Cytochrome c adsorption to supported, anionic lipid bilayers studied via atomic force microscopy
Cytochrome c adsorption to supported, anionic lipid bilayers studied via atomic force microscopy
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DOI：
10.1529/biophysj.104.047738
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发表时间：
2004-11-01
影响因子：
3.4
通讯作者：
Dimitriadis, EK
中科院分区：
文献类型：
--
作者：
Choi, EJ;Dimitriadis, EK
用原子力显微镜研究了低离子强度生理缓冲液中细胞色素c在二油酰磷脂酰甘油阴离子脂质双层膜上的吸附。双层被支撑在聚赖氨酸化的云母上。通过成像和力谱证实了稳定的单脂质双层的形成。在添加低浓度的细胞色素c时，蛋白质分子在脂质双层-缓冲液界面上在形貌上不可见。然而，所需的力量，通过压痕使用原子力显微镜探针穿透双层蛋白质吸附后显着降低，这表明，蛋白质插入到双层。此外，细胞色素c吸附后的双层的表观厚度保持不变。然而，质谱和可见光吸收光谱证实了细胞色素c的脂质双层的存在。这些结果表明：1），细胞色素c插入到双层，并驻留在其疏水核心; 2），细胞色素c的插入改变了双层的机械性能显着;和3），双层力谱可能是一个有用的工具，在研究脂质-蛋白质相互作用。
The adsorption of membrane-associated protein cytochrome c to anionic lipid bilayers of dioleoyl phosphatidylglycerol was studied in low ionic strength physiological buffer using atomic force microscopy. The bilayers were supported on polylysinated mica. The formation of stable, single lipid bilayers was confirmed by imaging and force spectroscopy. Upon addition of low concentrations of cytochrome c, protein molecules were not topographically visible on the lipid bilayer-buffer interface. However, the forces required to punch through the bilayer by indentation using the atomic force microscopy probe were significantly lower after protein adsorption, which suggest that the protein inserts into the bilayer. Moreover, the apparent thickness of the bilayer remained unchanged after cytochrome c adsorption. Yet, mass spectroscopy and visible light absorption spectroscopy confirmed the presence of cytochrome c in the lipid bilayers. These results suggest that 1), cytochrome c inserts into the bilayer and resides in its hydrophobic core; 2), cytochrome c insertion changes the mechanical properties of the bilayer significantly; and 3), bilayer force spectroscopy may be a useful tool in investigating lipid-protein interactions.