Dziura Dominik, Dib Isabelle J, Gbadamosi Omotayo, Castillo Stuart R, Dziura Maksymilian, Murphy Ryan P, Kelley Elizabeth G, Marquardt Drew
Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada.
NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland.
Biophys J. 2025 Feb 18;124(4):590-596. doi: 10.1016/j.bpj.2025.01.008. Epub 2025 Jan 17.
α-tocopherol (αtoc; vitamin E) is an essential nutrient sufficiently acquired through a balanced diet. This fat-soluble vitamin is most known for its antioxidative properties; however, its fundamental mechanism of action in cellular membranes remains unknown. To this end, we use time-resolved small-angle neutron scattering and a contrast matching scheme to determine the intervesicular exchange (k) and intrabilayer flip-flop (k) rates of αtoc in 1,2-dipalmitoyl-sn-glycero-3-phosphocholine vesicles. Moreover, we investigate the role of vesicle concentration and various types of cyclodextrins in affecting these rates. For a 25 mg/mL sample concentration, it was determined that k and k were 1.35 ± 0.03 × 10 and 0.54 ± 0.10 × 10 min, which represent half-lives of 513.4 ± 11.7 and 1285.1 ± 242.7 min, respectively. Differential scanning calorimetry confirmed the observed timescales of αtoc movement.
α-生育酚(αtoc;维生素E)是一种通过均衡饮食就能充分获取的必需营养素。这种脂溶性维生素最为人所知的是其抗氧化特性;然而,其在细胞膜中的基本作用机制仍不清楚。为此,我们使用时间分辨小角中子散射和对比匹配方案来确定αtoc在1,2-二棕榈酰-sn-甘油-3-磷酸胆碱囊泡中的囊泡间交换(k)和双层内翻转(k)速率。此外,我们研究了囊泡浓度和各种类型的环糊精对这些速率的影响。对于25毫克/毫升的样品浓度,确定k和k分别为1.35±0.03×10和0.54±0.10×10分钟,其半衰期分别为513.4±11.7和1285.1±242.7分钟。差示扫描量热法证实了观察到的αtoc运动时间尺度。