Peptide toxins from animals are potent inhibitors of ion channels and show great promise both as drugs to treat a range of disorders and as valuable tools in drug research. Utilizing Symphony® X peptide synthesizer from Gyros Protein Technologies, a research team based in France has explored ways of fluorescently labeling a scorpion peptide, BeKm-1, that inhibits the hERG ion channel. This channel is involved in cardiac activity and blocking it must be avoided when developing new drugs. The research team’s approach included protein-protein docking studies that enabled them to identify solvent-exposed residues in the peptide that were suitable for labeling. This enabled them to design and test analogs that maintained both specificity and mode of action of the native peptide.