Taking femtosecond snapshots of RNA conformational dynamics and complexity.

RNA conformational dynamics have been a subject of extensive biophysical studies by spectroscopic and computational techniques. Application of femtosecond time-resolved spectroscopy is a new addition to this field, where the technique is specifically designed to probe the ruggedness of RNA conformational landscape and recognition modes. Such technique allows resolution of heterogeneous conformations within a complex ensemble. Recent applications on GNRA tetraloops, dangling ends, and RNA-peptide complexes produced more quantitative and dynamic pictures for these motifs and interactions, including detection of alternative structures that have been overlooked. Integration of the ultrafast dynamics approach with other biophysical techniques promises to be a more powerful approach for providing unique insights for addressing the challenging task of decoding RNA conformational dynamics and the understanding of the mechanisms of molecular recognition of RNA.