Structural requirements of lipoteichoic acid carrier for recognition by the poly(ribitol phosphate) polymerase from Staphylococcus aureus H. A study of various lipoteichoic acids, derivatives, and related compounds.

A set of different, structurally defined lipoteichoic acids was tested for lipoteichoic acid carrier (LTC) activity using the poly(ribito1 phosphate) polymerase from Staphylococcus aureus H. Chemically and enzymically modified lipoteichoic acids and related poly01 phosphate-containing compounds were also studied.1) LTC and lipoteichoic acids were shown to be identical entities. 2)Differing structures of the glycolipid anchor had no effect on LTC activity.3) Deacylated lipoteichoic acid displayed no acceptor activity but acted as a competitive inhibitor. 4)Loss of activity and inhibitory properties were also observed when the terminal glycerophosphate was converted into ethylenediol phosphate or phosphomonoester.Removal of the phosphomonoester, however, restored LTC activity. 5 )Variations in the mean length of the hydrophilic chain from 4.6 to 40 glycerophosphate units were compatible with LTC activity.An optimum of activity was observed at a length of approximately 20 units, a complete loss of activity between 4.6 and 3.4 units.6) Partial substitution with galactosyl residues of the poly(g1ycerophosphate) significantly lowered LTC activity.We postulate that in LTC a nonsubstituted tetra(g1ycerophosphate) segment is necessary for recognition, a terminal glycerophosphate for acceptor function, and a nonspecific hydrophobic portion for appropriate orientation at the lipid-water interphase.The results are discussed with regard to the acceptor in the synthesis of poly(ribito1 phosphate) in uiuo.An unsolved problem in the biosynthesis of teichoic acid in Gram-positive bacteria concerns the acceptor on which the polymer is assembled in vivo.Purified poly(ribito1 phosphate) polymerase from Staphylococcus aureus H uses as acceptor lipoteichoic acid carrier (LTC) which is similar or identical with the lipoteichoic acid present in S. aureus membrane (1-4):