HIV-1包膜糖蛋白gp41介导病毒与细胞的膜融合过程，是病毒入侵感染的关键蛋白，也是重要的药物靶标。然而，目前尚缺乏完整的gp41结构与功能信息，特别对病毒融合前及融合中间状态时gp41的空间构象及分子内部的相互作用了解有限。申请人前期的研究发现，gp41近膜端的色氨酸富集基序（TRM）可以与N端螺旋（NHR）上的深口袋区相互作用，并破环NHR的二级结构，但具体的机制尚不清楚（Zhu et al. J Virol, 2020）。本申请旨在鉴定TRM与口袋区相互作用的结构基础。将通过分析TRM和NHR定点突变多肽之间的相互作用探究影响TRM干扰作用的关键氨基酸位点；通过解析TRM和NHR多肽复合物的晶体结构来确定TRM与口袋区作用并破坏螺旋结构的分子基础。本研究将对深入了解gp41的结构与功能关系、病毒膜融合机制以及设计新的HIV膜融合抑制剂提供重要信息。

The HIV-1 Env glycoprotein gp41 mediates viral membrane fusion, thus being a key protein for cell entry/infection and drug target. However, the structural and functional information on gp41 is lacking, especially for its steric conformation and internal molecular interactions during the prefusion and the fusion intermediate states. We recently found that the tryptophan-rich motif (TRM) in the membrane-proximal external region of gp41 can interact with its N-terminal deep hydrophobic pocket thus disrupting the secondary structure of the heptad repeat (NHR) helices, but the underlying mechanism remains unclear (Zhu et al. J Virol, 2020). This proposal aims to identify and characterize the structural basis of the TRM-pocket interaction. The key amino acids responsible for the disruptive effect of TRM will be explored by using TRM and NHR mutant peptides bearing specific substitutions; the crystal structures of TRM peptides complexed to the NHR peptides will be determined to reveal the structural basis underlying the TRM-pocket interaction that can disrupt the helical conformation. This study will provide important information for the structure-function relationship of gp41, viral fusion mechanism and design of novel HIV fusion inhibitors.