Glycosyl hydrolase family 9.

Catalytic NodB homology domain of rhizobial NodB-like proteins. 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 many rhizobial NodB chitooligosaccharide N-deacetylase (EC 3.5.1.-)-like proteins, mainly from bacteria and eukaryotes, such as chitin deacetylases (EC 3.5.1.41), bacterial peptidoglycan N-acetylglucosamine deacetylases (EC 3.5.1.-), and acetylxylan esterases (EC 3.1.1.72), which catalyze the N- or O-deacetylation of substrates such as acetylated chitin, peptidoglycan, and acetylated xylan. All members of this family contain a catalytic NodB homology domain with the same overall topology and a deformed (beta/alpha)8 barrel fold with 6- or 7 strands. Their catalytic activity is dependent on the presence of a divalent cation, preferably cobalt or zinc, and they employ a conserved His-His-Asp zinc-binding triad closely associated with the conserved catalytic base (aspartic acid) and acid (histidine) to carry out acid/base catalysis. Several family members show diversity both in metal ion specificities and in the residues that coordinate the metal.

N-terminal Early set domain associated with the catalytic domain of cellulase. E or "early" set domains are associated with the catalytic domain of cellulases at the N-terminal end. Cellulases are O-glycosyl hydrolases (GHs) that hydrolyze beta 1-4 glucosidic bonds in cellulose. They are usually categorized into either exoglucanases, which sequentially release terminal sugar units from the cellulose chain, or endoglucanases, which also attack the chain internally. The N-terminal domain of cellulase may be related to the immunoglobulin and/or fibronectin type III superfamilies. These domains are associated with different types of catalytic domains at either the N-terminal or C-terminal end and may be involved in homodimeric/tetrameric/dodecameric interactions. Members of this family include members of the alpha amylase family, sialidase, galactose oxidase, cellulase, cellulose, hyaluronate lyase, chitobiase, and chitinase, among others.

Peptidoglycan/xylan/chitin deacetylase, PgdA/CDA1 family [Carbohydrate transport and metabolism, Cell wall/membrane/envelope biogenesis].

Putative catalytic NodB homology domain of uncharacterized protein YlxY from Bacillus subtilis and its bacterial homologs. The Bacillus subtilis genome contains six polysaccharide deacetylase gene homologs: pdaA, pdaB (previously known as ybaN), yheN, yjeA, yxkH and ylxY. This family is represented by Bacillus subtilis putative polysaccharide deacetylase BsYlxY, encoded by the ylxY gene, which is a member of the carbohydrate esterase 4 (CE4) superfamily. Although its biological function still remains unknown, BsYlxY shows high sequence homology to the catalytic domain of Bacillus subtilis pdaB gene encoding a putative polysaccharide deacetylase (BsPdaB), which is essential for the maintenance of spores after the late stage of sporulation and is highly conserved in spore-forming bacteria. However, disruption of the ylxY gene in B. subtilis did not cause any sporulation defect. Moreover, the Asp residue in the classical His-His-Asp zinc-binding motif of CE4 esterases is mutated to a Val residue in this family. Other catalytically relevant residues of CE4 esterases are also not conserved, which suggest that members of this family may be inactive.

Crystalstructure of metagenome-derived glycoside hydrolase family 9 endoglucanase [uncultured bacterium],3X17_B Crystal structure of metagenome-derived glycoside hydrolase family 9 endoglucanase [uncultured bacterium]

ChainA, ENDOGLUCANASE D [Acetivibrio thermocellus],4CJ1_A Chain A, ENDOGLUCANASE D [Acetivibrio thermocellus]

ChainA, ENDOGLUCANASE CELD; EC: 3.2.1.4 [Acetivibrio thermocellus]

Crystalstructure of Zn-binding triple mutant of GH family 9 endoglucanase J30 [Thermobacillus composti KWC4]

Crystalstructure of GH family 9 endoglucanase J30 [Thermobacillus composti KWC4]

Endoglucanase D OS=Acetivibrio thermocellus (strain ATCC 27405 / DSM 1237 / JCM 9322 / NBRC 103400 / NCIMB 10682 / NRRL B-4536 / VPI 7372) OX=203119 GN=celD PE=1 SV=1

Endoglucanase D (Fragment) OS=Acetivibrio thermocellus OX=1515 GN=celD PE=1 SV=1

Cellodextrinase OS=Butyrivibrio fibrisolvens OX=831 GN=ced1 PE=1 SV=1

Cellulase 1 OS=Streptomyces reticuli OX=1926 GN=cel1 PE=1 SV=1

Endoglucanase C OS=Cellulomonas fimi (strain ATCC 484 / DSM 20113 / JCM 1341 / NBRC 15513 / NCIMB 8980 / NCTC 7547) OX=590998 GN=cenC PE=1 SV=2