Wood J M, Zadworny D
Can J Biochem. 1980 Oct;58(10):787-96. doi: 10.1139/o80-110.
The utilization of L-proline as carbon or nitrogen source for the growth of Escherichia coli K12 requires the activities of an L-proline porter (PP-I) and a bifunctional L-proline dehydrogenase-delta1-pyrroline carboxylate dehydrogenase. PP-I is inactivated by mutations at putP and the bifunctional dehydrogenase is encoded in the adjacent locus, putA, at 22 min on the chromosome map. Two additional loci, proP (at 92 min) and proT (at 82 min), have also been implicated in L-proline transport. We have studied four ColE1/E. coli K12 hybrid plasmids from the plasmid bank prepared by Clarke and Carbon. Each of these plasmids was shown previously to complement an L-proline transport defect in E. coli. Genetic complementation analysis and biochemical assays of L-proline transport and L-proline dehydrogenase activity show that three of these hybrid plasmids bear the putPA region of the E. coli chromosome (plasmids pLC4-45, pLC10-29, and pLC43-41). The fourth plasmid, pLC35-38, specifically enhances the L-proline transport activity of its host bacteria but not their L-proline dehydrogenase activity. It probably encodes putP. We have used these plasmids in an E. coli minicell system to identify the putA and putP gene products.
利用L-脯氨酸作为碳源或氮源供大肠杆菌K12生长，需要L-脯氨酸转运蛋白（PP-I）和双功能L-脯氨酸脱氢酶-δ1-吡咯啉羧酸脱氢酶的活性。PP-I因putP位点的突变而失活，双功能脱氢酶由相邻基因座putA编码，位于染色体图谱的22分钟处。另外两个基因座，proP（在92分钟处）和proT（在82分钟处），也与L-脯氨酸转运有关。我们研究了来自克拉克和卡尔文构建的质粒文库中的四个ColE1/大肠杆菌K12杂种质粒。先前已证明这些质粒中的每一个都能互补大肠杆菌中的L-脯氨酸转运缺陷。L-脯氨酸转运和L-脯氨酸脱氢酶活性的遗传互补分析及生化测定表明，其中三个杂种质粒带有大肠杆菌染色体的putPA区域（质粒pLC4-45、pLC10-29和pLC43-41）。第四个质粒pLC35-38特异性增强其宿主细菌的L-脯氨酸转运活性，但不增强其L-脯氨酸脱氢酶活性。它可能编码putP。我们已在大肠杆菌小细胞系统中使用这些质粒来鉴定putA和putP基因产物。
