title: Substitution of a conserved catalytic dyad into 2-KPCC causes loss of carboxylation activity.
abstract: The characteristic His-Glu catalytic dyad of the disulfide oxidoreductase (DSOR) family of enzymes is replaced in 2-ketopropyl coenzyme M oxidoreductase/carboxylase (2-KPCC) by the residues Phe-His. 2-KPCC is the only known carboxylating member of the DSOR family and has replaced this dyad potentially to eliminate proton-donating groups at a key position in the active site. Substitution of the Phe-His by the canonical residues results in production of higher relative concentrations of acetone versus the natural product acetoacetate. The results indicate that these differences in 2-KPCC are key in discriminating between carbon dioxide and protons as attacking electrophiles.
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Prussia
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
authors.forename: George H
authors.initials: GH
authors.lastname: Gauss
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
authors.forename: Florence
authors.initials: F
authors.lastname: Mus
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
authors.forename: Leah
authors.initials: L
authors.lastname: Conner
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: DuBois
authors.affiliation: Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA.
authors.forename: John W
authors.initials: JW
authors.lastname: Peters
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry; D002384:Catalysis; D020134:Catalytic Domain; D004151:Dipeptides / Q000737:chemistry* / Q000378:metabolism; D007658:Ketone Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D011522:Protons; D013379:Substrate Specificity; D020584:Xanthobacter / Q000737:chemistry / Q000201:enzymology
chemical_list: D004151:Dipeptides; D011522:Protons; D002245:Carbon Dioxide; C022144:histidylphenylalanine; D007658:Ketone Oxidoreductases; C425603:2-KPCC
keywords: carboxylation; catalytic dyad; protonation