Most drugs are effective because they bind to a particular target site on a protein (receptor site) and block the physiological function of the protein. Many drug companies will design structural variants for compounds that bind receptor sites in hope of making making a compound that is more effective. Until recently design of new drugs was very difficult. Scientists had no way to know what the binding site of the protein looked like.
Scientist now have a powerful new tool. Molecular modeling allows researchers to view the 3-D structure of proteins and their binding sites using data from X-ray crystallography and NMR spectoscopy.
The synthesis of several recent drugs (including HIV Protease Inhibitorsfor treatment of AIDS) have been assisted using the 3-D structure of protein.