Structural analysis of enzyme-resistant isomaltooligosaccharides reveals the elongation of α-(1→3)-linked branches in Weissella confusa dextran

Biomacromolecules. 2011 Feb 14;12(2):409-18. doi: 10.1021/bm1011536. Epub 2011 Jan 5.

Abstract

Weissella confusa VTT E-90392 is an efficient producer of a dextran that is mainly composed of α-(1→6)-linked D-glucosyl units and very few α-(1→3) branch linkages. A mixture of the Chaetomium erraticum endodextranase and the Aspergillus niger α-glucosidase was used to hydrolyze W. confusa dextran to glucose and a set of enzyme-resistant isomaltooligosaccharides. Two of the oligosaccharides (tetra- and hexasaccharide) were isolated in pure form and their structures elucidated. The tetrasaccharide had a nonreducing end terminal α-(1→3)-linked glucosyl unit (α-D-Glcp-(1→3)-α-D-Glcp-(1→6)-α-D-Glcp-(1→6)-α-D-Glc), whereas the hexasaccharide had an α-(1→3)-linked isomaltosyl side group (α-D-Glcp-(1→6)[α-D-Glcp-(1→6)-α-D-Glcp-(1→3)]-α-D-Glcp-(1→6)-α-D-Glcp-(1→6)-α-D-Glc). A mixture of two isomeric oligosaccharides was also obtained in the pentasaccharide fraction, which were identified as (α-D-Glcp-(1→6)-α-D-Glcp-(1→3)-α-D-Glcp-(1→6)-α-D-Glcp-(1→6)-α-D-Glc) and (α-D-Glcp-(1→6)[α-D-Glcp-(1→3)]-α-D-Glcp-(1→6)-α-D-Glcp-(1→6)-α-D-Glc). The structures of the oligosaccharides indicated that W. confusa dextran contains both terminal and elongated α-(1→3)-branches. This is the first report evidencing the presence of elongated branches in W. confusa dextran. The (1)H and (13)C NMR spectroscopic data on the enzyme-resistant isomaltooligosaccharides with α-(1→3)-linked glucosyl and isomaltosyl groups are published here for the first time.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aspergillus niger / enzymology
  • Carbohydrate Conformation
  • Chaetomium / enzymology
  • Dextranase / antagonists & inhibitors
  • Dextranase / metabolism
  • Dextrans / chemistry*
  • Glycoside Hydrolase Inhibitors
  • Hydrolysis
  • Leuconostocaceae / chemistry*
  • Oligosaccharides / chemistry*
  • Oligosaccharides / pharmacology
  • alpha-Glucosidases / metabolism

Substances

  • Dextrans
  • Glycoside Hydrolase Inhibitors
  • Oligosaccharides
  • Dextranase
  • alpha-Glucosidases