Onoa Bibiana, Dumont Sophie, Liphardt Jan, Smith Steven B, Tinoco Ignacio, Bustamante Carlos
Department of Physics and Department of Molecular and Cell Biology and Howard Hughes Medical Institute.
Science. 2003 Mar 21;299(5614):1892-5. doi: 10.1126/science.1081338.
Mechanical unfolding trajectories for single molecules of the Tetrahymena thermophila ribozyme display eight intermediates corresponding to discrete kinetic barriers that oppose mechanical unfolding with lifetimes of seconds and rupture forces between 10 and 30 piconewtons. Barriers are magnesium dependent and correspond to known intra- and interdomain interactions. Several barrier structures are "brittle," breakage requiring high forces but small (1 to 3 nanometers) deformations. Barrier crossing is stochastic, leading to variable unfolding paths. The response of complex RNA structures to locally applied mechanical forces may be analogous to the responses of RNA during translation, messenger RNA export from the nucleus, and viral replication.
嗜热四膜虫核酶单分子的机械展开轨迹显示出八个中间体，对应于离散的动力学屏障，这些屏障阻碍机械展开，其寿命为几秒，断裂力在10到30皮牛顿之间。屏障依赖于镁，对应于已知的域内和域间相互作用。几个屏障结构是“脆性的”，断裂需要高力但小（1至3纳米）变形。屏障穿越是随机的，导致可变的展开路径。复杂RNA结构对局部施加的机械力的响应可能类似于RNA在翻译、信使RNA从细胞核输出和病毒复制过程中的响应。
