Basic Sciences and Computational Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
Viruses. 2019 May 15;11(5):439. doi: 10.3390/v11050439.
Identifying drug resistance mutations is important for the clinical use of antivirals and can help define both a drug's mechanism of action and the mechanistic basis of resistance. Resistance mutations are often identified one-at-a-time by studying viral evolution within treated patients or during viral growth in the presence of a drug in cell culture. Such approaches have previously mapped resistance to enfuvirtide, the only clinically approved HIV-1 fusion inhibitor, to enfuvirtide's binding site in the N-terminal heptad repeat (NHR) of the Envelope (Env) transmembrane domain as well as a limited number of allosteric sites. Here, we sought to better delineate the genotypic determinants of resistance throughout Env. We used deep mutational scanning to quantify the effect of all single-amino-acid mutations to the subtype A BG505 Env on resistance to enfuvirtide. We identified both previously characterized and numerous novel resistance mutations in the NHR. Additional resistance mutations clustered in other regions of Env conformational intermediates, suggesting they may act during different fusion steps by altering fusion kinetics and/or exposure of the enfuvirtide binding site. This complete map of resistance sheds light on the diverse mechanisms of enfuvirtide resistance and highlights the utility of using deep mutational scanning to comprehensively map potential drug resistance mutations.
鉴定耐药突变对于抗病毒药物的临床应用非常重要，有助于确定药物的作用机制和耐药的机制基础。耐药突变通常通过研究治疗患者体内病毒的进化或在细胞培养中药物存在下病毒的生长来逐个鉴定。这些方法先前已经将对 enfuvirtide 的耐药性定位到 HIV-1 融合抑制剂 enfuvirtide 的 N 端七肽重复（NHR）结合位点以及少数变构位点， enfuvirtide 是唯一经临床批准的 HIV-1 融合抑制剂。在这里，我们试图更详细地描绘整个 Env 中耐药的基因型决定因素。我们使用深度突变扫描来量化对亚型 A BG505 Env 的所有单个氨基酸突变对 enfuvirtide 耐药性的影响。我们鉴定了 NHR 中以前表征的和许多新的耐药突变。其他耐药突变聚集在 Env 构象中间体的其他区域，表明它们可能通过改变融合动力学和/或暴露 enfuvirtide 结合位点来在不同的融合步骤中起作用。这种完整的耐药图谱阐明了 enfuvirtide 耐药的多种机制，并强调了使用深度突变扫描全面绘制潜在耐药突变的实用性。
