title: α-Tocopherol's Location in Membranes Is Not Affected by Their Composition.
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.
authors.affiliation: †Department of Physics, Brock University, St. Catharines, Ontario L2S 3A1, Canada.
authors.forename: Drew
authors.initials: D
authors.lastname: Marquardt
authors.affiliation: ‡National Research Council, Canadian Neutron Beam Centre, Chalk River, Ontario K0J 1J0, Canada.|§Department of Physical Chemistry of Drugs, Comenius University, 832 32 Bratislava, Slovakia.|∥Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna - Moscow Region, Russia.
authors.forename: Norbert
authors.initials: N
authors.lastname: Kučerka
authors.affiliation: †Department of Physics, Brock University, St. Catharines, Ontario L2S 3A1, Canada.|⊥Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393, United States.|#Joint Institute for Neutron Sciences, Oak Ridge, Tennessee37831-6453, United States.|∇Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States.
authors.forename: John
authors.initials: J
authors.lastname: Katsaras
authors.affiliation: †Department of Physics, Brock University, St. Catharines, Ontario L2S 3A1, Canada.
authors.forename: Thad A
authors.initials: TA
authors.lastname: Harroun
mesh_terms: D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry; D010714:Phosphatidylethanolamines / Q000737:chemistry; D010718:Phosphatidylserines / Q000737:chemistry; D013109:Sphingomyelins / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*; D024502:alpha-Tocopherol / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; D010718:Phosphatidylserines; D013109:Sphingomyelins; D014867:Water; C057561:1-palmitoyl-2-oleoylphosphatidylethanolamine; C050294:1-palmitoyl-2-oleoylglycero-3-phosphoserine; D024502:alpha-Tocopherol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine