Manohar R, Kutumbarao N H V, Krishna Nagampalli Raghavendra Sashi, Velmurugan D, Gunasekaran K
CAS in Crystallography and Biophysics, University of Madras, Chennai 600025, India.
Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, SP 13083-970, Brazil.
Biochem Biophys Res Commun. 2018 Jan 1;495(1):679-685. doi: 10.1016/j.bbrc.2017.11.033. Epub 2017 Nov 7.
In the age of growing infectious diseases, there is a great demand for new inhibitors which can exhibit minimum side effects. Owing to the importance of proteases in life cycle and invasion, they have been projected as attractive targets for structure based drug designing against microbes including viruses. Here we report the inhibitory activity of a well known natural compound succinic acid against both serine and cysteine proteases. The ligand is found co-crystallized with Bovine pancreatic trypsin in one of our crystallization trials and the diffraction data up to1.9 Å reveal its interactions with the catalytic triad residues Histidine 57 and Serine 195. Binding of the ligand with these proteases have been validated using caseinolysis inhibition. With trypsin, ITC analysis showed tight binding of the ligand, resulting in change in Gibb's free energy (ΔG) by -20.31 kJ/mol. To understand the existence of succinic acid at the active site, molecular docking was performed and it revealed binding of it with trypsin and papain at corresponding active sites. This dual inhibitory activity of natural ligand, succinic acid can be accounted for the recent reports on anti-viral property of plant extracts where dicarboxilic fatty acids are normally abundant.
在传染病不断增加的时代，对副作用最小的新型抑制剂有巨大需求。由于蛋白酶在生命周期和侵袭过程中的重要性，它们已被视为针对包括病毒在内的微生物进行基于结构的药物设计的有吸引力的靶点。在此，我们报道了一种著名的天然化合物琥珀酸对丝氨酸蛋白酶和半胱氨酸蛋白酶的抑制活性。在我们的一次结晶试验中，发现该配体与牛胰蛋白酶共结晶，高达1.9 Å的衍射数据揭示了它与催化三联体残基组氨酸57和丝氨酸195的相互作用。使用酪蛋白水解抑制法验证了该配体与这些蛋白酶的结合。对于胰蛋白酶，等温滴定量热分析表明配体紧密结合，导致吉布斯自由能（ΔG）变化为-20.31 kJ/mol。为了解琥珀酸在活性位点的存在情况，进行了分子对接，结果显示它在相应活性位点与胰蛋白酶和木瓜蛋白酶结合。天然配体琥珀酸的这种双重抑制活性可以解释最近关于植物提取物抗病毒特性的报道，其中二羧酸脂肪酸通常含量丰富。
