Does α-Tocopherol Flip-Flop Help to Protect Membranes Against Oxidation?

• DOI: 10.1021/acs.jpcb.8b09064
• Publication Date: 2018-10-24T21:02:54Z
• Authors: Phansiri Boonnoy; Mikko Karttunen; Jirasak Wong-ekkabut
• Keywords: Lipid Bilayers; alpha-Tocopherol; Phosphatidylcholines; Thermodynamics; Molecular Dynamics Simulation; Oxidation-Reduction; 01 natural sciences; Antioxidants; 0104 chemical sciences

α-Tocopherols (α-toc) are crucial in protecting biological membranes against oxidation by free radicals. We investigate the behavior of α-toc molecules lipid bilayers containing oxidized lipids molecular dynamics (MD) simulations. To verify approach, location and orientation first shown to be agreement with previous experimental results. The simulations further show that stay inside bilayer their hydroxyl groups contact surface. Interestingly, interbilayer flip-flop was observed both nonoxidized significantly higher frequency aldehyde bilayer. Free-energy calculations were performed, estimates rates across determined. As main finding, our results presence leads a significant decrease free-energy barriers depend on type present. Our suggest could potentially act as high-efficacy scavengers radicals protect from oxidative attack help stabilize them under stress.