On the basic structure of poly (glycerophosphate) lipoteichoic acids

Abstract

Poly(glycerophosphate) lipoteichoic acids from 24 Gram-positive bacteria of the genera Bacillus, Enterococcus, Lactobacillus, Lactococcus, Listeria, Staphylococcus, and the streptococcal pyogenic and oral group were analyzed. The 1,3-linked poly(glycerophosphate) structure was proved by analysis of glycerol and glycerophosphates after acid and alkaline hydrolysis. Using the molar ratios of glycolipid to phosphorus (A) and phosphomonoester to phosphorus after periodate oxidation followed by hydrazinolysis (B) or β-elimination (C), we show that all lipoteichoic acids contain a single unbranched poly(glycerophosphate) chain and that the chain is uniformly phosphodiester-linked to C-6 of the nonreducing hexopyranosyl residue of the glycolipid moiety. On some chains minor phosphate-containing substituents were detected whose structure remains to be clarified. The lipoteichoic acids of enterococci and listeria strains were separated by hydrophobic interaction chromatography into glycolipid- and phosphatidylglycolipid-containing molecular species. The phosphatidylglycolipid moieties were structurally characterized after liberation from lipoteichoic acids with moist acetic acid. After periodate oxidation of lipoteichoic acids β-elimination released both phosphatidic acid and the poly(glycerophosphate) chain. This indicates together with the sequence analysis of the released phosphatidylglycolipid that the phosphatidyl residue is located at C-6 of the reducing hexosyl residue of the glycolipid moiety and the poly(glycerophosphate) chain at C-6 of the nonreducing one. Together with earlier observations these results complete the evidence for the structural and possibly biosynthetic relationship between lipoteichoic acids and glycerophosphoglycolipids.Key words: lipoteichoic acids, poly(glycerophosphate) lipoteichoic acids, Gram-positive bacteria, bacterial membrane.