1PJU

Unbound form of Tomato Inhibitor-II

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.206 

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This is version 1.2 of the entry. See complete history. 

Literature

Unbound form of tomato inhibitor-II reveals interdomain flexibility and conformational variability in the reactive site loops

Barrette-Ng, I.H., Ng, K.K.-S., Cherney, M.M., Pearce, G., Ghani, U., Ryan, C.A., James, M.N.G.

(2003) J.Biol.Chem. 278: 31391-31400

  • DOI: 10.1074/jbc.M304562200

  • PubMed Abstract: 

    • The Potato II (Pot II) family of proteinase inhibitors plays important roles in the constitutive and inducible defense of plants against predation by a wide range of pests. The structural basis of inhibition by a multidomain Pot II family inhibitor w ...

    The Potato II (Pot II) family of proteinase inhibitors plays important roles in the constitutive and inducible defense of plants against predation by a wide range of pests. The structural basis of inhibition by a multidomain Pot II family inhibitor was revealed recently by the structure of the ternary complex between the two-headed tomato inhibitor-II (TI-II) and two molecules of subtilisin Carlsberg. Here we report the 2.15-A resolution crystal structure of the unbound form of TI-II that reveals significant conformational flexibility in the absence of bound proteinase molecules. The four independent copies of unbound TI-II in the asymmetric unit of the unit cell display a range of different conformations when compared with the bound form of the inhibitor, most strikingly in the orientations of the inhibitory domains and in the conformations of the reactive site loops. One of the two linker segments (residues 74 to 79) between the two domains as well as the adjacent beta-strand in Domain I (residues 80-85) is well ordered in all four copies of the unbound inhibitor, even though this region appeared to be disordered in the structure of the ternary complex. Conformational flexibility seen in the reactive site loops of unbound TI-II suggests a mechanism by which the inhibitor can balance the need for tight binding with the need for broad inhibitory function.

    Organizational Affiliation: 

    Canadian Institutes of Health Research Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Wound-induced proteinase inhibitor II
A, B, C, D
123Solanum lycopersicum
Find proteins for P05119 (Solanum lycopersicum)
Go to UniProtKB:  P05119
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4
Download SDF File 
Download CCD File 
A, B, C, D
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.206 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 58.688α = 90.00
b = 106.607β = 104.12
c = 81.804γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
DENZOdata reduction
CNSphasing
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-09-16
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Advisory, Derived calculations, Version format compliance