LeCuyer K A, Crothers D M
Department of Chemistry, Yale University, New Haven, CT 06511.
Proc Natl Acad Sci U S A. 1994 Apr 12;91(8):3373-7. doi: 10.1073/pnas.91.8.3373.
The spliced leader RNA from Leptomonas collosoma has two competing secondary structures of nearly equal free energy. Short, complementary oligonucleotides can drive the structure from one form of the other. We report stopped-flow rapid-mixing and temperature-jump measurements of the kinetics of the structural switch. At high concentrations of oligonucleotide, the rate of binding becomes limited by the rate of the structural switch, which occurs on a time scale of a fraction of a second. The low activation energy observed for the process implies a branch migration type of mechanism in which portions of the two competing helices transiently coexist.
来自巨大细滴虫的剪接前导RNA具有两种自由能几乎相等的相互竞争的二级结构。短的互补寡核苷酸可以促使结构从一种形式转变为另一种形式。我们报告了对结构转换动力学的停流快速混合和温度跃变测量。在高浓度寡核苷酸条件下，结合速率受结构转换速率的限制，结构转换发生在几分之一秒的时间尺度上。该过程观察到的低活化能意味着一种分支迁移类型的机制，即两个相互竞争的螺旋部分会短暂共存。
