Proline dipeptidase from Pyrococcus furiosus

Abstract

Prolyl residues are unique among the 20 common amino acid residues in that they confer a conformational constraint on peptide chains due to the cyclic nature of their pyrrolidine side group. This conformational constraint prevents cleavage of bonds adjacent to proline by most proteases; however, several enzymes have been characterized that are capable of hydrolyzing these bonds. Prolidases have been isolated from mammalian, bacterial ( Lactobacillus and Xanthomonas ), and archaeal (pyrococcus) sources and appear to be ubiquitous in nature. Although the physiological role of the enzyme is unclear in both bacteria and archaea, its absence in humans results in abnormalities of the skin and other collagenous tissues. Prolidases have several potential biotechnological applications. One possible use is in the dairy industry as a cheese-ripening agent, as removal of proline from proline-containing peptides in cheese reduces bitterness. A second application is as an enzyme to degrade organophosphorus acidcontaining compounds present in a number of chemical warfare agents and pesticides. The organophosphorus acid-hydrolyzing capabilities of prolidase have been suggested by the discovery that the protein characterized as an organophosphorus acid anhydrolase (OPAA) and prolidase are one in the same.