D
IPR000334

Glycoside hydrolase, family 45

InterPro entry
Short nameGlyco_hydro_45
Overlapping
homologous
superfamilies
 

Description

O-Glycosyl hydrolases (
3.2.1.
) 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 glycosyl hydrolases, based on sequence similarity, has led to the definition of 85 different families
[4, 3]
. This classification is available on the CAZy (CArbohydrate-Active EnZymes) website.

Glycoside hydrolase family 45
GH45
comprises enzymes with only one known activity; endoglucanase (
3.2.1.4
).

The microbial degradation of cellulose and xylans requires several types of enzymes such as endoglucanases, cellobiohydrolases (
3.2.1.91
) (exoglucanases), or xylanases (
3.2.1.8
)
[5, 2]
. Fungi and bacteria produce 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 K or as the glycosyl hydrolases family 45
[1]
. The best conserved regions in these enzymes is located in the N-terminal section. It contains an aspartic acid residue which has been shown
[6]
to act as a nucleophile in the catalytic mechanism. This also has several cysteines that are involved in forming disulphide bridges.

References

1.New families in the classification of glycosyl hydrolases based on amino acid sequence similarities. Henrissat B, Bairoch A. Biochem. J. 293 ( Pt 3), 781-8, (1993). View articlePMID: 8352747

2.Domains in microbial beta-1, 4-glycanases: sequence conservation, function, and enzyme families. Gilkes NR, Henrissat B, Kilburn DG, Miller RC Jr, Warren RA. Microbiol. Rev. 55, 303-15, (1991). View articlePMID: 1886523

3.Structures and mechanisms of glycosyl hydrolases. Davies G, Henrissat B. Structure 3, 853-9, (1995). View articlePMID: 8535779

4.Conserved catalytic machinery and the prediction of a common fold for several families of glycosyl hydrolases. Henrissat B, Callebaut I, Fabrega S, Lehn P, Mornon JP, Davies G. Proc. Natl. Acad. Sci. U.S.A. 92, 7090-4, (1995). View articlePMID: 7624375

5.Molecular biology of cellulose degradation. Beguin P. Annu. Rev. Microbiol. 44, 219-48, (1990). View articlePMID: 2252383

6.Structure and function of endoglucanase V. Davies GJ, Dodson GG, Hubbard RE, Tolley SP, Dauter Z, Wilson KS, Hjort C, Mikkelsen JM, Rasmussen G, Schulein M. Nature 365, 362-4, (1993). View articlePMID: 8377830

GO terms

cellular component

  • None

Cross References

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