In molecular biology, glycoside hydrolase family 5 is a family of glycoside hydrolasesEC3.2.1., which are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycoside hydrolases, based on sequence similarity, has led to the definition of >100 different families.[1][2][3] This classification is available on the CAZy web site,[4][5] and also discussed at CAZypedia, an online encyclopedia of carbohydrate active enzymes.[6][7]
The microbial degradation of cellulose and xylans requires several types of enzymes. Fungi and bacteria produces a spectrum of cellulolytic enzymes (cellulases) and xylanases which, on the basis of sequence similarities, can be classified into families. One of these families is known as the cellulase family A[9] or as the glycosyl hydrolases family 5.[10] One of the conserved regions in this family contains a conserved glutamic acid residue which is potentially involved[11] in the catalytic mechanism.
In a recent study using Molecular Dynamics simulations, a considerable correlation between thermal stability and structural rigidity of members of family 5 with solved structures has been proved.[12]
^Py B, Bortoli-German I, Haiech J, Chippaux M, Barras F (February 1991). "Cellulase EGZ of Erwinia chrysanthemi: structural organization and importance of His98 and Glu133 residues for catalysis". Protein Engineering. 4 (3): 325–33. doi:10.1093/protein/4.3.325. PMID1677466.
^Badieyan S, Bevan DR, Zhang C (January 2012). "Study and design of stability in GH5 cellulases". Biotechnology and Bioengineering. 109 (1): 31–44. doi:10.1002/bit.23280. PMID21809329. S2CID29281420.
