title: Escherichia coli YqhD exhibits aldehyde reductase activity and protects from the harmful effect of lipid peroxidation-derived aldehydes.
abstract: Evidence that Escherichia coli YqhD is involved in bacterial response to compounds that generate membrane lipid peroxidation is presented. Overexpression of yqhD results in increased resistance to the reactive oxygen species-generating compounds hydrogen peroxide, paraquat, chromate, and potassium tellurite. Increased tolerance was also observed for the lipid peroxidation-derived aldehydes butanaldehyde, propanaldehyde, acrolein, and malondialdehyde and the membrane-peroxidizing compound tert-butylhydroperoxide. Expression of yqhD was also associated with changes in the concentration of intracellular peroxides and cytoplasmic protein carbonyl content and with a reduction in intracellular acrolein levels. When compared with the wild type strain, an yqhD mutant exhibited a sensitive phenotype to all these compounds and also augmented levels of thiobarbituric acid-reactive substances, which may indicate an increased level of lipid peroxidation. Purified YqhD catalyzes the in vitro reduction of acetaldehyde, malondialdehyde, propanaldehyde, butanaldehyde, and acrolein in a NADPH-dependent reaction. Finally, yqhD transcription was induced in cells that had been exposed to conditions favoring lipid peroxidation. Taken together these results indicate that this enzyme may have a physiological function by protecting the cell against the toxic effect of aldehydes derived from lipid oxidation. We speculate that in Escherichia coli YqhD is part of a glutathione-independent, NADPH-dependent response mechanism to lipid peroxidation.
authors.affiliation: Laboratorio de Microbiología Molecular, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago 9170019, Chile.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Pérez
authors.forename: Felipe A
authors.initials: FA
authors.lastname: Arenas
authors.forename: Gonzalo A
authors.initials: GA
authors.lastname: Pradenas
authors.forename: Juan M
authors.initials: JM
authors.lastname: Sandoval
authors.forename: Claudio C
authors.initials: CC
authors.lastname: Vásquez
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D000449:Aldehyde Reductase / Q000096:biosynthesis* / Q000235:genetics; D000447:Aldehydes / Q000737:chemistry / Q000378:metabolism*; D002384:Catalysis; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D015227:Lipid Peroxidation / Q000187:drug effects / Q000502:physiology*; D016877:Oxidants / Q000494:pharmacology; D010545:Peroxides / Q000737:chemistry / Q000378:metabolism
chemical_list: D000447:Aldehydes; D029968:Escherichia coli Proteins; D016877:Oxidants; D010545:Peroxides; D000449:Aldehyde Reductase; C528732:YqhD protein, E coli; D000444:Aldehyde Dehydrogenase