Abrupt buckling transition observed during the plectoneme formation of individual DNA molecules
Abrupt buckling transition observed during the plectoneme formation of individual DNA molecules
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DOI：
10.1103/physrevlett.100.148301
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发表时间：
2008-04-11
影响因子：
8.6
通讯作者：
Wang, Michelle D.
中科院分区：
文献类型：
--
作者：
Forth, Scott;Deufel, Christopher;Wang, Michelle D.
单DNA分子对外力和扭矩的响应是使用角光阱直接测量的。过度缠绕后，DNA突然弯曲，表现为延伸急剧下降，随后出现扭矩平稳期。当DNA处于屈曲转变时，它的延伸在两种不同的状态之间迅速跳跃。此外，最初的plectonemic循环吸收大约两倍的扩展被吸收到plectoneme后，每增加一圈。屈曲后观察到的延伸变化和后屈曲扭矩支持最近的DNA弹性模型。
The response of single DNA molecules to externally applied forces and torques was directly measured using an angular optical trap. Upon overwinding, DNA buckled abruptly as revealed by a sharp extension drop followed by a torque plateau. When the DNA was held at the buckling transition, its extension hopped rapidly between two distinct states. Furthermore, the initial plectonemic loop absorbed approximately twice as much extension as was absorbed into the plectoneme upon each additional turn. The observed extension change after buckling and the postbuckling torque support a recent DNA elasticity model.