Трехмерная структура молекулы бета-лакторфина

Abstract

Opioid peptides cause pain relief, sedation and sleep, as well as a euphoric state and a number of autonomic reactions. These peptides are of animal and plant origin. A number of exogenous peptides obtained from food have opiate-like properties. This peptides were named exorphins. The discovery of the opioid activity of the peptide components of food has led to the assumption that certain types of food can act on the central nervous system like opiate drugs. A number of milk exorphins have been found that have opioid receptor antagonist properties. These include casoxins A, B, C, human casoxin D, as well as lactoferroxins A, B and C, as well as alpha and beta lactorphins. The possibility of the formation of these peptides during the hydrolysis of the corresponding proteins by peptidases of the gastrointestinal tract has been proven in vitro. Representatives of exorphins are also cytochrophins and hemorphins. It is assumed that these peptides can be formed in vivo during the proteolytic cleavage of cytochrome b and hemoglobin. The beta-lactorphine molecule is a representative of this class. The conformational possibilities of the beta-lactorphine Tyr-Leu-Leu-Phe molecule were studied by the method of theoretical conformational analysis. The potential function of the system is chosen as the sum of non-valence, electrostatic and torsion interactions and the energy of hydrogen bonds. The low-energy conformations of the alpha-lactorphine molecule, the values of the dihedral angles of the main and side chains of the amino acid residues that make up the molecules were found, and the energy of intra- and interresidual interactions was estimated. It has been shown that the spatial structure of the beta-lactorphine molecule can be represented by eight forms of the main chain. The results obtained can be used to elucidate the structural and structural-functional organization of exorphin molecules.