Serrano Marisol, Gonzalez Veronica, Ray Supriyo, Chavez Maria D, Narayan Mahesh
University of Texas at El Paso, 500W. University Ave, El Paso, TX, 79968, USA.
Cell Biochem Biophys. 2018 Jun;76(1-2):59-71. doi: 10.1007/s12013-017-0816-3. Epub 2017 Jul 29.
Cruzain, a cysteine protease in the cathepsin family, is pivotal to the life-cycle of Trypanosoma cruzi, the etiological agent in Chagas disease. Current inhibitors of cruzain suffer from drawbacks involving gastrointestinal and neurological side effects and as a result have spurred the search for alternative anti-trypanocidals. Through sequence alignment studies and intra-residue interaction analysis of the pro-protein of cruzain (pro-cruzain), we have identified a host of non-active site residues that are conserved among the cathepsins. We hypothesize that these conserved amino acids play a critical role in structure-stabilizing interactions among the cathepsins and are therefore crucial for eventually gaining protease activity. As predicted, mutation of selected conserved non-active site amino-acid candidates in cruzain resulted in a compromised structural stability and a corresponding loss in enzymatic activity relative to wild-type enzyme. By advancing the discovery of novel, non-active-site-based targets to arrest enzymatic activity our results potentially open the field of alternative inhibitor design. The advantages of defining such a non-active-site inhibitor design space is discussed.
克鲁兹蛋白酶是组织蛋白酶家族中的一种半胱氨酸蛋白酶，对恰加斯病的病原体克氏锥虫的生命周期至关重要。目前的克鲁兹蛋白酶抑制剂存在胃肠道和神经副作用等缺点，因此促使人们寻找替代的抗锥虫药物。通过对克鲁兹蛋白酶原（前体克鲁兹蛋白酶）的序列比对研究和残基间相互作用分析，我们确定了一系列在组织蛋白酶中保守的非活性位点残基。我们推测这些保守氨基酸在组织蛋白酶之间的结构稳定相互作用中起关键作用，因此对于最终获得蛋白酶活性至关重要。正如所预测的，克鲁兹蛋白酶中选定的保守非活性位点氨基酸候选物的突变导致结构稳定性受损，相对于野生型酶，酶活性相应丧失。通过推进基于非活性位点的新型靶点的发现以阻止酶活性，我们的结果可能为替代抑制剂设计领域开辟道路。本文讨论了定义这种非活性位点抑制剂设计空间的优势。
