Glycoside Hydrolase Family 130

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• Author: ^^^Wataru Saburi^^^
• Responsible Curator: ^^^Haruhide Mori^^^

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Glycoside Hydrolase Family GH130
Clan	GH-x
Mechanism	retaining/inverting
Active site residues	known/not known
CAZy DB link
https://www.cazy.org/GH130.html

Substrate specificities

GH130 contains phosphorylases catalyzing the phosphorolysis of β1-4mannosidic linkage at the non-reducing end of substrates. 4-O-β-D-Mannosyl-D-glucose phosphorylase (EC 2.4.1.281), β-1,4-mannooligosaccharide phosphorylase(EC 2.4.1.319), and 1,4-β-mannosyl-N-acetylglucosamine phosphorylase (EC 2.4.1.320) are members of this family.

Kinetics and Mechanism

GH130 phosphorylases phosphorolyze β1-4mannosidic linkage at the non-reducing end of substrates with net inversion of anomeric configuration. Senoura et al. [1] demonstrated that 4-O-β-D-Mannosyl-D-glucose phosphorylase from Bacteroides fragilis produces α-mannose 1-phosphate and glucose from 4-O-β-D-Mannosyl-D-glucose and inorganic phosphate. A unique reaction mechanism of GH130 enzymes has been proposed on the basis of the three-dimensional strucuture analysis of B. fragilis 4-O-β-D-Mannosyl-D-glucose phosphorylase [2]. In contrast to known inverting glycoside phosphorylases, whose general acid catalyst directly donates a proton to glycosidic oxygen, the catalytic Asp of GH130 enzymes (Asp131 in B. fragilis 4-O-β-D-Mannosyl-D-glucose phosphorylase) donates a proton to O3 of mannosyl group bond to subsite -1, and a proton is tranferred to the glycosidic oxygen from 3OH group of the mannosyl residue. Inorganic phosphate attacks C1 of the mannosyl residue at the non-reducing end of substrate and α-mannose 1-phosphate is generated.

Catalytic Residues

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Three-dimensional structures

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Family Firsts

First stereochemistry determination

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First catalytic nucleophile identification

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First general acid/base residue identification

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First 3-D structure

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References

3. Cantarel BL, Coutinho PM, Rancurel C, Bernard T, Lombard V, and Henrissat B. (2009). The Carbohydrate-Active EnZymes database (CAZy): an expert resource for Glycogenomics. Nucleic Acids Res. 2009;37(Database issue):D233-8. DOI:10.1093/nar/gkn663 |

4. Davies, G.J. and Sinnott, M.L. (2008) Sorting the diverse: the sequence-based classifications of carbohydrate-active enzymes. Biochem. J. (BJ Classic Paper, online only). DOI: 10.1042/BJ20080382