SPATIAL STRUCTURES OF THE N-TERMINAL ANALOGUES OF NOCICEPTIN MOLECULE

Summary: This scientific work is devoted to study the spatial structure and conformational possibilities of the tripeptide Phe1-Gly2-Gly3 and tetrapeptide Phe1-Gly2-Gly3-Phe4 molecules. The knowledge of the structural and functional properties of these peptide molecules is of great practical importance for medicine and pharmacology. This neuropeptide molecules are stable analogues of the nociceptin molecule. The calculations were carried out by the method of theoretical conformational analysis with regard to nonvalent, electrostatic and torsional interactions, energy of the hydrogen bonds and a special computer program. The low-energy conformations of these molecules and the values of the dihedral angles of the main chains and side chains are found and the energy of the intra- and inter-residue interactions were estimated. 15 low-energy conformations were found for tripeptide for four spatial structures and 12 low-energy conformations were found for tetrapeptide for six spatial structures. It is revealed that low energy conformations of these molecules have the half-folded and folded type of backbone. The side chains of the Phe1 and Phe4 amino acids in low-energy conformations carry out effective interactions and are conformationally labile amino acids. They bring together sections of the main chain and side chains of amino acids that are part of the tri- and tetrapeptide, which leads to important interactions.