Quantum mechanic studies on dipalmitoylphosphatidylcholine and dimyristoylphosphatidylcoline asnanoscales of membrane

Abstract

An understanding of static properties of membrane is an essential prelude to the study of movement of molecules within the membrane. In this investigation two molecules have been theoretically investigated through the quantum mechanical calculations. According to the obtained results of the structural optimization of the isolated DPPC (dipalmitoylphosphatidylcholine) and DMPC (dimyristoylphosphatidylcoline) in the gas phase, at the Hartree-Fock level utilize sto-3g,3-21G, 6-31G and 6-31G* basis sets. the most important dihedral angle of these molecules (DPPC and DMPC) have chosen and the energy, dipole moment, and atomic charges of 14 important atoms have scanned within 180 degrees rotation and sites that have most changes have determined and any rotated molecule separately has placed in the 19 solvents (The method is HF/6-31g* model) and then dielectric effect of surrounding has analyzed. The solvent effect on the stability of DPPC and DMPC molecule, dipole moment, and atomic charge of some atoms of those molecules have been discussed by using onsager model. Key words: Dipalmitoylphosphatidylcholine (DPPC), dimyristoylphosphatidylcoline (DMPC), quantum mechanics (QM), abinitio, solvent effect.