2Q0U

Structure of Pectenotoxin-2 and Latrunculin B Bound to Actin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.45 Å
  • R-Value Free: 0.181 
  • R-Value Work: 0.165 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

A structural basis for regulation of actin polymerization by pectenotoxins.

Allingham, J.S.Miles, C.O.Rayment, I.

(2007) J.Mol.Biol. 371: 959-970

  • DOI: 10.1016/j.jmb.2007.05.056
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • (PTXs) are polyether macrolides found in certain dinoflagellates, sponges and shellfish, and have been associated with diarrhetic shellfish poisoning. In addition to their in vivo toxicity, some PTXs are potently cytotoxic in human cancer cell lines. ...

    (PTXs) are polyether macrolides found in certain dinoflagellates, sponges and shellfish, and have been associated with diarrhetic shellfish poisoning. In addition to their in vivo toxicity, some PTXs are potently cytotoxic in human cancer cell lines. Recent studies have demonstrated that disruption of the actin cytoskeleton may be a key function of these compounds, although no clarification of their mechanism of action at a molecular level was available. We have obtained an X-ray crystal structure of PTX-2 bound to actin, which, in combination with analyses of the effect of PTX-2 on purified actin filament dynamics, provides a molecular explanation for its effects on actin. PTX-2 formed a 1:1 complex with actin and engaged a novel site between subdomains 1 and 3. Based on models of the actin filament, PTX binding would disrupt key lateral contacts between the PTX-bound actin monomer and the lower lateral actin monomer within the filament, thereby capping the barbed-end. The location of this binding position within the interior of the filament indicates that it may not be accessible once polymerization has occurred, a hypothesis supported by our observation that PTX-2 caused filament capping without inducing filament severing. This mode of action is unique, as other actin filament destabilizing toxins appear to exclusively disrupt longitudinal monomer contacts, allowing many of them to sever filaments in addition to capping them. Examination of the PTX-binding site on actin provides a rationalization for the structure-activity relationships observed in vivo and in vitro, and may provide a basis for predicting toxicity of PTX analogues.


    Organizational Affiliation

    Department of Biochemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Actin
A
375Oryctolagus cuniculusMutation(s): 0 
Gene Names: ACTA1 (ACTA)
Find proteins for P68135 (Oryctolagus cuniculus)
Go to Gene View: ACTA1
Go to UniProtKB:  P68135
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ATP
Query on ATP

Download SDF File 
Download CCD File 
A
ADENOSINE-5'-TRIPHOSPHATE
C10 H16 N5 O13 P3
ZKHQWZAMYRWXGA-KQYNXXCUSA-N
 Ligand Interaction
CA
Query on CA

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Download CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
LAB
Query on LAB

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Download CCD File 
A
LATRUNCULIN B
C20 H29 N O5 S
NSHPHXHGRHSMIK-JRIKCGFMSA-N
 Ligand Interaction
PXT
Query on PXT

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Download CCD File 
A
PECTENOTOXIN-2
C47 H68 O14
UUHLZWPSPOPYFR-LTNDQFMQSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
HIC
Query on HIC
A
L-PEPTIDE LINKINGC7 H11 N3 O2HIS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.45 Å
  • R-Value Free: 0.181 
  • R-Value Work: 0.165 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 57.683α = 90.00
b = 54.342β = 90.27
c = 105.895γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
HKL-3000data collection
HKL-3000data reduction
PDB_EXTRACTdata extraction
SCALEPACKdata scaling
REFMACrefinement
MOLREPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-07-17
    Type: Initial release
  • Version 1.1: 2007-10-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-18
    Type: Refinement description