CONFORMATIONAL PROPERTIES AND ELECTRONİC STRUCTURE OF ANTİTUMOR AGENT TYR-SER-LEU

Molecular modeling methods were used to study the features of the spatial and electronic structure of the antitumor tripeptide YSL (Tyr-Ser-Leu), developed by Chinese scientists. The conformational analysis of the molecule revealed a limited set of its energetically preferable conformational states in a certain range of relative energy. The nature of the forces stabilizing the low-energy conformations of the tripeptide molecule was determined. As a result of the study, the energetically preferable ranges of dihedral angles, the energy contributions of interresidual interactions and hydrogen bonds, as well as the mutual arrangement of residues and their side chains in low-energy conformations of the tripeptide were also determined. Using the methods of molecular mechanics, the energy contributions of intramolecular interactions in low-energy conformational states of the molecule were obtained. Based on quantum-chemical calculations, the distribution of electron density and the values of dipole moments of the most optimal spatial structures of the YSL tripeptide molecule were determined. The reactivity of the tripeptide was also studied by quantum chemical calculations based on the obtained electronic characteristics of each low-energy conformation of the molecule. Using the calculated coordinates of the atoms of the energetically preferable structures of the molecule, their molecular models were built, the comparison of which makes it possible to identify the structural criteria necessary to create a drug suitable for clinical use.