Functional expression of a recombinant toxin - rPnTx2-6 - active in erectile function in rat.

In the current study, the putative cDNA for PnTx2-6 toxin of the Phoneutria nigriventer spider venom was cloned and expressed as tioredoxin fusion protein in the cytoplasm of Escherichia coli. The fusion protein was purified from the bacterial extracts by combination of immobilized Ni-ion affinity and gel filtration chromatographies. Then, it was cleaved by enterokinase and the generated recombinant PnTx2-6 (rPnTx2-6) was further purified by reverse-phase HPLC. Likewise the native toxin purified from the spider venom, rPnTx2-6 potentiates the erectile function when injected in rats. This result indicates that the production of functional recombinant PnTx2-6 might be an alternative to provide this basic and valuable tool for study, as well as for further understanding such complex physiological system, including its correlation with the central nervous system and local tissue factors.