Characterizing single-stranded RNA using SAXS and single-molecule FRET

Single-stranded RNA molecules play many important roles in biology, including in the formation of biomolecular condensates through liquid-liquid phase separation [1]. The flexibility of these molecules is critical, allowing them to take on a variety of conformations. However, their highly flexible nature makes the structures of these molecules difficult to characterize. We use two different methods, small angle x-ray scattering (SAXS) and single-molecule Förster resonance energy transfer (FRET), to quantify the size and shape of disordered molecules in an ensemble of conformations [2]. Using SAXS in combination with FRET allows for characterization of the structures of single-stranded RNA, giving insight into their biological roles.