Lim J C, Lee J, Jang J D, Lim J Y, Min K R, Kim C K, Kim Y
College of Pharmacy, Chungbuk National University, Cheongju, Korea.
Arch Pharm Res. 2000 Apr;23(2):187-95. doi: 10.1007/BF02975512.
Nucleotide sequence extending 2,3-dihydroxybiphenyl 1,2-dioxygenase gene (pcbC) and 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoate hydrolase gene (pcbD) of Pseudomonas sp. DJ-12 was previously analyzed and the two genes were present in the order of pcbD-pcbC preceded by a promoter from Pseudomonas sp. DJ-12. In this study, a 3.8-kb nucleotide sequence located downstream of the pcbC gene was analyzed to have three open reading frames (ORFs) that are designated as orf1, pcbE and orf2 genes. All of the ORFs were preceded by each ribosome-binding sequence of 5-GGAXA-3 (X=G or A). However, no promoter-like sequence and transcription terminator sequence were found in the analyzed region, downstream of pcbC gene. Therefore, the gene cluster appeared to be present in the order of pcbD-pcbC-orf1-pcbE-orf2 as an operon, which is unique organization characterized so far in biphenyl- and PCB-degrading bacteria. The orf1 gene was composed of 1,224 base pairs which can encode a polypeptide of molecular weight 44,950 containing 405 amino acid residues. A deduced amino acid sequence of the orf1 gene product exhibited 21-33% identity with those of indole dioxygenase and phenol hydroxylase components. The pcbE gene was composed of 783 base pairs encoding 2-hydroxypenta-2,4-dienoate hydratase involved in the 4-chlorobiphenyl catabolism. The orf2 gene was composed of 1,017 base pairs encoding a polypeptide of molecular weight 37,378 containing 338 amino acid residues. A deduced amino acid sequence of the orf2 gene product exhibited 31% identity with that of a nitrilotriacetate monooxygenase component.
先前已对假单胞菌属DJ - 12的2,3 - 二羟基联苯1,2 - 双加氧酶基因（pcbC）和2 - 羟基 - 6 - 氧代 - 6 - 苯基己 - 2,4 - 二烯酸水解酶基因（pcbD）的核苷酸序列进行了分析，这两个基因以pcbD - pcbC的顺序排列，其前面是来自假单胞菌属DJ - 12的一个启动子。在本研究中，对位于pcbC基因下游的一段3.8 kb核苷酸序列进行了分析，发现有三个开放阅读框（ORF），分别命名为orf1、pcbE和orf2基因。所有的开放阅读框前面都有各自的5 - GGAXA - 3（X = G或A）核糖体结合序列。然而，在分析区域（pcbC基因下游）未发现类似启动子的序列和转录终止子序列。因此，该基因簇似乎以pcbD - pcbC - orf1 - pcbE - orf2的顺序作为一个操纵子存在，这是迄今为止在联苯和多氯联苯降解细菌中所特有的组织形式。orf1基因由1224个碱基对组成，可编码一个分子量为44950、含有405个氨基酸残基的多肽。orf1基因产物的推导氨基酸序列与吲哚双加氧酶和苯酚羟化酶组分的氨基酸序列具有21% - 33%的同一性。pcbE基因由783个碱基对组成，编码参与4 - 氯联苯分解代谢的2 - 羟基戊 - 2,4 - 二烯酸水合酶。orf2基因由1017个碱基对组成，编码一个分子量为37378、含有338个氨基酸残基的多肽。orf2基因产物的推导氨基酸序列与次氮基三乙酸单加氧酶组分的氨基酸序列具有31%的同一性。
