Fig. 2.

Structural features of peptidoglycan and biosynthesis A) Chemical structure of peptidoglycan (see key for details). B) Diagram of the ‘scaffold model’ of peptidoglycan. The glycan (purple) of the peptidoglycan forms a matrix of helices orientated perpendicular to the plasma membrane, joined together by peptide cross-links and forming central pores to fit other structures, such as arabinogalactan (AG; orange and green helices) (Dmitriev et al., 2000). C) Biosynthesis of peptidoglycan. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)