title: Evolved stereoselective hydrolases for broad-spectrum G-type nerve agent detoxification.
abstract: A preferred strategy for preventing nerve agents intoxication is catalytic scavenging by enzymes that hydrolyze them before they reach their targets. Using directed evolution, we simultaneously enhanced the activity of a previously described serum paraoxonase 1 (PON1) variant for hydrolysis of the toxic S(P) isomers of the most threatening G-type nerve agents. The evolved variants show ≤340-fold increased rates and catalytic efficiencies of 0.2-5 × 10(7) M(-1) min(-1). Our selection for prevention of acetylcholinesterase inhibition also resulted in the complete reversion of PON1's stereospecificity, from an enantiomeric ratio (E) < 6.3 × 10(-4) in favor of the R(P) isomer of a cyclosarin analog in wild-type PON1, to E > 2,500 for the S(P) isomer in an evolved variant. Given their ability to hydrolyze G-agents, these evolved variants may serve as broad-range G-agent prophylactics.
authors.affiliation: Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Moshe
authors.initials: M
authors.lastname: Goldsmith
authors.forename: Yacov
authors.initials: Y
authors.lastname: Ashani
authors.forename: Yair
authors.initials: Y
authors.lastname: Simo
authors.forename: Moshe
authors.initials: M
authors.lastname: Ben-David
authors.forename: Haim
authors.initials: H
authors.lastname: Leader
authors.forename: Israel
authors.initials: I
authors.lastname: Silman
authors.forename: Joel L
authors.initials: JL
authors.lastname: Sussman
authors.forename: Dan S
authors.initials: DS
authors.lastname: Tawfik
mesh_terms: D043303:Aryldialkylphosphatase / Q000235:genetics / Q000378:metabolism*; D055162:Biocatalysis; D001711:Biotransformation; D002619:Chemical Warfare Agents / Q000378:metabolism* / Q000633:toxicity; D006801:Humans; D006868:Hydrolysis; D009154:Mutation; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D002619:Chemical Warfare Agents; D043303:Aryldialkylphosphatase