Acyldiglucosyldiacylglycerol-containing lipoteichoic acid with a poly(3-O-galabiosyl-2-O-galactosyl-sn-glycero-1-phosphate) chain from Streptococcus lactis Kiel 42172

Abstract

The lipoteichoic acid of S. lactis Kiel 42172 was isolated. The lipid portions were released by HF and were established to be 3-O-[O-.alpha.-D-galactopyranosyl-(1 .fwdarw. 6)-.alpha.-D-galactopyranosyl]-2-O-.alpha.-D-galactopyranosyl-sn-glycero-1-phosphate; they are joined by phosphodiester bonds. The repeating units of the hydrophilic chain were 3-O-[O-.alpha.-D-galactopyranosyl-(1 .fwdarw. 6)-.alpha.-D-galactopyranosyl]-2-O-.alpha.-D-galactopyranosyl-sn-glycero-1-phosphate; they are joined by phosphodiester bonds at carbon atom 6 of the galabiosyl residues. The innermost unit is linked to the glycolipid by a phosphodiester presumably at C-6 of the outer glucosyl moiety. The hydrophilic chain is 7.4-11.8 units in length, measuring 12-19 nm in extended conformation. The content of 2.7-2.96 acyl groups/2 glucosyl residues indicates that 70-96% of the glycolipid consists of acyldiglucosyldiacylglycerol. The novel poly(glycosylglycerophosphate) structure provided for the 1st time the opportunity to prove chemically that the glycerophosphates of lipoteichoic acids are the sn-1 isomer which was previously suggested from biosynthetic studies.