The solution structural ensembles of RNA kink-turn motifs and their protein complexes

• DOI: 10.1038/nchembio.1997
• Publication Date: 2016-01-04T16:51:53Z
• Authors: Xuesong Shi; Lin Huang; David M J Lilley; Pehr B Harbury; Daniel Herschlag
• Keywords: Turn (biochemistry); Structural motif

With the growing number of crystal structures of RNA and RNA-protein complexes, a critical next step is understanding the dynamic solution behavior of these entities in terms of conformational ensembles and energy landscapes. To this end, we have used X-ray scattering interferometry (XSI) to probe the ubiquitous RNA kink-turn motif and its complexes with the canonical kink-turn binding protein L7Ae. XSI revealed that the folded kink-turn is best described as a restricted conformational ensemble. The ions present in solution alter the nature of this ensemble, and protein binding can perturb the kink-turn ensemble without collapsing it to a unique state. This study demonstrates how XSI can reveal structural and ensemble properties of RNAs and RNA-protein complexes and uncovers the behavior of an important RNA-protein motif. This type of information will be necessary to understand, predict and engineer the behavior and function of RNAs and their protein complexes.