Steglitz-Mörsdorf U, Mörsdorf G, Kaltwasser H
Lehrstuhl für Mikrobiologie der Universität des Saarlandes, Saarbrücken, FRG.
FEMS Microbiol Lett. 1993 Jan 15;106(2):157-64. doi: 10.1111/j.1574-6968.1993.tb05952.x.
The glnAntrBC operon of Proteus vulgaris was cloned and heterologously expressed in Escherichia coli. The nucleotide sequence was determined. An open reading frame of 1407 bp was identified as the glnA gene and the deduced amino acid sequence showed 82% identity with the E. coli glutamine synthetase protein. Heterologous expression of the glnA gene in E. coli restored glutamine synthetase (GS) activity in a GS-negative mutant and a 52 kDa protein was detected and addressed as the GS subunit of P. vulgaris. Adjacent to the glnA gene the regulatory genes ntrB and ntrC were identified. Their coding regions comprised 1053 and 1452 bp, respectively, and the deduced gene products NRII (NtrB) and NRI (NtrC) shared 72% identity with the corresponding E. coli proteins. Heterologous expression in E. coli revealed only a 54 kDa protein which was shown to be NRI. NRII was not detectable using the methods employed.
普通变形杆菌的glnAntrBC操纵子被克隆并在大肠杆菌中进行异源表达。测定了其核苷酸序列。一个1407 bp的开放阅读框被鉴定为glnA基因，推导的氨基酸序列与大肠杆菌谷氨酰胺合成酶蛋白有82%的同一性。glnA基因在大肠杆菌中的异源表达恢复了谷氨酰胺合成酶（GS）阴性突变体中的谷氨酰胺合成酶活性，检测到一个52 kDa的蛋白，并将其确定为普通变形杆菌的GS亚基。在glnA基因旁边鉴定出调控基因ntrB和ntrC。它们的编码区分别包含1053和1452 bp，推导的基因产物NRII（NtrB）和NRI（NtrC）与相应的大肠杆菌蛋白有72%的同一性。在大肠杆菌中的异源表达仅显示出一个54 kDa的蛋白，该蛋白被证明是NRI。使用所采用的方法未检测到NRII。
