1WT7

Solution structure of BuTX-MTX: a butantoxin-maurotoxin chimera


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 25 
  • Selection Criteria: structures with the lowest energy, structures with the least restraint violations 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Increasing the molecular contacts between maurotoxin and Kv1.2 channel augments ligand affinity.

M'Barek, S.Chagot, B.Andreotti, N.Visan, V.Mansuelle, P.Grissmer, S.Marrakchi, M.El Ayeb, M.Sampieri, F.Darbon, H.Fajloun, Z.De Waard, M.Sabatier, J.M.

(2005) Proteins 60: 401-411

  • DOI: 10.1002/prot.20509

  • PubMed Abstract: 
  • Scorpion toxins interact with their target ion channels through multiple molecular contacts. Because a "gain of function" approach has never been described to evaluate the importance of the molecular contacts in defining toxin affinity, we experiment ...

    Scorpion toxins interact with their target ion channels through multiple molecular contacts. Because a "gain of function" approach has never been described to evaluate the importance of the molecular contacts in defining toxin affinity, we experimentally examined whether increasing the molecular contacts between a toxin and an ion channel directly impacts toxin affinity. For this purpose, we focused on two scorpion peptides, the well-characterized maurotoxin with its variant Pi1-like disulfide bridging (MTX(Pi1)), used as a molecular template, and butantoxin (BuTX), used as an N-terminal domain provider. BuTX is found to be 60-fold less potent than MTX(Pi1) in blocking Kv1.2 (IC(50) values of 165 nM for BuTX versus 2.8 nM for MTX(Pi1)). Removal of its N-terminal domain (nine residues) further decreases BuTX affinity for Kv1.2 by 5.6-fold, which is in agreement with docking simulation data showing the importance of this domain in BuTX-Kv1.2 interaction. Transfer of the BuTX N-terminal domain to MTX(Pi1) results in a chimera with five disulfide bridges (BuTX-MTX(Pi1)) that exhibits 22-fold greater affinity for Kv1.2 than MTX(Pi1) itself, in spite of the lower affinity of BuTX as compared to MTX(Pi1). Docking experiments performed with the 3-D structure of BuTX-MTX(Pi1) in solution, as solved by (1)H-NMR, reveal that the N-terminal domain of BuTX participates in the increased affinity for Kv1.2 through additional molecular contacts. Altogether, the data indicate that acting on molecular contacts between a toxin and a channel is an efficient strategy to modulate toxin affinity.


    Organizational Affiliation

    Laboratoire d'Ingénierie des Protéines, CNRS FRE 2738, IFR Jean Roche, Faculté de Médecine Nord, Marseille, France.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
BuTX-MTX
A
41Scorpio palmatusTityus serrulatus
This entity is chimeric
Mutation(s): 0 
Find proteins for P80719 (Scorpio palmatus)
Go to UniProtKB:  P80719
Find proteins for P59936 (Tityus serrulatus)
Go to UniProtKB:  P59936
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 25 
  • Selection Criteria: structures with the lowest energy, structures with the least restraint violations 
  • Olderado: 1WT7 Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-11-30
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance