Metal-catalyzed oxidation of Fe2+ dehydrogenases. Consensus target sequence between propanediol oxidoreductase of Escherichia coli and alcohol dehydrogenase II of Zymomonas mobilis.
We have studied two enzymes of a newly described family of dehydrogenases with high sequence homology, 1,2-propanediol oxidoreductase of Escherichia coli and alcohol dehydrogenase II of Zymomonas mobilis. These enzymes perform their metabolic role under anaerobic conditions; in the presence of oxygen, they show a very similar inactivation pattern by a metal-catalyzed oxidation system. Titration of histidine residues with diethyl pyrocarbonate showed one histidine residue less in the oxidized enzymes. Comparison of subtilisin peptide maps of active and inactivated enzymes showed a difference in one histidine-containing peptide, the sequence of which is YNTPH277GVAN for propanediol oxidoreductase and YNLPH277GV for alcohol dehydrogenase II. This histidine residue lies 10 residues away from a proposed metal-binding site, H263XXXH267, necessary to explain a site-specific free radical mechanism. The three histidine residues here described are strictly conserved in all enzymes of this family. In this report we propose that histidine 277 is a target for oxidation by a metal-catalyzed oxidation system and that this modification leads to the irreversible inactivation of both enzymes.
Cabiscol
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Departement de Ciències Mèdiques Basiques, Facultat de Medicina, Universitat de Lleida, Spain.
Aguilar
J
J
Ros
J
J
D000426:Alcohol Dehydrogenase / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D016384:Consensus Sequence; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D004228:Dithionitrobenzoic Acid / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology*; D019811:Hydroxylamine; D006898:Hydroxylamines / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D007527:Isoenzymes / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D017386:Sequence Homology, Amino Acid; D013401:Sugar Alcohol Dehydrogenases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D014302:Trinitrobenzenesulfonic Acid / Q000494:pharmacology; D017355:Zymomonas / Q000201:enzymology*
D006898:Hydroxylamines; D007527:Isoenzymes; D010446:Peptide Fragments; D019811:Hydroxylamine; D014302:Trinitrobenzenesulfonic Acid; D004228:Dithionitrobenzoic Acid; D007501:Iron; D013401:Sugar Alcohol Dehydrogenases; D000426:Alcohol Dehydrogenase; C020672:glycerol dehydrogenase; D004047:Diethyl Pyrocarbonate