BackgroundPeptides corresponding to N- and C-terminal heptad repeat regions (HR1 and HR2, respectively) of gp41 can inhibit HIV-1 infection in a dominant negative manner by interfering with refolding of the viral HR1 and HR2 to form a six-helix bundle (6HB) that induces fusion between viral and host cell membranes. Previously, we found that HIV-1 acquired the mutations of Glu560 (E560) in HR1 of envelope (Env) to escape peptide inhibitors. The present study aimed to elucidate the critical role of position 560 in the virus entry and potential resistance mechanisms.ResultsThe Glu560Lys/Asp/Gly (E560K/D/G) mutations in HR1 of gp41 that are selected under the pressure of N- and C-peptide inhibitors modified its molecular interactions with HR2 to change 6HB stability and peptide inhibitor binding. E560K mutation increased 6HB thermostability and resulted in resistance to N peptide inhibitors, but E560G or E560D as compensatory mutations destabilized the 6HB to reduce inhibitor binding and resulted in increased resistance to C peptide inhibitor, T20. Significantly, the neutralizing activities of all mutants to soluble CD4 and broadly neutralizing antibodies targeting membrane proximal external region, 2F5 and 4E10 were improved, indicating the mutations of E560 could regulate Env conformations through cross interactions with gp120 or gp41. The molecular modeling analysis of E560K/D/G mutants suggested that position 560 might interact with the residues within two potentially flexible topological layer 1 and layer 2 in the gp120 inner domain to apparently affect the CD4 utilization. The E560K/D/G mutations changed its interactions with Gln650 (Q650) in HR2 to contribute to the resistance of peptide inhibitors.ConclusionsThese findings identify the contributions of mutations of E560K/D/G in the highly conserved gp41 and highlight Env’s high degree of plasticity for virus entry and inhibitor design.

中文翻译：

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HIV-1 包膜糖蛋白 N 端七肽重复区域内 Glu560 的突变有助于抵抗病毒进入的肽抑制剂

背景对应于 gp41 的 N 端和 C 端七肽重复区域（分别为 HR1 和 HR2）的肽可以通过干扰病毒 HR1 和 HR2 的重折叠形成六螺旋束，以显性负方式抑制 HIV-1 感染。 6HB）诱导病毒和宿主细胞膜之间的融合。此前，我们发现 HIV-1 在包膜 (Env) 的 HR1 中获得了 Glu560 (E560) 的突变以逃避肽抑制剂。本研究旨在阐明560位在病毒进入和潜在耐药机制中的关键作用。 结果gp41 HR1中的Glu560Lys/Asp/Gly (E560K/D/G)突变在N-和C压力下选择-肽抑制剂修饰其与 HR2 的分子相互作用，以改变 6HB 稳定性和肽抑制剂结合。E560K 突变增加了 6HB 热稳定性并导致对 N 肽抑制剂的抗性，但作为补偿性突变的 E560G 或 E560D 使 6HB 不稳定以减少抑制剂结合并导致对 C 肽抑制剂 T20 的抗性增加。值得注意的是，所有突变体对可溶性 CD4 和广泛中和抗体的中和活性都得到了提高，这些抗体靶向膜近端外部区域 2F5 和 4E10，表明 E560 的突变可以通过与 gp120 或 gp41 的交叉相互作用来调节 Env 构象。E560K/D/G 突变体的分子建模分析表明，位置 560 可能与 gp120 内部域中两个潜在的灵活拓扑层 1 和层 2 内的残基相互作用，从而明显影响 CD4 的利用。