Electrostatic interactions dominate the catalytic contribution of arg39 in 4-oxalocrotonate tautomerase.
The synthesis and kinetic parameters of a comprehensive set of 4-OT analogues with arginine (X = NH2+) to citrulline (X = O) substitutions at positions 11, 39, and 61 are reported. These data suggest that the main contribution of Arg39' ' to catalysis is by electrostatic stabilization of the anionic transition state leading to intermediate 2, and not by hydrogen bonding.
Department of Chemistry and Institute of Catalysis Science and Technology, Technion-Israel Institute of Technology, Technion City, Haifa 32000 Israel.
Norman
N
Metanis
Ashraf
A
Brik
Philip E
PE
Dawson
Ehud
E
Keinan
D019943:Amino Acid Substitution; D001120:Arginine / Q000737:chemistry* / Q000378:metabolism*; D002384:Catalysis; D002942:Circular Dichroism; D002956:Citrulline / Q000737:chemistry / Q000378:metabolism; D007535:Isomerases / Q000737:chemistry* / Q000378:metabolism*; D007700:Kinetics; D017510:Protein Folding; D055672:Static Electricity
D002956:Citrulline; D001120:Arginine; C021918:4-oxalocrotonate tautomerase; D007535:Isomerases