Biologically active conformation of [Met5]- and [Leu5]enkephalin on delta opioid receptor

Investigations of the conformation of endogenous enkephalins are generally based on structural comparisons of enkephalins with other opiates and on experimental pharmacological studies. Based on such investigations, we now propose a novel model of the biologically active (receptor-bound) conformation of [Met5]- and [Leu5]enkephalin on the delta opioid receptor. The model helps with the design of new opioid analgesics.