Attachment of the main chain to the linkage unit in biosynthesis of teichoic acids.

The main chain of teichoic acids can be assembled in cell-free membrane preparations by the transfer of residues from the appropriate nucleotide precursors to an incompletely characterized amphiphilic molecule, lipoteichoic acid carrier (LTC). However, in the cell wall, the main chain is attached to peptidoglycan through a linkage unit which is synthesized independently. It is believed that, in these cell-free systems, lipid intermediates carrying linkage units are also able to accept residues directly from nucleotide precursors to build up the main chain. In this paper, we have shown that the main chain attached to LTC was transferred from LTC to lipids containing the linkage unit. Thus, in these systems, there appear to be two routes to the biosynthesis of teichoic acid-linkage unit complexes, one by direct assembly of the main chain on linkage unit lipids and the other by transfer of the preassembled main chain from LTC to the linkage unit. It was also shown that linkage unit lipids from different organisms were interchangeable and that these were used for polymer synthesis by Bacillus subtilis 3610, in which the teichoic acid is a poly(glycerol phosphate).