Ebrahim Ali, Riley Blake T, Kumaran Desigan, Andi Babak, Fuchs Martin R, McSweeney Sean, Keedy Daniel A
Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, England, United Kingdom.
Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY 10031, USA.
IUCrJ. 2022 Aug 17;9(Pt 5):682-694. doi: 10.1107/S2052252522007497. eCollection 2022 Sep 1.
The COVID-19 pandemic, instigated by the SARS-CoV-2 coronavirus, continues to plague the globe. The SARS-CoV-2 main protease, or M, is a promising target for the development of novel antiviral therapeutics. Previous X-ray crystal structures of M were obtained at cryogenic tem-per-ature or room tem-per-ature only. Here we report a series of high-resolution crystal structures of unliganded M across multiple tem-per-atures from cryogenic to physiological, and another at high humidity. We inter-rogate these data sets with parsimonious multiconformer models, multi-copy ensemble models, and isomorphous difference density maps. Our analysis reveals a perturbation-dependent conformational landscape for M, including a mobile zinc ion inter-leaved between the catalytic dyad, mercurial conformational heterogeneity at various sites including a key substrate-binding loop, and a far-reaching intra-molecular network bridging the active site and dimer inter-face. Our results may inspire new strategies for antiviral drug development to aid preparation for future coronavirus pandemics.
由严重急性呼吸综合征冠状病毒2（SARS-CoV-2）引发的新型冠状病毒肺炎（COVID-19）大流行继续困扰着全球。SARS-CoV-2主要蛋白酶（M）是开发新型抗病毒疗法的一个有前景的靶点。之前M的X射线晶体结构仅在低温或室温下获得。在此，我们报告了一系列未结合配体的M在从低温到生理温度的多个温度下以及在高湿度条件下的高分辨率晶体结构。我们用简约多构象模型、多拷贝集合模型和同晶型差异密度图来分析这些数据集。我们的分析揭示了M的一种依赖于扰动的构象态势，包括在催化二元体之间交错的一个移动锌离子、在包括一个关键底物结合环在内的各个位点的汞诱导构象异质性，以及一个连接活性位点和二聚体界面的广泛分子内网络。我们的结果可能会激发抗病毒药物开发的新策略，以帮助为未来的冠状病毒大流行做好准备。
