1A29

CALMODULIN COMPLEXED WITH TRIFLUOPERAZINE (1:2 COMPLEX)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.74 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.197 

Starting Model: experimental
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This is version 1.4 of the entry. See complete history


Literature

Simultaneous binding of drugs with different chemical structures to Ca2+-calmodulin: crystallographic and spectroscopic studies.

Vertessy, B.G.Harmat, V.Bocskei, Z.Naray-Szabo, G.Orosz, F.Ovadi, J.

(1998) Biochemistry 37: 15300-15310

  • DOI: https://doi.org/10.1021/bi980795a
  • Primary Citation of Related Structures:  
    1A29

  • PubMed Abstract: 

    The modulatory action of Ca2+-calmodulin on multiple targets is inhibited by trifluoperazine, which competes with target proteins for calmodulin binding. The structure of calmodulin crystallized with two trifluoperazine molecules is determined by X-ray crystallography at 2.74 A resolution. The X-ray data together with the characteristic and distinct signals obtained by circular dichroism in solution allowed us to identify the binding domains as well as the order of the binding of two trifluoperazine molecules to calmodulin. Accordingly, the binding of trifluperazine to the C-terminal hydrophobic pocket is followed by the interaction of the second drug molecule with an interdomain site. Recently, we demonstrated that the two bisindole derivatives, vinblastine and KAR-2 [3"-(beta-chloroethyl)-2",4"-dioxo-3, 5"-spirooxazolidino-4-deacetoxyvinblastine], interact with calmodulin with comparable affinity; however, they display different functional effects [Orosz et al. (1997) British J. Pharmacol. 121, 955-962]. The structural basis responsible for these effects were investigated by circular dichroism and fluorescence spectroscopy. The data provide evidence that calmodulin can simultaneously accommodate trifluoperazine and KAR-2 as well as vinblastine and KAR-2, but not trifluoperazine and vinblastine. The combination of the binding and structural data suggests that distinct binding sites exist on calmodulin for vinblastine and KAR-2 which correspond, at least partly, to that of trifluoperazine at the C-terminal hydrophobic pocket and at an interdomain site, respectively. This structural arrangement can explain why these drugs display different anticalmodulin activities. Calmodulin complexed with melittin is also able to bind two trifluoperazine molecules, the binding of which appears to be cooperative. Results obtained with intact and proteolytically cleaved calmodulin reveal that the central linker region of the protein is indispensable for simultanous interactions with two molecules of either identical or different ligands.


  • Organizational Affiliation

    Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CALMODULIN148Bos taurusMutation(s): 0 
UniProt
Find proteins for P62157 (Bos taurus)
Explore P62157 
Go to UniProtKB:  P62157
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP62157
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.74 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.197 
  • R-Value Observed: 0.197 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 40.75α = 90
b = 40.75β = 90
c = 177.57γ = 120
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
bioteXdata reduction
bioteXdata scaling
X-PLORphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-09-16
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-08-02
    Changes: Database references, Derived calculations, Other, Refinement description
  • Version 1.4: 2024-05-22
    Changes: Data collection