Science Division, New York University Abu Dhabi, PO Box 129188, Abu Dhabi, United Arab Emirates.
Sci Rep. 2020 Dec 17;10(1):22200. doi: 10.1038/s41598-020-79357-0.
Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is responsible for the novel coronavirus disease 2019 (COVID-19). An appealing antiviral drug target is the coronavirus 3C-like protease (3CLpro) that is responsible for the processing of the viral polyproteins and liberation of functional proteins essential for the maturation and infectivity of the virus. In this study, multiple thermal analytical techniques have been implemented to acquire the thermodynamic parameters of 3CLpro at different buffer conditions. 3CLpro exhibited relatively high thermodynamic stabilities over a wide pH range; however, the protease was found to be less stable in the presence of salts. Divalent metal cations reduced the thermodynamic stability of 3CLpro more than monovalent cations; however, altering the ionic strength of the buffer solution did not alter the stability of 3CLpro. Furthermore, the most stable thermal kinetic stability of 3CLpro was recorded at pH 7.5, with the highest enthalpy of activation calculated from the slope of Eyring plot. The biochemical and biophysical properties of 3CLpro explored here may improve the solubility and stability of 3CLpro for optimum conditions for the setup of an enzymatic assay for the screening of inhibitors to be used as lead candidates in the discovery of drugs and design of antiviral therapeutics against COVID-19.
严重急性呼吸系统综合症冠状病毒 2（SARS-CoV-2）是引发 2019 年新型冠状病毒病（COVID-19）的病原体。冠状病毒 3C 样蛋白酶（3CLpro）是一种有吸引力的抗病毒药物靶标，该酶负责病毒多蛋白的加工以及释放成熟和感染病毒所必需的功能蛋白。在这项研究中，采用了多种热分析技术来获取不同缓冲条件下 3CLpro 的热力学参数。3CLpro 在很宽的 pH 范围内表现出相对较高的热力学稳定性；然而，研究发现蛋白酶在盐存在下稳定性降低。二价金属阳离子比单价阳离子更能降低 3CLpro 的热力学稳定性；然而，改变缓冲溶液的离子强度不会改变 3CLpro 的稳定性。此外，在 pH7.5 时记录到 3CLpro 最稳定的热动力学稳定性，最高的活化焓是从 Eyring 图的斜率计算得出的。这里探索的 3CLpro 的生化和生物物理特性可能会提高 3CLpro 的溶解度和稳定性，从而优化建立酶促测定的条件，以筛选用于发现 COVID-19 药物和设计抗病毒治疗的抑制剂的先导候选物。
