1OM0

crystal structure of xylanase inhibitor protein (XIP-I) from wheat


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.197 

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This is version 2.0 of the entry. See complete history


Literature

Structural analysis of xylanase inhibitor protein I (XIP-I), a proteinaceous xylanase inhibitor from wheat (Triticum aestivum, var. Soisson).

Payan, F.Flatman, R.Porciero, S.Williamson, G.Juge, N.Roussel, A.

(2003) Biochem J 372: 399-405

  • DOI: 10.1042/BJ20021802
  • Primary Citation of Related Structures:  
    1OM0

  • PubMed Abstract: 
  • A novel class of proteinaceous inhibitors exhibiting specificity towards microbial xylanases has recently been discovered in cereals. The three-dimensional structure of xylanase inhibitor protein I (XIP-I) from wheat (Triticum aestivum, var. Soisson) was determined by X-ray crystallography at 1 ...

    A novel class of proteinaceous inhibitors exhibiting specificity towards microbial xylanases has recently been discovered in cereals. The three-dimensional structure of xylanase inhibitor protein I (XIP-I) from wheat (Triticum aestivum, var. Soisson) was determined by X-ray crystallography at 1.8 A (1 A=0.1 nm) resolution. The inhibitor possesses a (beta/alpha)(8) barrel fold and has structural features typical of glycoside hydrolase family 18, namely two consensus regions, approximately corresponding to the third and fourth barrel strands, and two non-proline cis -peptide bonds, Ser(36)-Phe and Trp(256)-Asp (in XIP-I numbering). However, detailed structural analysis of XIP-I revealed several differences in the region homologous with the active site of chitinases. The catalytic glutamic acid residue of family 18 chitinases [Glu(127) in hevamine, a chitinase/lysozyme from the rubber tree (Hevea brasiliensis)] is conserved in the structure of the inhibitor (Glu(128)), but its side chain is fully engaged in salt bridges with two neighbouring arginine residues. Gly(81), located in subsite -1 of hevamine, where the reaction intermediate is formed, is replaced by Tyr(80) in XIP-I. The tyrosine side chain fills the subsite area and makes a strong hydrogen bond with the side chain of Glu(190) located at the opposite side of the cleft, preventing access of the substrate to the catalytic glutamic acid. The structural differences in the inhibitor cleft structure probably account for the lack of activity of XIP-I towards chitin.


    Organizational Affiliation

    Architecture et Fonction des Macromolécules Biologiques, UMR6098, CNRS and Universities Aix-Marseille I and II, 31 chemin Joseph Aiguier, France. fran@afmb.cnrs-mrs.fr



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Xylanase Inhibitor Protein IA274Triticum aestivumMutation(s): 0 
Gene Names: XIPI
UniProt
Find proteins for Q8L5C6 (Triticum aestivum)
Explore Q8L5C6 
Go to UniProtKB:  Q8L5C6
Protein Feature View
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  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.197 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 58.475α = 90
b = 58.475β = 90
c = 191.954γ = 90
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling
AMoREphasing

Structure Validation

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Ligand Structure Quality Assessment  



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-06-03
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Non-polymer description, Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Non-polymer description, Structure summary