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Archaea
Volume 2011, Article ID 565127, 9 pages
http://dx.doi.org/10.1155/2011/565127
Research Article

Improving the Catalytic Activity of Hyperthermophilic Pyrococcus horikoshii Prolidase for Detoxification of Organophosphorus Nerve Agents over a Broad Range of Temperatures

1Division of Infectious Diseases, Department of Internal Medicine, The University of Michigan, Ann Arbor, MI 48109, USA
2Department of Microbiology, North Carolina State University, Campus Box 7615, Raleigh, NC 27695-7615, USA
3Biochemistry Branch, US Army Edgewood Chemical Biological Center, E3150 North Kingscreek Road, Aberdeen Proving Ground, Aberdeen, MD 21010-5183, USA

Received 14 June 2011; Accepted 1 September 2011

Academic Editor: Jerry Eichler

Copyright © 2011 Casey M. Theriot et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Prolidases hydrolyze Xaa-Pro dipeptides and can also cleave the P-F and P-O bonds found in organophosphorus (OP) compounds, including the nerve agents soman and sarin. Ph1prol (PH0974) has previously been isolated and characterized from Pyrococcus horikoshii and was shown to have higher catalytic activity over a broader pH range, higher affinity for metal, and increased thermostability compared to P. furiosus prolidase, Pfprol (PF1343). To obtain a better enzyme for OP nerve agent decontamination and to investigate the structural factors that may influence protein thermostability and thermoactivity, randomly mutated Ph1prol enzymes were prepared. Four Ph1prol mutants (A195T/G306S-, Y301C/K342N-, E127G/E252D-, and E36V-Ph1prol) were isolated which had greater thermostability and improved activity over a broader range of temperatures against Xaa-Pro dipeptides and OP nerve agents compared to wild type Pyrococcus prolidases.