The phospholipids of Pneumococcus I-192R, A.T.C.C. 12213. Some structural rearrangements occurring under mild conditions

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Abstract
The phospholipids from the non-capsulated strain of Pneumococcus I-192R, A. T. C. C. 12213, were separated into three fractions by chromatography on columns of silicic acid and DEAE -cellulose (acetate form). The water-soluble phosphate esters produced by deacylation of each fraction were separated by chromatography on columns of DEAE -cellulose (HCO3-form). Three deacylated products, diglycerol phosphate, glycerylphosphoryl-glycerol phosphate and bis(glycerylphosphoryl)glycerol, were identified by analysis, by chemical degradations and by comparison with synthetic materials. From a study of freshly isolated lipids prepared and worked up under conditions where exposure to acid was minimal, it was concluded that the Pneumococcus contains phosphatidylglycerol and bis-phosphatidylglycerol, in the molar proportion 1: 2-5-3-0, and that the deacylation product glycerylphosphorylglycerol phosphate was probably an artifact of the isolation procedure. Acid-catalyzed iso-merization (phosphodiester migration) of diglycerol phosphate and bis(glycerylphosphoryl)glycerol and transesterification (glycerol phosphate transfer) of diglycerol phosphate were observed. The structures of the products were established by degradation. A novel mechanism for the biosynthesis of bisphosphatidylglycerol is presented.