Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
Nano Lett. 2009 Dec;9(12):4441-5. doi: 10.1021/nl9027318.
Using solid-state nanopores with optical tweezers, we perform force spectroscopy on DNA molecules that are coated with RecA proteins. We observe that the electrophoretic force is 2-4 times larger for RecA-DNA filaments than for uncoated DNA molecules and that this force increases at lower salt concentrations. The data demonstrate the efficacy of solid-state nanopores for locally probing the forces on DNA-bound proteins. Our results are described quantitatively by a model that treats the electrophoretic and hydrodynamic forces. The conductance steps that occur when RecA-DNA enters the nanopore change from conductance decreases at high salt to conductance increases at low salt, which allows the apparent charge of the RecA-DNA filament to be extracted. The combination of conductance measurements with local force spectroscopy increases the potential for future solid-state nanopore screening devices.
利用带有光镊的固态纳米孔，我们对涂有 RecA 蛋白的 DNA 分子进行力谱分析。我们观察到，与未涂层的 DNA 分子相比，RecA-DNA 纤维的电泳力要大 2-4 倍，而且这种力在低盐浓度下会增加。这些数据证明了固态纳米孔在局部探测 DNA 结合蛋白上的力的有效性。我们的结果通过一个同时考虑电泳力和流体动力的模型进行了定量描述。当 RecA-DNA 进入纳米孔时，电导阶跃从高盐时的电导降低变为低盐时的电导增加，这使得可以提取 RecA-DNA 纤维的表观电荷。电导测量与局部力谱学的结合增加了未来固态纳米孔筛选装置的潜力。
