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From Proteopedia
Solution Structure of CssII
Structural highlights
FunctionSCX2_CENSU Beta toxin. Both native and non-amidated recombinant forms of this protein bind in a voltage-independent fashion at site-4 of Nav1.6/SCN8A voltage-gated sodium channels. This binding shifts the voltage of activation towards more negative potentials which in turn affects sodium channel activation and promotes spontaneous and repetitive firing. This toxin is only active against mammals. Binds to phospholipids.[1] [2] Publication Abstract from PubMedThe three-dimensional structures of the long-chain mammalian scorpion beta-toxin CssII from Centruroides suffusus suffusus and of its recombinant form, HisrCssII, were determined by NMR. The neurotoxin CssII (nCssII) is a 66 amino acid long peptide with four disulfide bridges; it is the most abundant and deadly toxin from the venom of this scorpion. Both native and recombinant CssII structures were determined by nuclear magnetic resonance using a total of 828 sequential distance constraints derived from the volume integration of the cross peaks observed in 2D NOESY spectra. Both nCssII and HisrCssII structures display a mixed alpha/beta fold stabilized by four disulfide bridges formed between pairs of cysteines: C1-C8, C2-C5, C3-C6, and C4-C7 (the numbers indicate the relative positions of the cysteine residues in the primary structure), with a distortion induced by two cis-prolines in its C-terminal part. The native CssII electrostatic surface was compared to both the recombinant one and to the Cn2 toxin, from the scorpion Centruroides noxius, which is also toxic to mammals. Structural features such N- and C-terminal differences could influence toxin specificity and affinity towards isoforms of different sub-types of Na(v) channels. Solution structure of native and recombinant expressed toxin CssII from the venom of the scorpion Centruroides suffusus suffusus, and their effects on Nav1.5 Sodium channels.,Saucedo AL, Del Rio-Portilla F, Picco C, Estrada G, Prestipino G, Possani LD, Delepierre M, Corzo G Biochim Biophys Acta. 2012 Mar;1824(3):478-87. Epub 2012 Jan 11. PMID:22251893[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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