Structure-activity studies on scorpion toxins that block potassium channels
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Cited by (29)
Venom therapy in multiple sclerosis
2007, NeuropharmacologyCitation Excerpt :Some of these toxins have affinity for high conductance Ca2(+)-activated K+ channels and for dendrotoxin-sensitive voltage-dependent K+ channels. It has been tested the effects of charybdotoxin and two homologues (Lqh 15-1 and Lqh 18-2), iberiotoxin, and kaliotoxin from the scorpions Leiurus quinquestriatus hebreus, Buthus tamulus and Androctonus mauretanicus mauretanicus, respectively on potassium channels (Harvey et al., 1995). Kaliotoxin (a 37 residue polypeptide) displays a sequence homology with other scorpion-derived inhibitors of Ca(2+)-activated or voltage-gated K+ channels: 44% homology with charybdotoxin, 52% with noxiustoxin, and 44% with iberiotoxin (Crest et al., 1992; Canto et al., 1999; Fernandez et al., 1994).
Heterogeneous competition of Kv1 channel toxins with kaliotoxin for binding in rat brain: Autoradiographic analysis
2004, Neurochemistry InternationalComputational simulations of interactions of scorpion toxins with the voltage-gated potassium ion channel
2004, Biophysical JournalCitation Excerpt :The hydrogen bonds and the hydrophobic contacts present in the refined complexes are listed in Tables 3 and 4, respectively. The refined 3D models clearly indicate the important residue pairs for the binding, which cover most of the key residues that were experimentally verified as important for scorpion toxin-potassium channel binding (Aiyar et al., 1996; DeCoursey et al., 1984; Freudenthaler et al., 2002; Harvey et al., 1995; Hopkins, 1998; Miller 1995; Naranjo and Miller, 1996). For example, the conserved toxin residue Lys-27 (or Lys-28 in NTX and MgTX,) protrudes into the pore, interacting with residues Tyr-400, Asp-402, or His-404 in the signature sequence GYGD of the potassium channel via hydrogen bonding and electrostatic and hydrophobic interactions.