A Nag-like dioxygenase initiates 3,4-dichloronitrobenzene degradation via 4,5-dichlorocatechol in Diaphorobacter sp. strain JS3050
A Nag-like dioxygenase initiates 3,4-dichloronitrobenzene degradation via 4,5-dichlorocatechol in Diaphorobacter sp. strain JS3050
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在 Diaphorobacter sp. 中，Nag 样双加氧酶通过 4,5-二氯儿茶酚启动 3,4-二氯硝基苯降解。
DOI：
10.1111/1462-2920.15295
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发表时间：
2020-11-10
影响因子：
5.1
通讯作者：
Zhou, Ning-Yi
中科院分区：
文献类型：
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作者：
Gao, Yi-Zhou;Palatucci, Mallory L.;Zhou, Ning-Yi
化学合成中间体3，4-二氯硝基苯（3，4-DCNB）是一种环境污染物。葡萄球菌属菌株JS 3050利用3，4-DCNB作为碳、氮和能量的唯一来源。然而，其催化剂的分子决定因素知之甚少。在此，对菌株JS 3050的全基因组进行测序，并异源表达关键基因，以确定其降解途径的细节。染色体编码的三组分硝基芳烃双加氧酶（DcnAaAbAcAd）将3，4-DCNB化学计量地转化为4，5-二氯邻苯二酚，其通过质粒携带的开环氯邻苯二酚1，2-双加氧酶（DcnC）转化为3，4-二氯粘康酸。在染色体上，还有编码酶（DcnDEF）的基因，该酶负责随后将3，4-二氯粘康酸转化为β-酮己二酸。负责分解代谢途径的基因分别位于质粒和染色体上的事实表明，编码该途径的基因可能最近组装并正在进行进化。DcnAaAbAcAd从3，4-DCNB形成4，5-二氯儿茶酚的区域特异性代表了硝基芳烃双加氧酶的复杂进化，避免了有毒中间体的错误路由。这些发现增强了对适应性进化过程中微生物分解代谢多样性的理解，以应对释放到环境中的外源性物质。
The chemical synthesis intermediate 3,4-dichloronitrobenzene (3,4-DCNB) is an environmental pollutant. Diaphorobacter sp. strain JS3050 utilizes 3,4-DCNB as a sole source of carbon, nitrogen and energy. However, the molecular determinants of its catabolism are poorly understood. Here, the complete genome of strain JS3050 was sequenced and key genes were expressed heterologously to establish the details of its degradation pathway. A chromosome-encoded three-component nitroarene dioxygenase (DcnAaAbAcAd) converted 3,4-DCNB stoichiometrically to 4,5-dichlorocatechol, which was transformed to 3,4-dichloromuconate by a plasmid-borne ring-cleavage chlorocatechol 1,2-dioxygenase (DcnC). On the chromosome, there are also genes encoding enzymes (DcnDEF) responsible for the subsequent transformation of 3,4-dichloromuconate to beta-ketoadipic acid. The fact that the genes responsible for the catabolic pathway are separately located on plasmid and chromosome indicates that recent assembly and ongoing evolution of the genes encoding the pathway is likely. The regiospecificity of 4,5-dichlorocatechol formation from 3,4-DCNB by DcnAaAbAcAd represents a sophisticated evolution of the nitroarene dioxygenase that avoids misrouting of toxic intermediates. The findings enhance the understanding of microbial catabolic diversity during adaptive evolution in response to xenobiotics released into the environment.