"There's a little yellow pill," the Rolling Stones once crooned, to get mom through her busy day. Whether or not the song was about Valium, the sedative became "mother's little helper" for a generation. Most of the millions who popped it to calm their nerves had no idea how it worked. Although Valium wasn't a perfect therapy, drugmakers are trying to co-opt the good side of its mechanism of action to develop new medicines aimed at G-protein-coupled receptors (GPCRs), one of the biggest classes of drug targets.

Valium and its molecular relatives, the benzodiazepines, are among the founding members of a growing family of allosteric drugs. Allosteric means "other site," and that is where allosteric drugs exert their effects-at protein sites outside of the one where the body's chemicals usually bind, known as the orthosteric site in pharmaceutical parlance. As a result, allosteric compounds have a host of attributes that make them attractive therapies.

Read More: Allosteric drugs promise precise control over diseases mediated by G-protein-coupled receptors