Genetic and biochemical manipulation of a broad-spectrum organophosphate degrading system. Final report
Recent studies on the plasmid-borne organophosphorus-degrading gene of Pseudomonas diminuta and its enzyme have sought to define both the genetic organization and the protein chemistry involved in this system. The bacterial gene encodes a single, unique enzyme, a phosphotriesterase (organophosphorus anhydrase), which is capable of hydrolyzing a wide spectrum of organophosphorus neurotoxins ranging from insecticides such a parathion, orthene, coumaphos and diazinon to mammalian neurotoxins such as diisopropylfluorophosphate (DFP), sarin, soman and mipafox. The organophosphorus degrading genes (opd) from two different plasmids in the soil bacteria P. diminuta and Flavobacterium have been sequenced andtheir structural organizations are being characterized. The cloned geneshave been expressed in a number of biological systems from bacteria to insect tissue culture, and the enzyme has been purified and characterized from several different sources. The catalytic reaction hasbeen determined to involve a stereospecific mechanism which proceeds by the direct nucleophilic attack of an activated water at the reaction center. The reaction rate approaches a diffusion limited catalysis at 2100/M/s and the enzyme is actively adsorbed to various column and particular matrices. This proposal will define the structure of the active site of the phosphotriesterase, evaluate its membrane signal sequence, and develop new genetic constructions to evaluate the heterologous expression/processing of the apoprotein.
- Research Organization:
- Texas A and M Univ., College Station, TX (United States). Research Foundation
- OSTI ID:
- 91497
- Report Number(s):
- AD-A-290426/6/XAB; CNN: Contract DAAL03-90-G-0045; TRN: 52261514
- Resource Relation:
- Other Information: PBD: Aug 1994
- Country of Publication:
- United States
- Language:
- English
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Genetic and biochemical manipulation of a broad-spectrum organophosphate degrading system. Final report