有机磷水解酶(OPH),迄今已知水解有机磷酸酯(OP)杀虫剂和神经剂的第三酯键,最近已被证明与外膜运输组件相互作用,即,TonB和ExbB/ExbD。在OPH负面背景下,Sphingopyxiswildii细胞无法运输铁肠杆菌素,并且在铁限制条件下表现出生长迟缓。现在,我们显示来自狮身人面像ATCC27551的编码OPH的有机磷酸酯降解(opd)基因是铁调节子的一部分。发现与opd基因的转录起始位点(TSS)重叠的毛盒基序与在opdmRNA的5'编码区中鉴定的铁响应元件(IRE)RNA基序协调,以紧密调节opd基因表达。在存在铁的情况下,毛皮盒基序是毛皮阻遏物的目标。铁浓度的降低导致opd的抑制。IRERNA抑制opdmRNA的翻译,并作为脱衣酸酶(IRP)的靶标。IRERNA招募的IRP消除了IRE介导的翻译抑制。我们的发现建立了一个小说,多层,铁反应性调节对铁载体介导的铁摄取转运中的OPH功能至关重要。重要狮身人面像,从农业土壤中分离出来的土壤微生物,被证明能降解各种杀虫剂和杀虫剂。这些合成化学物质作为有效的神经毒素,它们属于一类被称为有机磷酸酯的化学物质。OPH的S、fuliginis代码,一种被证明参与几种有机磷酸酯及其衍生物代谢的酶。有趣的是,OPH也被证明可以促进乌氏链球菌和另一种Sphingomonad中铁载体介导的铁摄取,即,Sphingopyxiswildii,暗示这种有机磷代谢蛋白在铁稳态中起作用,也是。我们的研究剖析了铁与OPH表达的潜在分子机制,促使人们重新考虑OPH在Sphingomonads中的作用,并重新评估土壤细菌中OPH蛋白的进化起源。
Organophosphate hydrolases (OPH), hitherto known to hydrolyze the third ester bond of organophosphate (OP) insecticides and nerve agents, have recently been shown to interact with outer membrane transport components, namely, TonB and ExbB/ExbD. In an OPH negative background, Sphingopyxis wildii cells failed to transport ferric enterobactin and showed retarded growth under iron-limiting conditions. We now show the OPH-encoding organophosphate degradation (opd) gene from Sphingobium fuliginis ATCC 27551 to be part of the iron regulon. A fur-box motif found to be overlapping with the transcription start site (TSS) of the opd gene coordinates with an iron responsive element (IRE) RNA motif identified in the 5\' coding region of the opd mRNA to tightly regulate opd gene expression. The fur-box motif serves as a target for the Fur repressor in the presence of iron. A decrease in iron concentration leads to the derepression of opd. IRE RNA inhibits the translation of opd mRNA and serves as a target for apo-aconitase (IRP). The IRP recruited by the IRE RNA abrogates IRE-mediated translational inhibition. Our findings establish a novel, multilayered, iron-responsive regulation that is crucial for OPH function in the transport of siderophore-mediated iron uptake. IMPORTANCE Sphingobium fuliginis, a soil-dwelling microbe isolated from agricultural soils, was shown to degrade a variety of insecticides and pesticides. These synthetic chemicals function as potent neurotoxins, and they belong to a class of chemicals termed organophosphates. S. fuliginis codes for OPH, an enzyme that has been shown to be involved in the metabolism of several organophosphates and their derivatives. Interestingly, OPH has also been shown to facilitate siderophore-mediated iron uptake in S. fuliginis and in another Sphingomonad, namely, Sphingopyxis wildii, implying that this organophosphate-metabolizing protein has a role in iron homeostasis, as well. Our research dissects the underlying molecular mechanisms linking iron to the expression of OPH, prompting a reconsideration of the role of OPH in Sphingomonads and a reevaluation of the evolutionary origins of the OPH proteins from soil bacteria.