1scy
DETERMINATION OF THE THREE-DIMENSIONAL STRUCTURE OF SCYLLATOXIN BY 1H NUCLEAR MAGNETIC RESONANCE
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OverviewOverview
The three-dimensional solution structure of Scyllatoxin (leiurotoxin I) a, venom peptide from the scorpion Leiurus quinquestriatus hebraeus was, determined at 1 A resolution by homonuclear proton n.m.r. methods at 500, MHz. Data analysis and structure calculation followed conventional, protocols inherent to DIANA and related programs with two exceptions., First, distance constraints were obtained from two-dimensional nuclear, Overhauser spectra by a previously described partial relaxation matrix, approach. Second, since the pairing pattern of the six cysteine residues, was not established a priori, the unequivocal assignment of the disulfide, bridges was achieved exclusively from the n.m.r. data by a statistical, analysis of preliminary DIANA structures. In the final calculation we used, 227 upper distance constraints, 67 torsional constraints from vicinal, coupling constants and ten stereospecific assignments of beta-methylene, protons. Scyllatoxin folds into a compact ellipsoidal shape. An, alpha-helix (defined with 0.24 A resolution) spanning 2.5 turns from Leu5, till Ser14 is stabilized by Cys8-Cys26 and Cys12-Cys28 disulfide bridges, to the carboxy-terminal strand of an anti-parallel beta-sheet. The, antiparallel beta-sheet (defined at 0.66 A resolution) extends from Leu18, to Val29 with a tight turn at Gly23-Asp24 and displays a right-handed, twist. Scyllatoxin competes with the toxins apamin from Apis mellifera, mellifera and P05 from Androctonus mauretanicus mauretanicus for the same, or similar high conductance calcium-activated potassium channels., Consideration of presently known biological activities and, three-dimensional structures of these toxins suggest a different, toxin-receptor interaction of scyllatoxin as compared to apamin and P05.
About this StructureAbout this Structure
1SCY is a Single protein structure of sequence from Leiurus quinquestriatus hebraeus with NH2 as ligand. Full crystallographic information is available from OCA.
ReferenceReference
Determination of the three-dimensional solution structure of scyllatoxin by 1H nuclear magnetic resonance., Martins JC, Van de Ven FJ, Borremans FA, J Mol Biol. 1995 Nov 3;253(4):590-603. PMID:7473736
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