intercellular adhesin biosynthesis polysaccharide N-deacetylase. A common motif in bacterial biosynthesis of polysaccharide for export is modification that follows polymerization. This model describes a subfamily of polysaccharide N-deacetylases that acts on poly-beta-1,6-N-acetyl-D-glyscosamine as produced by Staphylococcus epidermidis and S. aureus. The end product in these species is designated polysaccharide intercellular adhesin (PIA), and this gene designated icaB (intercellular adhesion protein B). [Cell envelope, Biosynthesis and degradation of surface polysaccharides and lipopolysaccharides, Cellular processes, Pathogenesis]

Putative catalytic polysaccharide deacetylase domain of bacterial intercellular adhesion protein IcaB and similar proteins. The family is represented by the surface-attached protein intercellular adhesion protein IcaB (Poly-beta-1,6-N-acetyl-D-glucosamine N-deacetylase, EC 3.5.1.-), encoded by Staphylococcus epidermidis icaB gene from the icaABC gene cluster that is involved in the synthesis of polysaccharide intercellular adhesin (PIA), which is located mainly on the cell surface. IcaB is a secreted, cell wall-associated protein that plays a crucial role in exopolysaccharide modification in bacterial biofilm formation. It catalyzes the N-deacetylation of poly-beta-1,6-N-acetyl-D-glucosamine (PNAG, also referred to as PIA), a biofilm adhesin polysaccharide. IcaB shows high homology to the N-terminal NodB homology domain of Escherichia coli PgaB. At this point, they are classified in the same family.

Putative catalytic polysaccharide deacetylase domain of uncharacterized protein yadE and similar proteins. This family contains an uncharacterized protein yadE from Escherichia coli and its bacterial homologs. Although its molecular function remains unknown, yadE shows high sequence similarity with the catalytic NodB homology domain of outer membrane lipoprotein PgaB and the surface-attached protein intercellular adhesion protein IcaB. Both PgaB and IcaB are essential in bacterial biofilm formation.

Putative catalytic NodB homology domain of PgaB, IcaB, and similar proteins which consist of a deformed (beta/alpha)8 barrel fold with 5- or 6-strands. This family belongs to the large and functionally diverse carbohydrate esterase 4 (CE4) superfamily, whose members show strong sequence similarity with some variability due to their distinct carbohydrate substrates. It includes bacterial poly-beta-1,6-N-acetyl-D-glucosamine N-deacetylase PgaB, hemin storage system HmsF protein in gram-negative species, intercellular adhesion proteins IcaB, and many uncharacterized prokaryotic polysaccharide deacetylases. It also includes a putative polysaccharide deacetylase YxkH encoded by the Bacillus subtilis yxkH gene, which is one of six polysaccharide deacetylase gene homologs present in the Bacillus subtilis genome. Sequence comparison shows all family members contain a conserved domain similar to the catalytic NodB homology domain of rhizobial NodB-like proteins, which consists of a deformed (beta/alpha)8 barrel fold with 6 or 7 strands. However, in this family, most proteins have 5 strands and some have 6 strands. Moreover, long insertions are found in many family members, whose function remains unknown.

Putative catalytic NodB homology domain of a hypothetical protein Ecf1 from Escherichia coli and similar proteins. This family contains a hypothetical protein Ecf1 from Escherichia coli and its prokaryotic homologs. Although their biochemical properties remain to be determined, members in this family contain a conserved domain with a 5-stranded beta/alpha barrel, which is similar to the catalytic NodB homology domain of rhizobial NodB-like proteins, belonging to the larger carbohydrate esterase 4 (CE4) superfamily.

Structureof IcaB from Ammonifex degensii [Ammonifex degensii KC4]

Poly-beta-1,6-N-acetyl-D-glucosamine N-deacetylase OS=Staphylococcus aureus (strain MSSA476) OX=282459 GN=icaB PE=3 SV=1

Poly-beta-1,6-N-acetyl-D-glucosamine N-deacetylase OS=Staphylococcus aureus (strain N315) OX=158879 GN=icaB PE=3 SV=1

Poly-beta-1,6-N-acetyl-D-glucosamine N-deacetylase OS=Staphylococcus aureus (strain MW2) OX=196620 GN=icaB PE=3 SV=1

Poly-beta-1,6-N-acetyl-D-glucosamine N-deacetylase OS=Staphylococcus aureus (strain Mu50 / ATCC 700699) OX=158878 GN=icaB PE=3 SV=1

Poly-beta-1,6-N-acetyl-D-glucosamine N-deacetylase OS=Staphylococcus aureus (strain NCTC 8325 / PS 47) OX=93061 GN=icaB PE=3 SV=2