Marquardt Drew, Kučerka Norbert, Katsaras John, Harroun Thad A
†Department of Physics, Brock University, St. Catharines, Ontario L2S 3A1, Canada.
‡National Research Council, Canadian Neutron Beam Centre, Chalk River, Ontario K0J 1J0, Canada.
Langmuir. 2015 Apr 21;31(15):4464-72. doi: 10.1021/la502605c. Epub 2014 Oct 29.
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.
时至今日，α-生育酚（aToc）在人体内的作用仍不为人所知。在之前的研究中，我们试图将aToc的生物学功能与其在脂质双层中的位置联系起来。在本研究中，我们通过小角中子衍射确定，不仅aToc的羟基位于膜的高处，其尾部也远离1-棕榈酰-2-油酰-sn-甘油-3-磷酸胆碱（POPC）双层的中心。此外，我们在1-棕榈酰-2-油酰-sn-甘油-3-磷酸乙醇胺（POPE）、1-棕榈酰-2-油酰-sn-甘油-3-磷酸-L-丝氨酸（POPS）和鞘磷脂双层中发现aToc的羟基位于脂质主链上方，这表明aToc在脂质-水界面附近的位置可能是维生素E的一个普遍特性。鉴于这些数据，aToc如何在膜中心有效地终止脂质氢过氧自由基仍是一个悬而未决的问题。
