Identifying kinetic barriers to mechanical unfolding of the T-thermophila ribozyme
Identifying kinetic barriers to mechanical unfolding of the T-thermophila ribozyme
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DOI：
10.1126/science.1081338
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发表时间：
2003-03-21
期刊：
影响因子：
56.9
通讯作者：
Bustamante, C
中科院分区：
文献类型：
--
作者：
Onoa, B;Dumont, S;Bustamante, C
嗜热四膜虫核酶单分子的机械展开轨迹显示出8个中间体，对应于离散的动能屏障，它们反对机械展开，寿命为秒，破碎力在10至30皮牛顿之间。障碍依赖于镁，并与已知的域内和域间相互作用相对应。有几种屏障结构是“脆性的”，需要很大的力，但变形很小(1到3纳米)。跨越障碍是随机的，导致了不同的展开路径。复杂的RNA结构对局部机械力的反应可能类似于RNA在翻译、信使RNA从细胞核输出和病毒复制过程中的反应。
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.