摘要：SummaryBase pairs are fundamental building blocks of RNA. The base pairs of low stability are often critical in RNA functions. Here, we develop a solid-state NMR-based water-RNA exchange spectroscopy (WaterREXSY) to characterize RNA in solid. The approach uses different chemical exchange rates between iminos and water to evaluate base pair stability; the less stable ones would exchange more frequently, leading to stronger cross-peaks on WaterREXSY. Applied to the riboA71-adenine complex (the 71nt-aptamer domain ofaddadenine riboswitch fromVibrio vulnificus), the U47⋅U51 base pair, which is critical in ligand binding, was found to be less stable than other base pairs. The imino-water exchange rates of U47 at different temperatures are about 500–800 s−1, indeed indicative of low stability. This implies a highly complex and plastic triad involving U47⋅U51 and that the opening of the U47⋅U51 base pair may be the early stage of ligand release.Graphical abstractDisplay OmittedHighlights•A solid-state nuclear magnetic resonance (NMR) exchange spectroscopy to study RNA base pair stability•Low stable base pair exhibits strong cross-peaks on WaterREXSY spectra•The U47-U51 base pair of riboA71-adenine is less stable than other base pairsBiological sciences; Biochemistry; Structural biology.
