Relationship between the structure and the enzymatic activity of crotoxin complex and its phospholipase A2 subunit: An in silico approach
Relationship between the structure and the enzymatic activity of crotoxin complex and its phospholipase A2 subunit: An in silico approach
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DOI：
10.1016/j.jmgm.2012.01.004
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发表时间：
2012-05-01
影响因子：
2.9
通讯作者：
Camilo Patino, Arley
中科院分区：
文献类型：
--
作者：
Andres Pereanez, Jaime;Dario Gomez, Ivan;Camilo Patino, Arley
Crotoxin是南美洲响尾蛇Crotalus durissus亚种的主要毒素之一，是由两个不同的亚基组成的异二聚体复合物：碱性磷脂酶A（2）（PLA（2），CB）和酸性无毒无催化活性蛋白crotapotin（CA）。众所周知，CB具有高酶活性;然而，决定这一事实的分子方面仍然未知。在这项研究中，在计算机上的方法被用来预测CA结构的同源性建模，并通过分子对接的crotoxin结构。以响尾蛇PLA（2）（1 PP 2：R）为模板，利用Modeller软件构建CA结构。通过Procheck、Verify 3D和ProSA测量的不同标准表明了CA预测结构模型的可靠性和正确折叠。然后，将该模型与CB晶体结构相结合，通过刚体蛋白质-蛋白质对接构建了crotoxin复合物的结构。crotoxin-3D模型表明，通过疏水和π-π堆积相互作用，CA-Y24和CA-F119分别与CB-F24和CB-F119相互作用。这些相互作用可以通过阻断PLA的部分界面结合表面来阻止CB在脂/水界面上的界面吸附（2）。这一事实可以解释巴豆毒素复合物和CB之间的酶活性差异。此外，crotoxin-3D模型显示CA的溶剂暴露区域可以结合靶细胞中表达的受体。皇冠版权所有（C）2012由Elsevier Inc.发布。All rights reserved.
Crotoxin, one of the major toxins of South American rattlesnake Crotalus durissus subspecies, is an heterodimeric complex composed of two distinct subunits: a basic phospholipase A(2) (PLA(2), CB) and an acidic nontoxic catalytically inactive protein, crotapotin (CA). It's well known that CB has a high enzymatic activity; however the molecular aspects that determine this fact remain unknown. In this study, an in silico approach was used to predict the CA structure by homology modeling, and the crotoxin structure by means of molecular docking. CA structure was built using the software Modeller taking Crotalus atrox PLA(2) (1PP2:R) as a template. Different criteria measured by Procheck, Verify 3D and ProSA were indicative of the reliability and the proper fold for the predicted structural model of CA. Then, a combination of this model and CB crystal structure was used to build the structure of crotoxin complex through rigid-body protein-protein docking. The crotoxin-3D model suggested that by means of hydrophobic and pi-pi stacking interactions, CA-Y24 and CA-F119 interact with CB-F24 and CB-F119, respectively. Those interactions could prevent the interfacial adsorption of the CB onto the lipid/water interface by blocking part of the interfacial binding surface of the PLA(2). This fact could explain the differences regarding to enzymatic activity between the crotoxin complex and CB. In addition, the crotoxin-3D model showed solvent-exposed regions of CA that could bind the receptor expressed in target cells. Crown Copyright (C) 2012 Published by Elsevier Inc. All rights reserved.