Two well-characterized systems produce polysaccharide based on N-acetyl-D-glucosamine in straight chains with beta-1,6 linkages. These are encoded by the icaADBC operon in Staphylococcus species, where the system is designated polysaccharide intercellular adhesin (PIA), and the pgaABCD operon in Gram-negative bacteria such as E. coli. Both systems include a putative polysaccharide deacetylase. The PgaB protein, described here, contains an additional domain lacking from its Gram-positive counterpart IcaB (TIGR03933). Deacetylation by this protein appears necessary to allow export through the porin PgaA [Cell envelope, Biosynthesis and degradation of surface polysaccharides and lipopolysaccharides]
Jiyao W et al.(2023). "The conserved domain database in 2023.",