Shafer W M, Morse S A
Department of Microbiology and Immunology, School of Medicine, Emory University, Atlanta, GA 30322.
J Gen Microbiol. 1987 Jan;133(1):155-62. doi: 10.1099/00221287-133-1-155.
Incubation of either 125I-labelled or unlabelled Neisseria gonorrhoeae with enzymically active preparations of human polymorphonuclear leucocyte lysosomal cathepsin G revealed that surface-exposed outer-membrane proteins were susceptible to proteolytic modification. Electroimmunoblotting experiments confirmed that outer-membrane protein III (PIII) and the major iron-regulated protein (MIRP), two conserved gonococcal proteins, were cleaved by cathepsin G. A direct relationship was observed between susceptibility to the antibacterial properties of cathepsin G and cleavage of PIII among isogenic strains differing in their level of resistance to the bactericidal activity of cathepsin G. Although the antibacterial property of cathepsin G is known to be independent of serine-esterase activity, the data suggest that gonococcal outer-membrane proteins are involved in the binding of cathepsin G, and that variation in the level of resistance reflects the degree to which target outer-membrane proteins such as PIII are exposed.
将125I标记的或未标记的淋病奈瑟菌与具有酶活性的人多形核白细胞溶酶体组织蛋白酶G制剂一起孵育，结果显示，表面暴露的外膜蛋白易受蛋白水解修饰。电免疫印迹实验证实，外膜蛋白III（PIII）和主要铁调节蛋白（MIRP）这两种保守的淋球菌蛋白被组织蛋白酶G切割。在对组织蛋白酶G杀菌活性抗性水平不同的同基因菌株中，观察到对组织蛋白酶G抗菌特性的敏感性与PIII的切割之间存在直接关系。虽然已知组织蛋白酶G的抗菌特性与丝氨酸酯酶活性无关，但数据表明淋球菌外膜蛋白参与了组织蛋白酶G的结合，并且抗性水平的变化反映了诸如PIII等靶向外膜蛋白的暴露程度。
