ABSTRACT
Peptidoglycans are important constituents of almost all bacterial cell walls and are more complex than the cell wall components of higher organisms such as chitin in fungi and cellulose in higher plants. It is made up of linear glycan strands interconnected by short peptides. It covers the inner membrane in both gram-positive and gram-negative bacteria. E. H. Oldmixon et al proposed two models – extended and compact – for the disaccharide-pentapeptide. They differ from the previous models mainly in the conformation of the peptide portion. In the extended model, the peptide is fully stretched and moves away from the surface of the glycan strand. R. E. Burge et al. observed sharp reflections in the X-ray diffraction patterns of the peptidoglycans isolated from different bacterial species and identified them with the axial advance of the glycan helix.
