Pharmacological profiling of Orthochirus scrobiculosus toxin 1 analogs with a trimmed N-terminal domain

Stéphanie Mouhat, Georgeta Teodorescu, Daniel Homerick, Violeta Visan, Heike Wulff, Yingliang Wu, Stephan Grissmer, Hervé Darbon, Michel De Waard, Jean Marc Sabatier

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


OSK1, a toxin from the venom of the Asian scorpion Orthochirus scrobiculosus, is a 38-residue peptide cross-linked by three disulfide bridges. A structural analog of OSK1, [Lys16,Asp20]-OSK1, was found previously to be one of the most potent blockers of the voltage-gated K + channel Kv1.3 hitherto characterized. Here, we demonstrate that progressive trimming of the N-terminal domain of [Lys16,Asp 20]-OSK1 results in marked changes in its pharmacological profile, in terms of both K+ channel affinity and selectivity. Whereas the affinity to Kv1.1 and Kv1.3 did not change significantly, the affinity to Kv1.2 and KCa3.1 was drastically reduced with the truncations. It is surprising that a striking gain in potency was observed for Kv3.2. In contrast, a truncation of the C-terminal domain, expected to partially disrupt the toxin β-sheet structure, resulted in a significant decrease or a complete loss of activity on all channel types tested. These data highlight the value of structure-function studies on the extended N-terminal domain of [Lys 16,Asp20]-OSK1 to identify new analogs with unique pharmacological properties.

Original languageEnglish (US)
Pages (from-to)354-362
Number of pages9
JournalMolecular Pharmacology
Issue number1
StatePublished - Jan 2006

ASJC Scopus subject areas

  • Pharmacology


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