Computational insights of two‐dimensional infrared spectroscopy under electric fields in phosphorylcholine

Abstract

AbstractInfluence of static electric field in biological cells causes electroporation, which results in the increase of permeability of the cells and phospholipid bilayer. However, the precise mode of action of electric fields on phospholipid bilayer and their quantum mechanics are still unclear. Therefore, to understand the quantum‐based biological effect, we aimed to study two‐dimensional infrared (2D‐IR) spectra‐adopted quantum mechanics/molecular mechanics (QM/MM) simulations under the influence of static electric fields on Phosphorylcholine, an important component in phospholipid membrane. Initially, QM/MM studies were performed under the influence of electric field, ranging from −1.543 to 1.028 V/nm. A multilayer ONIOM model (in combination with DFT/B3LYP/6‐31G [d, p] and DREIDING force fields) was used to obtain 2D‐IR simulated spectra to calculate electrostatic interaction in the biological system. The results demonstrated that the phosphate group played an important role on α‐rotation in LUMO and the chlorine atom had a major contribution in HOMO. In addition, decreased number of hydrogen bonds demonstrated that uncoupling reaction of the P‐O stretching vibrations while the electric field was −1.542 V/nm. Moreover, we observed that the electric field is −1.028 V/nm, there is no rotational isomerization in phosphorylcholine. We concluded that the static electric fields significantly affect the anharmonic frequencies, vibration coupling and the structure of the phosphorylcholine.