ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and related sarbecoviruses enter host cells by receptor-recognition and membrane-fusion. An indispensable step in fusion is the formation of 6-helix bundle by viral spike heptad repeats 1 and 2 (HR1 and HR2). Here, we report the construction of 5-helix bundle (5HB) proteins for virus infection inhibition. The optimal construct inhibits SARS-CoV-2 pseudovirus entry with sub-micromolar IC50. Unlike HR2-based peptides that cannot bind spike in the pre-fusion conformation, 5HB features with the capability of binding to pre-fusion spike. Furthermore, 5HB binds viral HR2 at both serological- and endosomal-pH, highlighting its entry-inhibition capacity when SARS-CoV-2 enters via either cell membrane fusion or endosomal route. Finally, we show that 5HB could neutralize S-mediated entry of the predominant SARS-CoV-2 variants and a wide spectrum of sarbecoviruses. These data provide proof-of-concept evidence that 5HB might be developed for the prevention and treatment of SARS-CoV-2 and other emerging sarbecovirus infections.

摘要

严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 和相关的 sarbecovirus 通过受体识别和膜融合进入宿主细胞。融合中一个不可或缺的步骤是通过病毒刺突七肽重复 1 和 2（HR1 和 HR2）形成 6 螺旋束。在这里，我们报告了用于抑制病毒感染的 5 螺旋束 (5HB) 蛋白的构建。最佳构建体以亚微摩尔 IC50 抑制 SARS-CoV-2 假病毒进入。与不能在融合前构象中结合尖峰的基于 HR2 的肽不同，5HB 具有与融合前尖峰结合的能力。此外，5HB 在血清和内体 pH 值下都与病毒 HR2 结合，突出了其在 SARS-CoV-2 通过细胞膜融合或内体途径进入时的进入抑制能力。最后，我们表明，5HB 可以中和 S 介导的主要 SARS-CoV-2 变体和广谱 sarbecovirus 的进入。这些数据提供了概念验证证据，表明 5HB 可能被开发用于预防和治疗 SARS-CoV-2 和其他新出现的 sarbecovirus 感染。