3HD8

Crystal structure of the Triticum aestivum xylanase inhibitor-IIA in complex with bacillus subtilis xylanase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.39 Å
  • R-Value Free: 0.275 
  • R-Value Work: 0.223 
  • R-Value Observed: 0.226 

wwPDB Validation   3D Report Full Report


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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:  
    2B42, 3HD8

  • 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. 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 ...

    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:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Xylanase inhibitorA, C389Triticum aestivumMutation(s): 0 
Gene Names: XYNAxi-IIA
UniProt
Find proteins for Q53IQ4 (Triticum aestivum)
Explore Q53IQ4 
Go to UniProtKB:  Q53IQ4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ53IQ4
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Endo-1,4-beta-xylanase AB, D185Bacillus subtilisMutation(s): 0 
Gene Names: xynA
EC: 3.2.1.8
UniProt
Find proteins for P18429 (Bacillus subtilis (strain 168))
Explore P18429 
Go to UniProtKB:  P18429
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP18429
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.39 Å
  • R-Value Free: 0.275 
  • R-Value Work: 0.223 
  • R-Value Observed: 0.226 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 77.351α = 90
b = 60.3β = 101.49
c = 134.187γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
CNSrefinement
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-06-30
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance