Comparison of Experimental and Theoretical study of Solvent effect on Interfacial head group and hydrocarbon chains of DPPC molecule.

Abstract

The bilayer's lipids head groups and hydrocarbon chains affect solvent transport activity.The dielectric constant of solvent can affect both of these interfacial  regions. The present article will focus on the effects of solvents on DPPC, 1, 2 - dipalmito l- sn - glycero - 3- phosphatidylcholine, as an important component of lipid membrane and its head group. We could detect and effectively mimic a  ten-dielectric model for conformational analysis, in which the obtained results on DPPC compared with its head group results. The effect of solvents on the  conformation and disordering of DPPC molecule has been investigated with calculation at the Hatree-Fock level using the 6-31G basis set with Onsager continuum solution, Frequency and GIAO models. Furthermore, the simulated model in solvents was confirmed experimentally by solution nmr technique. Results show that some of the obtained results on DPPC and its head group were different obviously. On the other hand hydrophobic force in tail group caused most atoms to show ordinary constant behavior.And high disordering in main transition temperature was shown for head group region. Therefore, the hydrophobic interaction of solvent partitioning into DPPC is the predominant force involved in DPPC packaging and has the most effect on dielectric constant and also it's totally related to temperature.