2axk

Solution structure of discrepin, a scorpion venom toxin blocking K+ channels.

spinqualitylabelsall models 2axk, 10 NMR models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2axk is a 1 chain structure. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. NonStd Res: PCA Resources: FirstGlance, OCA, RCSB, PDBsum Function [KA156_TITDI] Irreversibly blocks the A-type voltage-gated potassium channels in rat cerebellum granular cells. Publication Abstract from PubMed Discrepin, isolated from the venom of the Venezuelan scorpion Tityus discrepans, blocks preferentially the I(A) currents of the voltage-dependent K+ channel of rat cerebellum granular cells in an irreversible way. It contains 38 amino acid residues with a pyroglutamic acid as the N-terminal residue [D'Suze, G., Batista, C. V., Frau, A., Murgia, A. R., Zamudio, F. Z., Sevcik, C., Possani, L. D., and Prestipino, G. (2004) Arch. Biochem. Biophys. 430, 256-63]. It is the most distinctive member of the alpha-KTx15 subfamily of scorpion toxins. Six members of the alpha-KTx15 subfamily have been reported so far to be specific for this subtype of the K+ channel; however, none of them have had their three-dimensional structure determined, and no information for the residues possibly involved in channel recognition and binding is available. Natural discrepin (n-discrepin) was prepared from scorpion venom, and its synthetic analogue (s-discrepin) was obtained by solid-phase synthesis. Analysis of two-dimensional 1H NMR spectra of n- and s-discrepin indicates that both peptides have the same structure. Here we report the solution structure of s-discrepin determined by NMR using 565 meaningful distance constraints derived from the volume integration of the two-dimensional NOESY spectrum, 22 dihedrals, and three hydrogen bonds. Discrepin displays the alpha/beta scaffold, characteristic of scorpion toxins. Some features of the proposed interacting surface between the toxin and channel as well as the opposite "alpha-helix surface" are discussed in comparison with those of other alpha-KTx15 members. Both n- and s-discrepin exhibit similar physiological actions as verified by patch-clamp and binding and displacement experiments. Solution structure of discrepin, a new K+-channel blocking peptide from the alpha-KTx15 subfamily.,Prochnicka-Chalufour A, Corzo G, Satake H, Martin-Eauclaire MF, Murgia AR, Prestipino G, D'Suze G, Possani LD, Delepierre M Biochemistry. 2006 Feb 14;45(6):1795-804. PMID:16460026 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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