2VLW

Crystal structure of the muscarinic toxin MT7 diiodoTYR51 derivative.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.39 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.199 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Different Interactions between Mt7 Toxin and the Human Muscarinic M1 Receptor in its Free and N-Methylscopolamine-Occupied States.

Fruchart-Gaillard, C.Mourier, G.Marquer, C.Stura, E.Birdsall, N.J.M.Servent, D.

(2008) Mol.Pharmacol. 74: 1554

  • DOI: 10.1124/mol.108.050773

  • PubMed Abstract: 
  • Muscarinic MT7 toxin is a highly selective and potent antagonist of the M(1) subtype of muscarinic receptor and acts by binding to an allosteric site. To identify the molecular determinants by which MT7 toxin interacts with this receptor in its free ...

    Muscarinic MT7 toxin is a highly selective and potent antagonist of the M(1) subtype of muscarinic receptor and acts by binding to an allosteric site. To identify the molecular determinants by which MT7 toxin interacts with this receptor in its free and NMS-occupied states, the effect on toxin potency of alanine substitution was evaluated in equilibrium and kinetic binding experiments as well as in functional assays. The determination of the crystallographic structure of an MT7-derivative (MT7-diiodoTyr51) allowed the selection of candidate residues that are accessible and present on both faces of the three toxin loops. The equilibrium binding data are consistent with negative cooperativity between N-methylscopolamine (NMS) and wild-type or modified MT7 and highlight the critical role of the tip of the central loop of the toxin (Arg34, Met35 Tyr36) in its interaction with the unoccupied receptor. Examination of the potency of wild-type and modified toxins to allosterically decrease the dissociation rate of [(3)H]NMS allowed the identification of the MT7 residues involved in its interaction with the NMS-occupied receptor. In contrast to the results with the unoccupied receptor, the most important residue for this interaction was Tyr36 in loop II, assisted by Trp10 in loop I and Arg52 in loop III. The critical role of the tips of the MT7 loops was also confirmed in functional experiments. The high specificity of the MT7-M(1) receptor interaction exploits several MT7-specific residues and reveals a different mode of interaction of the toxin with the free and NMS-occupied states of the receptor.


    Related Citations: 
    • Comparison of the Structures of Two Muscarinic Toxins from Green Mamba Venom
      Menez, R.,Granata, V.,Mourier, G.,Ledu, M.H.,Servant, D.,Menez, A.,Stura, E.A.
      () TO BE PUBLISHED --: --


    Organizational Affiliation

    Commissariat à l'Energie Atomique, Institut de Biologie et de Tecnologies de Saclay, Service d'Ingénierie Moléculaire des Protéines, Laboratoire de Toxinologie Moléculaire et Biotechnologie, Gif sur Yvette, France.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
MUSCARINIC M1-TOXIN1
A, B
65Dendroaspis angusticepsMutation(s): 0 
Find proteins for Q8QGR0 (Dendroaspis angusticeps)
Go to UniProtKB:  Q8QGR0
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
ACT
Query on ACT

Download SDF File 
Download CCD File 
A
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
TYI
Query on TYI
A, B
L-PEPTIDE LINKINGC9 H9 I2 N O3TYR
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.39 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.199 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 26.766α = 90.00
b = 56.577β = 95.17
c = 45.308γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
MOLREPphasing
HKLdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-10-14
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance