Oligomeric structure and three-dimensional fold of the HIV gp41 membrane-proximal external region and transmembrane domain in phospholipid bilayers
The HIV-1 glycoprotein, gp41, mediates fusion of the virus lipid envelope with the target cell membrane during virus entry into cells. Despite extensive studies of this protein, inconsistent and contradictory structural information abounds in the literature about the C-terminal membrane-interacting...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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American Chemical Society (ACS)
2020
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| Online Access: | https://hdl.handle.net/1721.1/125941 |
| _version_ | 1826198401023213568 |
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| author | Kwon, Byungsu Lee, Myungwoon Waring, Alan J. Hong, Mei |
| author2 | Massachusetts Institute of Technology. Department of Chemistry |
| author_facet | Massachusetts Institute of Technology. Department of Chemistry Kwon, Byungsu Lee, Myungwoon Waring, Alan J. Hong, Mei |
| author_sort | Kwon, Byungsu |
| collection | MIT |
| description | The HIV-1 glycoprotein, gp41, mediates fusion of the virus lipid envelope with the target cell membrane during virus entry into cells. Despite extensive studies of this protein, inconsistent and contradictory structural information abounds in the literature about the C-terminal membrane-interacting region of gp41. This C-terminal region contains the membrane-proximal external region (MPER), which harbors the epitopes for four broadly neutralizing antibodies, and the transmembrane domain (TMD), which anchors the protein to the virus lipid envelope. Due to the difficulty of crystallizing and solubilizing the MPER-TMD, most structural studies of this functionally important domain were carried out using truncated peptides either in the absence of membrane-mimetic solvents or bound to detergents and lipid bicelles. To determine the structural architecture of the MPER-TMD in the native environment of lipid membranes, we have now carried out a solid-state NMR study of the full MPER-TMD segment bound to cholesterol-containing phospholipid bilayers. [superscript 13]C chemical shifts indicate that the majority of the peptide is α-helical, except for the C-terminus of the TMD, which has moderate β-sheet character. Intermolecular [superscript 19]F- [superscript 19]F distance measurements of singly fluorinated peptides indicate that the MPER-TMD is trimerized in the virus-envelope mimetic lipid membrane. Intramolecular [superscript 13]C- [superscript 19]F distance measurements indicate the presence of a turn between the MPER helix and the TMD helix. This is supported by lipid-peptide and water-peptide 2D [superscript 1]H- [superscript 13]C correlation spectra, which indicate that the MPER binds to the membrane surface whereas the TMD spans the bilayer. Together, these data indicate that full-length MPER-TMD assembles into a trimeric helix-turn-helix structure in lipid membranes. We propose that the turn between the MPER and TMD may be important for inducing membrane defects in concert with negative-curvature lipid components such as cholesterol and phosphatidylethanolamine, while the surface-bound MPER helix may interact with N-terminal segments of the protein during late stages of membrane fusion. |
| first_indexed | 2024-09-23T11:04:18Z |
| format | Article |
| id | mit-1721.1/125941 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T11:04:18Z |
| publishDate | 2020 |
| publisher | American Chemical Society (ACS) |
| record_format | dspace |
| spelling | mit-1721.1/1259412022-09-27T16:58:27Z Oligomeric structure and three-dimensional fold of the HIV gp41 membrane-proximal external region and transmembrane domain in phospholipid bilayers Kwon, Byungsu Lee, Myungwoon Waring, Alan J. Hong, Mei Massachusetts Institute of Technology. Department of Chemistry The HIV-1 glycoprotein, gp41, mediates fusion of the virus lipid envelope with the target cell membrane during virus entry into cells. Despite extensive studies of this protein, inconsistent and contradictory structural information abounds in the literature about the C-terminal membrane-interacting region of gp41. This C-terminal region contains the membrane-proximal external region (MPER), which harbors the epitopes for four broadly neutralizing antibodies, and the transmembrane domain (TMD), which anchors the protein to the virus lipid envelope. Due to the difficulty of crystallizing and solubilizing the MPER-TMD, most structural studies of this functionally important domain were carried out using truncated peptides either in the absence of membrane-mimetic solvents or bound to detergents and lipid bicelles. To determine the structural architecture of the MPER-TMD in the native environment of lipid membranes, we have now carried out a solid-state NMR study of the full MPER-TMD segment bound to cholesterol-containing phospholipid bilayers. [superscript 13]C chemical shifts indicate that the majority of the peptide is α-helical, except for the C-terminus of the TMD, which has moderate β-sheet character. Intermolecular [superscript 19]F- [superscript 19]F distance measurements of singly fluorinated peptides indicate that the MPER-TMD is trimerized in the virus-envelope mimetic lipid membrane. Intramolecular [superscript 13]C- [superscript 19]F distance measurements indicate the presence of a turn between the MPER helix and the TMD helix. This is supported by lipid-peptide and water-peptide 2D [superscript 1]H- [superscript 13]C correlation spectra, which indicate that the MPER binds to the membrane surface whereas the TMD spans the bilayer. Together, these data indicate that full-length MPER-TMD assembles into a trimeric helix-turn-helix structure in lipid membranes. We propose that the turn between the MPER and TMD may be important for inducing membrane defects in concert with negative-curvature lipid components such as cholesterol and phosphatidylethanolamine, while the surface-bound MPER helix may interact with N-terminal segments of the protein during late stages of membrane fusion. NIH (grant no. GM066976) 2020-06-23T18:03:50Z 2020-06-23T18:03:50Z 2018-07 2019-12-18T15:49:43Z Article http://purl.org/eprint/type/JournalArticle 1520-5126 https://hdl.handle.net/1721.1/125941 Kwon, Byungsu, et al., "Oligomeric structure and three-dimensional fold of the HIV gp41 membrane-proximal external region and transmembrane domain in phospholipid bilayers." Journal of the American Chemical Society 140, 26 (July 2018): p. 8246-59 doi 10.1021/JACS.8B04010 ©2018 Author(s) en 10.1021/JACS.8B04010 Journal of the American Chemical Society Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Chemical Society (ACS) PMC |
| spellingShingle | Kwon, Byungsu Lee, Myungwoon Waring, Alan J. Hong, Mei Oligomeric structure and three-dimensional fold of the HIV gp41 membrane-proximal external region and transmembrane domain in phospholipid bilayers |
| title | Oligomeric structure and three-dimensional fold of the HIV gp41 membrane-proximal external region and transmembrane domain in phospholipid bilayers |
| title_full | Oligomeric structure and three-dimensional fold of the HIV gp41 membrane-proximal external region and transmembrane domain in phospholipid bilayers |
| title_fullStr | Oligomeric structure and three-dimensional fold of the HIV gp41 membrane-proximal external region and transmembrane domain in phospholipid bilayers |
| title_full_unstemmed | Oligomeric structure and three-dimensional fold of the HIV gp41 membrane-proximal external region and transmembrane domain in phospholipid bilayers |
| title_short | Oligomeric structure and three-dimensional fold of the HIV gp41 membrane-proximal external region and transmembrane domain in phospholipid bilayers |
| title_sort | oligomeric structure and three dimensional fold of the hiv gp41 membrane proximal external region and transmembrane domain in phospholipid bilayers |
| url | https://hdl.handle.net/1721.1/125941 |
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