Glycoside hydrolase family 28
|Glycosyl hydrolases family 28|
rhamnogalacturonase a from aspergillus aculeatus
Glycoside hydrolases EC 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 glycoside hydrolases, based on sequence similarity, has led to the definition of >100 different families. This classification is available on the CAZy(http://www.cazy.org/GH1.html) web site, and also discussed at CAZypedia, an online encyclopedia of carbohydrate active enzymes.
Glycoside hydrolase family 28 CAZY GH_28 comprises enzymes with several known activities; polygalacturonase (EC 22.214.171.124); exo-polygalacturonase (EC 126.96.36.199); exo-polygalacturonase (EC 188.8.131.52); rhamnogalacturonase (EC not defined).
Polygalacturonase (PG) (pectinase) catalyzes the random hydrolysis of 1,4-alpha-D-galactosiduronic linkages in pectate and other galacturonans. In fruit, polygalacturonase plays an important role in cell wall metabolism during ripening. In plant bacterial pathogens such as Erwinia carotovora or Ralstonia solanacearum (Pseudomonas solanacearum) and fungal pathogens such as Aspergillus niger, polygalacturonase is involved in maceration[disambiguation needed] and soft-rotting of plant tissue. Exo-poly-alpha-D-galacturonosidase (EC 184.108.40.206) (exoPG) hydrolyzes peptic acid from the non-reducing end, releasing digalacturonate. PG and exoPG share a few regions of sequence similarity, and belong to family 28 of the glycosyl hydrolases.
- Henrissat B, Callebaut I, Mornon JP, Fabrega S, Lehn P, Davies G (1995). "Conserved catalytic machinery and the prediction of a common fold for several families of glycosyl hydrolases". Proc. Natl. Acad. Sci. U.S.A. 92 (15): 7090–7094. doi:10.1073/pnas.92.15.7090. PMC 41477. PMID 7624375.
- Henrissat B, Davies G (1995). "Structures and mechanisms of glycosyl hydrolases". Structure 3 (9): 853–859. doi:10.1016/S0969-2126(01)00220-9. PMID 8535779.
- Bairoch, A. "Classification of glycosyl hydrolase families and index of glycosyl hydrolase entries in SWISS-PROT". 1999.
- Henrissat, B. and Coutinho P.M. "Carbohydrate-Active Enzymes server". 1999.
- CAZypedia, an online encyclopedia of carbohydrate-active enzymes.
- Ruttkowski E, Labitzke R, Khanh NQ, Gottschalk M, Jany KD, Loffler F (1990). "Cloning and DNA sequence analysis of a polygalacturonase cDNA from Aspergillus niger RH5344". Biochim. Biophys. Acta 1087 (1): 104–106. doi:10.1016/0167-4781(90)90130-t. PMID 2400785.
- Schell MA, Huang JH (1990). "DNA sequence analysis of pglA and mechanism of export of its polygalacturonase product from Pseudomonas solanacearum". J. Bacteriol. 172 (7): 3879–3887. PMC 213369. PMID 2193922.
- He SY, Collmer A (1990). "Molecular cloning, nucleotide sequence, and marker exchange mutagenesis of the exo-poly-alpha-D-galacturonosidase-encoding pehX gene of Erwinia chrysanthemi EC16". J. Bacteriol. 172 (9): 4988–4995. PMC 213154. PMID 2168372.