Methylation analysis of extracellular glucans produced by Streptococcus mutans strain JC 2

Abstract

The fine structure of the soluble (SG) and the major insoluble (IG-1) glucans produced by Streptococcus mutans strain JC 2 cultured in sucrose medium was investigated by methylation analysis. These glucans are highly branched at the C-3 and C-6 positions of the d-glucopyranose residues, and each glucan contains α-1:3 and α-1:6 glucopyranosyl linkages in different proportions. The SG contained 10 per cent α-1,3,6 linked branching residues, 10 per cent non-reducing terminal residues, 47 per cent α-1:6 linked units and 33 per cent α-1:3 linked units. The IG-1 contained 9 per cent α-1,3,6 linked branches, 9 per cent terminals, 36 per cent α-1:6 linked units and 46 per cent α-1:3 linked units.