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 β‐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.

中文翻译：

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Nag样双加氧酶通过Diaphorobacter sp。中的4,5-二氯邻苯二酚引发3,4-二氯硝基苯降解。菌株JS3050

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。泛影杆菌sp。菌株JS3050利用3,4-DCNB作为碳，氮和能量的唯一来源。但是，对其分解代谢的分子决定因素了解甚少。在此，对菌株JS3050的完整基因组进行测序，并异源表达关键基因以建立其降解途径的详细信息。染色体编码的三成分硝基芳烃双加氧酶（DcnAaAbAcAd）在化学计量上将3,4-DCNB转化为4,5-二氯邻苯二酚，然后通过质粒环裂解的氯邻苯二酚1,2-双加氧酶将其转化为3,4-二氯粘康酸酯（ DcnC）。在染色体上，还存在编码酶（DcnDEF）的基因，这些基因负责随后将3,4-二氯粘康酸酯转化为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，可能存在编码途径的基因的最近组装和正在进行的进化。DcnAaAbAcAd从3,4-DCNB形成4,5-二氯邻苯二酚的区域专一性代表了硝基芳烃双加氧酶的复杂演变，避免了有毒中间体的错误转移。这些发现增强了对异种生物释放到环境中的适应性进化过程中微生物分解代谢多样性的认识。