New Sea Anemone Toxin RTX-Ⅵ Selectively Modulates Voltage-Gated Sodium Channels

摘要

A new neurotoxin RTX-VI that modulates the voltage-gated sodium channels (Na-V) was isolated from the ethanolic extract of the sea anemone Heteractis crispa. Its amino acid sequence was determined using the combination of Edman degradation and tandem mass spectrometry. RTX-VI turned out to be an unusual natural analogue of the previously described sea anemone toxin RTX-III. The RTX-VI molecule consists of two disulfide-linked peptide chains and is devoid of Arg13, which is important for the selectivity and affinity of such peptides for the Na-V channels. Electrophysiological screening of RTV-VI on Na-V channel subtypes showed its selective interaction with the central nervous system (Na(V)1.2, Na(V)1.6) and insect (BgNa(V)1, VdNa(V)1) sodium channels.