Kinetic and Thermodynamic Analysis of Cholesterol Transfer between Phospholipid Vesicles and Nanodiscs.
Kinetic and Thermodynamic Analysis of Cholesterol Transfer between Phospholipid Vesicles and Nanodiscs.
复制标题
磷脂囊泡和纳米圆盘之间胆固醇转移的动力学和热力学分析。
DOI：
10.1021/acs.jpcb.5b03682
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发表时间：
2015
期刊：
影响因子：
3.3
通讯作者：
M. Nakano
中科院分区：
文献类型：
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作者：
N. Matsuzaki;T. Handa;M. Nakano
我们研究了大单层囊泡（LUVs）和磷脂双层纳米盘之间的胆固醇（Chol）的颗粒间转移。Chol含量增加或供体磷脂酰胆碱/Chol LUVs中鞘磷脂的掺入降低了从LUVs到纳米盘的Chol转移速率，但不受受体颗粒的脂质组成的影响。这些结果表明，Chol从脂质双层解离到水相是转移的限速步骤，并且该过程取决于供体膜的流动性。来自纳米盘的Chol解离速率比来自具有相似脂质组成的LUV的Chol解离速率快。Chol优选分配到LUV而不是纳米盘，这与纳米盘的更快解离速率一致。Chol从纳米盘解离的活化能比从LUV解离的活化能低1.7 kJ/mol，这是由于活化熵和活化焓增加（负性较小）所致。此外，荧光寿命和各向异性数据显示，纳米盘的脂质双层比LUV更紧密地堆积。这些结果表明，纳米盘中更紧密的脂质包装通过降低熵使含Chol的双层不稳定，这有利于Chol解离。
We investigated interparticle transfer of cholesterol (Chol) between large unilamellar vesicles (LUVs) and phospholipid bilayer nanodiscs. The Chol transfer rate from LUVs to nanodiscs was decreased by an increase in the Chol content or incorporation of sphingomyelin in donor phosphatidylcholine/Chol LUVs but was not influenced by the lipid composition of acceptor particles. These results suggest that Chol dissociation from the lipid bilayer into aqueous phase is the rate-limiting step of the transfer and that the process depends on the fluidity of the donor membranes. The Chol dissociation rate from nanodiscs was faster than that from LUVs with similar lipid composition. Chol preferably partitioned to LUVs rather than nanodiscs, which is consistent with the faster dissociation rate from nanodiscs. The activation energy of Chol dissociation from nanodiscs was 1.7 kJ/mol lower than that from LUV, which was brought by increased (less negative) activation entropy and enthalpy. In addition, fluorescence lifetime and anisotropy data revealed that the lipid bilayer of nanodiscs is more tightly packed than that of LUVs. These results suggest that the tighter lipid packing in nanodiscs destabilizes the Chol-containing bilayer by reducing the entropy, which facilitates Chol dissociation.