New methods for the rational identification of molecules capable of interacting with specific naturally occurring proteins are provided, in order to yield new pharmacologically important compounds and treatment modalities. Broadly, the method comprises the steps of identifying a switch control ligand forming a part of a particular protein of interest, and also identifying a complemental switch control pocket forming a part of the protein and which interacts with said switch control ligand. The ligand interacts in vivo with Hie pocket to regulate the conformation and biological activity of the protein such that the protein assumes a first conformation and a first biological activity, upon the ligand-pocket interaction, and assumes a second, different conformation and biological activity in the absence of the ligand-pocket interaction. Next, respective samples of said protein in the first and second conformations are provided, and these are screened against one or more candidate molecules by contacting the molecules and the samples. Thereupon, small molecules which bind with the protein at the region of the pocket maybe identified. Novel protein-modulator adducts and methods of altering protein activity are also provided.