Xyloglucan is one of the most abundant polysaccharides of hemicellulose, and is one of the components that is closely associated with cellulose microfibers, thereby contributing to the complex network of polysaccharides that defines the architecture of the plant cell wall. In addition, xyloglucan plays both structural and signalling functions and enzymes that modify it are important in plant biology. The study of carbohydrate active enzymes is essential for understanding the structure of the plant cell wall and for the elucidation of the mechanisms involved in the depolymerisation of plant biomass. Our laboratory is dedicated to understanding the enzymatic degradation of cell wall polysaccharides of plants and during the course of doctoral project "Rational design of multifunctional enzymes for depolymerization of lignocellulosic material" (FAPESP 2012 / 24147-8), we have observed a synergistic effect between a ²-galactosidase (YesZ from B. subtilis) and an ±-xylosidase (YicI from E. coli) against xyloglucan oligosaccharides derived from Jatobá (Hymenaea courbaril), which resulted in the production of an unknown oligosaccharide as a hydrolysis product. We also observed that YesZ is capable of reacting with pNPGal in the presence of xylose and releases a transgalactosylation product of xylose and galactose, and we have assumed that this new oligosaccharide may be the result of transgalactosylation. Here we propose to characterize the composition and structure of the oligosaccharide used as substrate by YesZ and that produced as a consequence of the proposed trans ²-galactosidase activity. For this we intend to employ analytical techniques, including PACE (Polysaccharide Analysis by gel Carbohydrate Electrophoresis) and NMR (Nuclear Magnetic Resonance).
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