Catalytic domain of Helicobacter pylori peptidoglycan deacetylase (HpPgdA) and similar proteins
This family is represented by a peptidoglycan deacetylase (HP0310, HpPgdA) from the gram-negative pathogen Helicobacter pylori. HpPgdA has the ability to bind a metal ion at the active site and is responsible for a peptidoglycan modification that counteracts the host immune response. It functions as a homotetramer. The monomer is composed of a 7-stranded barrel with detectable sequence similarity to the 6-stranded barrel NodB homology domain of polysaccharide deacetylase (DCA)-like proteins in the CE4 superfamily, which removes N-linked or O-linked acetyl groups from cell wall polysaccharides. In contrast to typical NodB-like DCAs, HpPgdA does not exhibit a solvent-accessible polysaccharide binding groove, suggesting that the enzyme binds a small molecule at the active site.