins. By extending REDOR to the determination of 1H-X dipolar couplings in recent years, the limit of measurable distances has reached ~15-20 Å, making it an attractive method of choice for the study of complex biomolecular assemblies. Following a methodological introduction including the most recent implementations, examples are discussed to illustrate the versatility of REDOR in the study of biological systems.
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Affiliation(s)
- Orsolya Toke
- Laboratory for NMR Spectroscopy, Structural Research Centre, Research Centre for Natural Sciences, 2 Magyar tudósok körútja, H-1117 Budapest, Hungary
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5
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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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6
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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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7
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Somberg NH, Wu WW, Medeiros-Silva J, Dregni AJ, Jo H, DeGrado WF, Hong M. SARS-CoV-2 Envelope Protein Forms Clustered Pentamers in Lipid Bilayers. Biochemistry 2022; 61:2280-2294. [PMID: 36219675 PMCID: PMC9583936 DOI: 10.1021/acs.biochem.2c00464] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/26/2022] [Indexed: 11/30/2022]
Abstract
The SARS-CoV-2 envelope (E) protein is a viroporin associated with the acute respiratory symptoms of COVID-19. E forms cation-selective ion channels that assemble in the lipid membrane of the endoplasmic reticulum Golgi intermediate compartment. The channel activity of E is linked to the inflammatory response of the host cell to the virus. Like many viroporins, E is thought to oligomerize with a well-defined stoichiometry. However, attempts to determine the E stoichiometry have led to inconclusive results and suggested mixtures of oligomers whose exact nature might vary with the detergent used. Here, we employ 19F solid-state nuclear magnetic resonance and the centerband-only detection of exchange (CODEX) technique to determine the oligomeric number of E's transmembrane domain (ETM) in lipid bilayers. The CODEX equilibrium value, which corresponds to the inverse of the oligomeric number, indicates that ETM assembles into pentamers in lipid bilayers, without any detectable fraction of low-molecular-weight oligomers. Unexpectedly, at high peptide concentrations and in the presence of the lipid phosphatidylinositol, the CODEX data indicate that more than five 19F spins are within a detectable distance of about 2 nm, suggesting that the ETM pentamers cluster in the lipid bilayer. Monte Carlo simulations that take into account peptide-peptide and peptide-lipid interactions yielded pentamer clusters that reproduced the CODEX data. This supramolecular organization is likely important for E-mediated virus assembly and budding and for the channel function of the protein.
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Affiliation(s)
- Noah H. Somberg
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Westley W. Wu
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - João Medeiros-Silva
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Aurelio J. Dregni
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
| | - Hyunil Jo
- Department of Pharmaceutical Chemistry, 555 Mission Bay Blvd. South, University of California, San Francisco, San Francisco, CA 94158
| | - William F. DeGrado
- Department of Pharmaceutical Chemistry, 555 Mission Bay Blvd. South, University of California, San Francisco, San Francisco, CA 94158
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139
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8
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Villalaín J. Interaction of Lassa virus fusion and membrane proximal peptides with late endosomal membranes. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2022; 1864:184031. [PMID: 35964711 DOI: 10.1016/j.bbamem.2022.184031] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/15/2022] [Accepted: 08/08/2022] [Indexed: 06/15/2023]
Abstract
Mammarenaviruses include many significant worldwide-widespread human pathogens, among them Lassa virus (LASV), having a dramatic morbidity and mortality rate. They are a potential high-risk menace to the worldwide public health since there are no treatments and there is a high possibility of animal-to-human and human-to-human viral transmission. These viruses enter into the cells by endocytosis fusing its membrane envelope with the late endosomal membrane thanks to the glycoprotein GP2, a membrane fusion protein of class I. This protein contains different domains, among them the N-terminal fusion peptide (NFP), the internal fusion loop (IFL), the membrane proximal external region (MPER) and the transmembrane domain (TMD). All these domains are implicated in the membrane fusion process. In this work, we have used an all-atom molecular dynamics study to know the binding of these protein domains with a complex membrane mimicking the late endosome one. We show that the NFP/IFL domain is capable of spontaneously inserting into the membrane without a significant change of secondary structure, the MPER domain locates at the bilayer interface with an orientation parallel to the membrane surface and tends to interact with other MPER domains, and the TMD domain tilts inside the bilayer. Moreover, they predominantly interact with negatively charged phospholipids. Overall, these membrane-interacting domains would characterise a target that would make possible to find effective antiviral molecules against LASV in particular and Mammarenaviruses in general.
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Affiliation(s)
- José Villalaín
- Institute of Research, Development, and Innovation in Healthcare Biotechnology (IDiBE), Universitas "Miguel Hernández", E-03202 Elche-Alicante, Spain.
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9
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Yang S, Hiotis G, Wang Y, Chen J, Wang JH, Kim M, Reinherz EL, Walz T. Dynamic HIV-1 spike motion creates vulnerability for its membrane-bound tripod to antibody attack. Nat Commun 2022; 13:6393. [PMID: 36302771 PMCID: PMC9610346 DOI: 10.1038/s41467-022-34008-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 10/06/2022] [Indexed: 12/25/2022] Open
Abstract
Vaccines targeting HIV-1's gp160 spike protein are stymied by high viral mutation rates and structural chicanery. gp160's membrane-proximal external region (MPER) is the target of naturally arising broadly neutralizing antibodies (bnAbs), yet MPER-based vaccines fail to generate bnAbs. Here, nanodisc-embedded spike protein was investigated by cryo-electron microscopy and molecular-dynamics simulations, revealing spontaneous ectodomain tilting that creates vulnerability for HIV-1. While each MPER protomer radiates centrally towards the three-fold axis contributing to a membrane-associated tripod structure that is occluded in the upright spike, tilting provides access to the opposing MPER. Structures of spike proteins with bound 4E10 bnAb Fabs reveal that the antibody binds exposed MPER, thereby altering MPER dynamics, modifying average ectodomain tilt, and imposing strain on the viral membrane and the spike's transmembrane segments, resulting in the abrogation of membrane fusion and informing future vaccine development.
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Affiliation(s)
- Shuang Yang
- grid.134907.80000 0001 2166 1519Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY USA
| | - Giorgos Hiotis
- grid.134907.80000 0001 2166 1519Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY USA ,grid.134907.80000 0001 2166 1519Tri-Institutional PhD Program in Chemical Biology, The Rockefeller University, New York, NY USA
| | - Yi Wang
- grid.65499.370000 0001 2106 9910Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.38142.3c000000041936754XDepartment of Medicine, Harvard Medical School, Boston, MA USA
| | - Junjian Chen
- grid.65499.370000 0001 2106 9910Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.38142.3c000000041936754XDepartment of Medicine, Harvard Medical School, Boston, MA USA
| | - Jia-huai Wang
- grid.65499.370000 0001 2106 9910Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.38142.3c000000041936754XDepartment of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA USA ,grid.65499.370000 0001 2106 9910Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.38142.3c000000041936754XDepartment of Pediatrics, Harvard Medical School, Boston, MA USA
| | - Mikyung Kim
- grid.65499.370000 0001 2106 9910Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.38142.3c000000041936754XDepartment of Dermatology, Harvard Medical School, Boston, MA USA
| | - Ellis L. Reinherz
- grid.65499.370000 0001 2106 9910Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA USA ,grid.38142.3c000000041936754XDepartment of Medicine, Harvard Medical School, Boston, MA USA
| | - Thomas Walz
- grid.134907.80000 0001 2166 1519Laboratory of Molecular Electron Microscopy, The Rockefeller University, New York, NY USA
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10
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Insausti S, Garcia-Porras M, Torralba J, Morillo I, Ramos-Caballero A, de la Arada I, Apellaniz B, Caaveiro JMM, Carravilla P, Eggeling C, Rujas E, Nieva JL. Functional Delineation of a Protein-Membrane Interaction Hotspot Site on the HIV-1 Neutralizing Antibody 10E8. Int J Mol Sci 2022; 23:ijms231810767. [PMID: 36142694 PMCID: PMC9504841 DOI: 10.3390/ijms231810767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/29/2022] Open
Abstract
Antibody engagement with the membrane-proximal external region (MPER) of the envelope glycoprotein (Env) of HIV-1 constitutes a distinctive molecular recognition phenomenon, the full appreciation of which is crucial for understanding the mechanisms that underlie the broad neutralization of the virus. Recognition of the HIV-1 Env antigen seems to depend on two specific features developed by antibodies with MPER specificity: (i) a large cavity at the antigen-binding site that holds the epitope amphipathic helix; and (ii) a membrane-accommodating Fab surface that engages with viral phospholipids. Thus, besides the main Fab-peptide interaction, molecular recognition of MPER depends on semi-specific (electrostatic and hydrophobic) interactions with membranes and, reportedly, on specific binding to the phospholipid head groups. Here, based on available cryo-EM structures of Fab-Env complexes of the anti-MPER antibody 10E8, we sought to delineate the functional antibody-membrane interface using as the defining criterion the neutralization potency and binding affinity improvements induced by Arg substitutions. This rational, Arg-based mutagenesis strategy revealed the position-dependent contribution of electrostatic interactions upon inclusion of Arg-s at the CDR1, CDR2 or FR3 of the Fab light chain. Moreover, the contribution of the most effective Arg-s increased the potency enhancement induced by inclusion of a hydrophobic-at-interface Phe at position 100c of the heavy chain CDR3. In combination, the potency and affinity improvements by Arg residues delineated a protein-membrane interaction site, whose surface and position support a possible mechanism of action for 10E8-induced neutralization. Functional delineation of membrane-interacting patches could open new lines of research to optimize antibodies of therapeutic interest that target integral membrane epitopes.
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Affiliation(s)
- Sara Insausti
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain
| | - Miguel Garcia-Porras
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain
| | - Johana Torralba
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain
| | - Izaskun Morillo
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain
| | - Ander Ramos-Caballero
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain
| | - Igor de la Arada
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain
| | - Beatriz Apellaniz
- Department of Physiology, Faculty of Pharmacy, University of the Basque Country (UPV/EHU), Paseo de la Universidad, 7, 01006 Vitoria-Gasteiz, Spain
| | - Jose M. M. Caaveiro
- Laboratory of Global Healthcare, School of Pharmaceutical Sciences, Kyushu University, Fukuoka 819-0395, Japan
| | - Pablo Carravilla
- Leibniz Institute of Photonic Technology e.V., 07745 Jena, Germany
| | - Christian Eggeling
- Leibniz Institute of Photonic Technology e.V., 07745 Jena, Germany
- Faculty of Physics and Astronomy, Institute of Applied Optics and Biophysics, Friedrich Schiller University Jena, 07743 Jena, Germany
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX1 2JD, UK
| | - Edurne Rujas
- Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Spain
- Pharmacokinetic, Nanotechnology and Gene Therapy Group, Faculty of Pharmacy, University of the Basque Country UPV/EHU, 01006 Vitoria-Gasteiz, Spain
- Microbiology, Infectious Disease, Antimicrobial Agents, and Gene Therapy, Bioaraba, 01006 Vitoria-Gasteiz, Spain
- Correspondence: (E.R.); (J.L.N.)
| | - Jose L. Nieva
- Instituto Biofisika (CSIC-UPV/EHU), University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain
- Correspondence: (E.R.); (J.L.N.)
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11
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Harati Taji Z, Bielytskyi P, Shein M, Sani MA, Seitz S, Schütz AK. Transient RNA Interactions Leave a Covalent Imprint on a Viral Capsid Protein. J Am Chem Soc 2022; 144:8536-8550. [PMID: 35512333 PMCID: PMC9121876 DOI: 10.1021/jacs.1c12439] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The hepatitis B virus (HBV) is the leading cause of persistent liver infections. Its DNA-based genome is synthesized through reverse transcription of an RNA template inside the assembled capsid shell. In addition to the structured assembly domain, the capsid protein harbors a C-terminal extension that mediates both the enclosure of RNA during capsid assembly and the nuclear entry of the capsid during infection. The arginine-rich motifs within this extension, though common to many viruses, have largely escaped atomic-scale investigation. Here, we leverage solution and solid-state nuclear magnetic resonance spectroscopy at ambient and cryogenic temperatures, under dynamic nuclear polarization signal enhancement, to investigate the organization of the genome within the capsid. Transient interactions with phosphate groups of the RNA backbone confine the arginine-rich motifs to the interior capsid space. While no secondary structure is induced in the C-terminal extension, interactions with RNA counteract the formation of a disulfide bond, which covalently tethers this peptide arm onto the inner capsid surface. Electrostatic and covalent contributions thus compete in the spatial regulation of capsid architecture. This disulfide switch represents a coupling mechanism between the structured assembly domain of the capsid and the enclosed nucleic acids. In particular, it enables the redox-dependent regulation of the exposure of the C-terminal extension on the capsid surface, which is required for nuclear uptake of the capsid. Phylogenetic analysis of capsid proteins from hepadnaviruses points toward a function of this switch in the persistence of HBV infections.
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Affiliation(s)
- Zahra Harati Taji
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching 85748, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg 85764, Germany
| | - Pavlo Bielytskyi
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching 85748, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg 85764, Germany
| | - Mikhail Shein
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching 85748, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg 85764, Germany
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Stefan Seitz
- Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg 69120, Germany.,Division of Virus-Associated Carcinogenesis (F170), German Cancer Research Center (DKFZ), Heidelberg 69120, Germany
| | - Anne K Schütz
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching 85748, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg 85764, Germany
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12
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Global Increases in Human Immunodeficiency Virus Neutralization Sensitivity Due to Alterations in the Membrane-Proximal External Region of the Envelope Glycoprotein Can Be Minimized by Distant State 1-Stabilizing Changes. J Virol 2022; 96:e0187821. [PMID: 35289647 DOI: 10.1128/jvi.01878-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Binding to the receptor, CD4, drives the pretriggered, "closed" (State-1) conformation of the human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimer ([gp120/gp41]3) into more "open" conformations. HIV-1 Env on the viral membrane is maintained in a State-1 conformation that resists binding and neutralization by commonly elicited antibodies. Premature triggering of Env before the virus engages a target cell typically leads to increased susceptibility to spontaneous inactivation or ligand-induced neutralization. Here, we showed that single amino acid substitutions in the gp41 membrane-proximal external region (MPER) of a primary HIV-1 strain resulted in viral phenotypes indicative of premature triggering of Env to downstream conformations. Specifically, the MPER changes reduced viral infectivity and globally increased virus sensitivity to poorly neutralizing antibodies, soluble CD4, a CD4-mimetic compound, and exposure to cold. In contrast, the MPER mutants exhibited decreased sensitivity to the State 1-preferring inhibitor, BMS-806, and to the PGT151 broadly neutralizing antibody. Depletion of cholesterol from virus particles did not produce the same State 1-destabilizing phenotypes as MPER alterations. Notably, State 1-stabilizing changes in Env distant from the MPER could minimize the phenotypic effects of MPER alteration but did not affect virus sensitivity to cholesterol depletion. Thus, membrane-proximal gp41 elements contribute to the maintenance of the pretriggered Env conformation. The conformationally disruptive effects of MPER changes can be minimized by distant State 1-stabilizing Env modifications, a strategy that may be useful in preserving the native pretriggered state of Env. IMPORTANCE The pretriggered shape of the human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) is a major target for antibodies that can neutralize many strains of the virus. An effective HIV-1 vaccine may need to raise these types of antibodies, but this goal has proven difficult. One reason is that the pretriggered shape of Env is unstable and dependent on interactions near the viral membrane. Here, we showed that the membrane-proximal external region (MPER) of Env plays an important role in maintaining Env in a pretriggered shape. Alterations in the MPER resulted in global changes in Env conformation that disrupted its pretriggered shape. We also found that these disruptive effects of MPER changes could be minimized by distant Env modifications that stabilized the pretriggered shape. These modifications may be useful for preserving the native shape of Env for structural and vaccine studies.
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13
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Liang L, Ji Y, Chen K, Gao P, Zhao Z, Hou G. Solid-State NMR Dipolar and Chemical Shift Anisotropy Recoupling Techniques for Structural and Dynamical Studies in Biological Systems. Chem Rev 2022; 122:9880-9942. [PMID: 35006680 DOI: 10.1021/acs.chemrev.1c00779] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
With the development of NMR methodology and technology during the past decades, solid-state NMR (ssNMR) has become a particularly important tool for investigating structure and dynamics at atomic scale in biological systems, where the recoupling techniques play pivotal roles in modern high-resolution MAS NMR. In this review, following a brief introduction on the basic theory of recoupling in ssNMR, we highlight the recent advances in dipolar and chemical shift anisotropy recoupling methods, as well as their applications in structural determination and dynamical characterization at multiple time scales (i.e., fast-, intermediate-, and slow-motion). The performances of these prevalent recoupling techniques are compared and discussed in multiple aspects, together with the representative applications in biomolecules. Given the recent emerging advances in NMR technology, new challenges for recoupling methodology development and potential opportunities for biological systems are also discussed.
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Affiliation(s)
- Lixin Liang
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yi Ji
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kuizhi Chen
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
| | - Pan Gao
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
| | - Zhenchao Zhao
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
| | - Guangjin Hou
- State Key Laboratory of Catalysis, National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian 116023, China
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14
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Xue K, Movellan KT, Zhang XC, Najbauer EE, Forster MC, Becker S, Andreas LB. Towards a native environment: structure and function of membrane proteins in lipid bilayers by NMR. Chem Sci 2021; 12:14332-14342. [PMID: 34880983 PMCID: PMC8580007 DOI: 10.1039/d1sc02813h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 09/07/2021] [Indexed: 01/17/2023] Open
Abstract
Solid-state NMR (ssNMR) is a versatile technique that can be used for the characterization of various materials, ranging from small molecules to biological samples, including membrane proteins. ssNMR can probe both the structure and dynamics of membrane proteins, revealing protein function in a near-native lipid bilayer environment. The main limitation of the method is spectral resolution and sensitivity, however recent developments in ssNMR hardware, including the commercialization of 28 T magnets (1.2 GHz proton frequency) and ultrafast MAS spinning (<100 kHz) promise to accelerate acquisition, while reducing sample requirement, both of which are critical to membrane protein studies. Here, we review recent advances in ssNMR methodology used for structure determination of membrane proteins in native and mimetic environments, as well as the study of protein functions such as protein dynamics, and interactions with ligands, lipids and cholesterol.
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Affiliation(s)
- Kai Xue
- Max Planck Institute for Biophysical Chemistry, Department of NMR Based Structural Biology Am Fassberg. 11 Goettingen Germany
| | - Kumar Tekwani Movellan
- Max Planck Institute for Biophysical Chemistry, Department of NMR Based Structural Biology Am Fassberg. 11 Goettingen Germany
| | - Xizhou Cecily Zhang
- Max Planck Institute for Biophysical Chemistry, Department of NMR Based Structural Biology Am Fassberg. 11 Goettingen Germany
| | - Eszter E Najbauer
- Max Planck Institute for Biophysical Chemistry, Department of NMR Based Structural Biology Am Fassberg. 11 Goettingen Germany
| | - Marcel C Forster
- Max Planck Institute for Biophysical Chemistry, Department of NMR Based Structural Biology Am Fassberg. 11 Goettingen Germany
| | - Stefan Becker
- Max Planck Institute for Biophysical Chemistry, Department of NMR Based Structural Biology Am Fassberg. 11 Goettingen Germany
| | - Loren B Andreas
- Max Planck Institute for Biophysical Chemistry, Department of NMR Based Structural Biology Am Fassberg. 11 Goettingen Germany
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15
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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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16
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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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17
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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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18
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Porat-Dahlerbruch G, Goldbourt A, Polenova T. Virus Structures and Dynamics by Magic-Angle Spinning NMR. Annu Rev Virol 2021; 8:219-237. [PMID: 34586870 DOI: 10.1146/annurev-virology-011921-064653] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Techniques for atomic-resolution structural biology have evolved during the past several decades. Breakthroughs in instrumentation, sample preparation, and data analysis that occurred in the past decade have enabled characterization of viruses with an unprecedented level of detail. Here we review the recent advances in magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy for structural analysis of viruses and viral assemblies. MAS NMR is a powerful method that yields information on 3D structures and dynamics in a broad range of experimental conditions. After a brief introduction, we discuss recent structural and functional studies of several viruses investigated with atomic resolution at various levels of structural organization, from individual domains of a membrane protein reconstituted into lipid bilayers to virus-like particles and intact viruses. We present examples of the unique information revealed by MAS NMR about drug binding, conduction mechanisms, interactions with cellular host factors, and DNA packaging in biologically relevant environments that are inaccessible by other methods.
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Affiliation(s)
- Gal Porat-Dahlerbruch
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA;
| | - Amir Goldbourt
- School of Chemistry, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA; .,Pittsburgh Center for HIV Protein Interactions, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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19
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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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20
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Phyo P, Zhao X, Templeton AC, Xu W, Cheung JK, Su Y. Understanding molecular mechanisms of biologics drug delivery and stability from NMR spectroscopy. Adv Drug Deliv Rev 2021; 174:1-29. [PMID: 33609600 DOI: 10.1016/j.addr.2021.02.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/20/2021] [Accepted: 02/07/2021] [Indexed: 02/06/2023]
Abstract
Protein therapeutics carry inherent limitations of membrane impermeability and structural instability, despite their predominant role in the modern pharmaceutical market. Effective formulations are needed to overcome physiological and physicochemical barriers, respectively, for improving bioavailability and stability. Knowledge of membrane affinity, cellular internalization, encapsulation, and release of drug-loaded carrier vehicles uncover the structural basis for designing and optimizing biopharmaceuticals with enhanced delivery efficiency and therapeutic efficacy. Understanding stabilizing and destabilizing interactions between protein drugs and formulation excipients provide fundamental mechanisms for ensuring the stability and quality of biological products. This article reviews the molecular studies of biologics using solution and solid-state NMR spectroscopy on structural attributes pivotal to drug delivery and stability. In-depth investigation of the structure-function relationship of drug delivery systems based on cell-penetrating peptides, lipid nanoparticles and polymeric colloidal, and biophysical and biochemical stability of peptide, protein, monoclonal antibody, and vaccine, as the integrative efforts on drug product design, will be elaborated.
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Affiliation(s)
- Pyae Phyo
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Xi Zhao
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Allen C Templeton
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Wei Xu
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Jason K Cheung
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States
| | - Yongchao Su
- Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, NJ 07033, United States.
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21
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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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22
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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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23
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Parajuli B, Acharya K, Nangarlia A, Zhang S, Parajuli B, Dick A, Ngo B, Abrams CF, Chaiken I. Identification of a glycan cluster in gp120 essential for irreversible HIV-1 lytic inactivation by a lectin-based recombinantly engineered protein conjugate. Biochem J 2020; 477:4263-4280. [PMID: 33057580 DOI: 10.1042/bcj20200495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 11/17/2022]
Abstract
We previously discovered a class of recombinant lectin conjugates, denoted lectin DLIs ('dual-acting lytic inhibitors') that bind to the HIV-1 envelope (Env) protein trimer and cause both lytic inactivation of HIV-1 virions and cytotoxicity of Env-expressing cells. To facilitate mechanistic investigation of DLI function, we derived the simplified prototype microvirin (MVN)-DLI, containing an MVN domain that binds high-mannose glycans in Env, connected to a DKWASLWNW sequence (denoted 'Trp3') derived from the membrane-associated region of gp41. The relatively much stronger affinity of the lectin component than Trp3 argues that the lectin functions to capture Env to enable Trp3 engagement and consequent Env membrane disruption and virolysis. The relatively simplified engagement pattern of MVN with Env opened up the opportunity, pursued here, to use recombinant glycan knockout gp120 variants to identify the precise Env binding site for MVN that drives DLI engagement and lysis. Using mutagenesis combined with a series of biophysical and virological experiments, we identified a restricted set of residues, N262, N332 and N448, all localized in a cluster on the outer domain of gp120, as the essential epitope for MVN binding. By generating these mutations in the corresponding HIV-1 virus, we established that the engagement of this glycan cluster with the lectin domain of MVN*-DLI is the trigger for DLI-derived virus and cell inactivation. Beyond defining the initial encounter step for lytic inactivation, this study provides a guide to further elucidate DLI mechanism, including the stoichiometry of Env trimer required for function, and downstream DLI optimization.
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Affiliation(s)
- Bibek Parajuli
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Kriti Acharya
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Aakansha Nangarlia
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Shiyu Zhang
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Bijay Parajuli
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Alexej Dick
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Brendon Ngo
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
| | - Cameron F Abrams
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
- Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA 19104, U.S.A
| | - Irwin Chaiken
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, PA 19102, U.S.A
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24
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Mcl-1 and Bok transmembrane domains: Unexpected players in the modulation of apoptosis. Proc Natl Acad Sci U S A 2020; 117:27980-27988. [PMID: 33093207 DOI: 10.1073/pnas.2008885117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The Bcl-2 protein family comprises both pro- and antiapoptotic members that control the permeabilization of the mitochondrial outer membrane, a crucial step in the modulation of apoptosis. Recent research has demonstrated that the carboxyl-terminal transmembrane domain (TMD) of some Bcl-2 protein family members can modulate apoptosis; however, the transmembrane interactome of the antiapoptotic protein Mcl-1 remains largely unexplored. Here, we demonstrate that the Mcl-1 TMD forms homooligomers in the mitochondrial membrane, competes with full-length Mcl-1 protein with regards to its antiapoptotic function, and induces cell death in a Bok-dependent manner. While the Bok TMD oligomers locate preferentially to the endoplasmic reticulum (ER), heterooligomerization between the TMDs of Mcl-1 and Bok predominantly takes place at the mitochondrial membrane. Strikingly, the coexpression of Mcl-1 and Bok TMDs produces an increase in ER mitochondrial-associated membranes, suggesting an active role of Mcl-1 in the induced mitochondrial targeting of Bok. Finally, the introduction of Mcl-1 TMD somatic mutations detected in cancer patients alters the TMD interaction pattern to provide the Mcl-1 protein with enhanced antiapoptotic activity, thereby highlighting the clinical relevance of Mcl-1 TMD interactions.
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25
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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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26
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Xue K, Dervisoglu R, Sowa H, Andreas LB. Centerband-Only Detection of Exchange NMR with Natural-Abundance Correction Reveals an Expanded Unit Cell in Phenylalanine Crystals. Chemphyschem 2020; 21:1622-1626. [PMID: 32558171 PMCID: PMC7497148 DOI: 10.1002/cphc.202000517] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Indexed: 11/05/2022]
Abstract
The NMR pulse sequence CODEX (centerband-only detection of exchange) is a widely used method to report on the number of magnetically inequivalent spins that exchange magnetization via spin diffusion. For crystals, this rules out certain symmetries, and the rate of equilibration is sensitive to distances. Here we show that for 13 C CODEX, consideration of natural abundance spins is necessary for crystals of high complexity, demonstrated here with the amino acid phenylalanine. The NMR data rule out the C2 space group that was originally reported for phenylalanine, and are only consistent with a larger unit cell containing eight magnetically inequivalent molecules. Such an expanded cell was recently described based on single crystal data. The large unit cell dictates the use of long spin diffusion times of more than 200 seconds, in order to equilibrate over the entire unit cell volume of 1622 Å3 .
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Affiliation(s)
- Kai Xue
- Max Planck Institute for Biophysical ChemistryDepartment of NMR Based Structural BiologyAm Fassberg. 1137077GoettingenGermany
| | - Riza Dervisoglu
- Max Planck Institute for Biophysical ChemistryDepartment of NMR Based Structural BiologyAm Fassberg. 1137077GoettingenGermany
| | - Heidrun Sowa
- Georg-August-University GoettingenDepartment of CrystallographyGoldschmidtstr. 137077GoettingenGermany
| | - Loren B. Andreas
- Max Planck Institute for Biophysical ChemistryDepartment of NMR Based Structural BiologyAm Fassberg. 1137077GoettingenGermany
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27
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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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28
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Barrett CT, Dutch RE. Viral Membrane Fusion and the Transmembrane Domain. Viruses 2020; 12:v12070693. [PMID: 32604992 PMCID: PMC7412173 DOI: 10.3390/v12070693] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/24/2020] [Accepted: 06/25/2020] [Indexed: 01/05/2023] Open
Abstract
Initiation of host cell infection by an enveloped virus requires a viral-to-host cell membrane fusion event. This event is mediated by at least one viral transmembrane glycoprotein, termed the fusion protein, which is a key therapeutic target. Viral fusion proteins have been studied for decades, and numerous critical insights into their function have been elucidated. However, the transmembrane region remains one of the most poorly understood facets of these proteins. In the past ten years, the field has made significant advances in understanding the role of the membrane-spanning region of viral fusion proteins. We summarize developments made in the past decade that have contributed to the understanding of the transmembrane region of viral fusion proteins, highlighting not only their critical role in the membrane fusion process, but further demonstrating their involvement in several aspects of the viral lifecycle.
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29
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Wang W, Tan J, Ye S. Unsaturated Lipid Accelerates Formation of Oligomeric β-Sheet Structure of GP41 Fusion Peptide in Model Cell Membrane. J Phys Chem B 2020; 124:5169-5176. [PMID: 32453953 DOI: 10.1021/acs.jpcb.0c02464] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Membrane fusion of the viral and host cell membranes is the initial step of virus infection and is catalyzed by fusion peptides. Although the β-sheet structure of fusion peptides has been proposed to be the most important fusion-active conformation, it is still very challenging to experimentally identify different types of β-sheet structures at the cell membrane surface in situ and in real time. In this work, we demonstrate that the interface-sensitive amide II spectral signals of protein backbones, generated by the sum frequency generation vibrational spectroscopy, provide a sensitive probe for directly capturing the formation of oligomeric β-sheet structure of fusion peptides. Using human immunodeficiency virus (HIV) glycoprotein GP41 fusing peptide (FP23) as the model, we find that formation speed of oligomeric β-sheet structure depends on lipid unsaturation. The unsaturated lipid such as POPG can accelerate formation of oligomeric β-sheet structure of FP23. The β-sheet structure is more deeply inserted into the hydrophobic region of the POPG bilayer than the α-helical segment. This work will pave the way for future researches on capturing intermediate structures during membrane fusion processes and revealing the fusion mechanism.
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Affiliation(s)
- Wenting Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Junjun Tan
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Shuji Ye
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
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30
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Bukrinsky MI, Mukhamedova N, Sviridov D. Lipid rafts and pathogens: the art of deception and exploitation. J Lipid Res 2020; 61:601-610. [PMID: 31615838 PMCID: PMC7193957 DOI: 10.1194/jlr.tr119000391] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 10/07/2019] [Indexed: 02/06/2023] Open
Abstract
Lipid rafts, solid regions of the plasma membrane enriched in cholesterol and glycosphingolipids, are essential parts of a cell. Functionally, lipid rafts present a platform that facilitates interaction of cells with the outside world. However, the unique properties of lipid rafts required to fulfill this function at the same time make them susceptible to exploitation by pathogens. Many steps of pathogen interaction with host cells, and sometimes all steps within the entire lifecycle of various pathogens, rely on host lipid rafts. Such steps as binding of pathogens to the host cells, invasion of intracellular parasites into the cell, the intracellular dwelling of parasites, microbial assembly and exit from the host cell, and microbe transfer from one cell to another all involve lipid rafts. Interaction also includes modification of lipid rafts in host cells, inflicted by pathogens from both inside and outside the cell, through contact or remotely, to advance pathogen replication, to utilize cellular resources, and/or to mitigate immune response. Here, we provide a systematic overview of how and why pathogens interact with and exploit host lipid rafts, as well as the consequences of this interaction for the host, locally and systemically, and for the microbe. We also raise the possibility of modulation of lipid rafts as a therapeutic approach against a variety of infectious agents.
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Affiliation(s)
- Michael I Bukrinsky
- Department of Microbiology, Immunology, and Tropical Medicine,George Washington University School of Medicine and Health Science, Washington, DC 20037
| | | | - Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne 3004, Australia. mailto:
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31
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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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32
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NMR Structure of the FIV gp36 C-Terminal Heptad Repeat and Membrane-Proximal External Region. Int J Mol Sci 2020; 21:ijms21062037. [PMID: 32188158 PMCID: PMC7139756 DOI: 10.3390/ijms21062037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 03/10/2020] [Accepted: 03/13/2020] [Indexed: 12/13/2022] Open
Abstract
Feline immunodeficiency virus (FIV), a lentivirus causing an immunodeficiency syndrome in cats, represents a relevant model of pre-screening therapies for human immunodeficiency virus (HIV). The envelope glycoproteins gp36 in FIV and gp41 in HIV mediate the fusion of the virus with the host cell membrane. They have a common structural framework in the C-terminal region that includes a Trp-rich membrane-proximal external region (MPER) and a C-terminal heptad repeat (CHR). MPER is essential for the correct positioning of gp36 on the lipid membrane, whereas CHR is essential for the stabilization of the low-energy six-helical bundle (6HB) that is necessary for the fusion of the virus envelope with the cell membrane. Conformational data for gp36 are missing, and several aspects of the MPER structure of different lentiviruses are still debated. In the present work, we report the structural investigation of a gp36 construct that includes the MPER and part of the CHR domain (737-786gp36 CHR–MPER). Using 2D and 3D homo and heteronuclear NMR spectra on 15N and 13C double-labelled samples, we solved the NMR structure in micelles composed of dodecyl phosphocholine (DPC) and sodium dodecyl sulfate (SDS) 90/10 M: M. The structure of 737-786gp36 CHR–MPER is characterized by a helix–turn–helix motif, with a regular α-helix and a moderately flexible 310 helix, characterizing the CHR and the MPER domains, respectively. The two helices are linked by a flexible loop regulating their orientation at a ~43° angle. We investigated the positioning of 737-786gp36 CHR–MPER on the lipid membrane using spin label-enhanced NMR and ESR spectroscopies. On a different scale, using confocal microscopy imaging, we studied the effect of 737-786gp36 CHR–MPER on 1,2-dioleoyl-sn-glycero-3-phosphocholine/1,2-dioleoyl-sn-glycero-3-phospho-(1’-rac-glycerol) (DOPC/DOPG) multilamellar vesicles (MLVs). This effect results in membrane budding and tubulation that is reminiscent of a membrane-plasticizing role that is typical of MPER domains during the event in which the virus envelope merges with the host cell membrane.
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Branttie JM, Dutch RE. Parainfluenza virus 5 fusion protein maintains pre-fusion stability but not fusogenic activity following mutation of a transmembrane leucine/isoleucine domain. J Gen Virol 2020; 101:467-472. [PMID: 32100701 DOI: 10.1099/jgv.0.001399] [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: 01/27/2023] Open
Abstract
The paramyxoviruses Hendra virus (HeV) and parainfluenza virus 5 (PIV5) require the fusion (F) protein to efficiently infect cells. For fusion to occur, F undergoes dramatic, essentially irreversible conformational changes to merge the viral and cell membranes into a continuous bilayer. Recently, a transmembrane (TM) domain leucine/isoleucine (L/I) zipper was shown to be critical in maintaining the expression, stability and pre-fusion conformation of HeV F, allowing for fine-tuned timing of membrane fusion. To analyse the effect of the TM domain L/I zipper in another paramyxovirus, we created alanine mutations to the TM domain of PIV5 F, a paramyxovirus model system. Our data show that while the PIV5 F TM L/I zipper does not significantly affect total expression and only modestly affects surface expression and pre-fusion stability, it is critical for fusogenic activity. These results suggest that the roles of TM L/I zipper motifs differ among members of the family Paramyxoviridae.
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Affiliation(s)
- Jean Mawuena Branttie
- Department of Molecular and Cellular Biochemistry, College of Medicine University of Kentucky Biomedical Biological Sciences Research Bldg, 741 South Limestone Street, Lexington, KY, USA
| | - Rebecca Ellis Dutch
- Department of Molecular and Cellular Biochemistry, College of Medicine University of Kentucky Biomedical Biological Sciences Research Bldg, 741 South Limestone Street, Lexington, KY, USA
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Wang S, Gopinath T, Veglia G. Improving the quality of oriented membrane protein spectra using heat-compensated separated local field experiments. JOURNAL OF BIOMOLECULAR NMR 2019; 73:617-624. [PMID: 31463642 PMCID: PMC6861693 DOI: 10.1007/s10858-019-00273-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/21/2019] [Indexed: 05/03/2023]
Abstract
Oriented sample solid-state NMR (OS-ssNMR) spectroscopy is a powerful technique to determine the topology of membrane proteins in oriented lipid bilayers. Separated local field (SLF) experiments are central to this technique as they provide first-order orientational restraints, i.e., dipolar couplings and anisotropic chemical shifts. Despite the use of low-E (or E-free) probes, the heat generated during the execution of 2D and 3D SLF pulse sequences causes sizeable line-shape distortions. Here, we propose a new heat-compensated SE-SAMPI4 (hcSE-SAMPI4) pulse sequence that holds the temperature constant for the duration of the experiment. This modification of the SE-SAMPI4 results in sharper and more intense resonances without line-shape distortions. The spectral improvements are even more apparent when paramagnetic relaxation agents are used to speed up data collection. We tested the hcSE-SAMPI4 pulse sequence on a single-span membrane protein, sarcolipin (SLN), reconstituted in magnetically aligned lipid bicelles. In addition to eliminating peak distortions, the hcSE-SAMPI4 experiment increased the average signal-to-noise ratio by 20% with respect to the original SE-SAMPI4.
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Affiliation(s)
- Songlin Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - T Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA.
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35
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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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36
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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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37
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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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38
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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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Kwon B, Roos M, Mandala VS, Shcherbakov AA, Hong M. Elucidating Relayed Proton Transfer through a His-Trp-His Triad of a Transmembrane Proton Channel by Solid-State NMR. J Mol Biol 2019; 431:2554-2566. [PMID: 31082440 DOI: 10.1016/j.jmb.2019.05.009] [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] [Received: 01/29/2019] [Revised: 04/13/2019] [Accepted: 05/05/2019] [Indexed: 01/02/2023]
Abstract
Proton transfer through membrane-bound ion channels is mediated by both water and polar residues of proteins, but the detailed molecular mechanism is challenging to determine. The tetrameric influenza A and B virus M2 proteins form canonical proton channels that use an HxxxW motif for proton selectivity and gating. The BM2 channel also contains a second histidine (His), H27, equidistant from the gating tryptophan, which leads to a symmetric H19xxxW23xxxH27 motif. The proton-dissociation constants (pKa's) of H19 in BM2 were found to be much lower than the pKa's of H37 in AM2. To determine if the lower pKa's result from H27-facilitated proton dissociation of H19, we have now investigated a H27A mutant of BM2 using solid-state NMR. 15N NMR spectra indicate that removal of the second histidine converted the protonation and tautomeric equilibria of H19 to be similar to the H37 behavior in AM2, indicating that the peripheral H27 is indeed the origin of the low pKa's of H19 in wild-type BM2. Measured interhelical distances between W23 sidechains indicate that the pore constriction at W23 increases with the H19 tetrad charge but is independent of the H27A mutation. These results indicate that H27 both accelerates proton dissociation from H19 to increase the inward proton conductance and causes the small reverse conductance of BM2. The proton relay between H19 and H27 is likely mediated by the intervening gating tryptophan through cation-π interactions. This relayed proton transfer may exist in other ion channels and has implications for the design of imidazole-based synthetic proton channels.
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Affiliation(s)
- Byungsu Kwon
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, USA
| | - Matthias Roos
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, USA
| | - Venkata S Mandala
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, USA
| | - Alexander A Shcherbakov
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, USA
| | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139, USA.
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40
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Han R, Yang Y, Wang S. Longitudinal Relaxation Optimization Enhances 1 H-Detected HSQC in Solid-State NMR Spectroscopy on Challenging Biological Systems. Chemistry 2019; 25:4115-4122. [PMID: 30632195 DOI: 10.1002/chem.201805327] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Indexed: 11/10/2022]
Abstract
Solid-state (SS) NMR spectroscopy is a powerful technique for studying challenging biological systems, but it often suffers from low sensitivity. A longitudinal relaxation optimization scheme to enhance the signal sensitivity of HSQC experiments in SSNMR spectroscopy is reported. Under the proposed scheme, the 1 H spins of 1 H-X (15 N or 13 C) are selected for signal acquisition, whereas other vast 1 H spins are flipped back to the axis of the static magnetic field to accelerate the spin recovery of the observed 1 H spins, resulting in enhanced sensitivity. Three biological systems are used to evaluate this strategy, including a seven-transmembrane protein, an RNA, and a whole-cell sample. For all three samples, the proposed scheme largely shortens the effective 1 H longitudinal relaxation time and results in a 1.3-2.5-fold gain in sensitivity. The selected systems are representative of challenging biological systems for observation by means of SSNMR spectroscopy; thus indicating the general applicability of this method, which is particularly important for biological samples with a short lifetime or with limited sample quantities.
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Affiliation(s)
- Rong Han
- College of Chemistry and Molecular Engineering and Beijing NMR Center, Peking University, No. 5th, Yiheyuan Rd., Beijing, 100871, P.R. China
| | - Yufei Yang
- College of Chemistry and Molecular Engineering and Beijing NMR Center, Peking University, No. 5th, Yiheyuan Rd., Beijing, 100871, P.R. China
| | - Shenlin Wang
- College of Chemistry and Molecular Engineering and Beijing NMR Center, Peking University, No. 5th, Yiheyuan Rd., Beijing, 100871, P.R. China.,Beijing National Laboratory for Molecular Sciences, Beijing, P.R. China
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41
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Elkins MR, Sergeyev IV, Hong M. Determining Cholesterol Binding to Membrane Proteins by Cholesterol 13C Labeling in Yeast and Dynamic Nuclear Polarization NMR. J Am Chem Soc 2018; 140:15437-15449. [PMID: 30338997 PMCID: PMC6361393 DOI: 10.1021/jacs.8b09658] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present a general strategy for determining the cholesterol-binding site of eukaryotic membrane proteins in native-like lipid membranes by NMR spectroscopy. The strategy combines yeast biosynthetic 13C enrichment of cholesterol with detection of protein-cholesterol 13C-13C cross peaks in 2D correlation NMR spectra under the dynamic nuclear polarization (DNP) condition. Low-temperature DNP not only allows high-sensitivity detection of weak protein-cholesterol cross peaks in 2D spectra but also immobilizes cholesterol and protein to enable intermolecular distance measurements. We demonstrate this approach on the influenza M2 protein, which utilizes cholesterol to conduct membrane scission in the last step of virus budding and release from the host cell plasma membrane. A 13C-13C double-quantum filter was employed to significantly simplify the 2D 13C-13C correlation spectra and facilitate the identification of protein-cholesterol cross peaks. A number of cross peaks between the M2 transmembrane residues' side chains and the cholesterol sterol group were detected, which complement recently measured protein contacts to the isooctyl tail of cholesterol to define an extended binding interface. These results provide atomic-level evidence of M2-cholesterol interaction to cause membrane curvature and scission, and the approach is generally applicable to other eukaryotic membrane proteins for understanding the influence of cholesterol on membrane protein function.
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Affiliation(s)
- Matthew R. Elkins
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | | | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
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