1PJV

Cobatoxin 1 from Centruroides noxius Scorpion venom: Chemical Synthesis, 3-D Structure in Solution, Pharmacology and Docking on K+ channels


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 20 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum, structures with acceptable covalent geometry, structures with favorable non-bond energy, structures with the least restraint violations, structures with the lowest energy, target function 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Cobatoxin 1 from Centruroides noxius scorpion venom: chemical synthesis, three-dimensional structure in solution, pharmacology and docking on K+ channels.

Jouirou, B.Mosbah, A.Visan, V.Grissmer, S.M'Barek, S.Fajloun, Z.Van Rietschoten, J.Devaux, C.Rochat, H.Lippens, G.El Ayeb, M.De Waard, M.Mabrouk, K.Sabatier, J.M.

(2004) Biochem.J. 377: 37-49

  • DOI: 10.1042/BJ20030977

  • PubMed Abstract: 
  • CoTX1 (cobatoxin 1) is a 32-residue toxin with three disulphide bridges that has been isolated from the venom of the Mexican scorpion Centruroides noxius Hoffmann. Here we report the chemical synthesis, disulphide bridge organization, 3-D (three-dime ...

    CoTX1 (cobatoxin 1) is a 32-residue toxin with three disulphide bridges that has been isolated from the venom of the Mexican scorpion Centruroides noxius Hoffmann. Here we report the chemical synthesis, disulphide bridge organization, 3-D (three-dimensional) solution structure determination, pharmacology on K+ channel subtypes (voltage-gated and Ca2+-activated) and docking-simulation experiments. An enzyme-based cleavage of the synthetic folded/oxidized CoTX1 indicated half-cystine pairs between Cys3-Cys22, Cys8-Cys27 and Cys12-Cys29. The 3-D structure of CoTX1 (solved by 1H-NMR) showed that it folds according to the common alpha/beta scaffold of scorpion toxins. In vivo, CoTX1 was lethal after intracerebroventricular injection to mice (LD50 value of 0.5 microg/mouse). In vitro, CoTX1 tested on cells expressing various voltage-gated or Ca2+-activated (IKCa1) K+ channels showed potent inhibition of currents from rat K(v)1.2 ( K(d) value of 27 nM). CoTX1 also weakly competed with 125I-labelled apamin for binding to SKCa channels (small-conductance Ca2+-activated K+ channels) on rat brain synaptosomes (IC50 value of 7.2 microM). The 3-D structure of CoTX1 was used in docking experiments which suggests a key role of Arg6 or Lys10, Arg14, Arg18, Lys21 (dyad), Ile23, Asn24, Lys28 and Tyr30 (dyad) residues of CoTX1 in its interaction with the rat K(v)1.2 channel. In addition, a [Pro7,Gln9]-CoTX1 analogue (ACoTX1) was synthesized. The two residue replacements were selected aiming to restore the RPCQ motif in order to increase peptide affinity towards SKCa channels, and to alter the CoTX1 dipole moment such that it is expected to decrease peptide activity on K(v) channels. Unexpectedly, ACoTX1 exhibited an activity similar to that of CoTX1 towards SKCa channels, while it was markedly more potent on IKCa1 and several voltage-gated K+ channels.


    Organizational Affiliation

    Laboratoire International Associé d'Ingénierie Biomoléculaire, CNRS UMR 6560, Bd Pierre Dramard, 13916 Marseille Cedex 20, France.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cobatoxin 1
A
32Centruroides noxiusN/A
Find proteins for O46028 (Centruroides noxius)
Go to UniProtKB:  O46028
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 20 
  • Selection Criteria: back calculated data agree with experimental NOESY spectrum, structures with acceptable covalent geometry, structures with favorable non-bond energy, structures with the least restraint violations, structures with the lowest energy, target function 
  • Olderado: 1PJV Olderado

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-03-09
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance