Glycerol phosphate substituents

The cell walls of most Gram-positive bacteria contain (1 ->3) poly(glycerol phosphate) teichoic acids which can bear D-alanyl or glycosyl substituents.56 However, the cell walls of Bacillus stearothermophilus B65 contain a glycerol teichoic acid which is free of substituents.57 This is contrary to evidence that had been obtained from biosynthetic studies.58... 

The conversion of L-glycerol 3-phosphate to a phosphatidic acid does not affect any of the bonds to the stereogenic center, nor does it alter the sequence rule ranking of the substituents. 

Membrane teichoic acids contain polyglycero] phosphate chains linking positions t and 3 on adjacent glycerol units through the phosphodiesters, with glycosy] substituents and alanine residues on some or all of the 2 positions. Structural studies Kelemen, Baddiley Biochem. J, 50, 246 0961). Biosynthetic studies Burger, Glaser, 7. Biol. Chem. 239,... 

Phosphoacylglycerols contain fatty acids esterified to position 1 and 2 of glycerol and a phosphate (alone or with a substituent) attached to carbon 3. If only a phosphate group is attached to carbon 3, the compound is phosphatidic acid (see Fig. 5.21). Phosphatidic acid is a precursor for the synthesis of the other phosphoacylglycerols. 

The property of the glycerol-based lipids to form micelles even without saponification is especially pronounced in phospholipids. The basic structural unit of the phospholipid molecule is phosphatidic acid shown in the scheme below. The substituents R and R are long-chained alkane or alkene groups. The phosphate group can be bound in different structures such as choline or serine, molecules which play important roles in metabolism. 

Stereochemical numbering (sn) system will be utilized when referring to the configuration of chemical substituents. In this system, the glycerol backbone can be envisioned in a vertical orientation with the uppermost carbon (C-1) as sn-l, the middle carbon (C-2) as sn-2, and the lowest carbon (C-3) as sn-3 (Figure 1). In this nomenclature, the phosphate of glycerophospholipids is assigned to the sn-3 position. 

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