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Glycoside Hydrolase Family 97
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- Author: ^^^Tracey Gloster^^^
- Responsible Curator: ^^^Gideon Davies^^^
| Glycoside Hydrolase Family GH97 | |
| Clan | Not assigned |
| Mechanism | Retaining and Inverting |
| Active site residues | Inferred |
| CAZy DB link | |
| http://www.cazy.org/fam/GH97.html | |
Substrate specificities
Family 97 glycoside hydrolases hydrolyse alpha-linked substrates; the two enzymes from this family that have been characterised to date have alpha-glucosidase (EC 3.2.1.20) and alpha-galactosidase (EC 3.2.1.22) activity [1]. The alpha-glucosidase from Bacteroides thetaiotaomicron has been characterised in the most detail, and has been demonstrated to hydrolyse substrates ranging from maltose to maltoheptaose in length, and those containing alpha-1,6-, alpha-1,3- and alpha-1,2-, as well as alpha-1,4-, linkages [2, 3].
Kinetics and Mechanism
Family GH97 is unusual as it contains both retaining and inverting enzymes, as shown unequivocally by NMR [1] and HPLC [2], by characterization of two enzymes from Bacteroides thetaiotaomicron. Both mechanisms are strongly dependent on the presence of calcium, which coordinates the C2-OH group of the substrate in the -1 subsite, as well as four glutamate residues in the active site [1]. One of the glutamate residues coordinated by the calcium ion is predicted to be the acid/base residue, which may receive acid assistance from the calcium during hydrolysis.
Catalytic Residues
Content is to be added here.
Three-dimensional structures
Content is to be added here.
Family Firsts
- First sterochemistry determination
- Cite some reference here, with a short (1-2 sentence) explanation [4].
- First catalytic nucleophile identification
- Cite some reference here, with a short (1-2 sentence) explanation [5].
- First general acid/base residue identification
- Cite some reference here, with a short (1-2 sentence) explanation [6].
- First 3-D structure
- Cite some reference here, with a short (1-2 sentence) explanation [7].
References
- Gloster TM, Turkenburg JP, Potts JR, Henrissat B, and Davies GJ. (2008). Divergence of catalytic mechanism within a glycosidase family provides insight into evolution of carbohydrate metabolism by human gut flora. Chem Biol. 2008;15(10):1058-67. DOI:10.1016/j.chembiol.2008.09.005 |
- Smith KA and Salyers AA. (1991). Characterization of a neopullulanase and an alpha-glucosidase from Bacteroides thetaiotaomicron 95-1. J Bacteriol. 1991;173(9):2962-8. DOI:10.1128/jb.173.9.2962-2968.1991 |
- Kitamura M, Okuyama M, Tanzawa F, Mori H, Kitago Y, Watanabe N, Kimura A, Tanaka I, and Yao M. (2008). Structural and functional analysis of a glycoside hydrolase family 97 enzyme from Bacteroides thetaiotaomicron. J Biol Chem. 2008;283(52):36328-37. DOI:10.1074/jbc.M806115200 |
[[Category:Glycoside Hydrolase Families|GHnnn]]