2^nd Glycobiology World Congress

Biography

Biography: Manuel Maestre Reyna

Abstract

Vibrio cholerae, the causative agent of cholera, is a gram negative bacterium, which may swim freely, or grow in sessile biofilms associated with abiotic surfaces, zoo-plankton, mollusks, or crustaceans in estuarine and brackish waters. Vibrio cholerae biofilms are involved in many aspects of the pathogen's life-cycle, constituting a possible source of antibiotic resistances, and being very important for intestinal colonization. Particularly during exopolysaccharide- dependent biofilm formation, secreted proteins of the rbm gene cluster, including RbmA, RbmC, and Bap1 are key to biofilm ultrastructure, along with the vibrio polysaccharide (VPS) itself. While RbmC and Bap1 have been linked to biofilm-surface interactions , RbmA surrounds cells within the biofilm, which results in improved mechanical strength, and better biofilm accumulation by a not very well understood mechanism, but possibly involving glycan binding. Furthermore, RbmA has been linked to micro-colony formation during V. cholerae pathogenesis, significantly enhancing the infectivity of the pathogen. Here, we elucidated the RbmA crystal structure, as well as demonstrating glycan binding activity. Furthermore, we observed two distinct proteolytic pathways for RbmA. In the first one, protease mediated post-translational modification yielded a different RbmA isoform, RbmA*, involved in VPS independent cell recruitment. The second pathway, which is phosphate and magnesium dependent, possibly leads to RbmA inactivation, and may be involved in biofilm dispersal.