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 gellan lyase and similar proteins. This family is represented by the extracellular polysaccharide-degrading enzyme, gellan lyase (gellanase, EC 4.2.2.-), from Bacillus sp. The enzyme acts on gellan exolytically and releases a tetrasaccharide of glucuronyl-glucosyl-rhamnosyl-glucose with unsaturated glucuronic acid at the nonreducing terminus. The family also includes many uncharacterized prokaryotic polysaccharide deacetylases, which show high sequence similarity to Bacillus sp. gellan lyase. Although their biological functions remain unknown, all members of the family contain a conserved domain with a 6-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.

phosphatidyl-myo-inositol mannosyltransferase. This family is most closely related to the GT4 family of glycosyltransferases and named after PimA in Propionibacterium freudenreichii, which is involved in the biosynthesis of phosphatidyl-myo-inositol mannosides (PIM) which are early precursors in the biosynthesis of lipomannans (LM) and lipoarabinomannans (LAM), and catalyzes the addition of a mannosyl residue from GDP-D-mannose (GDP-Man) to the position 2 of the carrier lipid phosphatidyl-myo-inositol (PI) to generate a phosphatidyl-myo-inositol bearing an alpha-1,2-linked mannose residue (PIM1). Glycosyltransferases catalyze the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. The acceptor molecule can be a lipid, a protein, a heterocyclic compound, or another carbohydrate residue. This group of glycosyltransferases is most closely related to the previously defined glycosyltransferase family 1 (GT1). The members of this family may transfer UDP, ADP, GDP, or CMP linked sugars. The diverse enzymatic activities among members of this family reflect a wide range of biological functions. The protein structure available for this family has the GTB topology, one of the two protein topologies observed for nucleotide-sugar-dependent glycosyltransferases. GTB proteins have distinct N- and C- terminal domains each containing a typical Rossmann fold. The two domains have high structural homology despite minimal sequence homology. The large cleft that separates the two domains includes the catalytic center and permits a high degree of flexibility. The members of this family are found mainly in certain bacteria and archaea.

Putative catalytic NodB homology domain of uncharacterized prokaryotic polysaccharide deacetylases which consist of a 6-stranded beta/alpha barrel. This family contains uncharacterized prokaryotic polysaccharide deacetylases. Although their biological functions remain unknown, all members of the family contain a conserved domain with a 6-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.

Polysaccharide deacetylase. This domain is found in polysaccharide deacetylase. This family of polysaccharide deacetylases includes NodB (nodulation protein B from Rhizobium) which is a chitooligosaccharide deacetylase. It also includes chitin deacetylase from yeast, and endoxylanases which hydrolyzes glucosidic bonds in xylan.

Crystalstructure of the Xyl-CE4 domain of a multidomain xylanase from the hindgut metagenome of Trinervitermes trinervoides [uncultured bacterium]

T48deacetylase [Arthrobacter sp. AW19M34-1],5LGC_A T48 deacetylase with substrate [Arthrobacter sp. AW19M34-1]

Putative polysaccharide deacetylase YxkH OS=Bacillus subtilis (strain 168) OX=224308 GN=yxkH PE=3 SV=1

Uncharacterized protein YadE OS=Escherichia coli (strain K12) OX=83333 GN=yadE PE=3 SV=2

Uncharacterized glycosyltransferase MJ1178 OS=Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) OX=243232 GN=MJ1178 PE=3 SV=1