Glycoside Hydrolase Family 115

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• Author: ^^^Satoshi Kaneko^^^
• Responsible Curator: ^^^Satoshi Kaneko^^^

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Glycoside Hydrolase Family GH115
Clan	none
Mechanism	inverting
Active site residues	not known
CAZy DB link
http://www.cazy.org/GH115.html

Substrate specificities

Glycoside hydrolases of GH115 display alpha-glucuronidase activity (EC 3.2.1.131). In particular, members of this family are capable of cleaving 4-O-methyl D-glucuronic acid sidechains from native xylan polysaccharides. In contrast to GH67 enzymes, which only cleave glucuronosyl linkages at the non-reducing ends of xylooligosaccharides, GH115 enzymes remove glucuronic acid from the both terminal and internal regions of xylooligosaccharides and xylans [1]. This substrate specificity was first demonstrated by an alpha-glucuronidase purified from Thermoascus aurantiacus [2], and later for a Schizophyllum commune alpha-glucuronidase [3]. Although Glycoside Hydrolase Family 115 was established on the basis of biochemical and sequence analysis of Pichia stipitis (4-O-methyl)-alpha-glucuronidase, available N-terminal protein sequence of the S. commune enzyme [3] allowed the tentative assignment of this enzyme to GH115 [1]. A GH115 member from Streptomyces pristinaespiralis produces both 4-O-methyl D-glucuronic acid and non-methylated D-glucuronic acid the reaction products [4].

Kinetics and Mechanism

Using 1H NMR spectroscopy and reduced aldopentaouronic acid(MeGlcA3Xyl4-ol) as a substrate, it was demonstrated that both the enzymes from S. commune and P. stipitis releasing 4-O-methyl-D-glucuronic acid (MeGlcA) as its beta-anomer, suggesting a single displacement mechanism [5].

Catalytic Residues

The catalytic residues have not yet been identified in a member of this family.

Three-dimensional structures

No 3D structure has been solved for this family at present, although crystallization of a Streptomyces pristinaespiralis homolog has been reported [4].

Family Firsts

First stereochemistry determination

1H NMR demonstrated that the released 4-methyl-D-glucuronic acid was a beta anomer and thus that the enzyme is an inverter [5].

First catalytic nucleophile identification

Not yet identified.

First general acid/base residue identification

Not yet identified.

First 3-D structure

Just crystallization of S. pristinaespiralis enzyme is reported [4].

References

1. Ryabova O, Vrsanská M, Kaneko S, van Zyl WH, and Biely P. (2009). A novel family of hemicellulolytic alpha-glucuronidase. FEBS Lett. 2009;583(9):1457-62. DOI:10.1016/j.febslet.2009.03.057 |
2. Khandke KM, Vithayathil PJ, and Murthy SK. (1989). Purification and characterization of an alpha-D-glucuronidase from a thermophilic fungus, Thermoascus aurantiacus. Arch Biochem Biophys. 1989;274(2):511-7. DOI:10.1016/0003-9861(89)90464-5 |
3. Tenkanen M and Siika-aho M. (2000). An alpha-glucuronidase of Schizophyllum commune acting on polymeric xylan. J Biotechnol. 2000;78(2):149-61. DOI:10.1016/s0168-1656(99)00240-0 |

4. Fujimoto Z, Ichinose H, Biely P, Kaneko S. Crystallization and preliminary crystallographic analysis of the glycoside hydrolase family 115 α-glucuronidase from Streptomyces pristinaespiralis. Acta Crystallogr Sect F Struct Biol Cryst Commun. 2011 Jan 1;67(Pt 1):68-71.

   Note: Due to a problem with PubMed data, this reference is not automatically formatted. Please see these links out: DOI:10.1107/S1744309110043721 PMID: 21206027

5. Kolenová K, Ryabova O, Vrsanská M, Biely P. Inverting character of family GH115 α-glucuronidases. FEBS Lett. 2010 Sep 24;584(18):4063-4068.

   Note: Due to a problem with PubMed data, this reference is not automatically formatted. Please see these links out: DOI:10.1016/j.febslet.2010.08.031 PMID: 20804758