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Structure of the D170S/T457E double mutant of vanillyl-alcohol oxidase
Structural highlights
FunctionVAOX_PENSI Catalyzes the conversion of vanillin alcohol to vanillin, and also the conversion of a wide range of phenolic compounds bearing side chains of variable size at the para position of the aromatic ring. Crucial for the degradation of the secondary metabolites derived from the degradation of the lignin. Catalyzes besides the oxidation of 4-hydroxybenzyl alcohols, the oxidative deamination of 4-hydroxybenzylamines, the oxidative demethylation of 4-(methoxy-methyl)phenols and the oxidative hydration of 4-allylphenols. Most active with 4-allylphenols. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedVanillyl-alcohol oxidase (VAO) is the prototype of a newly recognized family of structurally related oxidoreductases sharing a conserved FAD-binding domain. The active site of VAO is formed by a cavity where the enzyme is able to catalyze many reactions with phenolic substrates. Among these reactions is the stereospecific hydroxylation of 4-ethylphenol-forming (R)-1-(4'-hydroxyphenyl)ethanol. During this conversion, Asp-170 is probably critical for the hydration of the initially formed p-quinone methide intermediate. By site-directed mutagenesis, the putative active site base has been relocated to the opposite face of the active site cavity. In this way, a change in stereospecificity has been achieved. Like native VAO, the single mutants T457E, D170A, and D170S preferentially converted 4-ethylphenol to the (R)-enantiomer of 1-(4'-hydroxyphenyl)ethanol. The double mutants D170A/T457E and D170S/T457E exhibited an inverted stereospecificity with 4-ethylphenol. Particularly, D170S/T457E was strongly (S)-selective, with an enantiomeric excess of 80%. The crystal structure of D170S/T457E, in complex with trifluoromethylphenol, showed a highly conserved mode of ligand binding and revealed that the distinctive catalytic properties of this mutant are not caused by major structural changes. Inversion of stereospecificity of vanillyl-alcohol oxidase.,van Den Heuvel RH, Fraaije MW, Ferrer M, Mattevi A, van Berkel WJ Proc Natl Acad Sci U S A. 2000 Aug 15;97(17):9455-60. PMID:10920192[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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