Criado L M, Martín J F, Gil J A
Departamento de Ecologia, Genética y Microbiología, Universidad de León, Spain.
Gene. 1993 Apr 15;126(1):135-9. doi: 10.1016/0378-1119(93)90602-y.
The nucleotide (nt) sequence of the gene (pab) encoding p-aminobenzoic acid (PABA) synthase, a key enzyme in the biosynthesis of candicidin by Streptomyces griseus IMRU3570, was determined and an open reading frame (ORF) of 2171 nt was found. The predicted amino acid sequence demonstrated extensive sequence identity with PABA synthases (Pab) from Gram-negative Enterobacteria. The protein encoded by ORF pab shows a clear relationship at the N terminus with PabA and at the C terminus with PabB from Escherichia coli, Serratia and Klebsiella. We also determined the extent of a spontaneous deletion that removed the ORF located upstream from pab near the 5' end of the cloned fragment. The deletion occurred when the gene was cloned in the BamHI site of pBR322 and allowed pab expression in E. coli.
测定了灰色链霉菌IMRU3570生物合成杀念菌素的关键酶——对氨基苯甲酸（PABA）合酶编码基因（pab）的核苷酸（nt）序列，发现了一个2171 nt的开放阅读框（ORF）。预测的氨基酸序列与革兰氏阴性肠道杆菌的PABA合酶（Pab）具有广泛的序列同一性。ORF pab编码的蛋白质在N端与大肠杆菌、沙雷氏菌和克雷伯氏菌的PabA明显相关，在C端与PabB明显相关。我们还确定了一个自发缺失的范围，该缺失去除了克隆片段5'端附近pab上游的ORF。当该基因克隆到pBR322的BamHI位点并在大肠杆菌中实现pab表达时发生了缺失。
