title: Structure determination and characterization of the vitamin B6 degradative enzyme (E)-2-(acetamidomethylene)succinate hydrolase.
abstract: The gene identification and kinetic characterization of (E)-2-(acetamidomethylene)succinate (E-2AMS) hydrolase has recently been described. This enzyme catalyzes the final reaction in the degradation of vitamin B(6) and produces succinic semialdehyde, acetate, ammonia, and carbon dioxide from E-2AMS. The structure of E-2AMS hydrolase was determined to 2.3 A using SAD phasing. E-2AMS hydrolase is a member of the alpha/beta hydrolase superfamily and utilizes a serine/histidine/aspartic acid catalytic triad. Mutation of either the nucleophilic serine or the aspartate resulted in inactive enzyme. Mutation of an additional serine residue in the active site causes the enzyme to be unstable and is likely structurally important. The structure also provides insight into the mechanism of hydrolysis of E-2AMS and identifies several potential catalytically important residues.
authors.affiliation: Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: McCulloch
authors.forename: Tathagata
authors.initials: T
authors.lastname: Mukherjee
authors.forename: Tadhg P
authors.initials: TP
authors.lastname: Begley
authors.forename: Steven E
authors.initials: SE
authors.lastname: Ealick
mesh_terms: D020561:Alphaproteobacteria / Q000201:enzymology*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D002384:Catalysis; D020134:Catalytic Domain; D004795:Enzyme Stability; D006867:Hydrolases / Q000737:chemistry* / Q000378:metabolism*; D006868:Hydrolysis; D008969:Molecular Sequence Data; D005810:Multigene Family; D011485:Protein Binding; D013379:Substrate Specificity; D025101:Vitamin B 6 / Q000737:chemistry / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D005680:gamma-Aminobutyric Acid; D025101:Vitamin B 6; C530614:2-(acetamidomethylene)succinate hydrolase, Mesorhizobium loti; D006867:Hydrolases; C009338:succinic semialdehyde