SPATIAL STRUCTURE OF THE HEPTAPEPTIDE ANALOGUE OF NOCICEPTIN MOLECULE

Abstract

It is known that nociceptins are a new type of regulatory peptide. Knowledge of these peptide molecules' structural and functional properties is of great practical importance for medicine and pharmacology. Their mechanisms of action are considered anti-opioid. This scientific work is devoted to studying the spatial structure of the heptapeptide H-Phe1-Gly2-Gly3-Phe4-Val5-Gly6-Pro7-OH. It examines the conformational capabilities of this heptapeptide molecule. This neuropeptide molecule is a stable analog of the nociceptin. The biologically active conformation of the peptide molecule, which is realized upon interaction with the receptor, is included in the set of low-energy structures. Therefore, studying the spatial structure of peptide molecules is of great interest. Theoretical conformational analysis about nonvalent, electrostatic, and torsional interactions, the energy of the hydrogen bonds, and a special computer program carried out the calculations. The 10 low-energy conformations of this molecule and the values of the dihedral angles of the main chain and side chains are found, and the energy of the intra- and inter-residue interactions is estimated. It is revealed that low energy conformations of this molecule 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 the regions of the main chain and the side chains of the amino acids included in the heptapeptide. These folded forms bring parts of the backbone and the amino acids' side chains together, resulting in important interactions.