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Glycoside Hydrolase Family 121

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Revision as of 18:59, 4 November 2012 by Kiyotaka Fujita (talk | contribs)
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Glycoside Hydrolase Family GH121
Clan GH-x
Mechanism retaining
Active site residues not known
CAZy DB link
http://www.cazy.org/GH121.html


Substrate specificities

This family of glycoside hydrolases contains β-L-arabinobiosidase, which was recently established for HypBA2 from Bifidobacterium longum JCM 1217[1]. HypBA2 liberated Arafβ1-2Araf (β-Ara2) from unmodified Arafβ1-2Arafβ1-2Arafβ-Hydroxyproline (Ara3-Hyp) but not Arafα1-3Arafβ1-2Arafβ1-2Arafβ-Hyp (Ara4-Hyp) or Arafβ1-2Arafβ-Hyp (Ara2-Hyp).

Kinetics and Mechanism

HypBA2 is a retaining enzyme.The stereochemical course of the reaction was shown by transglycosylation activity toward 1-alkanols, and following 1H-NMR and 13C-NMR analysis of the methanol-adducted transglycosylation product.

Catalytic Residues

Not known.

Three-dimensional structures

Not known.

Family Firsts

First stereochemistry determination
This was determined with HypBA2 enzyme by measurement of glycosyl transfer reactions to methanol and the 1H-NMR and 13C-NMR spectra.
First catalytic nucleophile identification
No experimental proof.
First general acid/base residue identification
No experimental proof.
First 3-D structure
Not known.

References

  1. Fujita K, Sakamoto S, Ono Y, Wakao M, Suda Y, Kitahara K, and Suganuma T. (2011). Molecular cloning and characterization of a beta-L-Arabinobiosidase in Bifidobacterium longum that belongs to a novel glycoside hydrolase family. J Biol Chem. 2011;286(7):5143-50. DOI:10.1074/jbc.M110.190512 | PubMed ID:21149454 [Fujita2011A]