NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology and Center for AIDS Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
Department of Lab Medicine, Institute of Hematology, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020, China.
Viruses. 2020 Mar 18;12(3):326. doi: 10.3390/v12030326.
Peptides derived from the C-terminal heptad repeat (CHR) region of HIV-1 gp41 is potent viral membrane fusion inhibitors, such as the first clinically approved peptide drug T20 and a group of newly-designed peptides. The resistance profiles of various HIV-1 fusion inhibitors were previously characterized, and the secondary mutation N126K in the gp41 CHR was routinely identified during the in vitro and in vivo selections. In this study, the functional and structural relevance of the N126K mutation has been characterized from multiple angles. First, we show that a single N126K mutation across several HIV-1 isolates conferred mild to moderate cross-resistances. Second, the N126K mutation exerted different effects on Env-mediated HIV-1 entry and cell-cell fusion. Third, the N126K mutation did not interfere with the expression and processing of viral Env glycoproteins, but it disrupted the Asn126-based glycosylation site in gp41. Fourth, the N126K mutation was verified to enhance the thermal stability of 6-HB conformation. Fifth, we determined the crystal structure of a 6-HB bearing the N126K mutation, which revealed the interhelical and intrahelical interactions underlying the increased thermostability. Therefore, our data provide new information to understand the mechanism of HIV-1 gp41-mediated cell fusion and its resistance mode to viral fusion inhibitors.
来自 HIV-1 gp41 卷曲螺旋（CHR）区的肽是有效的病毒膜融合抑制剂，例如首个临床批准的肽类药物 T20 和一组新设计的肽。先前已经对各种 HIV-1 融合抑制剂的耐药性特征进行了描述，并且在体外和体内选择过程中，gp41 CHR 中的次要突变 N126K 通常会被识别。在这项研究中，从多个角度对 N126K 突变的功能和结构相关性进行了表征。首先，我们表明，几种 HIV-1 分离株中的单个 N126K 突变赋予了轻度至中度的交叉耐药性。其次，N126K 突变对 Env 介导的 HIV-1 进入和细胞-细胞融合产生了不同的影响。第三，N126K 突变不干扰病毒Env 糖蛋白的表达和加工，但破坏了 gp41 中基于 Asn126 的糖基化位点。第四，N126K 突变被证实可增强 6-HB 构象的热稳定性。第五，我们确定了带有 N126K 突变的 6-HB 的晶体结构，揭示了增强热稳定性的螺旋间和螺旋内相互作用。因此，我们的数据提供了新的信息，有助于理解 HIV-1 gp41 介导的细胞融合及其对病毒融合抑制剂的耐药模式的机制。
