Unusual Relationship between Iron Deprivation and Organophosphate Hydrolase Expression.

Autor:	Nandavaram A; Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India., Nandakumar A; National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bengaluru, India.; The University of Trans-Disciplinary Health Sciences & Technology (TDU), Bengaluru, Karnataka, India., Kashif GM; Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India., Sagar AL; Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India., Shailaja G; Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India., Ramesh A; National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bengaluru, India., Siddavattam D; Department of Animal Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India.; Department of Biochemistry, School of Sciences, GITAM University, Visakhapatnam, India.
Jazyk:	angličtina
Zdroj:	Applied and environmental microbiology [Appl Environ Microbiol] 2023 May 31; Vol. 89 (5), pp. e0190322. Date of Electronic Publication: 2023 Apr 19.
DOI:	10.1128/aem.01903-22
Abstrakt:	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. Competing Interests: The authors declare no conflict of interest.
Databáze:	MEDLINE
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