How a single-point mutation in horseradish peroxidase markedly enhances enantioselectivity.
The effect of all possible mutations at position 178 on the enantioselectivity of yeast surface-bound horseradish peroxidase (HRP) toward chiral phenols has been investigated. In contrast to their wild-type predecessor, most HRP mutants are enantioselective, with the Arg178Glu variant exhibiting the greatest, 25-fold, (S)/(R) preference. Using kinetic analysis of enzymatic oxidation of various substrate analogues and molecular modeling of enzyme-substrate complexes, this enantioselectivity enhancement is attributed to changes in the transition state energy due to electrostatic repulsion between the carboxylates of the enzyme's Glu178 and the substrate's (R)-enantiomer.
Antipov
Eugene
E
Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Cho
Art E
AE
Klibanov
Alexander M
AM
D006735:Horseradish Peroxidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D017354:Point Mutation; D055672:Static Electricity; D013237:Stereoisomerism; D013379:Substrate Specificity; D015003:Yeasts / Q000201:enzymology
D006735:Horseradish Peroxidase