Influence of Hydrostatic Pressure and Cosolutes on RNA Tertiary Structure

摘要

The GAAA tetraloop-receptor was used as a model system to explore how both P and various cosolutes affect RNA— RNA interactions. FRET measurements of tetraloop—receptor docking showed that P up to 2.5 kbar slightly destabilizes docking (ΔΔG°_(dock) < 0.6 kcal/mol), yielding a ΔV of 5-9 mL/mol for the docking reaction. PEG and dextran cosolutes increased docking, suggesting a significant release of water/cosolute molecules is associated with docking. In contrast to many protein systems, this RNA—RNA interaction was not significantly stabilized by sucrose or glycerol. This study provides valuable insight into the role of hydration in GAAA tetraloop—receptor docking and demonstrates the potential for probing thermodynamics of RNA—RNA interactions with P and nondenaturing cosolutes.