NMR solution structure of the GS-TAMAPIN MUTATION R6A

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the least restraint violations 

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Cytotoxicity of recombinant tamapin and related toxin-like peptides on model cell lines.

Ramirez-Cordero, B.Toledano, Y.Cano-Sanchez, P.Hernandez-Lopez, R.Flores-Solis, D.Saucedo-Yanez, A.L.Chavez-Uribe, I.Brieba, L.G.Del Rio-Portilla, F.

(2014) Chem Res Toxicol 27: 960-967

  • DOI: https://doi.org/10.1021/tx4004193
  • Primary Citation of Related Structures:  
    2KY3, 2LU9, 2ME7, 2MEL, 2MEN, 2MEO

  • PubMed Abstract: 

    The scorpion toxin tamapin displays the most potent and selective blockage against KCa2.2 channels known to date. In this work, we report the biosynthesis, three-dimensional structure, and cytotoxicity on cancer cell lines (Jurkat E6-1 and human mammary breast cancer MDA-MB-231) of recombinant tamapin and five related peptides bearing mutations on residues (R6A,R7A, R13A, R6A-R7A, and GS-tamapin) that were previously suggested to be important for tamapin's activity. The indicated cell lines were used as they constitutively express KCa2.2 channels. The studied toxin-like peptides displayed lethal responses on Jurkat T cells and breast cancer cells; their effect is dose- and time-dependent with IC50 values in the nanomolar range. The order of potency is r-tamapin>GS-tamapin>R6A>R13A>R6A-R7A>R7A for Jurkat T cells and r-tamapin>R7A for MDA-MB-231 breast cancer cells. Our structural determination by NMR demonstrated that r-tamapin preserves the folding of the αKTx5 subfamily and that neither single nor double alanine mutations affect the three-dimensional structure of the wild-type peptide. In contrast, our activity assays show that changes in cytotoxicity are related to the chemical nature of certain residues. Our results suggest that the toxic activity of r-tamapin on Jurkat and breast cancer cells could be mediated by the interaction of charged residues in tamapin with KCa2.2 channels via the apoptotic cell death pathway.

  • Organizational Affiliation

    Instituto de Química, Universidad Nacional Autónoma de México , Ciudad Universitaria, Circuito Exterior s/n, México, D.F. 04510, México.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Potassium channel toxin alpha-KTx 5.433Mesobuthus tamulusMutation(s): 1 
Find proteins for P59869 (Hottentotta tamulus)
Explore P59869 
Go to UniProtKB:  P59869
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UniProt GroupP59869
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 200 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the least restraint violations 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-05-28
    Type: Initial release
  • Version 1.1: 2014-07-02
    Changes: Database references