CBD_II

• SMART accession number: SM00637
• Description: -
• Interpro abstract (IPR001919):

  The microbial degradation of cellulose and xylans requires several types of enzyme such as endoglucanases (EC 3.2.1.4), cellobiohydrolases (EC 3.2.1.91) (exoglucanases), or xylanases (EC 3.2.1.8) [ (PUBMED:1886523) ]. Structurally, cellulases and xylanases generally consist of a catalytic domain and a conserved region of ~100 amino acid residues, the carbohydrate-binding module 2 (CBM2) [ (PUBMED:1812490) ]. It is found either at the N-terminal or at the C-terminal extremity of these enzymes.

  CBM2 can be classified in 2 subfamilies according to substrate specificities: CBM2a which binds cellulose and CBM2b which interacts specifically with xylan. Like other CBM domains CBM2 is a beta-sheet domain containing a planar face which interacts with its ligand via a hydrophobic strip of aromatic residues [ (PUBMED:7766609) ]. In family 2a this hydrophobic surface consists of three tryptophan residues, which are all required for binding soluble and insoluble forms of cellulose [ (PUBMED:9662439) ]. In family 2b only 2 surface-exposed tryptophans are conserved and the first one is oriented differently. It is therefore not well oriented to interact with cellulose but is ideal for binding xylan [ (PUBMED:10425686) ].

  This domain recognises both CBM2 subfamilies.

• GO process: carbohydrate metabolic process (GO:0005975)
• GO function: hydrolase activity, hydrolyzing O-glycosyl compounds (GO:0004553), carbohydrate binding (GO:0030246)

There are 14472 CBD_II domains in 14006 proteins in SMART's nrdb database.

Metabolism (metabolic pathways involving proteins which contain this domain)

% proteins involved	KEGG pathway ID	Description
69.57	map00500	Starch and sucrose metabolism
30.43	map00530	Aminosugars metabolism

This information is based on mapping of SMART genomic protein database to KEGG orthologous groups. Percentage points are related to the number of proteins with CBD_II domain which could be assigned to a KEGG orthologous group, and not all proteins containing CBD_II domain. Please note that proteins can be included in multiple pathways, ie. the numbers above will not always add up to 100%.

Structure (3D structures containing this domain)

3D Structures of CBD_II domains in PDB

PDB code	Title
1e5b	Internal xylan binding domain from C. fimi Xyn10A, R262G mutant
1e5c	Internal xylan binding domain from C. fimi Xyn10A, R262G mutant
1exg	SOLUTION STRUCTURE OF A CELLULOSE BINDING DOMAIN FROM CELLULOMONAS FIMI BY NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY
1exh	SOLUTION STRUCTURE OF A CELLULOSE BINDING DOMAIN FROM CELLULOMONAS FIMI BY NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY
1heh	C-terminal xylan binding domain from Cellulomonas fimi xylanase 11A
1hej	C-terminal xylan binding domain from Cellulomonas fimi xylanase 11A
1xbd	INTERNAL XYLAN BINDING DOMAIN FROM CELLULOMONAS FIMI XYLANASE D, NMR, 5 STRUCTURES
2cwr	Crystal structure of chitin biding domain of chitinase from Pyrococcus furiosus
2czn	Solution structure of the chitin-binding domain of hyperthermophilic chitinase from pyrococcus furiosus
2rtt	2RTT
2xbd	INTERNAL XYLAN BINDING DOMAIN FROM CELLULOMONAS FIMI XYLANASE D, NMR, MINIMIZED AVERAGE STRUCTURE
3ndy	The structure of the catalytic and carbohydrate binding domain of endoglucanase D from Clostridium cellulovorans
3ndz	The structure of the catalytic and carbohydrate binding domain of endoglucanase D from Clostridium cellulovorans bound to cellotriose
5dhd	5DHD
5dhe	5DHE

Links (links to other resources describing this domain)

• INTERPRO: IPR001919