Strauch K L, Johnson K, Beckwith J
Department of Microbiology and Molecular Genetics, Harvard University Medical School, Boston, Massachusetts 02115.
J Bacteriol. 1989 May;171(5):2689-96. doi: 10.1128/jb.171.5.2689-2696.1989.
The degP gene, required for proteolysis in the cell envelope of Escherichia coli, maps at approximately 3.5 min on the chromosome. Null mutations in degP result in temperature-sensitive growth. In certain genetic backgrounds, expression of abnormal periplasmic or inner membrane proteins (protein fusions or proteins with internal deletions) enhances the temperature-sensitive phenotype. Such growth defects were used as a selection for cloning the degP gene into Mud4042 and pACYC184 plasmid vectors, and a restriction map was determined. Analysis of deletion and insertion mutations on one of these plasmids showed that the degP gene is approximately 1.5 kilobases in size. The plasmid-encoded DegP protein had an apparent molecular weight of 50,000, as determined by maxicell analysis. Protein fusions between DegP and alkaline phosphatase had high alkaline phosphatase enzymatic activity, indicating that DegP is a periplasmic or membrane protein.
degP基因是大肠杆菌细胞膜蛋白水解所必需的，定位于染色体上约3.5分钟处。degP基因的无效突变导致温度敏感型生长。在某些遗传背景下，异常周质或内膜蛋白（蛋白融合体或内部缺失的蛋白）的表达会增强温度敏感表型。利用这种生长缺陷作为选择，将degP基因克隆到Mud4042和pACYC184质粒载体中，并确定了限制性图谱。对其中一个质粒上的缺失和插入突变进行分析表明，degP基因大小约为1.5千碱基。通过最大细胞分析确定，质粒编码的DegP蛋白的表观分子量为50,000。DegP与碱性磷酸酶之间的蛋白融合体具有高碱性磷酸酶酶活性，表明DegP是一种周质或膜蛋白。
