Cloning and characterization of the pnb genes, encoding enzymes for 4-nitrobenzoate catabolism in Pseudomonas putida TW3
Cloning and characterization of the pnb genes, encoding enzymes for 4-nitrobenzoate catabolism in Pseudomonas putida TW3
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DOI：
10.1128/jb.183.4.1225-1232.2001
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发表时间：
2001-02-01
影响因子：
3.2
通讯作者：
Williams, PA
中科院分区：
文献类型：
--
作者：
Hughes, MA;Williams, PA
恶臭假单胞菌菌株 TW3 能够通过硝基苯甲酸 (4NBen) 和 3, 4-二羟基苯甲酸（原儿茶酸 [PCA]）将 4-硝基甲苯代谢为中心代谢物。我们克隆、测序并鉴定了 TW3 DNA 的 6 kbp 片段，该片段包含 5 个基因，其中两个编码参与 4NBen 分解代谢为 PCA 的酶。按顺序，它们编码一种 4NBen 还原酶 (PnbA)，负责催化 4NBen 直接还原为 4-羟基氨基苯甲酸，每 mol 4NBen 氧化 2 mol NADH，一种还原酶样酶 (Orf1)，似乎在该途径中没有功能，LysR 家族的调节蛋白 (PnbR)， 4-羟氨基苯甲酸裂解酶 (PnbB) 催化 4-羟氨基苯甲酸转化为 PCA 和铵，以及第二种裂解酶样酶 (Orf2)，它与 pnbB 密切相关，但似乎在该途径中没有功能。中央 pnbR 基因的转录方向与其他四个基因相反。这些基因完成了恶臭假单胞菌菌株 TW3 中 4-硝基甲苯分解代谢至环裂解底物 PCA 的整个途径的表征。
Pseudomonas putida strain TW3 is able to metabolize 4-nitrotoluene via il nitrabenzoate (4NBen) and 3, 4-dihydroxybenzoic acid (protocatechuate [PCA]) to central metabolites. We have cloned, sequenced, and characterized a 6-kbp fragment of TW3 DNA which contains five genes, two of which encode the enzymes involved in the catabolism of 4NBen to PCA. In order, they encode a 4NBen reductase (PnbA) which is responsible for catalyzing the direct reduction of 4NBen to 4-hydroxylaminobenzoate with the oxidation of 2 mol of NADH per mol of 4NBen, a reductase-like enzyme (Orf1) which appears to have no function in the pathway, a regulator protein (PnbR) of the LysR family, a 4-hydroxylaminobenzoate lyase (PnbB) which catalyzes the conversion of 4-hydroxylaminobenzoate to PCA and ammonium, and a second lyase-like enzyme (Orf2) which is closely associated with pnbB but appears to have no function in the pathway. The central pnbR gene is transcribed in the opposite direction to the other four genes. These genes complete the characterization of the whole pathway of 4-nitrotoluene catabolism to the ring cleavage substrate PCA in P. putida strain TW3.