Estudo do efeito da solvatação aquosa sobre os parâmetros geométricos da epinefrina usando dinâmica molecular de Car-Parrinello

Abstract

Epinephrine is an amine belonging to the cathecholamine group and acts as a circulating hormone and neurotransmitter. It regulates heart rate, blood vessel and air passage diameter. It’s water soluble and in a biological system has its amine group totally protonated. Given that the interaction between pharmaceuticals and water is fundamentally important for our understanding of the absorption, transportation and biological action; this dissertation aims to study the effects of the water solvation structure on epinephrine’s geometric and electronic parameters. The dynamic of the solvation structure was studied using the Car-Parrinello molecular dynamics with PBE exchange correlation functional. The wave functions were expanded in terms of plane waves with a cutoff energy of 25 Ry, 400 a.u. fictitious mass and a cutoff energy of 100 Ry for the charge density expansion. The studied system temperatures were controlled at 300 K using the Nosé-Hoover thermostat. The simulation results show that the water solvation significantly changes epinephrine’s geometric parameters, especially those related to the hydrophilic groups. Various hydrogen bonds were observed forming between the water molecules and epinephrine, and the spontaneous protonation of epinephrine’s nitrogen by the hydrogens from the water molecules was also seen.