Structural highlights
Publication Abstract from PubMedThe 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 GA and AG 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. RNA tertiary interactions in a riboswitch stabilize the structure of a kink turn.,Schroeder KT, Daldrop P, Lilley DM Structure. 2011 Sep 7;19(9):1233-40. PMID:21893284[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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