Organization and regulation of pentachlorophenol-degrading genes in Sphingobium chlorophenolicum ATCC 39723
Organization and regulation of pentachlorophenol-degrading genes in Sphingobium chlorophenolicum ATCC 39723
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DOI：
10.1128/jb.184.17.4672-4680.2002
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发表时间：
2002-09-01
影响因子：
3.2
通讯作者：
Xun, LY
中科院分区：
文献类型：
--
作者：
Cai, M;Xun, LY
氯酚鞘氨醇（以前称为氯酚鞘氨醇单胞菌）ATCC 39723 中五氯苯酚 (PCP) 降解途径的前三种酶已得到表征，相应的基因 pcpA、pcpB 和 pcpC 已分别克隆和测序。为了寻找参与 PCP 降解的新基因并绘制 pcp 基因的物理位置图，对包含 pcpA 和 pcpC 的 24 kb 片段进行了完整测序。在 pcpA 上游发现了一个假定的 LysR 型转录调节基因 pcpM 和一个马来酰乙酸还原酶基因 pepE。研究发现 pepE 在五氯苯酚降解中发挥作用。在 24 kb 片段上未找到 pcpB。四种基因产物 PcpB、PcpC、PcpA 和 PcpE 负责 ATCC 39723 中 PCP 代谢为 3-氧代己二酸，每个基因的失活突变都会破坏降解途径。 pep 基因的组织很不寻常，因为四个 PCP 降解基因（pepA、pepB、pcpC 和 pcpE）被发现位于四个离散位置。已鉴定出两个假设的 LysR 型调节基因 pcpM 和 pcpR； pcpM 不是必需的，但 pepR 对于 pcpB、pcpA 和 pepE 的诱导至关重要。 PcpR的诱导剂是PCP和其他多氯酚。 pcpC的表达是组成型的。因此，记录了参与五氯苯酚降解为 3-氧代己二酸的基因的组织和调节。
The first three enzymes of the pentachlorophenol (PCP) degradation pathway in Sphingobium chlorophenolicum (formerly Sphingomonas chlorophenolica) ATCC 39723 have been characterized, and the corresponding genes, pcpA, pcpB, and pcpC, have been individually cloned and sequenced. To search for new genes involved in PCP degradation and map the physical locations of the pcp genes, a 24-kb fragment containing pcpA and pcpC was completely sequenced. A putative LysR-type transcriptional regulator gene, pcpM, and a maleylacetate reductase gene, pepE, were identified upstream of pcpA. pepE was found to play a role in PCP degradation. pcpB was not found on the 24-kb fragment. The four gene products PcpB, PcpC, PcpA, and PcpE were responsible for the metabolism of PCP to 3-oxoadipate in ATCC 39723, and inactivational mutation of each gene disrupted the degradation pathway. The organization of the pep genes is unusual because the four PCP-degrading genes, pepA, pepB, pcpC, and pcpE, were found to be located at four discrete locations. Two hypothetical LysR-type regulator genes, pcpM and pcpR, have been identified; pcpM was not required, but pepR was essential for the induction of pcpB, pcpA, and pepE. The coinducers of PcpR were PCP and other polychlorinated phenols. The expression of pcpC was constitutive. Thus, the organization and regulation of the genes involved in PCP degradation to 3-oxoadipate were documented.