Laboratório de Planejamento e Desenvolvimento de Fármacos, Instituto de Ciências Exatas e Naturais, Universidade Federal do Pará, Belem 66075-110, Brazil.
Institute of Biological Sciences, Federal University of Pará, Belem 66075-110, Brazil.
Int J Mol Sci. 2021 Dec 28;23(1):300. doi: 10.3390/ijms23010300.
The inhibition of key enzymes that may contain the viral replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have assumed central importance in drug discovery projects. Nonstructural proteins (nsps) are essential for RNA capping and coronavirus replication since it protects the virus from host innate immune restriction. In particular, nonstructural protein 16 (nsp16) in complex with nsp10 is a Cap-0 binding enzyme. The heterodimer formed by nsp16-nsp10 methylates the 5'-end of virally encoded mRNAs to mimic cellular mRNAs and thus it is one of the enzymes that is a potential target for antiviral therapy. In this study, we have evaluated the mechanism of the 2'- methylation of the viral mRNA cap using hybrid quantum mechanics/molecular mechanics (QM/MM) approach. It was found that the calculated free energy barriers obtained at M062X/6-31+G(d,p) is in agreement with experimental observations. Overall, we provide a detailed molecular analysis of the catalytic mechanism involving the 2'- methylation of the viral mRNA cap and, as expected, the results demonstrate that the TS stabilization is critical for the catalysis.
抑制可能包含严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）病毒复制的关键酶在药物发现项目中具有重要意义。非结构蛋白（nsps）对于 RNA 加帽和冠状病毒复制至关重要，因为它可以保护病毒免受宿主固有免疫限制。特别是，与 nsp10 形成复合物的非结构蛋白 16（nsp16）是一种 Cap-0 结合酶。nsp16-nsp10 形成的异二聚体将病毒编码的 mRNA 的 5'端甲基化以模拟细胞 mRNA，因此它是抗病毒治疗的潜在靶标之一。在这项研究中，我们使用混合量子力学/分子力学（QM/MM）方法评估了病毒 mRNA 帽的 2'-甲基化机制。结果发现，在 M062X/6-31+G（d，p）上获得的计算自由能垒与实验观察结果一致。总的来说，我们提供了涉及病毒 mRNA 帽 2'-甲基化的催化机制的详细分子分析，结果表明 TS 稳定对于催化至关重要。
