CONFORMATIONAL CALCULATIONS ON GASTRIN C-TERMINAL TETRAPEPTIDE

Energy optimizations were performed on some typical conformations of the gastrin C‐terminal peptide amide NAc‐Trp‐Met‐Asp‐Phe‐NH2. Two families of lowest energy conformations were found corresponding to: (a) α‐helical structures; (b) conformations having β‐structure at the level of Trp residue, and C7‐structure at the level of Asp residue. The two aromatic rings were folded on the peptide backbone and ca. 5 Å distant from each other (centre to centre). The last family, favoured by energy and population probability, can better account for conformational experimental results and biological activity observations.