The problem of determining the native conformations of neuropeptides is one of the most relevant ones in modern molecular biophysics, since such conformations are in most cases is the main factor in the manifestation of their biological activity. Despite the huge variety of neuropeptide molecules, it is obvious that the molecular mechanisms of their similar functional activity are based on the same elements of spatial organization. In this work the spatial structure and conformational properties of a neuropeptide from the allatostatin family and containing 14 amino acid residues in its chemical structure Leu-Asn-Glu-Glu-Arg-Arg-Ala-Asn-Arg-Tyr-Gly-Phe-Gly-Leu-NH2 was studied by the method of molecular mechanics in the approximation of atom atomic potential functions and as a result was called Leu-callatostatin 2. Since Leu-callatostatin 2 includes eight amino acid residues of Leu-callatostatin 3, its spatial structure was studied based on the results of calculation of Leu-callatostatin 3. Calculations were carried out in stages and were based on minimizing the energy of intramolecular interactions (non-valent, electrostatic, torsion) in the vicinity of the angles of internal rotation, corresponding to all combinations of stable conformations of monopeptide residues that form the molecule. 47 energetically stable conformations of the neuropeptide were established, which are realized under conditions of an implicitly specified aqueous environment, the relative conformational energy of which varies in the range of 0-10 kcal / mol. It was shown that the hydrogen bond system, despite a small contribution to the total energy of the molecule, is very important for maintaining a stable structure and limiting the mobility of Leu-callatostatin 2. According to the results of the study, the main contribution to the stabilization of low-energy conformations of the molecule is made by non-valent interactions, the contribution of which varies within -59 ¸ -66 kcal / mol.
neuropeptides, structure, conformational analysis
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