Efficient NADPH-dependent dehalogenation afforded by a self-sufficient reductive dehalogenase.

Autor:	Fisher K; Manchester Institute of Biotechnology, University of Manchester, Manchester, UK., Halliwell T; Manchester Institute of Biotechnology, University of Manchester, Manchester, UK., Payne KAP; Manchester Institute of Biotechnology, University of Manchester, Manchester, UK., Ragala G; Manchester Institute of Biotechnology, University of Manchester, Manchester, UK., Hay S; Manchester Institute of Biotechnology, University of Manchester, Manchester, UK., Rigby SEJ; Manchester Institute of Biotechnology, University of Manchester, Manchester, UK., Leys D; Manchester Institute of Biotechnology, University of Manchester, Manchester, UK. Electronic address: david.leys@manchester.ac.uk.
Jazyk:	angličtina
Zdroj:	The Journal of biological chemistry [J Biol Chem] 2023 Sep; Vol. 299 (9), pp. 105086. Date of Electronic Publication: 2023 Jul 25.
DOI:	10.1016/j.jbc.2023.105086
Abstrakt:	Reductive dehalogenases are corrinoid and iron-sulfur cluster-containing enzymes that catalyze the reductive removal of a halogen atom. The oxygen-sensitive and membrane-associated nature of the respiratory reductive dehalogenases has hindered their detailed kinetic study. In contrast, the evolutionarily related catabolic reductive dehalogenases are oxygen tolerant, with those that are naturally fused to a reductase domain with similarity to phthalate dioxygenase presenting attractive targets for further study. We present efficient heterologous expression of a self-sufficient catabolic reductive dehalogenase from Jhaorihella thermophila in Escherichia coli. Combining the use of maltose-binding protein as a solubility-enhancing tag with the btuCEDFB cobalamin uptake system affords up to 40% cobalamin occupancy and a full complement of iron-sulfur clusters. The enzyme is able to efficiently perform NADPH-dependent dehalogenation of brominated and iodinated phenolic compounds, including the flame retardant tetrabromobisphenol, under both anaerobic and aerobic conditions. NADPH consumption is tightly coupled to product formation. Surprisingly, corresponding chlorinated compounds only act as competitive inhibitors. Electron paramagnetic resonance spectroscopy reveals loss of the Co(II) signal observed in the resting state of the enzyme under steady-state conditions, suggesting accumulation of Co(I)/(III) species prior to the rate-limiting step. In vivo reductive debromination activity is readily observed, and when the enzyme is expressed in E. coli strain W, supports growth on 3-bromo-4-hydroxyphenylacetic as a sole carbon source. This demonstrates the potential for catabolic reductive dehalogenases for future application in bioremediation. Competing Interests: Conflict of interest The authors declare that they have no conflict of interest with the contents of this article. (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
Externí odkaz:	Zobrazit plný text záznamu