HYDROLYSIS OF POLYPHOSPHATES IN PSEUDOMONAS AERUGINOSA PAO1: MORE THAN ONE ENZYME RESPONSIBLE

VICARIO, JC; GALLARATO, LA; SERRA, AL; BEASSONI, PR; GARRIDO, MN

Huerta Grande, Cordoba

Congreso; XVII Jornadas de la Sociedad de Biología de Córdoba; 2009

Sociedad de Biologia de Cuyo

In bacteria, inorganic polyphosphates (PPs) are involved in various physiological functions and in virulence of pathogens organisms such as P. aeruginosa. In our laboratory we are studding the P. aeruginosa PAO1 exopolyphosphatase (PPX) encoded by the gene PA5241. The aim of this study was to obtain a mutant strain unable to express the ppx  gene to investigate the possible existence of more than activity responsible for the hydrolysis of PPs. A deletional mutant strain was constructed according to Choi and Schweizer (Microbiol. 2005, 5: 1-11). Hydrolysis of PPs was measured by Pi release from substrates PP10, PP25 and PP65. The measurement of PPX activity in cytoplasmic extracts from stationary phase cells showed a specific activity decrease of only 30-35% for the mutant strain compared with that of the wild type (WT). Isoelectric focusing studies performed with extracts of WT and mutant strain showed three and two PPX activity areas respectively. The missing zone corresponded with PPX (pI 6.25). Enzymatic activities differing from PPX showed pI of approximately 7.1 and 5.2. Bioinformatics background suggests that the last protein could correspond to the survival protein SurE (PA3625)