Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson, AZ 85721, USA.
Sci Adv. 2020 Dec 9;6(50). doi: 10.1126/sciadv.abe0751. Print 2020 Dec.
The main protease (M) of SARS-CoV-2 is a key antiviral drug target. While most M inhibitors have a γ-lactam glutamine surrogate at the P1 position, we recently found that several M inhibitors have hydrophobic moieties at the P1 site, including calpain inhibitors II and XII, which are also active against human cathepsin L, a host protease that is important for viral entry. In this study, we solved x-ray crystal structures of M in complex with calpain inhibitors II and XII and three analogs of The structure of M with calpain inhibitor II confirmed that the S1 pocket can accommodate a hydrophobic methionine side chain, challenging the idea that a hydrophilic residue is necessary at this position. The structure of calpain inhibitor XII revealed an unexpected, inverted binding pose. Together, the biochemical, computational, structural, and cellular data presented herein provide new directions for the development of dual inhibitors as SARS-CoV-2 antivirals.
新型冠状病毒主蛋白酶（M）是抗病毒药物的一个重要靶点。虽然大多数 M 蛋白酶抑制剂的 P1 位置都有一个γ-内酰胺谷氨酸类似物，但我们最近发现，一些 M 蛋白酶抑制剂的 P1 位有疏水基团，包括钙蛋白酶抑制剂 II 和 XII，它们也对人组织蛋白酶 L 有活性，人组织蛋白酶 L 是一种对病毒进入很重要的宿主蛋白酶。在这项研究中，我们解析了 M 与钙蛋白酶抑制剂 II 和 XII 以及三种类似物复合物的 X 射线晶体结构。M 与钙蛋白酶抑制剂 II 的结构证实 S1 口袋可以容纳疏水性的蛋氨酸侧链，这对亲水残基在这个位置是必需的观点提出了挑战。钙蛋白酶抑制剂 XII 的结构揭示了一个意想不到的、倒置的结合构象。本研究提供的生物化学、计算、结构和细胞数据为开发作为 SARS-CoV-2 抗病毒药物的双重抑制剂提供了新的方向。
