The University of Queensland team made the claim at a Biophysical Society meeting this week after presenting data showing the toxin - ProTx-II – is attracted to nerve cells in such an orientation that it can inhibit a pain receptor called Nav1.7.
Understanding this interaction may aid drug design says researcher Sonia Troeira Henriques, who told us compounds based on ProTx-II that can block Nav1.7 could be used to treat patients who have developed resistance to opioid painkillers.
“At this stage we can’t guarantee that ProTx-II will be pursued as a painkiller, but the fact that inhibits receptors distinct from opioid receptors, is of potential therapeutic interest as it might bring alternatives to the current drugs.”
ProTx-II is found in the venom of the Peruvian green velvet tarantula (Thrixopelma pruriens). An earlier study suggested it could block the transmission of pain, however, prior to Henriques’ work the interaction was poorly understood.
“We are interested in the three-dimensional structure and in characterizing the mode-of-action of this toxin” she said, explaining that the ProTx-II being studied by her team is synthesized chemically rather than being extracted from tarantula venom.
“Currently we produce it chemically, but we are also making progresses in expressing it recombinantely using bacterial expression” Henriques said, adding that “at this stage we can’t be sure which way will be best to obtain the peptide toxin in greater amounts.”
ProTx-II may never bused therapeutically but a better understanding its mode of action “will help the design of painkillers that can target Nav1.7 in an efficient and selective manner and with fewer side effects than current drugs on the market” Henriques said.