1OM0

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.197 

wwPDB Validation 3D Report Full Report


This is version 1.2 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

  • 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) ...

    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: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Xylanase Inhibitor Protein I
A
274Triticum aestivumGene Names: XIPI
Find proteins for Q8L5C6 (Triticum aestivum)
Go to UniProtKB:  Q8L5C6
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
EDO
Query on EDO

Download SDF File 
Download CCD File 
A
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
NDG
Query on NDG

Download SDF File 
Download CCD File 
A
2-(ACETYLAMINO)-2-DEOXY-A-D-GLUCOPYRANOSE
C8 H15 N O6
OVRNDRQMDRJTHS-PVFLNQBWSA-N
 Ligand Interaction
NAG
Query on NAG

Download SDF File 
Download CCD File 
A
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.197 
  • Space Group: P 43 21 2
Unit Cell:
Length (Å)Angle (°)
a = 58.475α = 90.00
b = 58.475β = 90.00
c = 191.954γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
CNSrefinement
SCALEPACKdata scaling
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-06-03
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Non-polymer description, Version format compliance