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 
  • R-Value Observed: 0.200 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.3 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: https://doi.org/10.1124/mol.108.050773
  • Primary Citation of Related Structures:  
    2VLW

  • 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 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.


  • 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:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
MUSCARINIC M1-TOXIN1
A, B
65Dendroaspis angusticepsMutation(s): 0 
Membrane Entity: Yes 
UniProt
Find proteins for Q8QGR0 (Dendroaspis angusticeps)
Explore Q8QGR0 
Go to UniProtKB:  Q8QGR0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8QGR0
Sequence Annotations
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  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D 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 
  • R-Value Observed: 0.200 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 26.766α = 90
b = 56.577β = 95.17
c = 45.308γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
HKLdata reduction
SCALEPACKdata scaling
MOLREPphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-10-14
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-12-13
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description