Laboratory of Molecular Biophysics, Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
Department of Molecular Genetics & Microbiology, School of Medicine, Stony Brook University, Stony Brook, NY, 11794-5222, USA.
Nat Commun. 2017 Nov 9;8(1):1391. doi: 10.1038/s41467-017-01426-2.
HIV-1 replication requires Tsg101, a component of cellular endosomal sorting complex required for transport (ESCRT) machinery. Tsg101 possesses an ubiquitin (Ub) E2 variant (UEV) domain with a pocket that can bind PT/SAP motifs and another pocket that can bind Ub. The PTAP motif in the viral structural precursor polyprotein, Gag, allows the recruitment of Tsg101 and other ESCRTs to virus assembly sites where they mediate budding. It is not known how or even whether the UEV Ub binding function contributes to virus production. Here, we report that disruption of UEV Ub binding by commonly used drugs arrests assembly at an early step distinct from the late stage involving PTAP binding disruption. NMR reveals that the drugs form a covalent adduct near the Ub-binding pocket leading to the disruption of Ub, but not PTAP binding. We conclude that the Ub-binding pocket has a chaperone function involved in bud initiation.
HIV-1 的复制需要 Tsg101，这是细胞内内体分选复合物必需的运输（ESCRT）机制的一个组成部分。Tsg101 具有泛素（Ub）E2 变体（UEV）结构域，该结构域具有一个可以结合 PT/SAP 基序的口袋和另一个可以结合 Ub 的口袋。病毒结构前体多蛋白 Gag 中的 PTAP 基序允许 Tsg101 和其他 ESCRTs 募集到病毒组装部位，在那里它们介导出芽。目前尚不清楚 UEV Ub 结合功能如何或甚至是否有助于病毒产生。在这里，我们报告说，常用药物破坏 UEV Ub 结合会在不同于涉及 PTAP 结合破坏的晚期阶段的早期步骤中断组装。NMR 揭示，这些药物在 Ub 结合口袋附近形成一个共价加合物，导致 Ub 但不是 PTAP 结合的破坏。我们得出结论，Ub 结合口袋具有涉及芽起始的伴侣功能。
