Entrance of human immunodeficiency virus type 1 (HIV-1) into cells is mediated by envelope glycoprotein (Env), which contains a receptor-binding unit, gpl20, and a membrane-fusion unit, gp41. HIV-1 gp41 consists of three major functional regions: ectodomain, membrane-spanning domain (MSD) and endodomain. The ectodomain is the structural basis for membrane fusion during viral infection; the hydrophobic residues of the MSD anchor Env to the bilayer membrane; and the endodomain plays multiple functions in viral infection, replication, and assembly. The most important motifs in the endodomain are three lentivirus Iytic peptides (LLP 1-3), two Tyr-contained motifs (Y712XXL and Y802 W803), and a di-leucine motif (LL866/857). Additionally, the topological change of the endodomain such as those at Kennedy epitope, indicates that there are interactions among the three regions of gp41. Progress in understanding the function-structure relationship of gp41 not only improves our knowledge about replication and pathogenesis of HIV-1 but also provides some insight into the development of new antiviral drugs.%人类免疫缺陷病毒1型(HIV-1)通过其包膜糖蛋白(Env)介导侵入靶细胞.Env由受体特异性结合单位gp120和膜融合单位gp41组成.HIV-1的gp41分为3个功能区:膜外区、跨膜区和膜内区.膜外区是病毒感染时膜融合的主要结构基础；跨膜区通过疏水残基使Env锚定在脂质膜上；膜内区则表现多重功能,参与病毒的感染、复制、装配等过程.膜内区的功能由其特定的结构域或基序完成,包括3个慢病毒裂解肽(LLP-1、LLP-2、LLP-3)、含Tyr基序(Y712 XXL和Y802 W803)和双Leu基序(LL855/856)等.病毒诱导的融合过程中,包含Kennedy表位在内的膜内区发生拓扑学改变,表明gp41的3个功能区之间存在相互作用.这些进展对了解HIV-1的感染、复制和致病机制,开发新的抗病毒药物具有重要意义.
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