a-tocopherol is one of a family of molecules referred to as vitamin E. It is hydrophobic and may have several roles in the cell membrane, including acting as an antioxidant. Therefore understanding its positioning in lipid bilayers can provide valuable insight into the mechanism of lipid-peroxidation inhibition. Free energy (PMF) calculations show that a-tocopherol has a strong affinity for DMPC bilayers compared to water (25 kT difference in free energy). They also show that flipping from one leaflet to the other is relatively easy (5 kT barrier). Aggregation of a-tocopherol molecules in a bilayer was observed, and a PMF calculation was performed for that process. During the PMF calculations, quantities related to the orientation of the a-tocopherol molecule(s) and the lipid structure as a function of the reaction coordinate were calculated.Work supported by NSF-EPSCoR LA-SiGMA Grant #EPS-1003897, and USDA Grant #2009-35603-05055. Computational resources were provided by LONI and HPC@LSU.

Mechanistic insights into a-tocopherol (vitamin E) antioxidant action: A molecular dynamics simulation study

245th National Meeting (2013)

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