title: How a single-point mutation in horseradish peroxidase markedly enhances enantioselectivity.
abstract: 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.
authors.affiliation: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Eugene
authors.initials: E
authors.lastname: Antipov
authors.forename: Art E
authors.initials: AE
authors.lastname: Cho
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Klibanov
mesh_terms: 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
chemical_list: D006735:Horseradish Peroxidase