THE APPLICATION OF STEREOLITHOGRAPHY TO THE FABRICATION OF ACCURATE MOLECULAR-MODELS

The process of stereolithography, which automatically fabricates plast ic models from designs created in certain computer-aided design progra ms,: has been applied to the production of accurate plastic molecular models. Atomic coordinates obtained from quantum mechanical calculatio ns and from neutron diffraction data were used to locate spheres in th e I-DEAS CAD program with radii propertional to the appropriate van de r Waals radii. The sterolithography apparatus was used to build the mo dels using a photosensitive liquid resin, resulting in hard plastic mo dels that accurately represent the computed or experimental input stru ctures. Three examples are given to illustrate how the models can be u sed to interpret experimental structure-activity data for systems of b iological importance or host-guest chemistry: (1) Interpretation of ki netic data for the formation of a stable blocking complex between amil oride analogs and the epithelial sodium channel, (2) interpretation of binding and neural activity data for the interaction of certain amino acids and their analogs at the L-alanine taste receptor of the channel catfish, and (3) interpretation of shape! selectivity and rate accele ration in cyclodextrin catalysis using models of the neutron diffracti on structure of beta-cyclodextrin and of the transition state for the cleavage of phenyl acetate by the secondary hydroxyl oxygen of beta-cy clodextrin.