Department of Chemistry and Biochemistry
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Browsing Department of Chemistry and Biochemistry by Author "Aiken, Christopher"
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Item Cyclophilin A stabilizes the HIV-1 capsid through a novel non-canonical binding site(Nature Publishing Group, 2016-03-04) Liu, Chuang; Perilla, Juan R.; Ning, Jiying; Lu, Manman; Hou, Guangjin; Ramalho, Ruben; Himes, Benjamin A.; Zhao, Gongpu; Bedwell, Gregory J.; Byeon, In-Ja; Ahn, Jinwoo; Gronenborn, Angela M.; Prevelige, Peter E.; Rousso, Itay; Aiken, Christopher; Polenova, Tatyana; Schulten, Klaus; Zhang, Peijun; Chuang Liu, Juan R. Perilla, Jiying Ning, Manman Lu, Guangjin Hou, Ruben Ramalho, Benjamin A. Himes, Gongpu Zhao, Gregory J. Bedwell, In-Ja Byeon, Jinwoo Ahn, Angela M. Gronenborn, Peter E. Prevelige, Itay Rousso, Christopher Aiken, Tatyana Polenova, Klaus Schulten & Peijun Zhang; Lu, Manman; Hou, Guangjin; Polenova, TatyanaThe host cell factor cyclophilin A (CypA) interacts directly with the HIV-1 capsid and regulates viral infectivity. Although the crystal structure of CypA in complex with the N-terminal domain of the HIV-1 capsid protein (CA) has been known for nearly two decades, how CypA interacts with the viral capsid and modulates HIV-1 infectivity remains unclear. We determined the cryoEM structure of CypA in complex with the assembled HIV-1 capsid at 8-Å resolution. The structure exhibits a distinct CypA-binding pattern in which CypA selectively bridges the two CA hexamers along the direction of highest curvature. EM-guided all-atom molecular dynamics simulations and solid-state NMR further reveal that the CypA-binding pattern is achieved by single-CypA molecules simultaneously interacting with two CA subunits, in different hexamers, through a previously uncharacterized non-canonical interface. These results provide new insights into how CypA stabilizes the HIV-1 capsid and is recruited to facilitate HIV-1 infection.Item HIV-1 mutants that escape the cytotoxic T-lymphocytes are defective in viral DNA integration(PNAS Nexus, 2022-05-20) Balasubramaniam, Muthukumar; Davids, Benem-Orom; Bryer, Alex; Xu, Chaoyi; Thapa, Santosh; Shi, Jiong; Aiken, Christopher; Pandhare, Jui; Perilla, Juan R.; Dash, ChandravanuHIV-1 replication is durably controlled without antiretroviral therapy (ART) in certain infected individuals called elite controllers (ECs). These individuals express specific human leukocyte antigens (HLA) that tag HIV-infected cells for elimination by presenting viral epitopes to CD8+ cytotoxic T-lymphocytes (CTL). In HIV-infected individuals expressing HLA-B27, CTLs primarily target the viral capsid protein (CA)-derived KK10 epitope. While selection of CA mutation R264K helps HIV-1 escape this potent CTL response, the accompanying fitness cost severely diminishes virus infectivity. Interestingly, selection of a compensatory CA mutation S173A restores HIV-1 replication. However, the molecular mechanism(s) underlying HIV-1 escape from this ART-free virus control by CTLs is not fully understood. Here, we report that the R264K mutation-associated infectivity defect arises primarily from impaired HIV-1 DNA integration, which is restored by the S173A mutation. Unexpectedly, the integration defect of the R264K variant was also restored upon depletion of the host cyclophilin A. These findings reveal a nuclear crosstalk between CA and HIV-1 integration as well as identify a previously unknown role of cyclophilin A in viral DNA integration. Finally, our study identifies a novel immune escape mechanism of an HIV-1 variant escaping a CA-directed CTL response.