Screening method for drug discovery and investigating protein-protein interactions.
Drug discovery is typically dependant on screening methods that involve negative selection, or the death of cell cultures when exposed to a specific drug. This invention, a cytoxicity-based genetic selection method (TOXSEL), introduces a new screening method for drug discovery and protein-protein interactions in which the selection method is dependant on cell survival.
The technology utilizes a construct containing a segment of the diphtheria toxic (DT) gene causing cell death. The toxin causes cell death by ADP-ribosylating elongation factor-2, thereby inhibiting protein synthesis. Consequently, the control for such experiments is 100% cell death. The expression of the toxin is dependent on the interaction of two specific proteins. If the interaction is disrupted, the toxin is not expressed and the cell survives. Therefore, any small molecules, i.e., drugs, amino acids, or mutations which target the domains of interaction will disrupt expression of the toxin, resulting in cell survival. "Positive selection" for a novel drug will be based on cell survival.
TOXSEL enables investigators to i) define residues or motifs directly involved in protein-protein interactions, ii) identify specific targets for drug intervention and structure based drug design, iii) select small molecules for drug development, iv) identify new drugs that interfere with specific protein-protein interactions, and v) identify novel drugs that penetrate cell walls and act intracellularly.
The TOXSEL technology can be applied to the yeast 2-hybrid system.