Interactions of human von Willebrand factor with a hydrophobic self-assembled monolayer studied by atomic force microscopy.
Interactions of human von Willebrand factor with a hydrophobic self-assembled monolayer studied by atomic force microscopy.
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DOI：
10.1002/jbm.820280902
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发表时间：
1994-09
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影响因子：
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通讯作者：
Christopher A. Siedlecki;S. Eppell;R. Marchant
中科院分区：
文献类型：
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作者：
Christopher A. Siedlecki;S. Eppell;R. Marchant
用原子力显微镜研究了人von Willebrand因子(VWF)在十八烷基三氯硅烷自组装单分子膜上的生理缓冲作用。沉积在玻璃上的自组装单分子膜足够光滑(均方根粗糙度=0.25+/-0.12 nm)，可以识别吸附的vWF。蛋白质与疏水底物的粘附性足以使原子力显微镜探针重复扫描，并获得了亚分子尺度上的vWF图像。表面与蛋白质之间的摩擦力足以承受19nN的侧向力。这一结果表明，vWF在水介质中与疏水表面发生了强烈的相互作用。对吸附的vWF的统计分析表明，该蛋白质由大的球状结构域组成，平均横截面大小为56+/-24 nm(长轴)、26+/-19 nm(短轴)和2.8+/-1.0 nm(高度)。进一步的主轴尺寸分析表明，vWF的分子链包含两个结构域大小不同的群体。然而，没有发现单个分子内不同结构域的序列顺序。基于我们对球状结构域的分析，我们提出了一个描述生理溶液中吸附在疏水表面上的vWF原核的三维结构的模型。
Human von Willebrand Factor (vWF) was studied by atomic force microscopy under physiologic buffer on a hydrophobic octadecyltrichlorosilane self-assembled monolayer. The self-assembled monolayer deposited on glass was sufficiently smooth (root mean square roughness = 0.25 +/- 0.12 nm) to permit identification of adsorbed vWF. Adhesion of the protein to the hydrophobic substrate was sufficient to allow repeated scanning by the atomic force microscope probe, and images of vWF on a submolecular scale were obtained. The frictional force between the surface and the protein was sufficient to withstand an applied lateral force of 19 nN. This result shows that vWF experiences strong interaction with a hydrophobic surface in aqueous media. Statistical analysis of adsorbed vWF shows that the protein is composed of large globular domains with elliptical cross sections of average dimensions 56 +/- 24 nm (major axis) 26 +/- 19 nm (minor axis), and 2.8 +/- 1.0 nm (height). Further analysis of the major axis dimension shows that the molecular chain of vWF contains two statistically different populations of domain size. However, no sequence order of the different domains within the individual molecule was found. On the basis of our analysis of the globular domains, we present a model describing the three-dimensional structure of vWF protomer adsorbed on a hydrophobic surface in a physiologic solution.