Final Report: Structural Analysis and Bioengineering of Thermostable Pyrococcus furiosus Prolidase for the Optimization of Organophosphorus Nerve Agent Detoxification

The aims of this project were to structurally study and bioengineer thermostable prolidases from Pyrococcus furiosus (Pf) and horikoshii (Ph) to enable their use for oganophosphorus nerve agent detoxification. Pf prolidase contains one dinuclear Co metal-center/monomer and has optimal activity at 100?C, exhibiting no activity without Co2+ or at temperatures <50?C. Requirement for metal ions is characteristic of all organophosphorus nerve agent hydrolases and results from these enzymes containing dinuclear metal-centers with one tight-binding metal atom and a second loose-binding metal atom. Our understanding of the metal cluster structures was used in this project to design a prolidase mutant with two integral metal sites, which will relieve the requirement for exogenous metal and improve its efficacy in OP nerve agent detoxification. In addition, a Ph prolidase homolog has been identified and has been biochemically characterized to determine its potential utility in OP nerve agent decontamination. Another objective was to produce Pf and Ph prolidase mutants that have increased catalytic activity over temperatures ranging from 20-60?C to increase their use for decontamination of OP nerve agents in the field. To this end, a random mutation and low-temperature selection method was successfully used. (a) Papers published in peer-reviewed journals (N/A for none) Enter List of papers submitted or published that acknowledge ARO support from the start of the project to the date of this printing. List the papers, including journal references, in the following categories: