Carbohydrate Binding Module Family 79

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• Author: ^^^Immacolata Venditto^^^
• Responsible Curator: ^^^Harry Gilbert^^^

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CAZy DB link

https://www.cazy.org/CBM79.html

Ligand specificities

CBM79 is a family identified in the Ruminococcus flavefaciens cellulosome, an anaerobic, cellulolytic bacterium that plays an important role in the ruminal digestion of plant cell walls [1]. Two CBM79s (CBM79-1_GH9 and CBM79-2_GH9) were identified in an enzyme that contains a catalytic module derived from GH9 with endo-β1,4-glucanases activity. Both CBM79s bind to a range of β-1,4- and mixed linked β-1,3-1,4-glucans [2]. The ligand binding of CBM79-1_GH9 was quantified by isothermal titration calorimetry and semi-quantitatively using microarrays [2]. CBM79-1_GH9 binds barley β-glucan and hydroxyethylcellulose (HEC) with similar affinities. The small increase in KA from cellotetraose to cellohexaose suggests that ligand recognition is dominated by four sugar binding sites. The binding to xyloglucan is weaker than the other β-glucans, indicating that the protein cannot recognize the xylose side chains. CBM79-1_GH9 binds regenerated (noncrystalline) insoluble cellulose (RC) with a K_A of 4.8 x 10⁴ M^-1 .

Structural Features

Content in this section should include, in paragraph form, a description of:

• Fold: Structural fold (beta trefoil, beta sandwich, etc.)
• Type: Include here Type A, B, or C and properties
• Features of ligand binding: Describe CBM binding pocket location (Side or apex) important residues for binding (W, Y, F, subsites), interact with reducing end, non-reducing end, planar surface or within polysaccharide chains. Include examples pdb codes. Metal ion dependent. Etc.

Functionalities

Content in this section should include, in paragraph form, a description of:

• Functional role of CBM: Describe common functional roles such as targeting, disruptive, anchoring, proximity/position on substrate.
• Most Common Associated Modules: 1. Glycoside Hydrolase Activity; 2. Additional Associated Modules (other CBM, FNIII, cohesin, dockerins, expansins, etc.)
• Novel Applications: Include here if CBM has been used to modify another enzyme, or if a CBM was used to label plant/mammalian tissues? Etc.

Family Firsts

First Identified

Insert archetype here, possibly including very brief synopsis.

First Structural Characterization

Insert archetype here, possibly including very brief synopsis.

References

3. Cantarel BL, Coutinho PM, Rancurel C, Bernard T, Lombard V, and Henrissat B. (2009). The Carbohydrate-Active EnZymes database (CAZy): an expert resource for Glycogenomics. Nucleic Acids Res. 2009;37(Database issue):D233-8. DOI:10.1093/nar/gkn663 |

4. Davies, G.J. and Sinnott, M.L. (2008) Sorting the diverse: the sequence-based classifications of carbohydrate-active enzymes. The Biochemist, vol. 30, no. 4., pp. 26-32. Download PDF version.

5. Boraston AB, Bolam DN, Gilbert HJ, and Davies GJ. (2004). Carbohydrate-binding modules: fine-tuning polysaccharide recognition. Biochem J. 2004;382(Pt 3):769-81. DOI:10.1042/BJ20040892 |
6. Hashimoto H (2006). Recent structural studies of carbohydrate-binding modules. Cell Mol Life Sci. 2006;63(24):2954-67. DOI:10.1007/s00018-006-6195-3 |
7. Shoseyov O, Shani Z, and Levy I. (2006). Carbohydrate binding modules: biochemical properties and novel applications. Microbiol Mol Biol Rev. 2006;70(2):283-95. DOI:10.1128/MMBR.00028-05 |
8. Guillén D, Sánchez S, and Rodríguez-Sanoja R. (2010). Carbohydrate-binding domains: multiplicity of biological roles. Appl Microbiol Biotechnol. 2010;85(5):1241-9. DOI:10.1007/s00253-009-2331-y |
9. Armenta S, Moreno-Mendieta S, Sánchez-Cuapio Z, Sánchez S, and Rodríguez-Sanoja R. (2017). Advances in molecular engineering of carbohydrate-binding modules. Proteins. 2017;85(9):1602-1617. DOI:10.1002/prot.25327 |