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Glycoside Hydrolase Family 115

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Glycoside Hydrolase Family GH115
Clan GH-x
Mechanism inverting
Active site residues not known
CAZy DB link
http://www.cazy.org/GH115.html


Substrate specificities

Glycoside hydrolases of this family display alpha-glucuronidase activity. The enzymes possible to release 4-O-methyl D-glucuronic acid from polymeric xylans. The substrate specificity could be distinguished from GH67 enzymes. In contrast to GH67 enzymes which only cleave glucuronosyl linkage at the non-reducing end of xylooligosaccharides, GH115 enzymes remove glucuronic acid from the both terminal and internal regions of xylooligosaccharides and xylans. This kind of substrate specificty firstly demonstrated by an alpha-glucuronidase purified from Thermoascus aurantiacus [1] and N-terminal amino acid sequence of Schizophyllum commune firstly provided [2]. In spite of the N-terminal amino acid sequence of Pichia stipitis did not show significant similarity with the sequence of S. commune, the information lead to find full amino acid sequence and establish this family [3]. It has been demonstrated that these enzymes release 4-O-methyl D-glucuronic acid, the enzyme from Streptomyces pristinaespiralis produced the both 4-O-methyl D-glucuronic acid and non methylated D-glucuronic acid as the reaction product [4].

This is an example of how to make references to a journal article [5]. (See the References section below). Multiple references can go in the same place like this [5, 6]. You can even cite books using just the ISBN [7]. References that are not in PubMed can be typed in by hand [8].


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

Not identified.


Three-dimensional structures

No 3D-structure is solved for this family of enzyme.


Family Firsts

Normal 0 0 2 false false false EN-US JA X-NONE 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]. [5].
First catalytic nucleophile identification
unproved [8].
First general acid/base residue identification
unproved [6].
First 3-D structure
Just crystallization of S. pristinaespiralis enzyme is reported [4]. [7].

References

  1. He S and Withers SG. (1997) Assignment of sweet almond beta-glucosidase as a family 1 glycosidase and identification of its active site nucleophile. J Biol Chem. 272, 24864-7. PubMed ID:9312086 | HubMed [He1999]
  2. ISBN: 978-0-240-52118-3 | Google Books | Open Library [StickWilliams]
  3. Sinnott, M.L. (1990) Catalytic mechanisms of enzymic glycosyl transfer. Chem. Rev. 90, 1171-1202. DOI: 10.1021/cr00105a006
    [Sinnott1990]
  4. 0 0 2 false false false EN-US JA X-NONE Khandke1989 pmid=2082623
    [Normal]