The polar lipids of group B Streptococci. I. Glucosylated diphosphatidylglycerol, a novel glycopholipid.

1. From group B Streptococci a novel glycophospholipid was isolated, which contained D-glucose, glycerol, acyl groups and phosphorus in a molar ratio of approx. 1:3:4:2. It was established to be 2'-O-alpha-D-glucopyranosyl-, 1',3'-bis-(1,2-diacyl-sn-glycero-3-phospho)-glycerol. 2. The structure of the deacylated core was accomplished by analyses of the breakdown products obtained on (i) strong alkaline hydrolysis, (ii) Smith-degradation, and (iii) periodate oxidation with subsequent hydrazinolysis. The four acyl groups were located by sequential degradation of the native lipid with phospholipase A2 and 98% acetic acid. 2. In group B Streptococci approximately 25% of diphosphatidylglycerol occurs in the form of its glucosylated derivative which accounts for 18% of the lipid phosphorus. The glucosylated phosphatidylglycerol analogue could not be detected. A phosphoglucolipid, however, was present, which was tentatively identified as glycerophosphodiglucosyldiacylglycerol.