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

Experimental Data Snapshot

  • Resolution: 1.80 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.167 
  • R-Value Observed: 0.169 

wwPDB Validation   3D Report Full Report

Ligand Structure Quality Assessment 

This is version 1.1 of the entry. See complete history


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: https://doi.org/10.1021/bi401697j
  • Primary Citation of Related Structures:  
    4C7D, 4C7F, 4C7G

  • 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 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.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
BETA-N-ACETYLHEXOSAMINIDASE494Streptomyces coelicolorMutation(s): 1 
Find proteins for Q9L068 (Streptomyces coelicolor (strain ATCC BAA-471 / A3(2) / M145))
Explore Q9L068 
Go to UniProtKB:  Q9L068
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9L068
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on NGO

Download Ideal Coordinates CCD File 
C8 H14 N O5
Query on EDO

Download Ideal Coordinates CCD File 
C [auth A]
D [auth A]
E [auth A]
F [auth A]
G [auth A]
C [auth A],
D [auth A],
E [auth A],
F [auth A],
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth A],
L [auth A],
M [auth A]
C2 H6 O2
Experimental Data & Validation

Experimental Data

  • Resolution: 1.80 Å
  • R-Value Free: 0.210 
  • R-Value Work: 0.167 
  • R-Value Observed: 0.169 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 58.17α = 90
b = 64.45β = 90
c = 143.67γ = 90
Software Package:
Software NamePurpose
iMOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-03-12
    Type: Initial release
  • Version 1.1: 2023-12-20
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description