2men | pdb_00002men

NMR solution structure of the GS-TAMAPIN MUTATION R13A

spinqualitylabelsall models 2men, 20 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2men is a 1 chain structure. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 2me7, 2mel, 2meo Resources: FirstGlance, OCA, RCSB, PDBsum Function [KAX54_MESTA] Blocks small conductance calcium-activated potassium channels in pyramidal neurons of the hippocampus. Displays a unique, remarkable selectivity for SK2/KCNN2 versus SK1/KCNN1 and SK3/KCNN3 channels. Publication Abstract from PubMed 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 alphaKTx5 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. 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 AL, Chavez-Uribe I, Brieba LG, Del Rio-Portilla F Chem Res Toxicol. 2014 May 12. PMID:24821061 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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