Koomey J M, Gill R E, Falkow S
Proc Natl Acad Sci U S A. 1982 Dec;79(24):7881-5. doi: 10.1073/pnas.79.24.7881.
The biological significance of bacterial extracellular proteases that specifically cleave human IgA1 is unknown. We have prepared a gene bank of gonococcal chromosomal DNA in Escherichia coli K-12 using a cosmid cloning system. Among these clones, we have identified and characterized an E. coli strain that elaborates an extracellular endopeptidase that is indistinguishable from gonococcal IgA1 protease in its substrate specificity and action on human IgA1. Analysis of recombinant plasmids and examination of plasmid-specific peptides in minicells have shown that the IgA1 protease activity in E. coli is associated with expression of a Mr 140,000 peptide. We have isolated IgA1 protease-deficient mutants of Neisseria gonorrhoeae by reintroduction of physically defined deletions of the cloned gene into the gonococcal chromosome by transformation.
特异性切割人IgA1的细菌胞外蛋白酶的生物学意义尚不清楚。我们使用黏粒克隆系统在大肠杆菌K-12中构建了淋球菌染色体DNA文库。在这些克隆中，我们鉴定并表征了一株大肠杆菌菌株，该菌株产生一种胞外内肽酶，其底物特异性和对人IgA1的作用与淋球菌IgA1蛋白酶无法区分。对重组质粒的分析以及对小细胞中质粒特异性肽的检测表明，大肠杆菌中的IgA1蛋白酶活性与一条分子量为140,000的肽的表达相关。我们通过将克隆基因的物理定义缺失重新导入淋球菌染色体中，通过转化分离出了淋病奈瑟菌的IgA1蛋白酶缺陷型突变体。
