{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,4]],"date-time":"2026-10-04T09:07:57Z","timestamp":1791104877496,"version":"4.1.0"},"reference-count":52,"publisher":"Portland Press Ltd.","issue":"2","content-domain":{"domain":["portlandpress.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2005,6,1]]},"abstract":"<jats:p>We have purified and characterized two peptides, named KAaH1 and KAaH2 (AaH polypeptides 1 and 2 active on K+ channels, where AaH stands for Androctonus australis Hector), from the venom of A. australis Hector scorpions. Their sequences contain 58 amino acids including six half-cysteines and differ only at positions 26 (Phe\/Ser) and 29 (Lys\/Gln). Although KAaH1 and KAaH2 show important sequence similarity with anti-mammal \u03b2 toxins specific for voltage-gated Na+ channels, only weak \u03b2-like effects were observed when KAaH1 or KAaH2 (1\u00a0\u03bcM) were tested on brain Nav1.2 channels. In contrast, KAaH1 blocks Kv1.1 and Kv1.3 channels expressed in Xenopus oocytes with IC50 values of 5 and 50\u00a0nM respectively, whereas KAaH2 blocks only 20% of the current on Kv1.1 and is not active on Kv1.3 channels at a 100\u00a0nM concentration. KAaH1 is thus the first member of a new subfamily of long-chain toxins mainly active on voltage-gated K+ channels. NMR spectra of KAaH1 and KAaH2 show good dispersion of signals but broad lines and poor quality. Self-diffusion NMR experiments indicate that lines are broadened due to a conformational exchange on the millisecond time scale. NMR and CD indicate that both polypeptides adopt a similar fold with \u03b1-helical and \u03b2-sheet structures. Homology-based molecular models generated for KAaH1 and KAaH2 are in accordance with CD and NMR data. In the model of KAaH1, the functionally important residues Phe26 and Lys29 are close to each other and are located in the \u03b1-helix. These residues may constitute the so-called functional dyad observed for short \u03b1-KTx scorpion toxins in the \u03b2-sheet.<\/jats:p>","DOI":"10.1042\/bj20041407","type":"journal-article","created":{"date-parts":[[2005,6,7]],"date-time":"2005-06-07T09:42:14Z","timestamp":1118137334000},"page":"455-464","update-policy":"https:\/\/doi.org\/10.1042\/crossmark_policy","source":"Crossref","is-referenced-by-count":39,"title":["A new type of scorpion Na+-channel-toxin-like polypeptide active on K+ channels"],"prefix":"10.1042","volume":"388","author":[{"given":"Najet","family":"SRAIRI-ABID","sequence":"first","affiliation":[{"name":"Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13, place Pasteur, BP-74 Tunis 1002, Tunisia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joseba\u00a0I\u00f1aki","family":"GUIJARRO","sequence":"additional","affiliation":[{"name":"Unit\u00e9 de RMN des Biomol\u00e9cules, D\u00e9pt. de Biologie Structurale et Chimie, Institut Pasteur (CNRS URA 2185), 28 rue du Docteur Roux, 75724 Paris Cedex 15, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rym","family":"BENKHALIFA","sequence":"additional","affiliation":[{"name":"Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13, place Pasteur, BP-74 Tunis 1002, Tunisia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Massimo","family":"MANTEGAZZA","sequence":"additional","affiliation":[{"name":"Cellular Neurophysiology Laboratory, Istituto Neurologico, Besta Via Libero Temolo 4, 20126 Milano, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Amani","family":"CHEIKH","sequence":"additional","affiliation":[{"name":"Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13, place Pasteur, BP-74 Tunis 1002, Tunisia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Manel","family":"BEN\u00a0AISSA","sequence":"additional","affiliation":[{"name":"Unit\u00e9 de RMN des Biomol\u00e9cules, D\u00e9pt. de Biologie Structurale et Chimie, Institut Pasteur (CNRS URA 2185), 28 rue du Docteur Roux, 75724 Paris Cedex 15, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pierre-Yves","family":"HAUMONT","sequence":"additional","affiliation":[{"name":"Soci\u00e9t\u00e9 Applied Biosystems, 25 avenue de la Baltique, BP 96, 91943 Courtaboeuf Cedex, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Muriel","family":"DELEPIERRE","sequence":"additional","affiliation":[{"name":"Unit\u00e9 de RMN des Biomol\u00e9cules, D\u00e9pt. de Biologie Structurale et Chimie, Institut Pasteur (CNRS URA 2185), 28 rue du Docteur Roux, 75724 Paris Cedex 15, France"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mohamed","family":"EL\u00a0AYEB","sequence":"additional","affiliation":[{"name":"Laboratoire des Venins et Toxines, Institut Pasteur de Tunis, 13, place Pasteur, BP-74 Tunis 1002, Tunisia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"288","published-online":{"date-parts":[[2005,5,24]]},"reference":[{"key":"2021112217432545100_B1","doi-asserted-by":"crossref","first-page":"514","DOI":"10.1111\/j.1432-1033.1970.tb01111.x","article-title":"Purification of animal neurotoxins. 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