Efficient recombinant production of RpII, a NaV-modulating peptide from the sea anemone Heteractis magnifica

The gene structure and amino acid sequences of the precursor proteins of the sea anemone Heteractis magnifica neurotoxin RpII, a modulator of voltage-gated sodium channels, have been determined. A technology has been developed for the recombinant production of RpII in the Escherichia coli BL21(DE3) expression system based on the pET32b vector containing the thioredoxin gene, which opens up the possibility of obtaining a pure neurotoxin for further structural and/or pharmacological studies. The neurotoxin exhibits a neurotropic effect when administered intravenously to mice in doses greater than 1 mg kg⁻¹, but is not lethal in doses up to 6 mg kg⁻¹ and, in addition, RpII in the nm range does significantly increase the metabolism of human malignant glioblastoma U87-MG.