1HP2

SOLUTION STRUCTURE OF A TOXIN FROM THE SCORPION TITYUS SERRULATUS (TSTX-K ALPHA) DETERMINED BY NMR.


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 30 
  • Selection Criteria: structures with acceptable covalent geometry,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

Interaction of a toxin from the scorpion Tityus serrulatus with a cloned K+ channel from squid (sqKv1A).

Ellis, K.C.Tenenholz, T.C.Jerng, H.Hayhurst, M.Dudlak, C.S.Gilly, W.F.Blaustein, M.P.Weber, D.J.

(2001) Biochemistry 40: 5942-5953


  • PubMed Abstract: 
  • A toxin from the scorpion Tityus serrulatus (TsTX-Kalpha) blocks native squid K(+) channels and their cloned counterpart, sqKv1A, at pH 8 ((native)K(d) approximately 20 nM; (sqKv1A)K(d) approximately 10 nM). In both cases, decreasing the pH below 7.0 ...

    A toxin from the scorpion Tityus serrulatus (TsTX-Kalpha) blocks native squid K(+) channels and their cloned counterpart, sqKv1A, at pH 8 ((native)K(d) approximately 20 nM; (sqKv1A)K(d) approximately 10 nM). In both cases, decreasing the pH below 7.0 significantly diminishes the TsTX-Kalpha effect (pK = 6.6). In the cloned squid channel, the pH dependence of the block is abolished by a single point mutation (H351G), and no change in toxin affinity was observed at higher pH values (pH > or =8.0). To further investigate the TsTX-Kalpha-sqKv1A interaction, the three-dimensional structure of TsTX-Kalpha was determined in solution by NMR spectroscopy, and a model of the TsTX-Kalpha-sqKv1A complex was generated. As found for other alpha-K toxins such as charybdotoxin (CTX), site-directed mutagenesis at toxin residue K27 (K27A, K27R, and K27E) significantly reduced the toxin's affinity for sqKv1A channels. This is consistent with the TsTX-Kalpha-sqKv1A model reported here, which has K27 of the toxin inserted into the ion conduction pathway of the K(+) channel. This toxin-channel model also illustrates a possible mechanism for the pH-dependent block whereby lysine residues from TsTX-Kalpha (K6 and K23) are repelled by protonated H351 on sqKv1A at low pH.


    Related Citations: 
    • Polypeptide Toxins from the Venoms of Old World and New World Scorpions Preferentially Block Different Potassium Channels
      Blaustein, M.P.,Rogowski, R.S.,Schneider, M.J.,Krueger, B.K.
      (1991) MOL.PHARMACOL. 40: 932


    Organizational Affiliation

    Department of Biochemistry, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
TITYUSTOXIN K ALPHA
A
37Tityus serrulatus
Find proteins for P46114 (Tityus serrulatus)
Go to UniProtKB:  P46114
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 30 
  • Selection Criteria: structures with acceptable covalent geometry,structures with the least restraint violations,structures with the lowest energy 
  • Olderado: 1HP2 Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-06-13
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance