Molecular characterization and substrate specificity of nitrobenzene dioxygenase from Comamonas sp strain JS765
Molecular characterization and substrate specificity of nitrobenzene dioxygenase from Comamonas sp strain JS765
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DOI：
10.1128/aem.68.2.634-641.2002
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发表时间：
2002-02-01
影响因子：
4.4
通讯作者：
Gibson, DT
中科院分区：
文献类型：
--
作者：
Lessner, DJ;Johnson, GR;Gibson, DT
Comamonas sp.菌株JS765可以在硝基苯作为碳、氮和能量的唯一来源的情况下生长。本文报道了菌株JS765催化硝基苯降解的第一步——硝基苯双加氧酶（NBDO）的基因序列。NBDO的组成成分分别被命名为还原酶（NBZ）、铁氧还蛋白（NBZ）、加氧酶（nbzα）和加氧酶（nbzβ），基因编号分别为nbzAa、nbzAb、nbzAc和nbzAd。序列分析表明，NBDO与Rieske非血红素铁加氧酶的萘家族具有高度的同源性，特别是与Pseudomonas sp.菌株JS42的2-硝基甲苯双加氧酶具有高度的同源性。该酶能氧化多种底物，与部分纯化的加氧酶（NBZ）的相对反应速率表明，JS765更倾向于3-硝基甲苯，这被证明是JS765的生长底物。NBDO是Rieske非血红素铁加氧酶萘家族的第一个成员，据报道，它可以氧化一硝基甲苯和二硝基甲苯的所有异构体，同时释放亚硝酸盐。
Comamonas sp. strain JS765 can grow with nitrobenzene as the sole source of carbon, nitrogen, and energy. We report here the sequence of the genes encoding nitrobenzene dioxygenase (NBDO), which catalyzes the first step in the degradation of nitrobenzene by strain JS765. The components of NBDO were designated Reductase(NBZ), Ferredoxin(NBZ), Oxygenase(NBZalpha), and Oxygenase(NBZbeta), with the gene designations nbzAa, nbzAb, nbzAc, and nbzAd, respectively. Sequence analysis showed that the components of NBDO have a high level of homology with the naphthalene family of Rieske nonheme iron oxygenases, in particular, 2-nitrotoluene dioxygenase from Pseudomonas sp. strain JS42. The enzyme oxidizes a wide range of substrates, and relative reaction rates with partially purified Oxygenase(NBZ) revealed a preference for 3-nitrotoluene, which was shown to be a growth substrate for JS765. NBDO is the first member of the naphthalene family of Rieske nonheme iron oxygenases reported to oxidize all of the isomers of mono- and dinitrotoluenes with the concomitant release of nitrite.