Variations in the Metabolism of Peptidoglycan Prior to Polymerization

The biosynthesis of bacterial cell wall peptidoglycan is a complex process which comprises two major stages (Rogers et al., 1980). The first one concerns the sequential formation of a series of cytoplasmic and membrane precursors. The second one concerns the polymerisation reactions with the insertion of the new peptidoglycan material and its maturation. The first stage of peptidoglycan synthesis is considered to begin with UDP-N-acetylglucosamine (UDP-GlcNAc) and to end with N-acetylglucosaminyl-N-acetylmuramyl (pentapeptide) -pyrophosphate undecaprenol (lipid II in Fig.1) which is the substrate for the polymerization reactions. The different steps prior to polymerization have long been identified and certain studied to some extent (Rogers et al., 1980). However little attention had been paid to their in vivo functioning.