Molecular characterization of pldA, the structural gene for a phospholipase A from Campylobacter coli, and its contribution to cell-associated hemolysis
Molecular characterization of pldA, the structural gene for a phospholipase A from Campylobacter coli, and its contribution to cell-associated hemolysis
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DOI：
10.1128/iai.65.4.1172-1180.1997
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发表时间：
1997-04-01
影响因子：
3.1
通讯作者：
Park, SF
中科院分区：
文献类型：
--
作者：
Grant, KA;Belandia, IU;Park, SF
一个基因（pldA）编码的35.0 kDa的蛋白质具有显着的同源性大肠杆菌外膜磷脂酶被确定为上游的操纵子编码的肠螯合素运输系统的弯曲杆菌呼叫。本研究结果表明，该基因编码的外膜磷脂酶A在C。杆菌首先，在大肠杆菌PldA缺陷突变体中表达pldA基因产物。coli中的磷脂酶A活性恢复，重组产物也分布于外膜，表明它可能在C.杆菌其次，在大肠杆菌中异源表达，然后体外折叠和纯化C。coil PldA，产生在体外显示钙依赖性溶血磷脂酶和磷脂酶A活性的纯蛋白，最后，其中pldA基因已经通过等位基因交换失活的大肠杆菌突变体缺乏磷脂酶A活性，磷脂酶与许多细菌病原体的红细胞裂解有关，pldA突变体显示出与野生型菌株相比具有降低的溶血活性，提示磷脂酶A在C.由于溶血素与许多细菌病原体的致病潜力密切相关，因此磷脂酶A可能在弯曲杆菌的毒力中起一定作用。
A gene (pldA) encoding a 35.0-kDa protein with significant homology to the Escherichia coli outer membrane phospholipase was identified upstream of an operon encoding an enterochelin transport system in Campylobacter call. The results of this study suggest that this gene encodes an outer membrane phospholipase A in C. coli. First, expression of the pldA gene product in a PldA-deficient mutant of E. coli led to the restoration of phospholipase A activity, The recombinant product also partitioned to the outer membrane, suggesting that it may be similarly located in C. coli. Second, heterologous overexpression in E, coli, followed by in vitro folding and purification of C. coil PldA, resulted in pure protein which displayed calcium-dependent lysophospholipase and phospholipase A activities in vitro, Finally mutants of C, coli in which the pldA gene had been inactivated by allelic exchange were deficient in phospholipase A activity, Phospholipases are associated with lysis of erythrocytes by a number of bacterial pathogens, The pldA mutant was shown to have a reduced hemolytic activity compared to the wild-type strain, suggesting a role for the phospholipase A in the lysis of erythrocytes by C. coli, Since hemolysins are intimately associated with the disease-causing potential of a number of bacterial pathogens, it is likely that the phospholipase A plays some role in Campylobacter virulence.