Novikova, M, Adams, LJ, Fontana, J orcid.org/0000-0002-9084-2927 et al. (8 more authors) (2018) Identification of a Structural Element in HIV-1 Gag Required for Virus Particle Assembly and Maturation. mBio, 9 (5). e01567-18. ISSN 2150-7511
Abstract
Late in the HIV-1 replication cycle, the viral structural protein Gag is targeted to virus assembly sites at the plasma membrane of infected cells. The capsid (CA) domain of Gag plays a critical role in the formation of the hexameric Gag lattice in the immature virion, and, during particle release, CA is cleaved from the Gag precursor by the viral protease and forms the conical core of the mature virion. A highly conserved Pro-Pro-Ile-Pro (PPIP) motif (CA residues 122 to 125) [PPIP(122–125)] in a loop connecting CA helices 6 and 7 resides at a 3-fold axis formed by neighboring hexamers in the immature Gag lattice. In this study, we characterized the role of this PPIP(122–125) loop in HIV-1 assembly and maturation. While mutations P123A and P125A were relatively well tolerated, mutation of P122 and I124 significantly impaired virus release, caused Gag processing defects, and abolished infectivity. X-ray crystallography indicated that the P122A and I124A mutations induce subtle changes in the structure of the mature CA lattice which were permissive for in vitro assembly of CA tubes. Transmission electron microscopy and cryo-electron tomography demonstrated that the P122A and I124A mutations induce severe structural defects in the immature Gag lattice and abrogate conical core formation. Propagation of the P122A and I124A mutants in T-cell lines led to the selection of compensatory mutations within CA. Our findings demonstrate that the CA PPIP(122–125) loop comprises a structural element critical for the formation of the immature Gag lattice.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | This is a work of the U.S. Government and is not subject to copyright protection in the United States. Foreign copyrights may apply. Articles in mBio™ are published under the Creative Commons CC BY license, which allows unrestricted reuse of the material with proper attribution. Users have the right to read, download, copy, distribute, print, search, or link to the full texts of these articles. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
Keywords: | cryo-EM; HIV-1; assembly; capsid; maturation; virus replication |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Molecular and Cellular Biology (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 11 Oct 2018 08:52 |
Last Modified: | 25 Jun 2023 21:32 |
Status: | Published |
Publisher: | American Society for Microbiology |
Identification Number: | 10.1128/mBio.01567-18 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:136929 |