Molecular characterization of a phenanthrene degradation pathway in Mycobacterium vanbaalenii PYR-1.
Molecular characterization of a phenanthrene degradation pathway in Mycobacterium vanbaalenii PYR-1.
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DOI：
10.1016/j.bbrc.2004.07.089
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发表时间：
2004-09
影响因子：
3.1
通讯作者：
R. Stingley;Ashraf Khan;C. Cerniglia
中科院分区：
文献类型：
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作者：
R. Stingley;Ashraf Khan;C. Cerniglia
范氏分枝杆菌PYR-1能够通过多种途径降解多环芳烃（PAHs），生成开环代谢物。芘双加氧酶的大亚基和小亚基基因，分别为nidA和nidB，以前在M. vanbaalenii PYR-1 [Appl. Microbiol. 67（2001）3577]。图书馆的M。vanbaalenii PYR-1基因组构建在fosmid载体中，以鉴定参与PAH降解的其他基因。Southern杂交鉴定出12个含nidA的fosmid克隆。一个nidA阳性克隆，pFOS 608，序列分析显示，一些额外的基因参与PAH降解。在这个位点，一个假定的操纵子含有邻苯二甲酸酯降解相关基因，另一个含有编码假定的ABC转运蛋白的基因。在该区域发现的许多基因与通过邻苯二甲酸途径参与菲降解的基因同源。大多数菲降解基因位于转座酶基因之间。在大肠杆菌中，pFOS 608将菲转化为菲顺式-3，4-二氢二醇，并将1-羟基-2-萘甲酸转化为2′-羧基苄叉丙酮酸、2-羧基苯甲醛和邻苯二甲酸。含有nidA和nidB的亚克隆将菲转化为菲顺式-3，4-二氢二醇，表明NidAB双加氧酶负责菲的初始攻击。这项研究是第一个确定的基因负责降解菲通过邻苯二甲酸途径在分枝杆菌物种。
Mycobacterium vanbaalenii PYR-1 is capable of degrading a number of polycyclic aromatic hydrocarbons (PAHs) to ring cleavage metabolites via multiple pathways. Genes for the large and small subunits of a pyrene dioxygenase, nidA and nidB, respectively, were previously identified in M. vanbaalenii PYR-1 [Appl. Environ. Microbiol. 67 (2001) 3577]. A library of the M. vanbaalenii PYR-1 genome was constructed in a fosmid vector to identify additional genes involved in PAH degradation. Twelve fosmid clones containing nidA were identified by Southern hybridization. Sequence analysis of one nidA-positive clone, pFOS608, revealed a number of additional genes involved in PAH degradation. At this locus, one putative operon contained genes involved in phthalate degradation, and another contained genes encoding a putative ABC transporter(s). A number of the genes found in this region are homologous to those involved in phenanthrene degradation via the phthalic acid pathway. The majority of phenanthrene degradation genes were located between putative transposase genes. In Escherichia coli, pFOS608 converted phenanthrene into phenanthrene cis-3,4-dihydrodiol, and converted 1-hydroxy-2-naphthoic acid into 2′-carboxybenzalpyruvate, 2-carboxybenzaldehyde, and phthalic acid. A subclone containing nidA and nidB converted phenanthrene into phenanthrene cis-3,4-dihydrodiol, suggesting that the NidAB dioxygenase is responsible for an initial attack on phenanthrene. This study is the first to identify genes responsible for the degradation of phenanthrene via the phthalic acid pathway in Mycobacterium species.