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STRUCTURE OF THE H61T MUTANT OF THE FLAVOENZYME VANILLYL-ALCOHOL OXIDASE IN THE APO FORM
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 member of a newly recognized flavoprotein family of structurally related oxidoreductases. The enzyme contains a covalently linked FAD cofactor. To study the mechanism of flavinylation we have created a design point mutation (His-61 --> Thr). In the mutant enzyme the covalent His-C8alpha-flavin linkage is not formed, while the enzyme is still able to bind FAD and perform catalysis. The H61T mutant displays a similar affinity for FAD and ADP (K(d) = 1.8 and 2.1 microm, respectively) but does not interact with FMN. H61T is about 10-fold less active with 4-(methoxymethyl)phenol) (k(cat) = 0.24 s(-)(1), K(m) = 40 microm) than the wild-type enzyme. The crystal structures of both the holo and apo form of H61T are highly similar to the structure of wild-type VAO, indicating that binding of FAD to the apoprotein does not require major structural rearrangements. These results show that covalent flavinylation is an autocatalytical process in which His-61 plays a crucial role by activating His-422. Furthermore, our studies clearly demonstrate that in VAO, the FAD binds via a typical lock-and-key approach to a preorganized binding site. Structural analysis of flavinylation in vanillyl-alcohol oxidase.,Fraaije MW, van Den Heuvel RH, van Berkel WJ, Mattevi A J Biol Chem. 2000 Dec 8;275(49):38654-8. PMID:10984479[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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