Structure of type 3Gn coaggregation receptor polysaccharide from Streptococcus cristatus LS4

Abstract

The presence of a novel coaggregation receptor polysaccharide (RPS) on the dental plaque isolate Streptococcus cristatus LS4 was suggested by this strain’s antigenic and coaggregation properties. Examination of RPS isolated from strain LS4 by a combination of 2-dimensional and pseudo 3-dimensional single quantum heteronuclear NMR methods that included detection of 13C chemical shifts at high resolution revealed the following repeat unit structure: →6)-β- d-Gal f-(1→6)-β- d-Gal pNAc-(1→3)-α- d-Gal p-(1→P→6)-α- d-Gal p-(1→3)-β-L-Rha p-(1→4)-β- d-Glc p-(1→. The identification of this polysaccharide as RPS3Gn, a new structural type, was established by the α- d-Gal p-containing epitope of RPS serotype 3 and Gn recognition motif (i.e., β- d-Gal pNAc (1→3)-α- d-Gal p) for coaggregation with other bacteria.