Observation of preQ1-II riboswitch dynamics using single-molecule FRET. Issue 9 (2nd September 2019)

• Record Type: Journal Article
• Authors: Warnasooriya, Chandani; Ling, Clarence; Belashov, Ivan A.; Salim, Mohammad; Wedekind, Joseph E.; Ermolenko, Dmitri N.
• Is Part Of: RNA biology. Volume 16:Issue 9(2019)
• Page Start: 1086
• Page End: 1092
• Publication Date: 2019-09-02
• Subjects: Riboswitch -- smFRET -- conformation selection -- RNA dynamics; RNA -- Periodicals; Molecular biology -- Periodicals; Molecular biology; RNA; Periodicals; 572.8805
• DOI: 10.1080/15476286.2018.1536591
• Languages: English
• ISSNs: 1547-6286

Abstract

ABSTRACT: PreQ1 riboswitches regulate the synthesis of the hypermodified tRNA base queuosine by sensing the pyrrolopyrimidine metabolite preQ1 . Here, we use single-molecule FRET to interrogate the structural dynamics of apo and preQ1 -bound states of the preQ1 -II riboswitch from Lactobacillus rhamnosus . We find that the apo-form of the riboswitch spontaneously samples multiple conformations. Magnesium ions and preQ1 stabilize conformations that sequester the ribosome-binding site of the mRNA within the pseudoknotted structure, thus inhibiting translation initiation. Our results reveal that folding of the preQ1 -II riboswitch is complex and provide evidence favoring a conformational selection model of effector binding by riboswitches of this class.