Glycoside hydrolase family 45 explained

In molecular biology, glycoside hydrolase family 45 is a family of glycoside hydrolases.

Glycoside hydrolases 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]}

Glycoside hydrolase family 45 CAZY GH_45 comprises enzymes with only one known activity; endoglucanase . This family is also known as cellulase family K.^[8] The best conserved region in these enzymes is located in the N-terminal section. It contains an aspartic acid residue which has been shown^[9] to act as a nucleophile in the catalytic mechanism. This also has several cysteines that are involved in forming disulphide bridges.

Notes and References

1. Henrissat B, Callebaut I, Fabrega S, Lehn P, Mornon JP, Davies G . Conserved catalytic machinery and the prediction of a common fold for several families of glycosyl hydrolases . Proceedings of the National Academy of Sciences of the United States of America . 92 . 15 . 7090–4 . July 1995 . 7624375 . 41477 . 10.1073/pnas.92.15.7090 . 1995PNAS...92.7090H . free .
2. Davies G, Henrissat B . Structures and mechanisms of glycosyl hydrolases . Structure . 3 . 9 . 853–9 . September 1995 . 8535779 . 10.1016/S0969-2126(01)00220-9 . free .
3. Henrissat B, Bairoch A . Updating the sequence-based classification of glycosyl hydrolases . The Biochemical Journal . 316 (Pt 2) . Pt 2 . 695–6 . June 1996 . 8687420 . 1217404 . 10.1042/bj3160695 .
4. Web site: Home. CAZy.org. en. 2018-03-06.
5. Lombard V, Golaconda Ramulu H, Drula E, Coutinho PM, Henrissat B . The carbohydrate-active enzymes database (CAZy) in 2013 . Nucleic Acids Research . 42 . Database issue . D490-5 . January 2014 . 24270786 . 3965031 . 10.1093/nar/gkt1178 .
6. Web site: Glycoside Hydrolase Family 45. CAZypedia.org. en. 2018-03-06.
7. Ten years of CAZypedia: a living encyclopedia of carbohydrate-active enzymes . Glycobiology . 28 . 1 . 3–8 . December 2018 . 29040563 . 10.1093/glycob/cwx089 . CAZypedia Consortium . 21.11116/0000-0003-B7EB-6 . free .
8. Henrissat B, Bairoch A . New families in the classification of glycosyl hydrolases based on amino acid sequence similarities . The Biochemical Journal . 293 (Pt 3) . 3. 781–8 . August 1993 . 8352747 . 1134435 . 10.1042/bj2930781 .
9. Davies GJ, Dodson GG, Hubbard RE, Tolley SP, Dauter Z, Wilson KS, Hjort C, Mikkelsen JM, Rasmussen G, Schülein M . Structure and function of endoglucanase V . Nature . 365 . 6444 . 362–4 . September 1993 . 8377830 . 10.1038/365362a0 . 1993Natur.365..362D . 4277867 .