CHARACTERIZATION OF AN ACYL-COA CARBOXYLASE COMPLEX FROM Xanthomonas

TOMASSETTI, M.; BETIANA S. GARAVAGLIA; GOTTIG, N.; JORGELINA OTTADO; GRAMAJO, H.; DIACOVICH, L.

Congreso; L Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2014

Phytopatogen Xanthomonas axonopodis pv. citri (Xac) produce canker, pathology that affects citric. Xac, as anobliged plant parasite, is unable to survive out of its host for long periods of time. Nevertheless, during the epiphyticsurvival state, over the leaf, many metabolic and nutritional aspects remain unknown. Branched-chain amino acidcatabolism prevents their over-accumulation, facilitates branched-chain fatty acids biosynthesis and provides energyfor the cell. The enzymatic complex 3-methyl-crotonyl-CoA carboxylase (MCC) is essential for leucine degradationpathway. MCC carboxylates its substrate, 3-methyl-crotonyl, to finally generate acetyl-CoA and acetoacetate whichare latter incorporated into different metabolic pathways in case of nutritional stress or amino acid excess. MCC complexes belong to the biotin-dependent acyl-CoA carboxylases (ACCases) group. We identified by bioinformaticstwo genes that may encode subunits of an ACCase complex in Xanthomonas, and others gram negative bacterialpathogens. The amino acidic sequences of these subunits present a high level of similarity to proteins of previouslycharacterized MCC complexes from human and Pseudomonas aeruginosa. In this project we purified the MCCsubunits and performed enzymatic activity assays using different acyl-CoAs as substrate. Now we propose to analyzethe role of this complex in bacterial virulence.