An OPAA enzyme mutant with increased catalytic efficiency on the nerve agents sarin, soman, and GP

• Published in: Enzyme and microbial technology Vol. 112; pp. 65 - 71
• Main Authors: Bae, Sue Y., Myslinski, James M., McMahon, Leslie R., Height, Jude J., Bigley, Andrew N., Raushel, Frank M., Harvey, Steven P.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2018
• Subjects: Amino Acid Sequence; Amino Acid Substitution; Aryldialkylphosphatase - genetics; Aryldialkylphosphatase - metabolism; Biocatalysis; Kinetics; LC-APCI-MS; Mutagenesis; Mutagenesis, Site-Directed; Nerve Agents - metabolism; OPAA; Organophosphorus Compounds - metabolism; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Sarin; Sarin - metabolism; Soman; Soman - metabolism; Stereoisomerism; Substrate Specificity; GP; Soman; OPAA; Mutagenesis; Sarin; LC-APCI-MS
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/j.enzmictec.2017.11.001

•OPAA FL mutant has increased activity on several organophosphate nerve agents.•OPAA FL has GP activity comparable to soman activity.•Sarin enantiomers identified by stereospecific catalysis by two different enzymes.•Separation of sarin enantiomers by normal phase chiral LC column with APCI-MS. The wild-type OPAA enzyme has relatively high levels of catalytic activity against several organophosphate G-type nerve agents. A series of mutants containing replacement amino acids at the OPAA Y212, V342, and I215 sites showed several fold enhanced catalytic efficiency on sarin, soman, and GP. One mutant, Y212F/V342L, showed enhanced stereospecificity on sarin and that enzyme along with a phosphotriesterase mutant, GWT, which had the opposite stereospecificity, were used to generate enriched preparations of each sarin enantiomer. Inhibition of acetylcholinesterase by the respective enantioenriched sarin solutions subsequently provided identification of the sarin enantiomers as separated by normal phase enantioselective liquid chromatography coupled with atmospheric pressure chemical ionization–mass spectrometry.