4C7D

Structure and activity of the GH20 beta-N-acetylhexosaminidase from Streptomyces coelicolor A3(2)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.202 
  • R-Value Work: 0.163 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structure and Activity of the Streptomyces Coelicolor A3(2) Beta-N-Acetylhexosaminidase Provides Further Insight Into Gh20 Family Catalysis and Inhibition.

Nguyen Thi, N.Offen, W.A.Shareck, F.Davies, G.J.Doucet, N.

(2014) Biochemistry 53: 1789

  • DOI: 10.1021/bi401697j
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • β-N-acetylhexosaminidases (HEX) are glycosidases that catalyze the glycosidic linkage hydrolysis of gluco- and galacto-configured N-acetyl-β-d-hexosaminides. These enzymes are important in human physiology and are candidates for the biocatalytic prod ...

    β-N-acetylhexosaminidases (HEX) are glycosidases that catalyze the glycosidic linkage hydrolysis of gluco- and galacto-configured N-acetyl-β-d-hexosaminides. These enzymes are important in human physiology and are candidates for the biocatalytic production of carbohydrates and glycomimetics. In this study, the three-dimensional structure of the wild-type and catalytically impaired E302Q HEX variant from the soil bacterium Streptomyces coelicolor A3(2) (ScHEX) were solved in ligand-free forms and in the presence of 6-acetamido-6-deoxy-castanospermine (6-Ac-Cas). The E302Q variant was also trapped as an intermediate with oxazoline bound to the active center. Crystallographic evidence highlights structural variations in the loop 3 environment, suggesting conformational heterogeneity for important active-site residues of this GH20 family member. The enzyme was investigated for its β-N-acetylhexosaminidase activity toward chitooligomers and pNP-acetyl gluco- and galacto-configured N-acetyl hexosaminides. Kinetic analyses confirm the β(1-4) glycosidic linkage substrate preference, and HPLC profiles support an exoglycosidase mechanism, where the enzyme cleaves sugars from the nonreducing end of substrates. ScHEX possesses significant activity toward chitooligosaccharides of varying degrees of polymerization, and the final hydrolytic reaction yielded pure GlcNAc without any byproduct, promising high applicability for the enzymatic production of this highly valued chemical. Thermostability and activation assays further suggest efficient conditions applicable to the enzymatic production of GlcNAc from chitooligomers.


    Organizational Affiliation

    INRS-Institut Armand-Frappier, Université du Québec , 531 Boul. des Prairies, Laval, Québec H7V 1B7, Canada.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
BETA-N-ACETYLHEXOSAMINIDASE
A, B
494Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145)Mutation(s): 0 
Find proteins for Q9L068 (Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145))
Go to UniProtKB:  Q9L068
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
EDO
Query on EDO

Download SDF File 
Download CCD File 
A, B
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.202 
  • R-Value Work: 0.163 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 72.660α = 90.00
b = 128.900β = 90.00
c = 150.320γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
REFMACrefinement
SCALAdata scaling
iMOSFLMdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-03-12
    Type: Initial release
  • Version 1.1: 2014-04-09
    Type: Database references