RNA Tertiary Interactions in a Riboswitch Stabilize the Structure of a Kink Turn

Kersten T. Schroeder, Peter Daldrop, David M. J. Lilley (Lead / Corresponding author)

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    42 Citations (Scopus)

    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.

    Original languageEnglish
    Pages (from-to)1233-1240
    Number of pages8
    JournalStructure
    Volume19
    Issue number9
    DOIs
    Publication statusPublished - 7 Sep 2011

    Keywords

    • SMALL NUCLEOLAR RNAS
    • U4 SNRNA
    • S-ADENOSYLMETHIONINE
    • PRERIBOSOMAL RNA
    • I RIBOSWITCH
    • L7AE PROTEIN
    • MOTIF
    • BINDING
    • SITE
    • C/D

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