Isomalto-oligosaccharide-containing lipoteichoic acid of Streptococcus sanguis. Microheterogeneity and distribution of chain substituents.

The lipoteichoic acid of Streptococcus sanguis DSM 20567 contains a poly(glycerophosphate) chain, with 49% of the glycerophosphate residues being substituted with D-alanine ester, 35% with alpha-D-glucopyranosyl and alpha-isomalto-oligosaccharide residues. Analysis of molecular species by affinity chromatography on concanavalin A showed all chains to be substituted and alanine ester and glycosyl residues to be present on the same rather than on separate chains. Molecular species varied in the length of the poly(glycerophosphate) chain, the extent of glycosylation, and had a constant alanine-ester content. An alkali-hydrolysis procedure revealed a distribution pattern between random and regular for the glycosyl substituents and suggested a similar distribution for the alanyl residues which occupy the free positions between the glycosyl substituents.