Crystal Structure of a Cell Wall Invertase Inhibitor from Tobacco (pH 9.5)

Experimental Data Snapshot

  • Resolution: 2.38 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.202 

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This is version 1.3 of the entry. See complete history


Multiple Crystal Forms of the Cell-Wall Invertase Inhibitor from Tobacco Support High Conformational Rigidity Over a Broad Ph-Range

Hothorn, M.Scheffzek, K.

(2006) Acta Crystallogr D Biol Crystallogr 62: 665

  • DOI: https://doi.org/10.1107/S0907444906011693
  • Primary Citation of Related Structures:  
    2CJ4, 2CJ5, 2CJ6, 2CJ7, 2CJ8

  • PubMed Abstract: 

    Plant acid invertases catalyse the breakdown of sucrose. Their activity is tightly regulated through interaction with specific protein inhibitors. The complex between the cell-wall invertase inhibitor Nt-CIF and its target enzyme is stable only at acidic pH, as found in the plant cell wall. Since the pH in this compartment can be modulated between pH 4 and 6 in planta, the rapid dissociation of the inhibitor-enzyme complex at neutral pH may represent a regulatory event. Here, it is analyzed whether the inhibitory component undergoes structural rearrangements upon changes in the pH environment. Six crystal forms grown at pH 4.6-9.5 and diffracting up to 1.63 Angstrom indicate only small structural changes in CIF. This suggests that complex dissociation at neutral pH is mediated either by rearrangements in the enzyme or by a complex pattern of surface charges in the inhibitor-enzyme binding interface.

  • Organizational Affiliation

    European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
150Nicotiana tabacumMutation(s): 0 
Find proteins for O49908 (Nicotiana tabacum)
Explore O49908 
Go to UniProtKB:  O49908
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO49908
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on IOD

Download Ideal Coordinates CCD File 
C [auth A]
D [auth A]
E [auth A]
F [auth A]
G [auth A]
C [auth A],
D [auth A],
E [auth A],
F [auth A],
G [auth A],
H [auth A],
I [auth A],
J [auth A],
K [auth A],
L [auth B],
M [auth B],
N [auth B],
O [auth B],
P [auth B],
Q [auth B],
R [auth B],
S [auth B],
T [auth B]
Experimental Data & Validation

Experimental Data

  • Resolution: 2.38 Å
  • R-Value Free: 0.273 
  • R-Value Work: 0.198 
  • R-Value Observed: 0.202 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 40.05α = 90
b = 50.22β = 90
c = 131.38γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
XDSdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-04-03
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2019-07-24
    Changes: Data collection
  • Version 1.3: 2023-12-13
    Changes: Data collection, Database references, Other, Refinement description