Southern J A, Parker J R, Woods D R
J Gen Microbiol. 1986 Oct;132(10):2827-35. doi: 10.1099/00221287-132-10-2827.
A glutamine synthetase (GS) gene, glnA, from Bacteroides fragilis was cloned on a recombinant plasmid pJS139 which enabled Escherichia coli glnA deletion mutants to utilize (NH4)2SO4 as a sole source of nitrogen. DNA homology was not detected between the B. fragilis glnA gene and the E. coli glnA gene. The cloned B fragilis glnA gene was expressed from its own promoter and was subject to nitrogen repression in E. coli, but it was not able to activate histidase activity in an E. coli glnA ntrB ntrC deletion mutant containing the Klebsiella aerogenes hut operon. The GS produced by pJS139 in E. coli was purified; it had an apparent subunit Mr of approximately 75,000, which is larger than that of any other known bacterial GS. There was very slight antigenic cross-reactivity between antibodies to the purified cloned B. fragilis GS and the GS subunit of wild-type E. coli.
从脆弱拟杆菌中克隆出一个谷氨酰胺合成酶（GS）基因glnA，该基因克隆于重组质粒pJS139上，此质粒能使大肠杆菌glnA缺失突变体利用硫酸铵作为唯一氮源。在脆弱拟杆菌glnA基因与大肠杆菌glnA基因之间未检测到DNA同源性。克隆的脆弱拟杆菌glnA基因从其自身启动子表达，且在大肠杆菌中受氮阻遏，但它无法在含有产气克雷伯菌hut操纵子的大肠杆菌glnA ntrB ntrC缺失突变体中激活组氨酸酶活性。pJS139在大肠杆菌中产生的GS被纯化；其表观亚基Mr约为75,000，比任何其他已知细菌的GS都大。纯化的克隆脆弱拟杆菌GS的抗体与野生型大肠杆菌的GS亚基之间存在非常微弱的抗原交叉反应。
