University of St. Thomas
2115 Summit Avenue
St. Paul, MN 55105
Speaker: Dr. Frank Rauschel - Texas A&M University
Date & Time:
12:00 PM - 1:30 PM
UST Alum Dr. Frank Rauschel will present his current research:
"Evolution of Enzymes for the Homeland Defense: Catalytic Hydrolysis of Organophosphate Nerve Agents"
The phosphotriesterase (PTE) enzyme, originally isolated from Pseudomonas diminuta, is capable of catalyzing the hydrolysis and detoxification of organophosphate nerve agents. At saturating substrate concentrations the turnover number for the enzymatic hydrolysis of the insecticide paraoxon (diethyl p-nitrophenyl phosphate) by this enzyme is ~10,000 s-1. Compounds such as paraoxon are highly toxic because they rapidly inactivate the enzyme acetyl cholinesterase. The extreme toxicity and persistence of the G-type (sarin and soman) V-type (VX and VR) chemical warfare agents makes the detoxification and decontamination of these compounds of significant interest. The wild-type bacterial PTE is also capable of hydrolyzing sarin, soman, and VX but at rates significantly lower than the hydrolysis of paraoxon. In this seminar the catalytic reaction mechanism and the three-dimensional structure of the bacterial PTE will be presented. This information will be then be utilized to develop a rational and random mutagenesis strategy for the directed evolution of mutant forms of PTE that are optimized for the catalytic destruction and detoxification of the organophosphate nerve agents GB (sarin), GD (soman) and VX.