2B42

Crystal structure of the Triticum xylanse inhibitor-I in complex with bacillus subtilis xylanase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.183 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Identification of structural determinants for inhibition strength and specificity of wheat xylanase inhibitors TAXI-IA and TAXI-IIA.

Pollet, A.Sansen, S.Raedschelders, G.Gebruers, K.Rabijns, A.Delcour, J.A.Courtin, C.M.

(2009) Febs J. 276: 3916-3927

  • DOI: 10.1111/j.1742-4658.2009.07105.x
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Triticum aestivum xylanase inhibitor (TAXI)-type inhibitors are active against microbial xylanases from glycoside hydrolase family 11, but the inhibition strength and the specificity towards different xylanases differ between TAXI isoforms. Mutationa ...

    Triticum aestivum xylanase inhibitor (TAXI)-type inhibitors are active against microbial xylanases from glycoside hydrolase family 11, but the inhibition strength and the specificity towards different xylanases differ between TAXI isoforms. Mutational and biochemical analyses of TAXI-I, TAXI-IIA and Bacillus subtilis xylanase A showed that inhibition strength and specificity depend on the identity of only a few key residues of inhibitor and xylanase [Fierens K et al. (2005) FEBS J 272, 5872-5882; Raedschelders G et al. (2005) Biochem Biophys Res Commun335, 512-522; Sorensen JF & Sibbesen O (2006) Protein Eng Des Sel 19, 205-210; Bourgois TM et al. (2007) J Biotechnol 130, 95-105]. Crystallographic analysis of the structures of TAXI-IA and TAXI-IIA in complex with glycoside hydrolase family 11 B. subtilis xylanase A now provides a substantial explanation for these observations and a detailed insight into the structural determinants for inhibition strength and specificity. Structures of the xylanaseinhibitor complexes show that inhibition is established by loop interactions with active-site residues and substrate-mimicking contacts in the binding subsites. The interaction of residues Leu292 of TAXI-IA and Pro294 of TAXI-IIA with the -2 glycon subsite of the xylanase is shown to be critical for both inhibition strength and specificity. Also, detailed analysis of the interaction interfaces of the complexes illustrates that the inhibition strength of TAXI is related to the presence of an aspartate or asparagine residue adjacent to the acid/base catalyst of the xylanase, and therefore to the pH optimum of the xylanase. The lower the pH optimum of the xylanase, the stronger will be the interaction between enzyme and inhibitor, and the stronger the resulting inhibition.


    Organizational Affiliation

    Laboratory of Food Chemistry and Biochemistry, Katholieke Universiteit Leuven, Belgium.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
xylanase inhibitor-I
A
381Triticum aestivumMutation(s): 0 
Gene Names: xiI (taxi-I)
Find proteins for Q8H0K8 (Triticum aestivum)
Go to UniProtKB:  Q8H0K8
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Endo-1,4-beta-xylanase A
B
185Bacillus subtilis (strain 168)Mutation(s): 0 
Gene Names: xynA
EC: 3.2.1.8
Find proteins for P18429 (Bacillus subtilis (strain 168))
Go to UniProtKB:  P18429
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.183 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 107.890α = 90.00
b = 95.340β = 122.24
c = 69.310γ = 90.00
Software Package:
Software NamePurpose
CNSphasing
MOSFLMdata reduction
SCALAdata scaling
CNSrefinement
CCP4data scaling
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-09-19
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance