Substitution of a conserved catalytic dyad into 2-KPCC causes loss of carboxylation activity
- Prussia, Gregory A [ Montana State University: Chemistry & Biochemistry ]
- Gauss, George H [ Montana State University: Chemistry & Biochemistry ]
- Mus, Florence [ Montana State University: Chemistry & Biochemistry ]
- Conner, Leah [ Montana State University: Chemistry & Biochemistry ]
- DuBois, Jennifer L [ Montana State University: Chemistry & Biochemistry ]
- Peters, John W [ Montana State University: Chemistry & Biochemistry ]
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 to discriminating between carbon dioxide and protons as attacking electrophiles.