Modifications-Ghs-Hydrolysis-Transglycosylation-Activity-Enzymes-y

The clear insight of the roles of each amino acid in these sites provides a platform for designing an enzyme that could synthesize a specific oligosaccharide CONCLUSIONS The key strategies presented here are important for future improvement of GHs as a biocatalyst for oligosaccharide synthesis.Enhancing the chemoenzymatic synthesis of arabinosylated xylo-oligosaccharides Arab-Jaziri F(1), Bissaro B(2), Tellier C(3), Dion M(3), Fauré R(2), O'Donohue Toulouse, France; INRA, UMR792, Ingénierie des Systèmes Biologiques et des Procédés, F-310 Toulouse, France; CNRS, UMR54, F-310 Toulouse, France; Agence de l'environnement et de la Maîtrise de l'Energie, Avenue du Grésillé-BP 6, 404 Angers Cedex1, France.Toulouse, France; INRA, UMR792, Ingénierie des Systèmes Biologiques et des Procédés, F-310 Toulouse, France; CNRS, UMR54, F-310 Toulouse, France.Nantes, 2 rue de la Houssinière, F-44322 Nantes, France.Toulouse, France; INRA, UMR792, Ingénierie des Systèmes Biologiques et des Procédés, F-310 Toulouse, France; CNRS, UMR54, F-310 Toulouse, France. Random mutagenesis was performed on the α-l-arabinofuranosidase of Thermobacillus xylanilyticus in order to enhance its ability to perform transarabinofuranosylation using natural xylo-oligosaccharides as acceptors.

To achieve this goal, a two-step, high-throughput digital imaging protocol involving a colorimetric substrate was used to screen a library of mutants. In the first step this screen selected for hydrolytically-impaired mutants, and in the second step the screen identified mutants whose global activity was improved in the presence of a xylo-oligosaccharide mixture. Thereby, 199 mutants displaying lowered hydrolytic activity and modified properties were detected. In the presence of these xylo-oligosaccharides, most of the 199 (i.e., %) enzymes were less inhibited and some (18) mutants displayed an unambiguous alleviation of inhibition (25% loss of activity). Seebio 2'-FL of reactions catalyzed by the most promising mutants revealed a significant improvement of the synthesis yields of transglycosylation products the reaction.

Genetic analysis of improved mutants revealed that many of the amino acid substitutions that correlate with the modified phenotype are located in the vicinity of the active site, particularly in subsite -1. Consequently, Seebio 2'-Fucose lactose hypothesize that these mutations modify the active site topology or the molecular interaction network of the l-arabinofuranoside donor substrate, thus impairing the hydrolysis and concomitantly favoring transglycosylation onto Identification and structural analysis of synthetic oligosaccharides of Shigella MALDI-TOF mass spectroscopy was used for the molecular weight determination of protected synthetic oligosaccharides related to a cell surface bacterial polysaccharide. By-products containing chlorinated protecting groups caused isotopic patterns characteristic of the natural isotopic distribution of chlorine, were identified on the basis of isotopic distribution. 2,4,6-Trihydroxyacetophenone (THAP) as a matrix was better than 2,5-dihydroxybenzoic acid (DHB) for compounds containing chlorine, since monoisotopic resolution and no fragmentation were observed. In the post source decay (PSD) mode the identification of the oligosaccharide sequence through cleavage of the interglycosidic linkages was also possible, thus providing a sensitive and accurate tool for the structural verification of synthetic The potential for oligosaccharide production from the hemicellulose fraction of biomasses through pretreatment processes xylooligosaccharides (XOS), arabinooligosaccharides (AOS), and mannooligosaccharides (MOS).Hemicellulosic oligosaccharides are sugar molecules that contain xylose, mannose, and arabinose in variable concentrations ranging from 3 to molecules. These medium and long chain sugars can be classified as non-digestible carbohydrates, thus playing an important role in gastrointestinal health as prebiotics.

Their physiological benefits, primarily stimulation of the proliferation of lactic acid bacteria and bifidobacteria in the colon informs their significance as high value nutraceuticals in the food and pharmaceutical industry. In addition they are well known as useful components of important pharmaceutical products. There are two main ways of producing these sugars from biomass, which include enzymatic and non-enzymatic pretreatments. Each of the two processes has advantages and disadvantages. Enzymatic processes are associated with high costs, higher concentration of monomeric sugars, and low oligosaccharide yields while thermo-chemical processes are usually associated with undesirable byproducts such as furfural and lower oligosaccharide yields.