1QH7

CATALYSIS AND SPECIFICITY IN ENZYMATIC GLYCOSIDE HYDROLASES: A 2,5B CONFORMATION FOR THE GLYCOSYL-ENZYME INTERMIDIATE REVEALED BY THE STRUCTURE OF THE BACILLUS AGARADHAERENS FAMILY 11 XYLANASE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.78 Å
  • R-Value Free: 0.176 
  • R-Value Work: 0.117 

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This is version 3.1 of the entry. See complete history


Literature

Catalysis and specificity in enzymatic glycoside hydrolysis: a 2,5B conformation for the glycosyl-enzyme intermediate revealed by the structure of the Bacillus agaradhaerens family 11 xylanase.

Sabini, E.Sulzenbacher, G.Dauter, M.Dauter, Z.Jorgensen, P.L.Schulein, M.Dupont, C.Davies, G.J.Wilson, K.S.

(1999) Chem Biol 6: 483-492

  • DOI: https://doi.org/10.1016/s1074-5521(99)80066-0
  • Primary Citation of Related Structures:  
    1H4G, 1H4H, 1QH6, 1QH7

  • PubMed Abstract: 

    The enzymatic hydrolysis of glycosides involves the formation and subsequent breakdown of a covalent glycosyl-enzyme intermediate via oxocarbenium-ion-like transition states. The covalent intermediate may be trapped on-enzyme using 2-fluoro-substituted glycosides, which provide details of the intermediate conformation and noncovalent interactions between enzyme and oligosaccharide. Xylanases are important in industrial applications - in the pulp and paper industry, pretreating wood with xylanases decreases the amount of chlorine-containing chemicals used. Xylanases are structurally similar to cellulases but differ in their specificity for xylose-based, versus glucose-based, substrates. The structure of the family 11 xylanase, Xyl11, from Bacillus agaradhaerens has been solved using X-ray crystallography in both native and xylobiosyl-enzyme intermediate forms at 1.78 A and 2.0 A resolution, respectively. The covalent glycosyl-enzyme intermediate has been trapped using a 2-fluoro-2-deoxy substrate with a good leaving group. Unlike covalent intermediate structures for glycoside hydrolases from other families, the covalent glycosyl-enzyme intermediate in family 11 adopts an unusual 2,5B conformation. The 2,5B conformation found for the alpha-linked xylobiosyl-enzyme intermediate of Xyl11, unlike the 4C1 chair conformation observed for other systems, is consistent with the stereochemical constraints required of the oxocarbenium-ion-like transition state. Comparison of the Xyl11 covalent glycosyl-enzyme intermediate with the equivalent structure for the related family 12 endoglucanase, CelB, from Streptomyces lividans reveals the likely determinants for substrate specificity in this clan of glycoside hydrolases.


  • Organizational Affiliation

    Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York, Y010 5DD, UK.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
XYLANASE
A, B
207Salipaludibacillus agaradhaerensMutation(s): 0 
EC: 3.2.1.8
UniProt
Find proteins for Q7SIE3 (Salipaludibacillus agaradhaerens)
Explore Q7SIE3 
Go to UniProtKB:  Q7SIE3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ7SIE3
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
PCA
Query on PCA
A, B
L-PEPTIDE LINKINGC5 H7 N O3GLN
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.78 Å
  • R-Value Free: 0.176 
  • R-Value Work: 0.117 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 71.86α = 90
b = 75.36β = 90
c = 78.4γ = 90
Software Package:
Software NamePurpose
AMoREphasing
REFMACrefinement
SCALEPACKdata scaling

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-05-17
    Type: Initial release
  • Version 1.1: 2007-10-16
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 2.0: 2019-12-25
    Changes: Database references, Derived calculations, Polymer sequence
  • Version 3.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary
  • Version 3.1: 2023-12-27
    Changes: Data collection, Database references, Structure summary