3EXU

A glycoside hydrolase family 11 xylanase with an extended thumb region


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.81 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.191 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystallographic and activity-based evidence for thumb flexibility and its relevance in glycoside hydrolase family 11 xylanases

Pollet, A.Vandermarliere, E.Lammertyn, J.Strelkov, S.V.Delcour, J.A.Courtin, C.M.

(2009) Proteins 77: 395-403

  • DOI: 10.1002/prot.22445

  • PubMed Abstract: 
  • Enzyme intramolecular mobility and conformational changes of loops in particular play a significant role in biocatalysis. In this respect, the highly conserved thumb loop of glycoside hydrolase family (GH) 11 xylanases is an intriguing and characteri ...

    Enzyme intramolecular mobility and conformational changes of loops in particular play a significant role in biocatalysis. In this respect, the highly conserved thumb loop of glycoside hydrolase family (GH) 11 xylanases is an intriguing and characteristic structural element, of which the true dynamic nature and function in catalysis is still unknown. Crystallographic analysis of the structure of a Bacillus subtilis xylanase A mutant, found as a dimer in an asymmetric unit, revealed that the thumb region can adopt an extended conformation, which is stabilized in the crystal lattice through intermolecular contacts. In contrast to the closed thumb conformation of GH11 xylanases and the previously observed small conformational changes upon substrate binding, a relocation of the tip of the thumb of more than 15 A was observed. Site-directed mutagenesis of five thumb residues, including putative hinge point residues, and enzyme kinetics assays showed that Arg112, Asn114, and Thr126 play a role in the open-close thumb movement. Replacement of Arg112 by glycine or proline caused a strong decrease of turnover numbers and elevated Michaelis constants on xylan. Mutant N114P hindered thumb movement, provoking a fourfold decrease of turnover numbers and a sharp rise in Michaelis constants, whereas the proline mutant of Thr126 displayed an increase in specific activity. The observation that extensive thumb opening is possible combined with the kinetic data suggests that the thumb plays a crucial role in both binding of substrate and release of product from the active site.


    Organizational Affiliation

    Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre, Katholieke Universiteit Leuven, Kasteelpark Arenberg, B-3001 Leuven, Belgium.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Endo-1,4-beta-xylanase
A, B
185Bacillus subtilis (strain 168)Mutation(s): 2 
Gene Names: xynA
EC: 3.2.1.8
Find proteins for P18429 (Bacillus subtilis (strain 168))
Go to UniProtKB:  P18429
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

Download SDF File 
Download CCD File 
A, B
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
MES
Query on MES

Download SDF File 
Download CCD File 
B
2-(N-MORPHOLINO)-ETHANESULFONIC ACID
C6 H13 N O4 S
SXGZJKUKBWWHRA-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.81 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.191 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 43.910α = 90.00
b = 51.880β = 94.20
c = 84.730γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
SCALAdata scaling
REFMACrefinement
iMOSFLMdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-08-25
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Non-polymer description, Version format compliance