Organophosphate and organophosphonate esters are among the most toxic compounds that have ever been synthesized. These compounds are toxic because of their inherent ability to interfere with nerve transmission through the rapid and irreversible inactivation of the enzyme acetyl cholinesterase. The toxic properties of the organophosphates have been exploited as agricultural insecticides and as chemical weapons. A bacterial phosphotriesterase enzyme has been identified that can function as a catalyst for the recognition, hydrolysis, and detoxification of a broad spectrum of organophosphate nerve agents. The primary objective of this application is to design and characterize modified forms of the bacterial phosphotriesterase that are optimized for the selective recognition and destruction of those organophosphates that pose the most serious threats to human health. Rational and combinatorial libraries of mutant enzymes will be constructed and those variants with enhanced catalytic proficiency will be identified through novel screening and selection procedures. The progressive changes in the amino acid sequence of the bacterial phosphotriesterase will be directly correlated with the enhancements in the catalytic constants and the modifications within the active site as determined by X-ray diffraction methods.

Public Health Relevance

The toxic properties of the organophosphate nerve agents represent a serious threat to the health and well being of civilized societies. The primary objective of this project is to create novel catalytic enzymes that are optimized in their ability to detect, destroy and detoxify a broad spectrum of organophosphate nerve agents. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
2R01GM068550-05
Application #
7373200
Study Section
Macromolecular Structure and Function E Study Section (MSFE)
Program Officer
Ikeda, Richard A
Project Start
2003-07-01
Project End
2012-06-30
Budget Start
2008-07-17
Budget End
2009-06-30
Support Year
5
Fiscal Year
2008
Total Cost
$302,007
Indirect Cost
Name
Texas A&M University
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
078592789
City
College Station
State
TX
Country
United States
Zip Code
77845
Bigley, Andrew N; Xu, Chengfu; Henderson, Terry J et al. (2013) Enzymatic neutralization of the chemical warfare agent VX: evolution of phosphotriesterase for phosphorothiolate hydrolysis. J Am Chem Soc 135:10426-32
Meier, Monika M; Rajendran, Chitra; Malisi, Christoph et al. (2013) Molecular engineering of organophosphate hydrolysis activity from a weak promiscuous lactonase template. J Am Chem Soc 135:11670-7
Bigley, Andrew N; Raushel, Frank M (2013) Catalytic mechanisms for phosphotriesterases. Biochim Biophys Acta 1834:443-53
Tsai, Ping-Chuan; Fox, Nicholas; Bigley, Andrew N et al. (2012) Enzymes for the homeland defense: optimizing phosphotriesterase for the hydrolysis of organophosphate nerve agents. Biochemistry 51:6463-75
Tsai, Ping-Chuan; Fan, Yubo; Kim, Jungwook et al. (2010) Structural determinants for the stereoselective hydrolysis of chiral substrates by phosphotriesterase. Biochemistry 49:7988-97
Tsai, Ping-Chuan; Bigley, Andrew; Li, Yingchun et al. (2010) Stereoselective hydrolysis of organophosphate nerve agents by the bacterial phosphotriesterase. Biochemistry 49:7978-87
Kim, Jungwook; Tsai, Ping-Chuan; Chen, Shi-Lu et al. (2008) Structure of diethyl phosphate bound to the binuclear metal center of phosphotriesterase. Biochemistry 47:9497-504
Li, Yingchun; Raushel, Frank M (2007) Differentiation of chiral phosphorus enantiomers by P and H NMR spectroscopy using amino acid derivatives as chemical solvating agents. Tetrahedron Asymmetry 18:1391-1397
Ghanem, Eman; Li, Yingchun; Xu, Chengfu et al. (2007) Characterization of a phosphodiesterase capable of hydrolyzing EA 2192, the most toxic degradation product of the nerve agent VX. Biochemistry 46:9032-40
Samples, Cynthia R; Raushel, Frank M; DeRose, Victoria J (2007) Activation of the binuclear metal center through formation of phosphotriesterase-inhibitor complexes. Biochemistry 46:3435-42

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