Download MendeleyRNA Tertiary Interactions in a Riboswitch Stabilize the Structure of a Kink Turn.
Schroeder, K.T., Daldrop, P., Lilley, D.M.J.(2011) Structure 19: 1233
- PubMed: 21893284
- DOI: https://doi.org/10.1016/j.str.2011.07.003
- Primary Citation of Related Structures:
2YDH, 2YGH - PubMed Abstract:
The kink turn is a widespread RNA motif that introduces an acute kink into the axis of duplex RNA, typically comprising a bulge followed by a G⋅A and A⋅G pairs. The kinked conformation is stabilized by metal ions, or the binding of proteins including L7Ae. We now demonstrate a third mechanism for the stabilization of k-turn structure, involving tertiary interactions within a larger RNA structure. The SAM-I riboswitch contains an essential standard k-turn sequence that kinks a helix so that its terminal loop can make a long-range interaction. We find that some sequence variations in the k-turn within the riboswitch do not prevent SAM binding, despite preventing the folding of the k-turn in isolation. Furthermore, two crystal structures show that the sequence-variant k-turns are conventionally folded within the riboswitch. This study shows that the folded structure of the k-turn can be stabilized by tertiary interactions within a larger RNA structure.
Organizational Affiliation:
Cancer Research UK Nucleic Acid Structure Research Group, MSI/WTB Complex, The University of Dundee, Dundee DD1 5EH, UK.
