Issue 8, 2017

Alpha-tocopherol inhibits pore formation in oxidized bilayers

Abstract

In biological membranes, alpha-tocopherols (α-toc; vitamin E) protect polyunsaturated lipids from free radicals. Although the interactions of α-toc with non-oxidized lipid bilayers have been studied, their effects on oxidized bilayers remain unknown. In this study, atomistic molecular dynamics (MD) simulations of oxidized lipid bilayers were performed with varying concentrations of α-toc. Bilayers with 1-palmitoyl-2-lauroyl-sn-glycero-3-phosphocholine (PLPC) lipids and their aldehyde derivatives at a 1 : 1 ratio were studied. Our simulations show that oxidized lipids self-assemble into aggregates with a water pore rapidly developing across the bilayer. The free energy of transporting an α-toc molecule in a bilayer suggests that α-tocs can passively adsorb into it. When α-toc molecules were present at low concentrations in bilayers containing oxidized lipids, water pore formation was slowed down. At high α-toc concentrations, no pores were observed. Based on the simulations, we propose that the mechanism of how α-toc inhibits pore formation in bilayers with oxidized lipids is the following: α-tocs trap the polar groups of the oxidized lipids at the membrane–water interface resulting in a decreased probability of the oxidized lipids making contact with the two leaflets and initiating pore formation. This demonstrates that α-toc molecules not only protect the bilayer from oxidation but also help to stabilize the bilayer after lipid peroxidation occurs. These results will help in designing more efficient molecules to protect membranes from oxidative stress.

Graphical abstract: Alpha-tocopherol inhibits pore formation in oxidized bilayers

Supplementary files

Article information

Article type
Communication
Submitted
24 noy 2016
Accepted
24 yan 2017
First published
24 yan 2017

Phys. Chem. Chem. Phys., 2017,19, 5699-5704

Alpha-tocopherol inhibits pore formation in oxidized bilayers

P. Boonnoy, M. Karttunen and J. Wong-ekkabut, Phys. Chem. Chem. Phys., 2017, 19, 5699 DOI: 10.1039/C6CP08051K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements