Stucky K, Klein J R, Schüller A, Matern H, Henrich B, Plapp R
Universität Kaiserslautern, Abteilung Mikrobiologie, Germany.
Mol Gen Genet. 1995 May 20;247(4):494-500. doi: 10.1007/BF00293152.
From a genomic library of Lactobacillus delbrueckii subsp. lactis (DSM7290) DNA, in the low-copy-number vector pLG339, a recombinant clone was selected, which complemented a mutation in the prolidase gene (pepQ) of Escherichia coli UK173. Nucleotide sequence analysis revealed an open reading frame of 1104 nucleotides corresponding to a protein of 368 amino acids with a calculated pI of 4.64 and a molecular mass of 41,087 Da. The start site of pepQ transcription was determined by primer extension analysis with mRNA prepared from L. delbrueckii. Based on homology of the gene product to various peptidases and on the substrate specificity determined, the peptidase was designated PepQ. The influence of various protease inhibitors and cations on peptidase activity indicated that PepQ is a metalloprotease. The absence of a membrane-spanning domain and a signal peptide sequence argues for a cytoplasmic localization of the enzyme.
从德氏乳杆菌乳酸亚种（DSM7290）的基因组文库中，以低拷贝数载体pLG339提取DNA，筛选出一个重组克隆，该克隆可弥补大肠杆菌UK173脯氨酰肽酶基因（pepQ）的突变。核苷酸序列分析显示一个1104个核苷酸的开放阅读框，对应一个368个氨基酸的蛋白质，计算得到的pI为4.64，分子量为41,087道尔顿。通过对从德氏乳杆菌制备的mRNA进行引物延伸分析，确定了pepQ转录的起始位点。基于该基因产物与各种肽酶的同源性以及所确定的底物特异性，该肽酶被命名为PepQ。各种蛋白酶抑制剂和阳离子对肽酶活性的影响表明PepQ是一种金属蛋白酶。缺乏跨膜结构域和信号肽序列表明该酶定位于细胞质中。
