2axk
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="2axk" size="450" color="white" frame="true" align="right" spinBox="true" caption="2axk" /> '''Solution structure of discrepin, a scorpion ...)
Next diff →
Revision as of 06:18, 21 November 2007
|
Solution structure of discrepin, a scorpion venom toxin blocking K+ channels.
Overview
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.
About this Structure
2AXK is a Single protein structure of sequence from [1]. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Wed Nov 21 08:26:11 2007
