肺炎链球菌双组份系统中的组氨酸激酶(YycG)的同源模建与分析

Histidine kinase (YycG) protein of Streptococcus pneumoniae: Homology modeling and analysis

摘要:

对肺炎链球菌双组份系统中的组氨酸激酶YycG进行同源模建, 并分析其与底物ADP的相互作用, 为寻找特异性的激酶抑制剂提供了理论依据。采用同源模建的方法构建YycG蛋白的三维结构, 并用ProCheck、Profile_3D软件对此结构模型的合理性进行验证; 用Autodock4.0软件将结构模型与ADP进行自动对接, 分析二者之间的相互作用。序列比对结果显示肺炎链球菌YycG蛋白与Thermotoga maritima X-ray晶体结构序列的同一性达33%; YycG模建后的结构与模板能很好的叠合; 在活性口袋处的保守的氨基酸残基Asn145、Asn149、Lys152以及口袋内部的疏水残基在结合、水解底物ADP的过程中发挥重要作用。组氨酸激酶YycG的模建合理, 该结构模型可作为设计抗菌药的研究起点。

Abstract:

To construct a three-dimensional (3D) model of histidine kinase (HK) YycG protein in Streptococcus pneumoniae and to investigate the interaction between YycG and its substrate ADP for the purpose of providing a theoretical basis for YycG selective inhibitor discovery, we constructed a 3D model of YycG protein by homology modeling, and assessed the reliability of the model using ProCheck and Profile_3D software. Besides, the active-site cavity of YycG and the residues key for substrate interaction were analyzed by Autodock4.0. Sequence alignment indicated that the YycG of S. pneumoniae was homologous to that of Thermotoga maritima. The constructed 3D model of YycG adopted a similar folding pattern to the template and the two matched well. The conservative amino acids in the substrate-binding pocket, such as Asn145, Asn149 and Lys152, as well as the hydrophobic residues at the bottom of the pocket played important role in binding and hydrolyzing substrate ADP. We have successfully constructed a reliable model of YycG protein. The model can be used as a starting point for designing antibacterial drugs.