Static and Dynamic Properties of Phospholipid Bilayer Nanodiscs
Static and Dynamic Properties of Phospholipid Bilayer Nanodiscs
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DOI：
10.1021/ja9017013
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发表时间：
2009-06-17
影响因子：
15
通讯作者：
Handa, Tetsurou
中科院分区：
文献类型：
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作者：
Nakano, Minoru;Fukuda, Masakazu;Handa, Tetsurou
纳米盘是与新生高密度脂蛋白相关的磷脂-蛋白质复合物，可用作药物载体和包裹膜蛋白的工具。我们评估的结构和动力学的纳米粒子组成的二肉豆蔻酰磷脂酰胆碱（DMPC）和载脂蛋白A-I（apoA-I）的小角中子散射（SANS）和荧光方法，并比较它们与静态/动态性能的大单层囊泡。SANS显示，纳米盘包括厚度为44埃，半径为37埃的脂质双层，其中每个脂质占据的面积小于囊泡中DMPC的分子面积。荧光测量表明，DMPC具有较低的熵在nanodisces比在囊泡，因为载脂蛋白A-I分子，包围双层，迫使更紧密的脂质包装，但允许水渗透到酰基链末端。时间分辨SANS实验表明，纳米盘代表了通过熵有利过程的20倍更高的脂质转移。结果提出了一个连接的静态/动态性能的纳米盘，其中的熵约束负责加速解吸的脂质。
Nanodiscs are phospholipid-protein complexes which are relevant to nascent high-density lipoprotein and are applicable as a drug carrier and a tool to immobilize membrane proteins. We evaluated the structure and dynamics of the nanoparticles consisting of dimyristoylphosphatidylcholine (DMPC) and apolipoprotein A-I (apoA-I) with small-angle neutron scattering (SANS) and fluorescence methods and compared them with static/dynamic properties for large unilamellar vesicles. SANS revealed that the nanodisc includes a lipid bilayer with a thickness of 44 angstrom and a radius of 37 angstrom, in which each lipid occupies a smaller area than the reported molecular area of DMPC in vesicles. Fluorescence measurements suggested that DMPC possesses a lower entropy in nanodiscs than in vesicles, because apoA-I molecules, which surround the bilayer, force closer lipid packing, but allow water penetration to the acyl chain ends. Time-resolved SANS experiments revealed that nanodiscs represent a 20-fold higher lipid transfer via an entropically favorable process. The results put forward a conjunction of static/dynamic properties of nanodiscs, where the entropic constraints are responsible for the accelerated desorption of lipids.