Animal toxins and ion channels

Animal venoms contain various toxins which act on ion-channels, responsible for either sodium, potassium, calcium or chloride permeation. Structure determination of these toxins demonstrate that they are organised around two different structural motifs: potassium and sodium channel effectors are organised around an alpha-helix connected by two disulfide bridges to a two- or three-stranded beta sheet whereas calcium channels effectors are structured around an "Inhibitory Cystine Knot" motif made of a dense disulfide-rich core from which emerge several loops. Analysis of local structural modifications allows us to understand the structural basis of the selectivity of these effectors towards the various ion channels. This is the first step in the design of new synthetic molecules which are potent therapeutic drugs for diseases involving ion channel dysfunctioning.