Expression, renaturation and biological activity of recombinant conotoxin GeXIVAWT

Conotoxins are a diverse array of small peptides mostly with multiple disulfide bridges. These peptides become an increasing significant source of neuro-pharmacological probes and drugs as a result of the high selectivity for ion channels and receptors. Conotoxin GeXIVAWT (CTX-GeXIVAWT) is a 28-amino acid peptide containing five cysteines isolated from the venom of Conus generalis. Here, we present a simple and fast strategy of producing disulfide-rich conotoxins via recombinant expression. The codes of novel conotoxin gene GeXIVAWT were optimized and generated two pairs of primers by chemical synthesis for construction of expression vector. Recombinant expression vector pET22b(+)-GeXIVAWT fused with pelB leader and His-tag was successfully expressed as an insoluble body in Escherichia coli BL21(DE3) cells. Recombinant conotoxin GeXIVAWT (rCTX-GeXIVAWT) was obtained by dissolving the insoluble bodies and purifying with a Ni-NTA affinity column, which was further purified using reverse-phase high-performance liquid chromatography and identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The rCTX-GeXIVAWT renatured in vitro could inhibited the growth of Sf9 cell with biological activity assay. This expression system may prove valuable for future structure-function studies of conotoxins.