Identification and functional analysis of the genes for naphthalenesulfonate catabolism by Sphingomonas xenophaga BN6
Identification and functional analysis of the genes for naphthalenesulfonate catabolism by Sphingomonas xenophaga BN6
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DOI：
10.1099/mic.0.28783-0
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发表时间：
2006-07-01
期刊：
影响因子：
2.8
通讯作者：
Klein, Joachim
中科院分区：
文献类型：
--
作者：
Keck, Andreas;Conradt, Doris;Klein, Joachim
鞘氨醇单胞菌BN6能将各种取代的萘磺酸盐降解成相应的取代水杨酸盐，在pBN6上发现了一个基因簇，该基因簇编码了几种参与萘磺酸盐降解途径的酶。测序得到一条16915bp的DNA片段，包含17个ORF。在DNA片段上鉴定了编码1，2-二羟基萘双加氧酶、2-羟基色烯-2-羧酸异构酶和2‘-羟基苯丙酮酸缩醛酶的基因，并在大肠杆菌中进行了异源表达。此外，通过插入失活鉴定了编码多组分、环羟化的萘磺酸双加氧酶的铁氧还蛋白和铁氧还蛋白还原酶的基因。已鉴定的基因通常与菲降解菌Sphingomonas sp.编码的酶具有最高的同源性。P2，也就是对萘和联苯有裂解作用的芳香鞘氨醇单胞菌F199的巨质粒pNL1。参与降解萘磺酸盐的异源链球菌BN6的基因在三个不同的转录单位中也与鞘氨醇单胞菌中参与降解萘、联苯和菲的基因具有相同的组织结构。P2和芳香链霉菌F199。这些基因位于异源链球菌BN6的两侧，由ORF指定的蛋白质与可移动遗传元件的蛋白质显示出最高的同源性。
Sphingromonas xenophaga BN6 degrades various (substituted) naphthalenesulfonates to the corresponding (substituted) salicylates, A gene cluster was identified on the plasmid pBN6 which coded for several enzymes participating in the degradative pathway for naphthalenesulfonates. A DNA fragment of 16 915 bp was sequenced which contained 17 ORFs. The genes encoding the 1,2-dihydroxynaphthalene dioxygenase, 2-hydroxychromene-2-carboxylate isomerase, and 2 '-hydroxybenzalpyruvate aldolase of the naphthalenesulfonate pathway were identified on the DNA fragment and the encoded proteins heterologously expressed in Escherichia coli. Also, the genes encoding the ferredoxin and ferredoxin reductase of a multi-component, ring-hydroxylating naphthalenesulfonate dioxygenase were identified by insertional inactivation. The identified genes generally demonstrated the highest degree of homology to enzymes encoded by the phenanthrene-degrading organism Sphingomonas sp. P2, or the megaplasmid pNL1 of the naphthalene- and biphenyl-clegrading strain Sphingomonas aromaticivorans F199. The genes of S. xenophaga BN6 participating in the degradation of naphthalenesulfonates also shared the same organization in three different transcriptional units as the genes involved in the degradation of naphthalene, biphenyl, and phenanthrene previously found in Sphingomonas sp. P2 and S. aromaticivorans F199. The genes were flanked in S. xenophaga BN6 by ORFs which specify proteins that show the highest homologies to proteins of mobile genetic elements.