利用丙氨酸突变探究PSMα4结构与功能的关系  

Structure-function relationships in phenol-soluble modulinα4 using an alanine screen

作　　者：王辉 郑玉玲 江华 姜永强 WANG Hui;ZHENG Yu-ling;JIANG Hua;JIANG Yong-qiang(Institute of Microbiology and Epidemiology,Academy of Military Medical Sciences,Academy of Military Sciences, Beijing 100071,China)

机构地区：[1]军事科学院军事医学研究院微生物流行病研究所,北京100071

出　　处：《军事医学》2018年第7期528-532,共5页Military Medical Sciences

摘　　要：目的探究金黄色葡萄球菌酚可溶性调控蛋白α4 (PSMα4)氨基酸残基发生突变后,对其细胞毒、趋化等功能的影响。方法利用人工合成将多肽PSMα4中的非丙氨酸残基进行丙氨酸扫描定点突变,比色法测定溶血活性,LDH试剂盒测定细胞HCMEC/D3和PMN裂解程度,圆二色性(CD)检测以比较其结构上的改变,荧光标记法检测PMN的趋化强度,最后利用同源模拟初步预测了PSMα4的三维立体结构。结果与结论 PSMα4的I3、V4、I15、I17位氨基酸残基替换为丙氨酸后其细胞毒作用有所增强,结合CD的结果发现,细胞毒作用与其α螺旋程度呈正相关; PSMα4的第I7、I8、F18位氨基酸残基是影响其趋化作用的关键位点。Objective To investigate the effect of amino acid residues mutation of phenol-soluble modulin α4( PSMα4)in Staphylococcus aureus on cytotoxicity and chemotaxis. Methods An alanine substitution peptide library of PSMα4 was constructed by artificial synthesis. The hemolysis was measured by colorimetric D540 and cytolysis of HCMEC/D3 and PMN was measured using LDH kit. The CD measurements with the selected PSMα4 derivatives were used to determine whether the structural changes were correlated with PSM-mediated phenotypes. The chemotaxis of PMN was detected by fluorescence labeling. The 3 D structure of PSMα4 was modeled by homology modeling. Results and Conclusion Amino acid positions in which the exchange with alanine led to increased cytotoxicity were the residues at positions I3,V4,I15,and I17,and the degree of α-helicity is positively correlated with PSMα4 derivatives’ cytotoxicity. I7,I8,and F18 are the key amino acids on the chemotaxis of PSMα4.

关 键 词：金黄色葡萄球菌 酚可溶性调控蛋白α4 细胞裂解 趋化 

分 类 号：Q93-3[生物学—微生物学]