Bates Mark, Burns Michael, Meller Amit
The Rowland Institute at Harvard University, Cambridge, Massachusetts 02142, USA.
Biophys J. 2003 Apr;84(4):2366-72. doi: 10.1016/S0006-3495(03)75042-5.
The dynamics of single-stranded DNA in an alpha-Hemolysin protein pore was studied at the single-molecule level. The escape time for DNA molecules initially drawn into the pore was measured in the absence of an externally applied electric field. These measurements revealed two well-separated timescales, one of which is surprisingly long (on the order of milliseconds). We characterized the long timescale as being associated with the binding and unbinding of DNA from the pore. We have also found that a transmembrane potential as small as 20 mV strongly biased the escape of DNA from the pore. These experiments have been made possible due to the development of a feedback control system, allowing the rapid modulation of the applied force on individual DNA molecules while inside the pore.
在单分子水平上研究了α-溶血素蛋白孔中单链DNA的动力学。在没有外部施加电场的情况下，测量了最初被吸入孔中的DNA分子的逃逸时间。这些测量揭示了两个明显分开的时间尺度，其中一个长得惊人（在毫秒量级）。我们将长的时间尺度表征为与DNA在孔中的结合和解离有关。我们还发现，低至20 mV的跨膜电位会强烈影响DNA从孔中的逃逸。由于反馈控制系统的发展，这些实验得以实现，该系统允许在DNA分子位于孔内时快速调节施加在单个DNA分子上的力。
