Saxild H H, Jacobsen J H, Nygaard P
Department of Microbiology, Technical University of Denmark, Lyngby.
Microbiology (Reading). 1995 Sep;141 ( Pt 9):2211-8. doi: 10.1099/13500872-141-9-2211.
The purT gene from Bacillus subtilis encoding the formate-dependent glycinamide ribonucleotide transformylase T was cloned by functional complementation of an Escherichia coli purN purT double mutant. The nucleotide sequence revealed an open reading frame of 384 amino acids. The purT amino acid sequence showed similarity to the enzyme phosphoribosylaminoimidazole carboxylase encoded by the purK gene but not to the N10-formyltetrahydrofolate-dependent glycinamide ribonucleotide transformylase N enzyme encoded by the purN gene. The glycinamide ribonucleotide transformylase T level was repressed in cells grown in rich medium compared to minimal-medium-grown cells. However, when the culture entered the stationary-growth phase the enzyme level increased in rich medium and decreased in minimal medium. By comparing the deduced amino acid sequence of the B. subtilis purT gene product with translated nucleotide sequences in various databanks, evidence for the existence of putative purT genes in the Gram-negative bacteria Pasteurella haemolytica and Pseudomonas aeruginosa was obtained.
通过对大肠杆菌purN purT双突变体进行功能互补，克隆了来自枯草芽孢杆菌的编码甲酸依赖性甘氨酰胺核糖核苷酸转甲酰酶T的purT基因。核苷酸序列显示有一个384个氨基酸的开放阅读框。purT氨基酸序列与由purK基因编码的磷酸核糖氨基咪唑羧ylase酶相似，但与由purN基因编码的N10-甲酰四氢叶酸依赖性甘氨酰胺核糖核苷酸转甲酰酶N不相似。与在基本培养基中生长的细胞相比，在丰富培养基中生长的细胞中甘氨酰胺核糖核苷酸转甲酰酶T水平受到抑制。然而，当培养物进入稳定生长期时，丰富培养基中的酶水平增加，而基本培养基中的酶水平降低。通过将枯草芽孢杆菌purT基因产物的推导氨基酸序列与各种数据库中的翻译核苷酸序列进行比较，获得了革兰氏阴性菌溶血巴斯德氏菌和铜绿假单胞菌中存在推定purT基因的证据。
