title: NMR Structural Profiling of Transcriptional Intermediates Reveals Riboswitch Regulation by Metastable RNA Conformations.
abstract: Gene repression induced by the formation of transcriptional terminators represents a prime example for the coupling of RNA synthesis, folding, and regulation. In this context, mapping the changes in available conformational space of transcription intermediates during RNA synthesis is important to understand riboswitch function. A majority of riboswitches, an important class of small metabolite-sensing regulatory RNAs, act as transcriptional regulators, but the dependence of ligand binding and the subsequent allosteric conformational switch on mRNA transcript length has not yet been investigated. We show a strict fine-tuning of binding and sequence-dependent alterations of conformational space by structural analysis of all relevant transcription intermediates at single-nucleotide resolution for the I-A type 2'dG-sensing riboswitch from Mesoplasma florum by NMR spectroscopy. Our results provide a general framework to dissect the coupling of synthesis and folding essential for riboswitch function, revealing the importance of metastable states for RNA-based gene regulation.
authors.affiliation: Institute for Organic Chemisty and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität , Frankfurt/M. 60438, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Helmling
authors.affiliation: Institute for Organic Chemisty and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität , Frankfurt/M. 60438, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Wacker
authors.affiliation: Medical University of Vienna , Center for Anatomy and Cell Biology, Währingerstraße 13, 1090 Vienna, Austria.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Wolfinger
authors.forename: Ivo L
authors.initials: IL
authors.lastname: Hofacker
authors.affiliation: Institute for Organic Chemisty and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität , Frankfurt/M. 60438, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Hengesbach
authors.affiliation: Institute for Organic Chemisty and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität , Frankfurt/M. 60438, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Fürtig
authors.affiliation: Institute for Organic Chemisty and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität , Frankfurt/M. 60438, Germany.
authors.forename: Harald
authors.identifier: 0000-0001-5693-7909
authors.initials: H
authors.lastname: Schwalbe
mesh_terms: D000494:Allosteric Regulation; D001665:Binding Sites; D015870:Gene Expression; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D009690:Nucleic Acid Conformation; D059370:RNA Folding; D058928:Riboswitch; D014158:Transcription, Genetic
chemical_list: D008024:Ligands; D058928:Riboswitch