Determination of the absolute configuration of the glycerol component in poly(glycosylglycerolphosphates) by GLC-MS

Abstract

The identification of an increasing number of teichoic acid-like capsular polysaccharide structures containing glycerol phosphate linkages (see, for example, refs l-141, has necessitated the development of accurate and versatile methods for the determination of the absolute configuration of the chiral glycerol components. Only in a few instances has the assignment of the stereochemistry of 0-glycosyl glycerol, phosphorylated at one of the primary hydroxymethyl groups, within this type of polymer been reported 12-15 On the other hand, the stereochemistry of the . teichoic acids in the cell walls and membranes of gram-positive bacteria appears to be well established16,i7. Assignment of the stereochemistry of the glycerol residue in poly(glycosylglycerol phosphates) may be achieved by release of the chiral glycerol component, followed by its conversion to an appropriate derivative, and assignment of absolute stereochemistry by comparison with standards of known chirality by means of spectroscopic CORD, CD, or NMR), chromatographic or enzymic methods18,i9. In the case of polymers joined by + l)-glycerol-(3 + phosphodiester linkages, depolymerization can be accomplished with aqueous HF to afford a 1-0-glycosylated glycerol fragment. Configurational analysis is then possible by comparison of the chromatographic properties with standards of known absolute configuration2’ or by stereospecific enzymic assay following oxidation to the corresponding chiral glyceric acid . 21 More recen tl y a method based on the measurement of the chiroptical properties of 2,3-di-0-benzyl-sn-glycerol obtained from 1-0-glycosyl-sn-glycerols has been describedz2. When the teichoic acid contains 2-O-substituted glycerol phosphate linkages,