耐甲氧西林金黄色葡萄球菌EsxA蛋白的生物学信息预测

Bioinformatics predication of methicillin-resistant Staphylococcus aureus EsxA protein

目的在线软件分析耐甲氧西林金黄色葡萄球菌EsxA蛋白的生物学信息,为防治金黄色葡萄球菌感染提供理论基础。方法采用在线分析系统蛋白质EXPASYP Protemic(http://www. espasy. org)中的Protparam(http://expasy.org/tools/protparam.html),分析耐甲氧西林金黄色葡萄球菌EsxA蛋白的分子质量、分子式,氨基酸数目、等电点、正负电荷残基,预测该蛋白的稳定性等理化性质;利用在线分析蛋白质软件Protscale(http://www.espasy.org/cgibin/protscale.p1)分析EsxA蛋白亲(疏)水性;采用SOPMA软件预测和分析耐甲氧西林金黄色葡萄球菌EsxA蛋白的二、三级结构。结果 EsxA蛋白二级结构α螺旋(Hh)占26.15%(68个),延伸链(Ee)占32.69%(85个),无规则卷曲(Cc)占33.46%(87个)。蛋白分子质量为30 428.46 ku;理论pI值为8.18;氨基酸序列Ala占1.9%,Arg占1.9%,Val占3.5%。可能是亲水性蛋白;预测耐甲氧西林金黄色葡萄球菌EsxA蛋白的糖基化位点为71、87、146、176、200、243氨基酸处,预测存在1个丝氨酸、1个苏氨酸、3个酪氨酸磷酸化位点;同源建模中EsxA蛋白的GMQE值为0.75,Qmean向上手势,模型质量获得较高。结论耐甲氧西林金黄色葡萄球菌EsxA蛋白含有磷酸化位点和糖基化位点,具有免疫原性的基础结构。

Objective To analyze the biological information of Staphylococcus aureus EsxA protein by the online software, so as to provide a theoretical basis for the prevention and treatment of S. aureus infection. Methods The physicochemical properties of EsxA protein, including the molecular weight, molecular formula, the number of amino acids, isoelectric point, positive and negative charge residues, predicted protein stability, etc. were analyzed by using Protparam(http://expasy.org/tools/protparam.html) of the protein analysis system EXPASYP Protemic(http://www. espasy.org);the affinity(R)water of EsxA protein was analyzed by using the protein online analysis software Protscale(http://www.espasy.org/cgibin/protscale.p1);the secondary and tertiary structures of the S. aureus EsxA protein were predicted and analyzed by using SOPMA prediction software. Results 2804 The alpha helix(Hh) of the secondary structure of the S. aureus EsxA protein accounted for 26.15%(68), the extended chain(Ee) accounted for 32.69%(85), and the random coil(Cc) accounted for 33.46%(87). The molecular mass of the protein was 30 428.46 ku;the theoretical pI value was 8.18;the amino acid sequence Ala was 1.9%, Arg was 1.9%, and Val was 3.5%, which might be hydrophilic. The glycosylation sites of S. aureus EsxA protein were predicted as 71, 87, 146, 176, 200, 243 amino acids, and there was 1 serine, 1 threonine, and 3 tyrosine phosphorylation site;the GMQE score of the EsxA protein in homology modeling was 0.75, and its Qmean gesture was upward, and the quality of the obtained model was high. Conclusion The bioinformatics can provide the reference for the research of S. aureus EsxA antigenicity and high-efficiency epitope vaccine.Therefore, it is speculated that it may be immunogenic,which can provide the basic data for the functional study of the protein.