Figure 5.H. pylori peptidoglycan structure and modification. (A) The H. pylori PG monomer consists of an extended backbone chain of β(1,4)-linked GlcNAc-MurNAc sugars, linked to a short peptide chain by the 3-carboxyl group of the MurNAc residue. (B and C)H. pylori encodes a number of PG-modifying enzymes. Enzymes, genes, and activities are listed in table B, and the impact on the PG layer for each enzyme is illustrated in C.