title: Branching pattern of gluco-oligosaccharides and 1.5kDa dextran grafted by the α-1,2 branching sucrase GBD-CD2.
abstract: GBD-CD2, an engineered sucrose-acting enzyme of glycoside hydrolase family 70, transfers D-glucopyranosyl (D-Glcp) units from sucrose onto dextrans or gluco-oligosaccharides (GOS) through the formation of α-(1→2) linkages leading to branched products of interest for health, food and cosmetic applications. Structural characterization of the branched products obtained from sucrose and pure GOS of degree of polymerization (DP) 4 or DP 5 revealed that highly α-(1→2) branched and new molecular structures can be synthesized by GBD-CD2. The formation of α-(1→2) branching is kinetically controlled and can occur onto vicinal α-(1→6)-linked D-Glcp residues. To investigate the mode of branching of 1.5 kDa dextran, simulations of various branching scenarios and resistance to glucoamylase degradation were performed. Analysis of the simulation results suggests that the branching process is stochastic and indicates that the enzyme acceptor site can accommodate both linear and poly-branched acceptors. This opens the way to the design of novel enzyme-based processes yielding carbohydrate structures varying in size and resistance to hydrolytic enzymes.
authors.affiliation: Université de Toulouse; INSA, UPS, INP; LISBP, 135 Avenue de Rangueil, F-31077 Toulouse, France.
authors.forename: Yoann
authors.initials: Y
authors.lastname: Brison
authors.forename: Sandrine
authors.initials: S
authors.lastname: Laguerre
authors.forename: François
authors.initials: F
authors.lastname: Lefoulon
authors.forename: Sandrine
authors.initials: S
authors.lastname: Morel
authors.forename: Nelly
authors.initials: N
authors.lastname: Monties
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Potocki-Véronèse
authors.forename: Pierre
authors.initials: P
authors.lastname: Monsan
authors.forename: Magali
authors.initials: M
authors.lastname: Remaud-Simeon
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000737:chemistry*; D055162:Biocatalysis; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002852:Chromatography, Ion Exchange; D003911:Dextrans / Q000737:chemistry*; D005964:Glucosyltransferases / Q000096:biosynthesis / Q000737:chemistry*; D006031:Glycosylation; D006868:Hydrolysis; D008969:Molecular Sequence Data; D025942:Oligosaccharides, Branched-Chain / Q000138:chemical synthesis* / Q000737:chemistry / Q000302:isolation & purification; D021241:Spectrometry, Mass, Electrospray Ionization; D013395:Sucrose / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D003911:Dextrans; D025942:Oligosaccharides, Branched-Chain; D013395:Sucrose; D005964:Glucosyltransferases; C020025:dextransucrase