MetaCyc Enzyme: cellulase Q

Gene: celQ Accession Numbers: G-12701 (MetaCyc), Cthe_0625

Synonyms: endoglucanase Q

Species: Ruminiclostridium thermocellum ATCC 27405

The celQ gene of Ruminiclostridium thermocellum is located immediately following the celJ gene. The gene was cloned and sequenced, and found to contain a signal peptide, a family 9 cellulase domain (GH9), a family IIIc carbohydrate binding module (CBM), and a dockerin domain.

A truncated derivative of CelQ consisting of only the catalytic domain and the CBM was constructed and investigated. The truncated protein showed strong activity toward carboxymethyl cellulose and barley β-glucan and low activity toward avicel, acid-swollen cellulose, lichenan, and xylan.

A second mutant that was devoid of the CBM showed negligible activity toward carboxymethyl cellulose, supporting the idea that family IIIc CBMs participate in the catalytic function of the enzyme.

An antibody raised against the recombinant protein was used to verify that the enzyme is a component of the Ruminiclostridium thermocellum cellulosome [Arai01].

Molecular Weight of Polypeptide: 79.811 kD (from nucleotide sequence)

Unification Links: Entrez-gene:4808227 , Entrez-Nucleotide:AB047845 , Protein Model Portal:A3DD31 , String:203119.Cthe_0625 , UniProt:A3DD31

Relationship Links: CAZy:IN-FAMILY:CBM3 , CAZy:IN-FAMILY:GH9 , InterPro:IN-FAMILY:IPR001701 , InterPro:IN-FAMILY:IPR001956 , InterPro:IN-FAMILY:IPR002105 , InterPro:IN-FAMILY:IPR008928 , InterPro:IN-FAMILY:IPR008965 , InterPro:IN-FAMILY:IPR012341 , InterPro:IN-FAMILY:IPR016134 , InterPro:IN-FAMILY:IPR018221 , InterPro:IN-FAMILY:IPR018242 , InterPro:IN-FAMILY:IPR018247 , Pfam:IN-FAMILY:PF00404 , Pfam:IN-FAMILY:PF00759 , Pfam:IN-FAMILY:PF00942 , Prosite:IN-FAMILY:PS00018 , Prosite:IN-FAMILY:PS00448 , Prosite:IN-FAMILY:PS00592 , Prosite:IN-FAMILY:PS00698 , Prosite:IN-FAMILY:PS51172 , Smart:IN-FAMILY:SM01067

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Created 30-Mar-2011 by Caspi R , SRI International

Enzymatic reaction of: cellulase

EC Number:

cellulose + n H2O <=> n a cellodextrin

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

Alternative Substrates for cellulose: barley β-glucan [Arai01 ] , carboxymethyl cellulose [Arai01 ] , avicel [Arai01 ] , acid-swollen cellulose [Arai01 ] , lichenan [Arai01 ] , xylan [Arai01 ]


Arai01: Arai T, Ohara H, Karita S, Kimura T, Sakka K, Ohmiya K (2001). "Sequence of celQ and properties of celQ, a component of the Clostridium thermocellum cellulosome." Appl Microbiol Biotechnol 57(5-6);660-6. PMID: 11778875

Biely85: Biely P. (1985). "Microbial xylanolytic enzymes." Trends in Biotechnology.

deVries01: de Vries RP, Visser J (2001). "Aspergillus enzymes involved in degradation of plant cell wall polysaccharides." Microbiol Mol Biol Rev 65(4);497-522, table of contents. PMID: 11729262

Gordillo06: Gordillo F, Caputo V, Peirano A, Chavez R, Van Beeumen J, Vandenberghe I, Claeyssens M, Bull P, Ravanal MC, Eyzaguirre J (2006). "Penicillium purpurogenum produces a family 1 acetyl xylan esterase containing a carbohydrate-binding module: characterization of the protein and its gene." Mycol Res 110(Pt 10);1129-39. PMID: 17008082

Joseleau92: Joseleau J. P., Comptat J., Ruel K. (1992). "Chemical structure of xylans and their interaction in the plant cell wall." Progress in Biotechnology.

Schadel10: Schadel C, Richter A, Blochl A, Hoch G (2010). "Hemicellulose concentration and composition in plant cell walls under extreme carbon source-sink imbalances." Physiol Plant 139(3);241-55. PMID: 20113432

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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