Structural and functional studies of PelF, a glycosyl transferase responsible for extracellular matrix production in biofilms from Pseudomonas aeruginosa and Xanthomonas axonopodis

Abstract

A new cellular lifestyle is becoming more popular in the scientific world - biofilms. The biofilm is characterized as a cellular community adhered to a substrate and surrounded by a matrix of polysaccharides. By presenting greater resistance to antibiotics, cells in the biofilm state are generating many medical problems. The human pathogen Pseudomonas aeruginosa has been widely studied for its ease of colonization in different environments. This organism is able to synthesize three different types of extracellular polysaccharides: alginate, Pel and Pls. The production of the exopolysaccharidic matrix (EPS) relies on the regulation of intracellular levels of c-di-GMP, the main messenger of biofilm formation) Among the polysaccharides that make up the EPS, Pel is the only with unknown molecular structure. Seven proteins that are part of the operon Pel are necessary to its synthesis, called PelA-G. However, the molecular mechanism underling Pel production is poorly understood. Based on computational analyzes and predictions, as well as comparisons with other similar operons, a model of molecular arrangement of proteins in the Pel operon was proposed, although some proteins do not have a clearly defined function. In this context, the proposed work aims to study and characterization the intracellular enzyme glycosyl transferase PelF, as well as their mode of action and possible interaction with the intracellular domain of the regulatory protein of polysaccharide production, PelD.