Figure 2.
Scheme of putative functions of the phage-encoded O-acetyl esterase in the large intestine. Pathogenic STEC cells have to traverse the loose and the tight mucus layer to reach the epithelium for adherence and colonization. Mucinases and other proteases play a role in that process. Cleavage of O-acteyl residues from terminal O-glycans (e.g., Neu5,9Ac2) by chromosomal and phage-encoded O-acetyl esterases results in deacetylated free sialic acids such as N-acetyl neuraminic acid, which can be metabolized by the bacteria [113]. The chemical structure of Neu5,9Ac2 is shown. Honeycomb structure = mucin network. Paneth cells and goblet cells are indicated.