Conotoxins: review and docking studies to determine potentials of conotoxin as an anticancer drug molecule.

It is known that potassium channels are important for cell proliferation. HERG, a potassium channel protein, is a transmembrane protein, which increases in concentration on the cell surface of cancer cells. Apart from cancer cells, this protein is found only in the brain & heart tissue, in very low number. The proliferation of cells in cancer is dependent on activation of this protein, and it has been noted that blocking of this protein with drug molecule, helps inhibit the proliferation of the cells further. The current work aims to study the binding potentials of κ-PVIIA, conotoxin isolated from Conus purpurascens venom with HERG K+ channel of tumor cells, where HERG mutation has been noted. The toxin under consideration i.e. κ-conotoxins-PVIIA (κ-PVIIA) is a 27 residue peptide. The docking studies suggest that the conotoxin binds stably to the HERG protein. The study shows that the peptide interacts with the charged extracellular unit of the HERG protein, i.e. the extracellular portion of the S5 domain named S5-P extracellular linker. Study of binding of toxins of similar origin, with normal potassium channels has been studied in silico. Further, wet laboratory work needs to be conducted for development of a drug molecule from this toxin, to treat some number of cancers.