Structure of the lipoteichoic acids from Bifidobacterium bifidum spp. pennsylvanicum

Abstract

The lipoteichoic acids from Bifidobucterium bifidum spp. pennsylvanicum were extracted from cytoplasmic membranes or from disintegrated bacteria with aqueous phenol and purified by gel chromatography. The lipoteichoic acid preparations contained phosphate, glycerol, galactose, glucose and fatty acids in a molar ratio of 1.0: 1.0: 1.3: 1.2 : 0.3. Chemical analysis and NMR studies of the native preparations and of products from various acid and alkaline hydrolysis procedures gave evidence for the structure of two lipoteichoic acids. The lipid anchor appeared to be 3-O-(6’-(sn-glycero-l-phosphoryl)diacyl-~D-galac~ofuranosyl)-s~-I,2-diacylglycerol. The polar part showed two structural features not previously described for lipoteichoic acids. A 1,2- (instead of the usual 1,3-) phosphodiester-linked sn-glycerol phosphate chain is only used substituted at the terminal glycerol unit with a linear polysaccharide, containing either /3(1 + 5)-linked D-galactofuranosyl groups or /3(1 + 6)-linked D-ghCOpyranOSyl groups.