title: Chemical synthesis and folding of APETx2, a potent and selective inhibitor of acid sensing ion channel 3.
abstract: Acid sensing ion channels (ASICs) are pH-sensitive channels that are distributed in the central and peripheral nervous system and which are believed to play a key role in pain perception. APETx2, a 42-residue peptide toxin isolated from the sea anemone Anthopleura elegantissima, is the only known selective inhibitor of ASIC3 channels. Here we describe the total chemical synthesis of APETx2 by solid-phase peptide synthesis and native chemical ligation. The folded synthetic toxin had an IC(50) of 57 nM for inhibition of rat ASIC3 channels expressed in Xenopus oocytes, in agreement with the IC(50) reported for the native toxin (63 nM). The native chemical ligation approach should provide an efficient route for synthesis of other pharmacologically useful disulfide-rich toxins from venomous animals.
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Road, St Lucia, QLD 4072, Australia.
authors.forename: Jonas E
authors.initials: JE
authors.lastname: Jensen
authors.forename: Thomas
authors.initials: T
authors.lastname: Durek
authors.forename: Paul F
authors.initials: PF
authors.lastname: Alewood
authors.forename: David J
authors.initials: DJ
authors.lastname: Adams
authors.forename: Glenn F
authors.initials: GF
authors.lastname: King
authors.forename: Lachlan D
authors.initials: LD
authors.lastname: Rash
mesh_terms: D062565:Acid Sensing Ion Channels; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003064:Cnidarian Venoms / Q000138:chemical synthesis* / Q000737:chemistry* / Q000494:pharmacology; D004220:Disulfides / Q000633:toxicity; D004594:Electrophysiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008387:Marine Toxins / Q000737:chemistry* / Q000494:pharmacology; D013058:Mass Spectrometry; D009419:Nerve Tissue Proteins / Q000187:drug effects*; D009865:Oocytes / Q000187:drug effects; D010084:Oxidation-Reduction; D017510:Protein Folding; D051381:Rats; D015222:Sodium Channels / Q000187:drug effects*; D014982:Xenopus laevis
chemical_list: C501880:APETx2 protein, Anthopleura elegantissima; C568269:ASIC3 protein, rat; D062565:Acid Sensing Ion Channels; D003064:Cnidarian Venoms; D004220:Disulfides; D008387:Marine Toxins; D009419:Nerve Tissue Proteins; D015222:Sodium Channels