Characterization of the kinetic and thermodynamic landscape of RNA folding using a novel application of isothermal titration calorimetry.
Characterization of the kinetic and thermodynamic landscape of RNA folding using a novel application of isothermal titration calorimetry.
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DOI：
10.1093/nar/gkr894
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发表时间：
2012-03
影响因子：
14.9
通讯作者：
Butcher SE
中科院分区：
文献类型：
--
作者：
Vander Meulen KA;Butcher SE
采用一种新的等温滴定量热法（ITC）研究了镁和钾溶液中GAAA四环-受体相互作用驱动的RNA螺旋堆积。动力学和热力学都是在单独的ITC实验中获得的，并且在一个温度范围内的动力学数据的分析提供了Arrhenius活化能（ΔH_∞）和Eyring过渡态熵（ΔS_∞）。由此产生的丰富的数据集揭示了强烈对比的动力学和热力学概况时，这种RNA折叠系统的钾与镁稳定。在钾中，缔合是高度放热的（在150 mM KCl中，ΔH25°C = −41.6 ± 1.2 kcal/mol），过渡态是无势垒的（ΔH25° C = −0.6 ± 0.5）。这些参数在镁中显著正移（在0.5 mM MgCl 2中，ΔH25°C = −20.5 ± 2.1 kcal/mol，ΔH ε = 7.3 ± 2.2 kcal/mol）。接近生理条件的混合盐溶液表现出中间热力学性质。阳离子依赖性热力学景观可以反映盐依赖性未结合受体构象，或者可替代地并且更一般地，它可以反映与折叠偶联镁摄取相关的小的阳离子排斥罚分。
A novel isothermal titration calorimetry (ITC) method was applied to investigate RNA helical packing driven by the GAAA tetraloop–receptor interaction in magnesium and potassium solutions. Both the kinetics and thermodynamics were obtained in individual ITC experiments, and analysis of the kinetic data over a range of temperatures provided Arrhenius activation energies (ΔH‡) and Eyring transition state entropies (ΔS‡). The resulting rich dataset reveals strongly contrasting kinetic and thermodynamic profiles for this RNA folding system when stabilized by potassium versus magnesium. In potassium, association is highly exothermic (ΔH25°C = −41.6 ± 1.2 kcal/mol in 150 mM KCl) and the transition state is enthalpically barrierless (ΔH‡ = −0.6 ± 0.5). These parameters are sigificantly positively shifted in magnesium (ΔH25°C = −20.5 ± 2.1 kcal/mol, ΔH‡ = 7.3 ± 2.2 kcal/mol in 0.5 mM MgCl2). Mixed salt solutions approximating physiological conditions exhibit an intermediate thermodynamic character. The cation-dependent thermodynamic landscape may reflect either a salt-dependent unbound receptor conformation, or alternatively and more generally, it may reflect a small per-cation enthalpic penalty associated with folding-coupled magnesium uptake.
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影响因子：
2.9
作者：
Downey, CD;Fiore, JL;Pardi, A
通讯作者：
Pardi, A
影响因子：
2.9
作者：
COLE, PE;CROTHERS, DM
通讯作者：
CROTHERS, DM
DOI：
10.1073/pnas.77.6.3360
发表时间：
1980-01-01
期刊：
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA-BIOLOGICAL SCIENCES
影响因子：
--
作者：
KAO, TH;CROTHERS, DM
通讯作者：
CROTHERS, DM
影响因子：
14.9
作者：
Geary C;Baudrey S;Jaeger L
通讯作者：
Jaeger L
影响因子：
5.6
作者：
Gluick, TC;Gerstner, RB;Draper, DE
通讯作者：
Draper, DE