α-Tocopherol's Location in Membranes Is Not Affected by Their Composition

Langmuir. 2015 Apr 21;31(15):4464-72. doi: 10.1021/la502605c. Epub 2014 Oct 29.

Abstract

To this day, α-tocopherol's (aToc) role in humans is not well known. In previous studies, we have tried to connect aToc's biological function with its location in a lipid bilayer. In the present study, we have determined, by means of small-angle neutron diffraction, that not only is aToc's hydroxyl group located high in the membrane but its tail also resides far from the center of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayers. In addition, we located aToc's hydroxyl group above the lipid backbone in 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine (POPS), and sphingomyelin bilayers, suggesting that aToc's location near the lipid-water interface may be a universal property of vitamin E. In light of these data, how aToc efficiently terminates lipid hydroperoxy radicals at the membrane center remains an open question.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Humans
  • Lipid Bilayers / chemistry*
  • Phosphatidylcholines / chemistry
  • Phosphatidylethanolamines / chemistry
  • Phosphatidylserines / chemistry
  • Sphingomyelins / chemistry
  • Surface Properties
  • Temperature
  • Thermodynamics
  • Water / chemistry*
  • alpha-Tocopherol / chemistry*

Substances

  • Lipid Bilayers
  • Phosphatidylcholines
  • Phosphatidylethanolamines
  • Phosphatidylserines
  • Sphingomyelins
  • Water
  • 1-palmitoyl-2-oleoylphosphatidylethanolamine
  • 1-palmitoyl-2-oleoylglycero-3-phosphoserine
  • alpha-Tocopherol
  • 1-palmitoyl-2-oleoylphosphatidylcholine