Proposal for the biologically active conformation of opiates and enkephalin.

A model for the opiate receptor has been defined by using a computer-based molecular display and x-ray crystallographic input data. The model can explain the stereochemical fashion in which the morphine, morphinan, and oripavine classes of compounds interact with the receptor. The minimal structural unit of the enkephalins demonstrated to be pharmacologically active. Tyr-Gly-Gly-Phe, was also fitted to this model by using a systematic search of conformational space.