Variability of Potassium Channel Blockers in Mesobuthus eupeus Scorpion Venom with Focus on Kv1.1: an Integrated Transcriptomic and Proteomic Study [Genomics and Proteomics]

March 19th, 2015 by Kuzmenkov, A. I., Vassilevski, A. A., Kudryashova, K. S., Nekrasova, O. V., Peigneur, S., Tytgat, J., Feofanov, A. V., Kirpichnikov, M. P., Grishin, E. V.

The lesser Asian scorpion Mesobuthus eupeus (Buthidae) is one of the most widely spread and dispersed species of the Mesobuthus genus and its venom is actively studied. Nevertheless, a considerable amount of active compounds is still under-investigated due to the high complexity of this venom. Here we report a comprehensive analysis of putative potassium channel toxins (KTxs) from the cDNA library of M. eupeus venom glands and compare the deduced KTx structures with peptides purified from the venom. For the transcriptome analysis we used conventional tools as well as a search for structural motifs characteristic of scorpion venom components in the form of regular expressions. We found 59 candidate KTxs distributed in 30 subfamilies and presenting the cysteine-stabilized α/β (CSα/β) and inhibitor cystine knot (ICK) types of fold. M. eupeus venom was then separated to individual components by multi-stage chromatography. A facile fluorescent system based on the expression of the KcsA-Kv1.1 hybrid channels in Escherichia coli and utilization of a labeled scorpion toxin was elaborated and applied to follow Kv1.1 pore-binding activity during venom separation. As a result, eight high-affinity Kv1.1 channel blockers were identified including five novel peptides, which extend the panel of potential pharmacologically important Kv1 ligands. Activity of the new peptides against rat Kv1.1 channel was confirmed (IC50 in the range of 1-750 nM) by the two-electrode voltage-clamp technique using a standard Xenopus oocyte system. Our integrated approach is of general utility and efficiency to mine natural venoms for KTxs.
  • Posted in Journal of Biological Chemistry, Publications
  • Comments Off on Variability of Potassium Channel Blockers in Mesobuthus eupeus Scorpion Venom with Focus on Kv1.1: an Integrated Transcriptomic and Proteomic Study [Genomics and Proteomics]