25218-29-5Relevant academic research and scientific papers
Bioengineering of Leuconostoc mesenteroides glucansucrases that gives selected bond formation for glucan synthesis and/or acceptor-product synthesis
Kang, Hee Kyoung,Kimura, Atsuo,Kim, Doman
experimental part, p. 4148 - 4155 (2011/10/30)
The variations in glucosidic linkage specificity observed in products of different glucansucrases appear to be based on relatively small differences in amino acid sequences in their sugar-binding acceptor subsites. Various amino acid mutations near active sites of DSRBCB4 dextransucrase from Leuconostoc mesenteroides B-1299CB4 were constructed. A triple amino acid mutation (S642N/E643N/V644S) immediately next to the catalytic D641 (putative transition state stabilizing residue) converted DSRBCB4 enzyme from the synthesis of mainly α-(1→6) dextran to the synthesis of α-(1→6) glucan containing branches of α-(1→3) and α-(1→4) glucosidic linkages. The subsequent introduction of mutation V532P/V535I, located next to the catalytic D530 (nucleophile), resulted in the synthesis of an α-glucan containing increased branched α-(1→4) glucosidic linkages (approximately 11%). The results indicate that mutagenesis can guide glucansucrase toward the synthesis of various oligosaccharides or novel polysaccharides with completely altered linkages without compromising high transglycosylation activity and efficiency.
CHARCTERISATION OF THE OLIGOSACCHARIDES PRODUCED ON HYDROLYSIS OF GALACTOMANNAN WITH β-D-MANNANASE
McCleary, Barry V.,Nurthen, Elizabeth,Taravel, Francois R.,Joseleau, Jean-Paul
, p. 91 - 110 (2007/10/02)
Treatment of hot-water-soluble carob galactomannan with β-D-mannanases from A. niger or lucerne seed affords an array of D-galactose-containing β-D-mannosaccharides as well as β-D-manno-biose, -triose, and tetraose (lucerne-seed enzyme only).The D-galactose-containing β-D-mannosaccharides of d.p. 3-9 produced by A. niger β-D-mannanase have been characterised, using enzymic, n.m.r., and chemical techniques, as 61-α-D-galactosyl-β-D-mannobiose, 61-α-D-galactosyl-β-D-mannotriose, 63,64-di-α-D-galactosyl-β-D-mannopentaose (the only heptasaccharide), and 63,64-di-α-D-galactosyl-β-D-mannohexaose, 64,65-di-α-D-galactosyl-β-D-mannohexaose, and 61,63,64-tri-α-D-galactosyl-β-D-mannopentaose (the only octasaccharides).Four nonasaccharides have also been characterised.Penta- and hexa-saccharides were absent.Lucerne-seed β-D-mannanase produced the same branched tri-, tetra- and hepta-saccharides, and also penta- and hexa-saccharides that were characterised as 61-α-D-galactosyl-β-D-mannotetraose, 63-α-D-galactosyl-β-D-mannotetraose, 61,63-di-α-D-galactosyl-β-D-mannotetraose, 63-α-D-galactosyl-β-D-mannopentaose, and 64-α-D-galactosyl-β-D-mannopentaose.None of the oligosaccharides contained a D-galactose stub on the terminal D-mannosyl group nor were they substituted on the second D-mannosyl residue from the reducing terminal.
