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item Richards, Gary

Submitted to: Biochimica et Biophysica Acta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/23/2004
Publication Date: 4/15/2005
Citation: Richards, G.P., Parveen, S.A. 2005. A survey for phosphoglucose isomerase with lysyl aminopeptidase activity in vibrionaceae and non-vibrio pathogens. Biochimica et Biophysica Acta. 1748:128-133.

Interpretive Summary: Previously, we identified a novel enzyme activity in Vibrio bacteria and determined a possible mechanism by which this enzyme may foster the spread of vibrios in infected individuals. Since a variety of Vibrio species cause disease in humans and fish, a survey was conducted to determine the prevalence of this enzyme in other members of the Vibrio family and in non-Vibrio human pathogens. This enzyme, known as phosphoglucose isomerase with a lysyl aminopeptidase activity (PGI-LysAP), was identified in chemically-purified cultures of all members from the Vibrio family. No activity was detected in the non-vibrios including Salmonella, Shigella and E. coli. Nutritionally rich culture media produced high levels of PGI-LysAP, suggesting that these bacteria, once in nutrient-rich tissues may produce more enzyme to enhance the invasiveness of vibrios in humans, fish, and other hosts. Our findings may lead to the development of improved methods to identify vibrios in food, water, and clinical settings.

Technical Abstract: Phosphoglucose isomerase (PGI) with a novel lysyl aminopeptidase (LysAP) activity was recently purified and characterized from Vibrio vulnificus. We showed that it cleaves the amino-terminal lysyl residue from des-Arg10-kallidin to produce des-Arg9-bradykinin, suggesting it plays a role in virulence. A survey was conducted to determine the presence of this potential virulence-enhancing enzyme among twenty-three halotolerant human and fish pathogens from eleven species within the Vibrionaceae family, including V. vulnificus, V. parahaemolyticus, V. cholerae, Aeromonas hydrophila, and Plesiomonas shigelloides. In addition, fourteen species of non-Vibrionaceae pathogens were screened for LysAP activity. Cell lysates were partially purified by anion exchange chromatography and fractions were screened for LysAP and isomerase activities. PGI-LysAP activity was detected in chromatographic fractions from all the Vibrionaceae, but was not detected in any of the non-Vibrionaceae pathogens. Levels of isomerase and LysAP activity correlated (R2 = 0.92) for nine strains of V. vulnificus. Since the Vibrionaceae represent an important family of human and fish pathogens, our identification of PGI-LysAP activity in a broad array of Vibrionaceae may lead to the development of improved analytical methods for their identification as well as interventions to reduce the high morbidity and mortality associated with some Vibrionaceae infections in clinical, veterinary, and aquaculture settings.