维氏气单胞菌MreB蛋白的结构分析及其系统发育学意义

Structural analysis and phylogenetic implication of MreB protein in Aeromonas veronii

摘要:

【目的】认识维氏气单胞菌MreB蛋白的各级结构，研究MreB蛋白的保守性与作为分子标记工具的可靠性。【方法】应用ProtParam、PredictProtein和SWISS-MODEL等在线软件分别分析蛋白的一级结构及理化性质，预测蛋白二级、三级结构；利用clustalX 2.0、ESpript 3.0和MEGA 6等软件对几类细菌中的MreB蛋白进行氨基酸序列比对分析和系统发育学研究。【结果】维氏气单胞菌MreB蛋白是由346个氨基酸组成的酸性蛋白，主要定位于细胞膜上；蛋白二级结构主要由α-螺旋、扩展长链和无规则卷曲结构构成，其中无规则卷曲所占比例最高；同源建模的结果显示蛋白的三级结构中含有12个α-螺旋结构、5个β-折叠结构、8个β-发夹结构、22个β-转角和4个γ-转角。【结论】获得了维氏气单胞菌MreB蛋白详细的理化信息，同源建模构建的模型具有合理的空间结构，PROCHECK评分较高，为实验研究提供了一定的结构基础；MreB蛋白具有保守位点与结构保守性，属高保守蛋白，且变异度适宜，可作为分子标记工具应用于细菌的分类鉴定。

Abstract:

[Objective] To understand all-level structures of Aeromonas veronii MreB protein, and study the conservation of MreB protein and its reliability as a molecular marker. [Methods] Online software such as ProtParam, PredictProtein and SWISS-MODEL were used to analyze the primary structure and physicochemical properties of the protein, and predict its secondary and tertiary structures. Amino acid sequence comparative analysis and phylogenetic study were done on MreB proteins in several types of bacteria through software like ClustalX 2.0, ESpript 3.0 and MEGA 6. [Results] MreB protein of Aeromonas veronii is an acidic protein composed of 346 amino acids, which is mainly located in the cell membrane. Secondary structure of the protein mainly consists of α-helices, extended long chains and random coil structures, of which random coils share the highest proportion. The results of homology modeling reveal that the tertiary structure of the protein contains 12 α-helical structures, 5 β-folded structures, 8 β-hairpin structures, 22 β-turns and 4 γ-turns. [Conclusion] Detailed physicochemical information on Aeromonas veronii MreB protein is obtained. The model built by homology modeling presents a reasonable spatial structure, and receives a relatively high PROCHECK score, which provides some structural basis for experimental research. Moreover, with conserved sites and structural conservation, MreB protein belongs to a highly conserved protein with appropriate variability. Therefore, it can be used as a molecular marker tool in the classification and identification of bacteria.