Recognition of cholinergic agonists by the muscarinic receptor. 2. Pilocarpine

The conformational potential energy surface of the muscarinic agonist pilocarpine is studied by molecular mechanics (MMP2) and by semiempirical (AM1) and ab initio self-consistent-field (SCF) calculations. Six minima were located, two of which correspond to the known X-ray structures of pilocarpine. Possible active conformations of pilocarpine are inferred from the potential energy surfaces used in conjunction with the proposed active conformation of muscarine previously obtained from a theoretical model.