1JLP

Solution Structure of the Noncompetitive Skeletal Muscle Nicotinic Acetylcholine Receptor Antagonist Psi-conotoxin PIIIF


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 17 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum, structures with the least restraint violations, structures with the lowest energy 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Characterization and Three-Dimensional Structure Determination of psi-Conotoxin Piiif, a Novel Noncompetitive Antagonist of Nicotinic Acetylcholine Receptors

Van Wagoner, R.M.Ireland, C.M.

(2003) Biochemistry 42: 6353-6362

  • DOI: 10.1021/bi0272757

  • PubMed Abstract: 
  • A novel inhibitor of nicotinic acetylcholine receptors (nAChRs), psi-conotoxin Piiif, was isolated from the venom of Conus purpurascens and found to have the sequence GOOCCLYGSCROFOGCYNALCCRK-NH2. The sequence is highly homologous to that of psi-cono ...

    A novel inhibitor of nicotinic acetylcholine receptors (nAChRs), psi-conotoxin Piiif, was isolated from the venom of Conus purpurascens and found to have the sequence GOOCCLYGSCROFOGCYNALCCRK-NH2. The sequence is highly homologous to that of psi-conotoxin Piiie, a previously identified noncompetitive inhibitor of Torpedo electroplax nAChR, also isolated from C. purpurascens. Both psi-conotoxins block Torpedo and mouse nicotinic acetylcholine receptors (nAChRs), but psi-Piiif is less potent by a factor of 10(1)-10(2). A high-resolution structure of psi-Piiif was determined by NMR and molecular modeling calculations. Psi-Piiif analogues containing [(13)C]-labeled cysteine at selected positions were synthesized to resolve spectral overlap of Cys side chain proton signals. The structures are well-converged, with backbone atom position RMSDs of 0.21 A for the main body of the peptide between residues 4 and 22 and 0.47 A for all residues. The overall backbone conformation is closely similar to psi-Piiie, the main difference being in the degree of conformational disorder at the two termini. Psi-Piiie and psi-Piiif have similar locations of positive charge density, although psi-Piiif has a lower overall charge. One disulfide bridge of psi-Piiif appears to undergo dynamic conformational fluctuations based on both the model and on experimental observation. Chimeras in which the three intercysteine loops were swapped between psi-Piiie and psi-Piiif were tested for inhibitory activity against Torpedo nAChRs. The third loop, which contains no charged residues in either peptide, is the prime determinant of potency in these psi-conotoxins.


    Related Citations: 
    • Three-dimensional Solution Structure of Conotoxin psi-PIIIE, an Acetylcholine Gated Ion Channel Antagonist
      Mitchell, S.S.,Shon, K.J.,Foster, M.P.,Davis, D.R.,Olivera, B.M.,Ireland, C.M.
      (1998) Biochemistry 37: 1215
    • A Noncompetitive Peptide Inhibitor of the Nicotinic Acetylcholine Receptor from Conus purpurascens Venom
      Shon, K.J.,Grilley, M.,Jacobsen, R.,Cartier, G.E.,Hopkins, C.,Gray, W.R.,Watkins, M.,Hillyard, D.R.,Rivier, J.,Torres, J.,Yoshikami, D.,Olivera, B.M.
      (1997) Biochemistry 36: 9581


    Organizational Affiliation

    Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah 84112, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PSI-CONOTOXIN PIIIF
A
25Conus purpurascensMutation(s): 0 
Find proteins for P60245 (Conus purpurascens)
Go to UniProtKB:  P60245
Small Molecules
Modified Residues  2 Unique
IDChainsTypeFormula2D DiagramParent
NH2
Query on NH2
A
NON-POLYMERH2 N

--

HYP
Query on HYP
A
L-PEPTIDE LINKINGC5 H9 N O3PRO
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 17 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum, structures with the least restraint violations, structures with the lowest energy 
  • Olderado: 1JLP Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-06-24
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance