Abstract As a vital byproduct of chemical intermediates for pesticides and cytotoxin inhibitors, 2-bromo-4-nitrophenol (2B4NP) is toxic to aquatic life. However, bacterial cultures mineralizing 2B4NP have not been reported. In this study, Cupriavidus sp. strain NyZ375 was isolated from aromatics-polluted soil and identified by 16S rRNA gene sequencing. Via an oxidative pathway, it grows on 120 μM 2B4NP as the only carbon source, releasing approximately equivalent amount of nitrite. Three genes (bnpABC) in a 4.8-kb DNA fragment from a draft genome was found to be responsible for the initial reactions in 2B4NP degradation. BnpAB are the monooxygenase and flavin reductase components, respectively, catalyzing the monooxygenation of 2B4NP to bromohydroquinone (BHQ, 63%) and 1,2,4-benzenetriol (BT, 37%) with concomitant nitrite release, in the presence of NADH and FAD. BnpC is a hydroxyquinol 1,2-dioxygenase catalyzing the ring-cleavage oxidation of BT to maleylacetate. The by-product BHQ was not further degraded by strain NyZ375 but was not toxic to its growth at a concentration of 100 μM. It can be tentatively concluded that BnpAB is evolutionary close to the 2,4,6-trichlorophenol monooxygenase TcpAX from Cupriavidus necator JMP134. The 2B4NP catabolism by this new isolate illustrates a pathway distinct from those of all identified 2-chloro-4-nitrophenol utilizers.

中文翻译：

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一种双组分单加氧酶在新分离的 Cupriavidus sp 中启动新的 2-bromo-4-nitrophenol 分解代谢途径。菌株 NyZ375

摘要 作为农药和细胞毒素抑制剂化学中间体的重要副产品，2-溴-4-硝基苯酚（2B4NP）对水生生物有毒。然而，尚未报道矿化 2B4NP 的细菌培养物。在这项研究中， Cupriavidus sp。菌株 NyZ375 从芳香烃污染的土壤中分离出来，并通过 16S rRNA 基因测序进行鉴定。通过氧化途径，它在作为唯一碳源的 120 μM 2B4NP 上生长，释放大约等量的亚硝酸盐。发现来自基因组草图的 4.8-kb DNA 片段中的三个基因 (bnpABC) 负责 2B4NP 降解的初始反应。BnpAB 分别是单加氧酶和黄素还原酶组分，催化 2B4NP 单加氧为溴氢醌（BHQ，63%）和 1,2,4-苯三醇（BT，37%），同时释放亚硝酸盐，在 NADH 和 FAD 存在的情况下。BnpC 是一种羟基喹啉 1,2-双加氧酶，可催化 BT 环裂解氧化为马来酰乙酸。副产物 BHQ 不会被菌株 NyZ375 进一步降解，但在 100 μM 的浓度下对其生长没有毒性。可以初步得出结论，BnpAB 的进化接近于来自 Cupriavidus necator JMP134 的 2,4,6-三氯苯酚单加氧酶 TcpAX。这种新分离株的 2B4NP 分解代谢说明了一条不同于所有已鉴定的 2-氯-4-硝基苯酚利用者的途径。来自Cupriavidus necator JMP134 的6-三氯苯酚单加氧酶TcpAX。这种新分离株的 2B4NP 分解代谢说明了一条不同于所有已鉴定的 2-氯-4-硝基苯酚利用者的途径。来自Cupriavidus necator JMP134 的6-三氯苯酚单加氧酶TcpAX。这种新分离株的 2B4NP 分解代谢说明了一条不同于所有已鉴定的 2-氯-4-硝基苯酚利用者的途径。