Docking kinetics and equilibrium of a GAAA tetra loop-receptor motif probed by single-molecule FRET
Docking kinetics and equilibrium of a GAAA tetra loop-receptor motif probed by single-molecule FRET
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DOI：
10.1073/pnas.0408645102
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发表时间：
2005-07-26
影响因子：
11.1
通讯作者：
Pardi, A
中科院分区：
文献类型：
--
作者：
Hodak, JH;Fiore, JL;Pardi, A
Docking kinetics and equilibrium of fluorescently labeled RNA molecules are studied with single-molecule FRET methods. Time-resolved FRET is used to monitor clocking/unclocking transitions for RNAs containing a single GAAA tetra loo p-receptor tertiary interaction connected by a flexible single-stranded linker. The rate constants for docking and unclocking are measured as a function of Mg2+, revealing a complex dependence on metal ion concentration. Despite the simplicity of this model system, conformational heterogeneity similar to that noted in more complex RNA systems is observed; relatively rapid docking/undocking transitions are detected for approximately two-thirds of the RNA molecules, with significant subpopulations exhibiting few or no transitions on the 10- to 30-s time scale for photobleaching. The rate constants are determined from analysis of probability densities, which allows a much wider range of time scales to be analyzed than standard histogram procedures. The data for the GAAA tetraloop receptor are compared with kinetic and equilibrium data for other RNA tertiary interactions.
