Besteman K, Hage S, Dekker N H, Lemay S G
Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628CJ Delft, The Netherlands.
Phys Rev Lett. 2007 Feb 2;98(5):058103. doi: 10.1103/PhysRevLett.98.058103. Epub 2007 Jan 30.
Using magnetic tweezers, we study in real time the condensation of single DNA molecules under tension. We find that DNA condensation occurs via discrete nucleated events. By measuring the influence of an imposed twist, we show that condensation is initiated by the formation of a plectonemic supercoil. This demonstrates a strong interplay between the condensation transition and externally imposed mechanical constraints.
我们使用磁镊实时研究了在张力作用下单条DNA分子的凝聚过程。我们发现DNA凝聚是通过离散的成核事件发生的。通过测量外加扭曲的影响，我们表明凝聚是由麻花状超螺旋的形成引发的。这证明了凝聚转变与外部施加的机械约束之间存在强烈的相互作用。
