1nrb
From Proteopedia
SOLUTION STRUCTURE OF AN OLD WORLD-LIKE NEUROTOXIN FROM THE VENOM OF THE NEW WORLD SCORPION CENTRUROIDES SCULPTURATUS EWING
Structural highlights
Function[SCXV_CENSC] Alpha toxins bind voltage-independently at site-3 of sodium channels (Nav) and inhibit the inactivation of the activated channels, thereby blocking neuronal transmission. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedWe have determined the solution structure of an alpha-toxin, CsE-V, isolated from the venom of the New World scorpion Centruroides sculpturatus Ewing (CsE). This toxin causes spontaneous rhythmic contractions in muscle. Unlike other New World toxins from CsE, this protein exhibits amino acid insertions and deletions at locations similar to Old World toxins and may thus represent a transition protein between the New World and Old World scorpion alpha-toxins. Sequence-specific assignments were made using 600 MHz 1H two-dimensional NMR data. NOESY, PH-COSY and amide-exchange data were used to deduce constraints for molecular modeling calculations. Distance geometry and dynamical simulated annealing calculations were performed to generate a family of 70 structures free of constraint violations. With respect to this family of structures, the energy-minimized average structure had root-mean-square deviations of 0.74 and 1.32 A for backbone and all atoms, respectively (excluding the C-terminal dipeptide, which is disordered). As with other scorpion toxins, the secondary structure of CsE-V consists of an alpha-helix, a three-strand anti-parallel beta-sheet, four beta-turns, and a hydrophobic patch that includes tyrosine residues in herringbone configuration. Unlike the CsE-v3 and -v1 proteins from C. sculpturatus, all of the proline residues were found to be in the trans configuration. The alpha-helix is slightly longer in CsE-V. The overall structure is more similar to the Old World alpha-toxin AaH-II from Androctonus australis Hector (r.m.s.d 1.59 A for backbone atoms of matching residues) than to the New World alpha-toxin CsE-v3 (r.m.s.d. 1.91 A). These structural data on CsE-V add further to our knowledge of the conformational repertoire exhibited by these sodium channel-binding neurotoxins. Solution structure of an Old World-like neurotoxin from the venom of the New World scorpion Centruroides sculpturatus Ewing.,Jablonsky MJ, Watt DD, Krishna NR J Mol Biol. 1995 Apr 28;248(2):449-58. PMID:7739052[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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