1
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Chauvier A, Walter NG. Beyond ligand binding: Single molecule observation reveals how riboswitches integrate multiple signals to balance bacterial gene regulation. Curr Opin Struct Biol 2024; 88:102893. [PMID: 39067113 DOI: 10.1016/j.sbi.2024.102893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 06/26/2024] [Accepted: 07/09/2024] [Indexed: 07/30/2024]
Abstract
Riboswitches are specialized RNA structures that orchestrate gene expression in response to sensing specific metabolite or ion ligands, mostly in bacteria. Upon ligand binding, these conformationally dynamic RNA motifs undergo structural changes that control critical gene expression processes such as transcription termination and translation initiation, thereby enabling cellular homeostasis and adaptation. Because RNA folds rapidly and co-transcriptionally, riboswitches make use of the low complexity of RNA sequences to adopt alternative, transient conformations on the heels of the transcribing RNA polymerase (RNAP), resulting in kinetic partitioning that defines the regulatory outcome. This review summarizes single molecule microscopy evidence that has begun to unveil a sophisticated network of dynamic, kinetically balanced interactions between riboswitch architecture and the gene expression machinery that, together, integrate diverse cellular signals.
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Affiliation(s)
- Adrien Chauvier
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, USA. https://twitter.com/adrienchauvier
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, USA.
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2
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Ding E, Chaudhury SN, Prajapati JD, Onuchic JN, Sanbonmatsu KY. Magnesium ions mitigate metastable states in the regulatory landscape of mRNA elements. RNA (NEW YORK, N.Y.) 2024; 30:992-1010. [PMID: 38777381 PMCID: PMC11251524 DOI: 10.1261/rna.079767.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 03/27/2024] [Indexed: 05/25/2024]
Abstract
Residing in the 5' untranslated region of the mRNA, the 2'-deoxyguanosine (2'-dG) riboswitch mRNA element adopts an alternative structure upon binding of the 2'-dG molecule, which terminates transcription. RNA conformations are generally strongly affected by positively charged metal ions (especially Mg2+). We have quantitatively explored the combined effect of ligand (2'-dG) and Mg2+ binding on the energy landscape of the aptamer domain of the 2'-dG riboswitch with both explicit solvent all-atom molecular dynamics simulations (99 μsec aggregate sampling for the study) and selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) experiments. We show that both ligand and Mg2+ are required for the stabilization of the aptamer domain; however, the two factors act with different modalities. The addition of Mg2+ remodels the energy landscape and reduces its frustration by the formation of additional contacts. In contrast, the binding of 2'-dG eliminates the metastable states by nucleating a compact core for the aptamer domain. Mg2+ ions and ligand binding are required to stabilize the least stable helix, P1 (which needs to unfold to activate the transcription platform), and the riboswitch core formed by the backbone of the P2 and P3 helices. Mg2+ and ligand also facilitate a more compact structure in the three-way junction region.
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Affiliation(s)
- Erdong Ding
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, USA
- Department of Chemistry, Rice University, Houston, Texas 77005, USA
| | - Susmit Narayan Chaudhury
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | | | - José N Onuchic
- Center for Theoretical Biological Physics, Rice University, Houston, Texas 77005, USA
- Department of Chemistry, Rice University, Houston, Texas 77005, USA
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
- Department of Biosciences, Rice University, Houston, Texas 77005, USA
| | - Karissa Y Sanbonmatsu
- Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- New Mexico Consortium, Los Alamos, New Mexico 87544, USA
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3
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Jin L, Zhang S, Song Z, Heng X, Chen SJ. Kinetic pathway of HIV-1 TAR cotranscriptional folding. Nucleic Acids Res 2024; 52:6066-6078. [PMID: 38738640 PMCID: PMC11162800 DOI: 10.1093/nar/gkae362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 04/09/2024] [Accepted: 04/24/2024] [Indexed: 05/14/2024] Open
Abstract
The Trans-Activator Receptor (TAR) RNA, located at the 5'-end untranslated region (5' UTR) of the human immunodeficiency virus type 1 (HIV-1), is pivotal in the virus's life cycle. As the initial functional domain, it folds during the transcription of viral mRNA. Although TAR's role in recruiting the Tat protein for trans-activation is established, the detailed kinetic mechanisms at play during early transcription, especially at points of temporary transcriptional pausing, remain elusive. Moreover, the precise physical processes of transcriptional pause and subsequent escape are not fully elucidated. This study focuses on the folding kinetics of TAR and the biological implications by integrating computer simulations of RNA folding during transcription with nuclear magnetic resonance (NMR) spectroscopy data. The findings reveal insights into the folding mechanism of a non-native intermediate that triggers transcriptional pause, along with different folding pathways leading to transcriptional pause and readthrough. The profiling of the cotranscriptional folding pathway and identification of kinetic structural intermediates reveal a novel mechanism for viral transcriptional regulation, which could pave the way for new antiviral drug designs targeting kinetic cotranscriptional folding pathways in viral RNAs.
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Affiliation(s)
- Lei Jin
- Department of Physics and Institute of Data Science and Informatics, University of Missouri, Columbia, MO 65211, USA
| | - Sicheng Zhang
- Department of Physics and Institute of Data Science and Informatics, University of Missouri, Columbia, MO 65211, USA
| | - Zhenwei Song
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - Xiao Heng
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | - Shi-Jie Chen
- Department of Physics and Institute of Data Science and Informatics, University of Missouri, Columbia, MO 65211, USA
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
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4
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Chauvier A, Dandpat SS, Romero R, Walter NG. A nascent riboswitch helix orchestrates robust transcriptional regulation through signal integration. Nat Commun 2024; 15:3955. [PMID: 38729929 PMCID: PMC11087558 DOI: 10.1038/s41467-024-48409-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 04/29/2024] [Indexed: 05/12/2024] Open
Abstract
Widespread manganese-sensing transcriptional riboswitches effect the dependable gene regulation needed for bacterial manganese homeostasis in changing environments. Riboswitches - like most structured RNAs - are believed to fold co-transcriptionally, subject to both ligand binding and transcription events; yet how these processes are orchestrated for robust regulation is poorly understood. Through a combination of single-molecule and bulk approaches, we discover how a single Mn2+ ion and the transcribing RNA polymerase (RNAP), paused immediately downstream by a DNA template sequence, are coordinated by the bridging switch helix P1.1 in the representative Lactococcus lactis riboswitch. This coordination achieves a heretofore-overlooked semi-docked global conformation of the nascent RNA, P1.1 base pair stabilization, transcription factor NusA ejection, and RNAP pause extension, thereby enforcing transcription readthrough. Our work demonstrates how a central, adaptable RNA helix functions analogous to a molecular fulcrum of a first-class lever system to integrate disparate signals for finely balanced gene expression control.
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Affiliation(s)
- Adrien Chauvier
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Shiba S Dandpat
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
- Intel Corporation, Hillsboro, OR, USA
| | - Rosa Romero
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, USA.
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5
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Rivera M, Ayon OS, Diaconescu-Grabari S, Pottel J, Moitessier N, Mittermaier A, McKeague M. A sensitive and scalable fluorescence anisotropy single stranded RNA targeting approach for monitoring riboswitch conformational states. Nucleic Acids Res 2024; 52:3164-3179. [PMID: 38375901 PMCID: PMC11014391 DOI: 10.1093/nar/gkae118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 02/02/2024] [Accepted: 02/07/2024] [Indexed: 02/21/2024] Open
Abstract
The capacity of riboswitches to undergo conformational changes in response to binding their native ligands is closely tied to their functional roles and is an attractive target for antimicrobial drug design. Here, we established a probe-based fluorescence anisotropy assay to monitor riboswitch conformational switching with high sensitivity and throughput. Using the Bacillus subtillis yitJ S-Box (SAM-I), Fusobacterium nucleatum impX RFN element of (FMN) and class-I cyclic-di-GMP from Vibrio cholerae riboswitches as model systems, we developed short fluorescent DNA probes that specifically recognize either ligand-free or -bound riboswitch conformational states. We showed that increasing concentrations of native ligands cause measurable and reproducible changes in fluorescence anisotropy that correlate with riboswitch conformational changes observed by native gel analysis. Furthermore, we applied our assay to several ligand analogues and confirmed that it can discriminate between ligands that bind, triggering the native conformational change, from those that bind without causing the conformational change. This new platform opens the possibility of high-throughput screening compound libraries to identify potential new antibiotics that specifically target functional conformational changes in riboswitches.
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Affiliation(s)
- Maira Rivera
- Department of Chemistry, Faculty of Science, McGill University, Montreal, QC H3A 0B8, Canada
| | - Omma S Ayon
- Department of Chemistry, Faculty of Science, McGill University, Montreal, QC H3A 0B8, Canada
| | | | - Joshua Pottel
- Molecular Forecaster Inc. 910-2075 Robert Bourassa, Montreal, QC H3A 2L1, Canada
| | - Nicolas Moitessier
- Department of Chemistry, Faculty of Science, McGill University, Montreal, QC H3A 0B8, Canada
- Molecular Forecaster Inc. 910-2075 Robert Bourassa, Montreal, QC H3A 2L1, Canada
| | - Anthony Mittermaier
- Department of Chemistry, Faculty of Science, McGill University, Montreal, QC H3A 0B8, Canada
| | - Maureen McKeague
- Department of Chemistry, Faculty of Science, McGill University, Montreal, QC H3A 0B8, Canada
- Pharmacology and Therapeutics, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3G 1Y6, Canada
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6
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Walter N, Chauvier A, Dandpat S, Romero R. A nascent riboswitch helix orchestrates robust transcriptional regulation through signal integration. RESEARCH SQUARE 2024:rs.3.rs-3849447. [PMID: 38352525 PMCID: PMC10862961 DOI: 10.21203/rs.3.rs-3849447/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/21/2024]
Abstract
Widespread manganese-sensing transcriptional riboswitches effect the dependable gene regulation needed for bacterial manganese homeostasis in changing environments. Riboswitches - like most structured RNAs - are believed to fold co-transcriptionally, subject to both ligand binding and transcription events; yet how these processes are orchestrated for robust regulation is poorly understood. Through a combination of single molecule and bulk approaches, we discovered how a single Mn 2+ ion and the transcribing RNA polymerase (RNAP), paused immediately downstream by a DNA template sequence, are coordinated by the bridging switch helix P1.1 in the paradigmatic Lactococcus lactis riboswitch. This coordination achieves a heretofore-overlooked semi-docked global conformation of the nascent RNA, P1.1 base pair stabilization, transcription factor NusA ejection, and RNAP pause extension, thereby enforcing transcription readthrough. Our work demonstrates how a central, adaptable RNA helix functions analogous to a molecular fulcrum of a first-class lever system to integrate disparate signals for finely balanced gene expression control.
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7
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Chauvier A, Walter NG. Regulation of bacterial gene expression by non-coding RNA: It is all about time! Cell Chem Biol 2024; 31:71-85. [PMID: 38211587 DOI: 10.1016/j.chembiol.2023.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 12/05/2023] [Accepted: 12/12/2023] [Indexed: 01/13/2024]
Abstract
Commensal and pathogenic bacteria continuously evolve to survive in diverse ecological niches by efficiently coordinating gene expression levels in their ever-changing environments. Regulation through the RNA transcript itself offers a faster and more cost-effective way to adapt than protein-based mechanisms and can be leveraged for diagnostic or antimicrobial purposes. However, RNA can fold into numerous intricate, not always functional structures that both expand and obscure the plethora of roles that regulatory RNAs serve within the cell. Here, we review the current knowledge of bacterial non-coding RNAs in relation to their folding pathways and interactions. We posit that co-transcriptional folding of these transcripts ultimately dictates their downstream functions. Elucidating the spatiotemporal folding of non-coding RNAs during transcription therefore provides invaluable insights into bacterial pathogeneses and predictive disease diagnostics. Finally, we discuss the implications of co-transcriptional folding andapplications of RNAs for therapeutics and drug targets.
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Affiliation(s)
- Adrien Chauvier
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Nils G Walter
- Single Molecule Analysis Group and Center for RNA Biomedicine, Department of Chemistry, University of Michigan, Ann Arbor, MI, USA.
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8
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Badelt S, Lorenz R. A Guide to Computational Cotranscriptional Folding Featuring the SRP RNA. Methods Mol Biol 2024; 2726:315-346. [PMID: 38780737 DOI: 10.1007/978-1-0716-3519-3_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Although RNA molecules are synthesized via transcription, little is known about the general impact of cotranscriptional folding in vivo. We present different computational approaches for the simulation of changing structure ensembles during transcription, including interpretations with respect to experimental data from literature. Specifically, we analyze different mutations of the E. coli SRP RNA, which has been studied comparatively well in previous literature, yet the details of which specific metastable structures form as well as when they form are still under debate. Here, we combine thermodynamic and kinetic, deterministic, and stochastic models with automated and visual inspection of those systems to derive the most likely scenario of which substructures form at which point during transcription. The simulations do not only provide explanations for present experimental observations but also suggest previously unnoticed conformations that may be verified through future experimental studies.
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Affiliation(s)
- Stefan Badelt
- Department of Theoretical Chemistry, University of Vienna, Vienna, Austria.
| | - Ronny Lorenz
- Department of Theoretical Chemistry, University of Vienna, Vienna, Austria
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9
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Berman KE, Steans R, Hertz LM, Lucks JB. A transient intermediate RNA structure underlies the regulatory function of the E. coli thiB TPP translational riboswitch. RNA (NEW YORK, N.Y.) 2023; 29:1658-1672. [PMID: 37419663 PMCID: PMC10578472 DOI: 10.1261/rna.079427.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 06/09/2023] [Indexed: 07/09/2023]
Abstract
Riboswitches are cis-regulatory RNA elements that regulate gene expression in response to ligand binding through the coordinated action of a ligand-binding aptamer domain (AD) and a downstream expression platform (EP). Previous studies of transcriptional riboswitches have uncovered diverse examples that utilize structural intermediates that compete with the AD and EP folds to mediate the switching mechanism on the timescale of transcription. Here we investigate whether similar intermediates are important for riboswitches that control translation by studying the Escherichia coli thiB thiamin pyrophosphate (TPP) riboswitch. Using cellular gene expression assays, we first confirmed that the riboswitch acts at the level of translational regulation. Deletion mutagenesis showed the importance of the AD-EP linker sequence for riboswitch function. Sequence complementarity between the linker region and the AD P1 stem suggested the possibility of an intermediate nascent RNA structure called the antisequestering stem that could mediate the thiB switching mechanism. Experimentally informed secondary structure models of the thiB folding pathway generated from chemical probing of nascent thiB structures in stalled transcription elongation complexes confirmed the presence of the antisequestering stem, and showed it may form cotranscriptionally. Additional mutational analysis showed that mutations to the antisequestering stem break or bias thiB function according to whether the antisequestering stem or P1 is favored. This work provides an important example of intermediate structures that compete with AD and EP folds to implement riboswitch mechanisms.
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Affiliation(s)
- Katherine E Berman
- Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, Illinois 60208, USA
| | - Russell Steans
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, USA
| | - Laura M Hertz
- Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, Illinois 60208, USA
| | - Julius B Lucks
- Department of Chemical and Biological Engineering, Northwestern University, Illinois 60208, USA
- Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, USA
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10
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Badelt S, Lorenz R, Hofacker IL. DrTransformer: heuristic cotranscriptional RNA folding using the nearest neighbor energy model. Bioinformatics 2023; 39:6992659. [PMID: 36655786 PMCID: PMC9889959 DOI: 10.1093/bioinformatics/btad034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 12/16/2022] [Accepted: 01/17/2023] [Indexed: 01/20/2023] Open
Abstract
MOTIVATION Folding during transcription can have an important influence on the structure and function of RNA molecules, as regions closer to the 5' end can fold into metastable structures before potentially stronger interactions with the 3' end become available. Thermodynamic RNA folding models are not suitable to predict structures that result from cotranscriptional folding, as they can only calculate properties of the equilibrium distribution. Other software packages that simulate the kinetic process of RNA folding during transcription exist, but they are mostly applicable for short sequences. RESULTS We present a new algorithm that tracks changes to the RNA secondary structure ensemble during transcription. At every transcription step, new representative local minima are identified, a neighborhood relation is defined and transition rates are estimated for kinetic simulations. After every simulation, a part of the ensemble is removed and the remainder is used to search for new representative structures. The presented algorithm is deterministic (up to numeric instabilities of simulations), fast (in comparison with existing methods), and it is capable of folding RNAs much longer than 200 nucleotides. AVAILABILITY AND IMPLEMENTATION This software is open-source and available at https://github.com/ViennaRNA/drtransformer. SUPPLEMENTARY INFORMATION Supplementary data are available at Bioinformatics online.
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Affiliation(s)
| | - Ronny Lorenz
- Department of Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Ivo L Hofacker
- Department of Theoretical Chemistry, University of Vienna, Vienna, Austria,Research Group Bioinformatics and Computational Biology, Faculty of Computer Science, University of Vienna, Vienna, Austria
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11
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Gupta P, Khadake RM, Panja S, Shinde K, Rode AB. Alternative RNA Conformations: Companion or Combatant. Genes (Basel) 2022; 13:1930. [PMID: 36360167 PMCID: PMC9689429 DOI: 10.3390/genes13111930] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 10/19/2022] [Accepted: 10/19/2022] [Indexed: 09/06/2024] Open
Abstract
RNA molecules, in one form or another, are involved in almost all aspects of cell physiology, as well as in disease development. The diversity of the functional roles of RNA comes from its intrinsic ability to adopt complex secondary and tertiary structures, rivaling the diversity of proteins. The RNA molecules form dynamic ensembles of many interconverting conformations at a timescale of seconds, which is a key for understanding how they execute their cellular functions. Given the crucial role of RNAs in various cellular processes, we need to understand the RNA molecules from a structural perspective. Central to this review are studies aimed at revealing the regulatory role of conformational equilibria in RNA in humans to understand genetic diseases such as cancer and neurodegenerative diseases, as well as in pathogens such as bacteria and viruses so as to understand the progression of infectious diseases. Furthermore, we also summarize the prior studies on the use of RNA structures as platforms for the rational design of small molecules for therapeutic applications.
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Affiliation(s)
| | | | | | | | - Ambadas B. Rode
- Regional Centre for Biotechnology, NCR Biotech Science Cluster, 3rd Milestone, Faridabad—Gurugram Expressway, Faridabad 121001, India
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12
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Landgraf T, Völklein AE, Fürtig B, Schwalbe H. The cotranscriptional folding landscape for two cyclic di-nucleotide-sensing riboswitches with highly homologous aptamer domains acting either as ON- or OFF-switches. Nucleic Acids Res 2022; 50:6639-6655. [PMID: 35736222 PMCID: PMC9262584 DOI: 10.1093/nar/gkac514] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 05/03/2022] [Accepted: 06/07/2022] [Indexed: 12/24/2022] Open
Abstract
Riboswitches are gene regulatory elements located in untranslated mRNA regions. They bind inducer molecules with high affinity and specificity. Cyclic-di-nucleotide-sensing riboswitches are major regulators of genes for the environment, membranes and motility (GEMM) of bacteria. Up to now, structural probing assays or crystal structures have provided insight into the interaction between cyclic-di-nucleotides and their corresponding riboswitches. ITC analysis, NMR analysis and computational modeling allowed us to gain a detailed understanding of the gene regulation mechanisms for the Cd1 (Clostridium difficile) and for the pilM (Geobacter metallireducens) riboswitches and their respective di-nucleotides c-di-GMP and c-GAMP. Binding capability showed a 25 nucleotide (nt) long window for pilM and a 61 nt window for Cd1. Within this window, binding affinities ranged from 35 μM to 0.25 μM spanning two orders of magnitude for Cd1 and pilM showing a strong dependence on competing riboswitch folds. Experimental results were incorporated into a Markov simulation to further our understanding of the transcriptional folding pathways of riboswitches. Our model showed the ability to predict riboswitch gene regulation and its dependence on transcription speed, pausing and ligand concentration.
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Affiliation(s)
| | | | - Boris Fürtig
- Correspondence may also be addressed to Boris Fürtig.
| | - Harald Schwalbe
- To whom correspondence should be addressed. Tel: +49 69 798 29737; Fax: +49 69 798 29515;
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13
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Xu X, Jin L, Xie L, Chen SJ. Landscape Zooming toward the Prediction of RNA Cotranscriptional Folding. J Chem Theory Comput 2022; 18:2002-2015. [PMID: 35133833 DOI: 10.1021/acs.jctc.1c01233] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
RNA molecules fold as they are transcribed. Cotranscriptional folding of RNA plays a critical role in RNA functions in vivo. Present computational strategies focus on simulations where large structural changes may not be completely sampled. Here, we describe an alternative approach to predicting cotranscriptional RNA folding by zooming in and out of the RNA folding energy landscape. By classifying the RNA structural ensemble into "partitions" based on long, stable helices, we zoom out of the landscape and predict the overall slow folding kinetics from the interpartition kinetic network, and for each interpartition transition, we zoom in on the landscape to simulate the kinetics. Applications of the model to the 117-nucleotide E. coli SRP RNA and the 59-nucleotide HIV-1 TAR RNA show agreements with the experimental data and new structural and kinetic insights into biologically significant conformational switches and pathways for these important systems. This approach, by zooming in/out of an RNA folding landscape at different resolutions, might allow us to treat large RNAs in vivo with transcriptional pause, transcription speed, and other in vivo effects.
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Affiliation(s)
- Xiaojun Xu
- Institute of Bioinformatics and Medical Engineering, Jiangsu University of Technology, Changzhou, Jiangsu 213001, China
| | - Lei Jin
- Department of Physics, Department of Biochemistry, and Institute of Data Science and Informatics, University of Missouri, Columbia, Missouri 65211, United States
| | - Liangxu Xie
- Institute of Bioinformatics and Medical Engineering, Jiangsu University of Technology, Changzhou, Jiangsu 213001, China
| | - Shi-Jie Chen
- Department of Physics, Department of Biochemistry, and Institute of Data Science and Informatics, University of Missouri, Columbia, Missouri 65211, United States
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14
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Sherlock ME, Higgs G, Yu D, Widner DL, White NA, Sudarsan N, Sadeeshkumar H, Perkins KR, Mirihana Arachchilage G, Malkowski SN, King CG, Harris KA, Gaffield G, Atilho RM, Breaker RR. Architectures and complex functions of tandem riboswitches. RNA Biol 2022; 19:1059-1076. [PMID: 36093908 PMCID: PMC9481103 DOI: 10.1080/15476286.2022.2119017] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022] Open
Abstract
Riboswitch architectures that involve the binding of a single ligand to a single RNA aptamer domain result in ordinary dose-response curves that require approximately a 100-fold change in ligand concentration to cover nearly the full dynamic range for gene regulation. However, by using multiple riboswitches or aptamer domains in tandem, these ligand-sensing structures can produce additional, complex gene control outcomes. In the current study, we have computationally searched for tandem riboswitch architectures in bacteria to provide a more complete understanding of the diverse biological and biochemical functions of gene control elements that are made exclusively of RNA. Numerous different arrangements of tandem homologous riboswitch architectures are exploited by bacteria to create more 'digital' gene control devices, which operate over a narrower ligand concentration range. Also, two heterologous riboswitch aptamers are sometimes employed to create two-input Boolean logic gates with various types of genetic outputs. These findings illustrate the sophisticated genetic decisions that can be made by using molecular sensors and switches based only on RNA.
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Affiliation(s)
- Madeline E. Sherlock
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado, Anschutz Medical Campus, Research-1S, Aurora, CO, USA
| | - Gadareth Higgs
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Diane Yu
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Danielle L. Widner
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Neil A. White
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | | | - Harini Sadeeshkumar
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Kevin R. Perkins
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Gayan Mirihana Arachchilage
- Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
- PTC Therapeutics, Inc, South Plainfield, NJ, USA
| | | | - Christopher G. King
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | | | - Glenn Gaffield
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Ruben M. Atilho
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
| | - Ronald R. Breaker
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT, USA
- Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
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15
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Dynamic competition between a ligand and transcription factor NusA governs riboswitch-mediated transcription regulation. Proc Natl Acad Sci U S A 2021; 118:2109026118. [PMID: 34782462 DOI: 10.1073/pnas.2109026118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2021] [Indexed: 11/18/2022] Open
Abstract
Cotranscriptional RNA folding is widely assumed to influence the timely control of gene expression, but our understanding remains limited. In bacteria, the fluoride (F-)-sensing riboswitch is a transcriptional control element essential to defend against toxic F- levels. Using this model riboswitch, we find that its ligand F- and essential bacterial transcription factor NusA compete to bind the cotranscriptionally folding RNA, opposing each other's modulation of downstream pausing and termination by RNA polymerase. Single-molecule fluorescence assays probing active transcription elongation complexes discover that NusA unexpectedly binds highly reversibly, frequently interrogating the complex for emerging, cotranscriptionally folding RNA duplexes. NusA thus fine-tunes the transcription rate in dependence of the ligand-responsive higher-order structure of the riboswitch. At the high NusA concentrations found intracellularly, this dynamic modulation is expected to lead to adaptive bacterial transcription regulation with fast response times.
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16
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Hohmann KF, Blümler A, Heckel A, Fürtig B. The RNA chaperone StpA enables fast RNA refolding by destabilization of mutually exclusive base pairs within competing secondary structure elements. Nucleic Acids Res 2021; 49:11337-11349. [PMID: 34614185 PMCID: PMC8565331 DOI: 10.1093/nar/gkab876] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/13/2021] [Accepted: 09/17/2021] [Indexed: 11/14/2022] Open
Abstract
In bacteria RNA gene regulatory elements refold dependent on environmental clues between two or more long-lived conformational states each associated with a distinct regulatory state. The refolding kinetics are strongly temperature-dependent and especially at lower temperatures they reach timescales that are biologically not accessible. To overcome this problem, RNA chaperones have evolved. However, the precise molecular mechanism of how these proteins accelerate RNA refolding reactions remains enigmatic. Here we show how the RNA chaperone StpA of Escherichia coli leads to an acceleration of a bistable RNA's refolding kinetics through the selective destabilization of key base pairing interactions. We find in laser assisted real-time NMR experiments on photocaged bistable RNAs that the RNA chaperone leads to a two-fold increase in refolding rates at low temperatures due to reduced stability of ground state conformations. Further, we can show that upon interaction with StpA, base pairing interactions in the bistable RNA are modulated to favor refolding through the dominant pseudoknotted transition pathway. Our results shed light on the molecular mechanism of the interaction between RNA chaperones and bistable RNAs and are the first step into a functional classification of chaperones dependent on their biophysical mode of operation.
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Affiliation(s)
- Katharina F Hohmann
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance BMRZ, Goethe University Frankfurt am Main, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
| | - Anja Blümler
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
| | - Alexander Heckel
- Institute for Organic Chemistry and Chemical Biology, Goethe University Frankfurt am Main, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
| | - Boris Fürtig
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance BMRZ, Goethe University Frankfurt am Main, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
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17
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Schärfen L, Neugebauer KM. Transcription Regulation Through Nascent RNA Folding. J Mol Biol 2021; 433:166975. [PMID: 33811916 DOI: 10.1016/j.jmb.2021.166975] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/14/2022]
Abstract
Folding of RNA into secondary structures through intramolecular base pairing determines an RNA's three-dimensional architecture and associated function. Simple RNA structures like stem loops can provide specialized functions independent of coding capacity, such as protein binding, regulation of RNA processing and stability, stimulation or inhibition of translation. RNA catalysis is dependent on tertiary structures found in the ribosome, tRNAs and group I and II introns. While the extent to which non-coding RNAs contribute to cellular maintenance is generally appreciated, the fact that both non-coding and coding RNA can assume relevant structural states has only recently gained attention. In particular, the co-transcriptional folding of nascent RNA of all classes has the potential to regulate co-transcriptional processing, RNP (ribonucleoprotein particle) formation, and transcription itself. Riboswitches are established examples of co-transcriptionally folded coding RNAs that directly regulate transcription, mainly in prokaryotes. Here we discuss recent studies in both prokaryotes and eukaryotes showing that structure formation may carry a more widespread regulatory logic during RNA synthesis. Local structures forming close to the catalytic center of RNA polymerases have the potential to regulate transcription by reducing backtracking. In addition, stem loops or more complex structures may alter co-transcriptional RNA processing or its efficiency. Several examples of functional structures have been identified to date, and this review provides an overview of physiologically distinct processes where co-transcriptionally folded RNA plays a role. Experimental approaches such as single-molecule FRET and in vivo structural probing to further advance our insight into the significance of co-transcriptional structure formation are discussed.
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Affiliation(s)
- Leonard Schärfen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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18
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Abdelsattar AS, Mansour Y, Aboul-Ela F. The Perturbed Free-Energy Landscape: Linking Ligand Binding to Biomolecular Folding. Chembiochem 2021; 22:1499-1516. [PMID: 33351206 DOI: 10.1002/cbic.202000695] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/19/2020] [Indexed: 12/24/2022]
Abstract
The effects of ligand binding on biomolecular conformation are crucial in drug design, enzyme mechanisms, the regulation of gene expression, and other biological processes. Descriptive models such as "lock and key", "induced fit", and "conformation selection" are common ways to interpret such interactions. Another historical model, linked equilibria, proposes that the free-energy landscape (FEL) is perturbed by the addition of ligand binding energy for the bound population of biomolecules. This principle leads to a unified, quantitative theory of ligand-induced conformation change, building upon the FEL concept. We call the map of binding free energy over biomolecular conformational space the "binding affinity landscape" (BAL). The perturbed FEL predicts/explains ligand-induced conformational changes conforming to all common descriptive models. We review recent experimental and computational studies that exemplify the perturbed FEL, with emphasis on RNA. This way of understanding ligand-induced conformation dynamics motivates new experimental and theoretical approaches to ligand design, structural biology and systems biology.
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Affiliation(s)
- Abdallah S Abdelsattar
- Center for X-Ray Determination of the Structure of Matter, Zewail City of Science and Technology, Ahmed Zewail Road, October Gardens, 12578, Giza, Egypt
| | - Youssef Mansour
- Center for X-Ray Determination of the Structure of Matter, Zewail City of Science and Technology, Ahmed Zewail Road, October Gardens, 12578, Giza, Egypt
| | - Fareed Aboul-Ela
- Center for X-Ray Determination of the Structure of Matter, Zewail City of Science and Technology, Ahmed Zewail Road, October Gardens, 12578, Giza, Egypt
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19
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Entzian G, Hofacker I, Ponty Y, Lorenz R, Tanzer A. RNAxplorer: Harnessing the Power of Guiding Potentials to Sample RNA Landscapes. Bioinformatics 2021; 37:2126-2133. [PMID: 33538792 PMCID: PMC8352504 DOI: 10.1093/bioinformatics/btab066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 12/16/2020] [Accepted: 02/02/2021] [Indexed: 11/13/2022] Open
Abstract
Motivation Predicting the folding dynamics of RNAs is a computationally difficult problem, first and foremost due to the combinatorial explosion of alternative structures in the folding space. Abstractions are therefore needed to simplify downstream analyses, and thus make them computationally tractable. This can be achieved by various structure sampling algorithms. However, current sampling methods are still time consuming and frequently fail to represent key elements of the folding space. Method We introduce RNAxplorer, a novel adaptive sampling method to efficiently explore the structure space of RNAs. RNAxplorer uses dynamic programming to perform an efficient Boltzmann sampling in the presence of guiding potentials, which are accumulated into pseudo-energy terms and reflect similarity to already well-sampled structures. This way, we effectively steer sampling toward underrepresented or unexplored regions of the structure space. Results We developed and applied different measures to benchmark our sampling methods against its competitors. Most of the measures show that RNAxplorer produces more diverse structure samples, yields rare conformations that may be inaccessible to other sampling methods and is better at finding the most relevant kinetic traps in the landscape. Thus, it produces a more representative coarse graining of the landscape, which is well suited to subsequently compute better approximations of RNA folding kinetics. Availabilityand implementation https://github.com/ViennaRNA/RNAxplorer/. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Gregor Entzian
- Faculty of Chemistry, Department of Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Ivo Hofacker
- Faculty of Chemistry, Department of Theoretical Chemistry, University of Vienna, Vienna, Austria.,Faculty of Computer Science, Bioinformatics and Computational Biology, University of Vienna, Vienna, Austria
| | - Yann Ponty
- LIX, CNRS UMR 7161, Ecole Polytechnique, Institut Polytechnique de Paris, France
| | - Ronny Lorenz
- Faculty of Chemistry, Department of Theoretical Chemistry, University of Vienna, Vienna, Austria
| | - Andrea Tanzer
- Faculty of Chemistry, Department of Theoretical Chemistry, University of Vienna, Vienna, Austria.,Center for Anatomy and Cell Biology, Division of Cell and Developmental Biology, Medical University of Vienna, Vienna, Austria
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20
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Binas O, de Jesus V, Landgraf T, Völklein AE, Martins J, Hymon D, Kaur Bains J, Berg H, Biedenbänder T, Fürtig B, Lakshmi Gande S, Niesteruk A, Oxenfarth A, Shahin Qureshi N, Schamber T, Schnieders R, Tröster A, Wacker A, Wirmer‐Bartoschek J, Wirtz Martin MA, Stirnal E, Azzaoui K, Richter C, Sreeramulu S, José Blommers MJ, Schwalbe H. 19 F NMR-Based Fragment Screening for 14 Different Biologically Active RNAs and 10 DNA and Protein Counter-Screens. Chembiochem 2021; 22:423-433. [PMID: 32794266 PMCID: PMC7436455 DOI: 10.1002/cbic.202000476] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/11/2020] [Indexed: 11/17/2022]
Abstract
We report here the nuclear magnetic resonance 19 F screening of 14 RNA targets with different secondary and tertiary structure to systematically assess the druggability of RNAs. Our RNA targets include representative bacterial riboswitches that naturally bind with nanomolar affinity and high specificity to cellular metabolites of low molecular weight. Based on counter-screens against five DNAs and five proteins, we can show that RNA can be specifically targeted. To demonstrate the quality of the initial fragment library that has been designed for easy follow-up chemistry, we further show how to increase binding affinity from an initial fragment hit by chemistry that links the identified fragment to the intercalator acridine. Thus, we achieve low-micromolar binding affinity without losing binding specificity between two different terminator structures.
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Affiliation(s)
- Oliver Binas
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Vanessa de Jesus
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Tom Landgraf
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Albrecht Eduard Völklein
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Jason Martins
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Daniel Hymon
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Jasleen Kaur Bains
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Hannes Berg
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Thomas Biedenbänder
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Boris Fürtig
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Santosh Lakshmi Gande
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Anna Niesteruk
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Andreas Oxenfarth
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Nusrat Shahin Qureshi
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Tatjana Schamber
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Robbin Schnieders
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Alix Tröster
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Anna Wacker
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Julia Wirmer‐Bartoschek
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Maria Alexandra Wirtz Martin
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Elke Stirnal
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Kamal Azzaoui
- Saverna TherapeuticsGewerbestrasse 244123AllschwilSwitzerland
| | - Christian Richter
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | - Sridhar Sreeramulu
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
| | | | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-University FrankfurtMax-von-Laue Strasse 760438Frankfurt am MainGermany
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21
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Parra-Rojas C, Fürtig B, Schwalbe H, Hernandez-Vargas EA. Quantitative modeling of the function of kinetically driven transcriptional riboswitches. J Theor Biol 2020; 506:110406. [PMID: 32771533 DOI: 10.1016/j.jtbi.2020.110406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 06/17/2020] [Accepted: 07/09/2020] [Indexed: 11/18/2022]
Abstract
Riboswitches are cis-acting regulatory mRNA elements in bacteria, that modulate the expression of their associated genes in response to a cognate metabolite, operating either on the level of translation or transcription. Transcriptional riboswitches have to fold into functional structures as they are being synthesized and, only if transcription rates and ligand binding kinetics match, structured transcription intermediates are enabled to undergo ligand-dependent conformational refolding as a prerequisite for ligand-mediated gene expression. Therefore, transcription rates are of essential importance for functional riboswitch-mediated gene regulation. Here, we propose a generalized modeling framework for the kinetic mechanisms of transcriptional riboswitches. The formalism accommodates time-dependent transcription rates and changes of metabolite concentration and permits incorporation of variations in transcription rate depending on transcript length. We derive explicit analytical expressions for the fraction of transcripts that determine repression or activation of gene expression as a function of pause site location and its slowing down of transcription for the case of the (2'dG)-sensing riboswitch from Mesoplasma florum. Our modeling challenges the current view on the exclusive importance of metabolite binding to transcripts containing only the aptamer domain. Numerical simulations of transcription proceeding in a continuous manner under time-dependent changes of metabolite concentration further suggest that rapid modulations in concentration result in a reduced dynamic range for riboswitch function regardless of transcription rate, while a combination of slow modulations and small transcription rates ensures a wide range of finely tuneable regulatory outcomes.
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Affiliation(s)
- César Parra-Rojas
- Frankfurt Institute for Advanced Studies, 60438 Frankfurt am Main, Germany
| | - Boris Fürtig
- Institute for Organic Chemistry and Chemical Biology Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, 60438 Frankfurt am Main, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, 60438 Frankfurt am Main, Germany.
| | - Esteban A Hernandez-Vargas
- Frankfurt Institute for Advanced Studies, 60438 Frankfurt am Main, Germany; Instituto de Matemáticas, Universidad Nacional Autonoma de Mexico, Boulevard Juriquilla 3001, Santiago de Querétaro, Qro. 76230, Mexico.
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22
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Advanced approaches for elucidating structures of large RNAs using NMR spectroscopy and complementary methods. Methods 2020; 183:93-107. [DOI: 10.1016/j.ymeth.2020.01.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 11/11/2019] [Accepted: 01/16/2020] [Indexed: 11/23/2022] Open
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23
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Real-time monitoring of single ZTP riboswitches reveals a complex and kinetically controlled decision landscape. Nat Commun 2020; 11:4531. [PMID: 32913225 PMCID: PMC7484762 DOI: 10.1038/s41467-020-18283-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 08/10/2020] [Indexed: 11/08/2022] Open
Abstract
RNAs begin to fold and function during transcription. Riboswitches undergo cotranscriptional switching in the context of transcription elongation, RNA folding, and ligand binding. To investigate how these processes jointly modulate the function of the folate stress-sensing Fusobacterium ulcerans ZTP riboswitch, we apply a single-molecule vectorial folding (VF) assay in which an engineered superhelicase Rep-X sequentially releases fluorescently labeled riboswitch RNA from a heteroduplex in a 5′-to-3′ direction, at ~60 nt s−1 [comparable to the speed of bacterial RNA polymerase (RNAP)]. We demonstrate that the ZTP riboswitch is kinetically controlled and that its activation is favored by slower unwinding, strategic pausing between but not before key folding elements, or a weakened transcription terminator. Real-time single-molecule monitoring captures folding riboswitches in multiple states, including an intermediate responsible for delayed terminator formation. These results show how individual nascent RNAs occupy distinct channels within the folding landscape that controls the fate of the riboswitch. Many RNAs become functional before their synthesis completes. Here the authors employ a single-molecule vectorial folding assay mimicking RNA transcription and show that the ZTP riboswitch is kinetically controlled and activated by slower unwinding and strategic pausing.
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24
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Sun Y, Wang Y, Tan ZJ, Zhang W. Regulation mechanism of lysC riboswitch in gram-positive bacterium Bacillus subtilis. J Biomol Struct Dyn 2020; 38:2784-2791. [DOI: 10.1080/07391102.2019.1639546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Yuying Sun
- Department of Physics, Wuhan University, Wuhan, Hubei, P.R. China
| | - Yanli Wang
- Department of Physics, Wuhan University, Wuhan, Hubei, P.R. China
| | - Zhi-Jie Tan
- Department of Physics, Wuhan University, Wuhan, Hubei, P.R. China
| | - Wenbing Zhang
- Department of Physics, Wuhan University, Wuhan, Hubei, P.R. China
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25
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Alaidi O, Aboul‐ela F. Statistical mechanical prediction of ligand perturbation to RNA secondary structure and application to riboswitches. J Comput Chem 2020; 41:1521-1537. [DOI: 10.1002/jcc.26195] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 01/03/2020] [Accepted: 03/09/2020] [Indexed: 02/04/2023]
Affiliation(s)
- Osama Alaidi
- Biocomplexity for Research and Consulting Cairo Egypt
| | - Fareed Aboul‐ela
- Center for X‐Ray Determination of the Structure of MatterZewail City of Science and Technology Giza Egypt
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26
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Fürtig B, Oberhauser EM, Zetzsche H, Klötzner DP, Heckel A, Schwalbe H. Refolding through a Linear Transition State Enables Fast Temperature Adaptation of a Translational Riboswitch. Biochemistry 2020; 59:1081-1086. [PMID: 32134253 DOI: 10.1021/acs.biochem.9b01044] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The adenine-sensing riboswitch from the Gram-negative bacterium Vibrio vulnificus is an RNA-based gene regulatory element that acts in response to both its cognate low-molecular weight ligand and temperature. The combined sensitivity to environmental temperature and ligand concentration is maintained by an equilibrium of three distinct conformations involving two ligand-free states and one ligand-bound state. The key structural element that undergoes refolding in the ligand-free states comprises a 35-nucleotide temperature response module. Here, we present the structural characterization of this temperature response module. We employ high-resolution NMR spectroscopy and photocaged RNAs as molecular probes to decipher the kinetic and thermodynamic framework of the secondary structure transition in the apo state of the riboswitch. We propose a model for the transition state adopted during the thermal refolding of the temperature response module that connects two mutually exclusive long-lived and stable conformational states. This transition state is characterized by a comparatively low free activation enthalpy. A pseudoknot conformation in the transition state, as commonly seen in RNA refolding, is therefore unlikely. More likely, the transition state of the adenine-sensing riboswitch temperature response module features a linear conformation.
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Affiliation(s)
- Boris Fürtig
- Johann Wolfgang Goethe University, Institute of Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Max von Laue Strasse 7, 60438 Frankfurt/Main, Germany
| | - Eva Marie Oberhauser
- Institute of Organic Chemistry and Chemical Biology, Max von Laue Strasse 7, 60438 Frankfurt/Main, Germany
| | - Heidi Zetzsche
- Johann Wolfgang Goethe University, Institute of Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Max von Laue Strasse 7, 60438 Frankfurt/Main, Germany
| | - Dean-Paulos Klötzner
- Institute of Organic Chemistry and Chemical Biology, Max von Laue Strasse 7, 60438 Frankfurt/Main, Germany
| | - Alexander Heckel
- Institute of Organic Chemistry and Chemical Biology, Max von Laue Strasse 7, 60438 Frankfurt/Main, Germany
| | - Harald Schwalbe
- Johann Wolfgang Goethe University, Institute of Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance (BMRZ), Max von Laue Strasse 7, 60438 Frankfurt/Main, Germany
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27
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Ganser LR, Kelly ML, Herschlag D, Al-Hashimi HM. The roles of structural dynamics in the cellular functions of RNAs. Nat Rev Mol Cell Biol 2020; 20:474-489. [PMID: 31182864 DOI: 10.1038/s41580-019-0136-0] [Citation(s) in RCA: 263] [Impact Index Per Article: 65.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
RNAs fold into 3D structures that range from simple helical elements to complex tertiary structures and quaternary ribonucleoprotein assemblies. The functions of many regulatory RNAs depend on how their 3D structure changes in response to a diverse array of cellular conditions. In this Review, we examine how the structural characterization of RNA as dynamic ensembles of conformations, which form with different probabilities and at different timescales, is improving our understanding of RNA function in cells. We discuss the mechanisms of gene regulation by microRNAs, riboswitches, ribozymes, post-transcriptional RNA modifications and RNA-binding proteins, and how the cellular environment and processes such as liquid-liquid phase separation may affect RNA folding and activity. The emerging RNA-ensemble-function paradigm is changing our perspective and understanding of RNA regulation, from in vitro to in vivo and from descriptive to predictive.
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Affiliation(s)
- Laura R Ganser
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Megan L Kelly
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Daniel Herschlag
- Department of Biochemistry, Stanford ChEM-H Chemistry, Engineering, and Medicine for Human Health, Stanford University, Stanford, CA, USA.,Department of Chemical Engineering, Stanford ChEM-H Chemistry, Engineering, and Medicine for Human Health, Stanford University, Stanford, CA, USA.,Department of Chemistry, Stanford ChEM-H Chemistry, Engineering, and Medicine for Human Health, Stanford University, Stanford, CA, USA
| | - Hashim M Al-Hashimi
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA. .,Department of Chemistry, Duke University, Durham, NC, USA.
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28
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Schnieders R, Keyhani S, Schwalbe H, Fürtig B. More than Proton Detection-New Avenues for NMR Spectroscopy of RNA. Chemistry 2020; 26:102-113. [PMID: 31454110 PMCID: PMC6973061 DOI: 10.1002/chem.201903355] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Indexed: 12/16/2022]
Abstract
Ribonucleic acid oligonucleotides (RNAs) play pivotal roles in cellular function (riboswitches), chemical biology applications (SELEX-derived aptamers), cell biology and biomedical applications (transcriptomics). Furthermore, a growing number of RNA forms (long non-coding RNAs, circular RNAs) but also RNA modifications are identified, showing the ever increasing functional diversity of RNAs. To describe and understand this functional diversity, structural studies of RNA are increasingly important. However, they are often more challenging than protein structural studies as RNAs are substantially more dynamic and their function is often linked to their structural transitions between alternative conformations. NMR is a prime technique to characterize these structural dynamics with atomic resolution. To extend the NMR size limitation and to characterize large RNAs and their complexes above 200 nucleotides, new NMR techniques have been developed. This Minireview reports on the development of NMR methods that utilize detection on low-γ nuclei (heteronuclei like 13 C or 15 N with lower gyromagnetic ratio than 1 H) to obtain unique structural and dynamic information for large RNA molecules in solution. Experiments involve through-bond correlations of nucleobases and the phosphodiester backbone of RNA for chemical shift assignment and make information on hydrogen bonding uniquely accessible. Previously unobservable NMR resonances of amino groups in RNA nucleobases are now detected in experiments involving conformational exchange-resistant double-quantum 1 H coherences, detected by 13 C NMR spectroscopy. Furthermore, 13 C and 15 N chemical shifts provide valuable information on conformations. All the covered aspects point to the advantages of low-γ nuclei detection experiments in RNA.
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Affiliation(s)
- Robbin Schnieders
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-Universität FrankfurtMax-von-Laue-Str. 760438FrankfurtGermany
| | - Sara Keyhani
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-Universität FrankfurtMax-von-Laue-Str. 760438FrankfurtGermany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-Universität FrankfurtMax-von-Laue-Str. 760438FrankfurtGermany
| | - Boris Fürtig
- Institute for Organic Chemistry and Chemical BiologyCenter for Biomolecular Magnetic Resonance (BMRZ)Johann Wolfgang Goethe-Universität FrankfurtMax-von-Laue-Str. 760438FrankfurtGermany
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29
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Abstract
RNA molecules fold into complex three-dimensional structures that sample alternate conformations ranging from minor differences in tertiary structure dynamics to major differences in secondary structure. This allows them to form entirely different substructures with each population potentially giving rise to a distinct biological outcome. The substructures can be partitioned along an existing energy landscape given a particular static cellular cue or can be shifted in response to dynamic cues such as ligand binding. We review a few key examples of RNA molecules that sample alternate conformations and how these are capitalized on for control of critical regulatory functions.
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Affiliation(s)
- Marie Teng-Pei Wu
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138
| | - Victoria D'Souza
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138
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30
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Wang F, Sun LZ, Sun T, Chang S, Xu X. Helix-Based RNA Landscape Partition and Alternative Secondary Structure Determination. ACS OMEGA 2019; 4:15407-15413. [PMID: 31572840 PMCID: PMC6761681 DOI: 10.1021/acsomega.9b01430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 09/03/2019] [Indexed: 06/10/2023]
Abstract
RNA is a versatile macromolecule with the ability to fold into and interconvert between multiple functional conformations. The elucidation of the RNA folding landscape, especially the knowledge of alternative structures, is critical to uncover the physical mechanism of RNA functions. Here, we introduce a helix-based strategy for RNA folding landscape partition and alternative secondary structure determination. The benchmark test of 27 RNAs involving alternative stable structures shows that the model has the ability to divide the whole landscape into distinct partitions at the secondary structure level and predict the representative structures for each partition. Furthermore, the predicted structures and equilibrium populations of metastable conformations for the 2'dG-sensing riboswitch reveal the allosteric conformational switch on transcript length, which is consistent with the experimental study, indicating the importance of metastable states for RNA-based gene regulation. The model delivers a starting point for the landscape-based strategy toward the RNA folding mechanism and functions.
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Affiliation(s)
- Fengfei Wang
- Institute
of Bioinformatics and Medical Engineering, School of Mathematics and
Physics, Jiangsu University of Technology, Changzhou, Jiangsu 213001, China
| | - Li-Zhen Sun
- Department
of Applied Physics, Zhejiang University
of Technology, Hangzhou, Zhejiang 310023, China
| | - Tingting Sun
- Department
of Physics, Zhejiang University of Science
and Technology, Hangzhou, Zhejiang 310023, China
| | - Shan Chang
- Institute
of Bioinformatics and Medical Engineering, School of Mathematics and
Physics, Jiangsu University of Technology, Changzhou, Jiangsu 213001, China
| | - Xiaojun Xu
- Institute
of Bioinformatics and Medical Engineering, School of Mathematics and
Physics, Jiangsu University of Technology, Changzhou, Jiangsu 213001, China
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31
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Evolving methods for rational de novo design of functional RNA molecules. Methods 2019; 161:54-63. [PMID: 31059832 DOI: 10.1016/j.ymeth.2019.04.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/26/2019] [Accepted: 04/29/2019] [Indexed: 12/16/2022] Open
Abstract
Artificial RNA molecules with novel functionality have many applications in synthetic biology, pharmacy and white biotechnology. The de novo design of such devices using computational methods and prediction tools is a resource-efficient alternative to experimental screening and selection pipelines. In this review, we describe methods common to many such computational approaches, thoroughly dissect these methods and highlight open questions for the individual steps. Initially, it is essential to investigate the biological target system, the regulatory mechanism that will be exploited, as well as the desired components in order to define design objectives. Subsequent computational design is needed to combine the selected components and to obtain novel functionality. This process can usually be split into constrained sequence sampling, the formulation of an optimization problem and an in silico analysis to narrow down the number of candidates with respect to secondary goals. Finally, experimental analysis is important to check whether the defined design objectives are indeed met in the target environment and detailed characterization experiments should be performed to improve the mechanistic models and detect missing design requirements.
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32
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Zhang H, Keane SC. Advances that facilitate the study of large RNA structure and dynamics by nuclear magnetic resonance spectroscopy. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1541. [PMID: 31025514 PMCID: PMC7169810 DOI: 10.1002/wrna.1541] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/18/2019] [Accepted: 04/02/2019] [Indexed: 12/22/2022]
Abstract
The characterization of functional yet nonprotein coding (nc) RNAs has expanded the role of RNA in the cell from a passive player in the central dogma of molecular biology to an active regulator of gene expression. The misregulation of ncRNA function has been linked with a variety of diseases and disorders ranging from cancers to neurodegeneration. However, a detailed molecular understanding of how ncRNAs function has been limited; due, in part, to the difficulties associated with obtaining high-resolution structures of large RNAs. Tertiary structure determination of RNA as a whole is hampered by various technical challenges, all of which are exacerbated as the size of the RNA increases. Namely, RNAs tend to be highly flexible and dynamic molecules, which are difficult to crystallize. Biomolecular nuclear magnetic resonance (NMR) spectroscopy offers a viable alternative to determining the structure of large RNA molecules that do not readily crystallize, but is itself hindered by some technical limitations. Recently, a series of advancements have allowed the biomolecular NMR field to overcome, at least in part, some of these limitations. These advances include improvements in sample preparation strategies as well as methodological improvements. Together, these innovations pave the way for the study of ever larger RNA molecules that have important biological function. This article is categorized under: RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems.
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Affiliation(s)
- Huaqun Zhang
- Biophysics Program, University of Michigan, Ann Arbor, Michigan
| | - Sarah C Keane
- Biophysics Program, University of Michigan, Ann Arbor, Michigan.,Department of Chemistry, University of Michigan, Ann Arbor, Michigan
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33
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Combined smFRET and NMR analysis of riboswitch structural dynamics. Methods 2019; 153:22-34. [DOI: 10.1016/j.ymeth.2018.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 10/08/2018] [Accepted: 10/09/2018] [Indexed: 12/13/2022] Open
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34
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Sun TT, Zhao C, Chen SJ. Predicting Cotranscriptional Folding Kinetics For Riboswitch. J Phys Chem B 2018; 122:7484-7496. [PMID: 29985608 DOI: 10.1021/acs.jpcb.8b04249] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
On the basis of a helix-based transition rate model, we developed a new method for sampling cotranscriptional RNA conformational ensemble and the prediction of cotranscriptional folding kinetics. Applications to E. coli. SRP RNA and pbuE riboswitch indicate that the model may provide reliable predictions for the cotranscriptional folding pathways and population kinetics. For E. coli. SRP RNA, the predicted population kinetics and the folding pathway are consistent with the SHAPE profiles in the recent cotranscriptional SHAPE-seq experiments. For the pbuE riboswitch, the model predicts the transcriptional termination efficiency as a function of the force. The theoretical results show (a) a force-induced transition from the aptamer (antiterminator) to the terminator structure and (b) the different folding pathways for the riboswitch with and without the ligand (adenine). More specifically, without adenine, the aptamer structure emerges as a short-lived kinetic transient state instead of a thermodynamically stable intermediate state. Furthermore, from the predicted extension-time curves, the model identifies a series of conformational switches in the pulling process, where the predicted relative residence times for the different structures are in accordance with the experimental data. The model may provide a new tool for quantitative predictions of cotranscriptional folding kinetics, and results can offer useful insights into cotranscriptional folding-related RNA functions such as regulation of gene expression with riboswitches.
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Affiliation(s)
- Ting-Ting Sun
- Department of Physics , Zhejiang University of Science and Technology , Hangzhou 310023 , P. R. China.,Department of Physics, Department of Biochemistry, and University of Missouri Informatics Institute , University of Missouri , Columbia , Missouri 65211 , United States
| | - Chenhan Zhao
- Department of Physics, Department of Biochemistry, and University of Missouri Informatics Institute , University of Missouri , Columbia , Missouri 65211 , United States
| | - Shi-Jie Chen
- Department of Physics, Department of Biochemistry, and University of Missouri Informatics Institute , University of Missouri , Columbia , Missouri 65211 , United States
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35
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Efficient computation of co-transcriptional RNA-ligand interaction dynamics. Methods 2018; 143:70-76. [PMID: 29730250 DOI: 10.1016/j.ymeth.2018.04.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 04/26/2018] [Accepted: 04/29/2018] [Indexed: 11/23/2022] Open
Abstract
Riboswitches form an abundant class of cis-regulatory RNA elements that mediate gene expression by binding a small metabolite. For synthetic biology applications, they are becoming cheap and accessible systems for selectively triggering transcription or translation of downstream genes. Many riboswitches are kinetically controlled, hence knowledge of their co-transcriptional mechanisms is essential. We present here an efficient implementation for analyzing co-transcriptional RNA-ligand interaction dynamics. This approach allows for the first time to model concentration-dependent metabolite binding/unbinding kinetics. We exemplify this novel approach by means of the recently studied I-A 2'-deoxyguanosine (2'dG)-sensing riboswitch from Mesoplasma florum.
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36
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Schlagnitweit J, Steiner E, Karlsson H, Petzold K. Efficient Detection of Structure and Dynamics in Unlabeled RNAs: The SELOPE Approach. Chemistry 2018; 24:6067-6070. [PMID: 29504639 PMCID: PMC5947647 DOI: 10.1002/chem.201800992] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Indexed: 01/10/2023]
Abstract
The knowledge of structure and dynamics is crucial to explain the function of RNAs. While nuclear magnetic resonance (NMR) is well suited to probe these for complex biomolecules, it requires expensive, isotopically labeled samples, and long measurement times. Here we present SELOPE, a new robust, proton-only NMR method that allows us to obtain site-specific overview of structure and dynamics in an entire RNA molecule using an unlabeled sample. SELOPE simplifies assignment and allows for cost-effective screening of the response of nucleic acids to physiological changes (e.g. ion concentration) or screening of drugs in a high throughput fashion. This single technique allows us to probe an unprecedented range of exchange time scales (the whole μs to ms motion range) with increased sensitivity, surpassing all current experiments to detect chemical exchange. For the first time we could describe an RNA excited state using an unlabeled RNA.
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Affiliation(s)
- Judith Schlagnitweit
- Department of Medical Biochemistry and BiophysicsKarolinska Institute17177StockholmSweden
| | - Emilie Steiner
- Department of Medical Biochemistry and BiophysicsKarolinska Institute17177StockholmSweden
| | - Hampus Karlsson
- Department of Medical Biochemistry and BiophysicsKarolinska Institute17177StockholmSweden
| | - Katja Petzold
- Department of Medical Biochemistry and BiophysicsKarolinska Institute17177StockholmSweden
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37
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Helmling C, Klötzner DP, Sochor F, Mooney RA, Wacker A, Landick R, Fürtig B, Heckel A, Schwalbe H. Life times of metastable states guide regulatory signaling in transcriptional riboswitches. Nat Commun 2018; 9:944. [PMID: 29507289 PMCID: PMC5838219 DOI: 10.1038/s41467-018-03375-w] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 02/06/2018] [Indexed: 11/26/2022] Open
Abstract
Transcriptional riboswitches modulate downstream gene expression by a tight coupling of ligand-dependent RNA folding kinetics with the rate of transcription. RNA folding pathways leading to functional ON and OFF regulation involve the formation of metastable states within well-defined sequence intervals during transcription. The kinetic requirements for the formation and preservation of these metastable states in the context of transcription remain unresolved. Here, we reversibly trap the previously defined regulatory relevant metastable intermediate of the Mesoplasma florum 2′-deoxyguanosine (2′dG)-sensing riboswitch using a photocaging-ligation approach, and monitor folding to its native state by real-time NMR in both presence and absence of ligand. We further determine transcription rates for two different bacterial RNA polymerases. Our results reveal that the riboswitch functions only at transcription rates typical for bacterial polymerases (10–50 nt s−1) and that gene expression is modulated by 40–50% only, while subtle differences in folding rates guide population ratios within the structural ensemble to a specific regulatory outcome. Riboswitches are RNA-based regulatory elements, which regulate downstream gene expression by binding of small molecular weight ligands. Here the authors demonstrate the molecular mechanism of a transcriptional riboswitch that integrates changes in transcription rates, metabolite concentration, and kinetic on- and off-rates of ligand binding.
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Affiliation(s)
- Christina Helmling
- Institute for Organic Chemistry and Chemical Biology Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany
| | - Dean-Paulos Klötzner
- Institute for Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany
| | - Florian Sochor
- Institute for Organic Chemistry and Chemical Biology Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany
| | - Rachel Anne Mooney
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Anna Wacker
- Institute for Organic Chemistry and Chemical Biology Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Boris Fürtig
- Institute for Organic Chemistry and Chemical Biology Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany
| | - Alexander Heckel
- Institute for Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany.
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology Center for Biomolecular Magnetic Resonance (BMRZ), Johann Wolfgang Goethe-Universität, Max-von-Laue-Straße 9, 60438, Frankfurt, Germany.
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38
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Dussault AM, Dubé A, Jacques F, Grondin JP, Lafontaine DA. Ligand recognition and helical stacking formation are intimately linked in the SAM-I riboswitch regulatory mechanism. RNA (NEW YORK, N.Y.) 2017; 23:1539-1551. [PMID: 28701520 PMCID: PMC5602112 DOI: 10.1261/rna.061796.117] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/10/2017] [Indexed: 06/07/2023]
Abstract
Riboswitches are noncoding mRNA elements that control gene expression by altering their structure upon metabolite binding. Although riboswitch crystal structures provide detailed information about RNA-ligand interactions, little knowledge has been gathered to understand how riboswitches modulate gene expression. Here, we study the molecular recognition mechanism of the S-adenosylmethionine SAM-I riboswitch by characterizing the formation of a helical stacking interaction involving the ligand-binding process. We show that ligand binding is intimately linked to the formation of the helical stacking, which is dependent on the presence of three conserved purine residues that are flanked by stacked helices. We also find that these residues are important for the formation of a crucial long-range base pair formed upon SAM binding. Together, our results lend strong support to a critical role for helical stacking in the folding pathway and suggest a particularly important function in the formation of the long-range base pair.
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Affiliation(s)
- Anne-Marie Dussault
- Department of Biology, Faculty of Sciences, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Audrey Dubé
- Department of Biology, Faculty of Sciences, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Frédéric Jacques
- Department of Biology, Faculty of Sciences, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Jonathan P Grondin
- Department of Biology, Faculty of Sciences, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Daniel A Lafontaine
- Department of Biology, Faculty of Sciences, RNA Group, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
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39
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Steinert H, Sochor F, Wacker A, Buck J, Helmling C, Hiller F, Keyhani S, Noeske J, Grimm S, Rudolph MM, Keller H, Mooney RA, Landick R, Suess B, Fürtig B, Wöhnert J, Schwalbe H. Pausing guides RNA folding to populate transiently stable RNA structures for riboswitch-based transcription regulation. eLife 2017; 6. [PMID: 28541183 PMCID: PMC5459577 DOI: 10.7554/elife.21297] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 05/24/2017] [Indexed: 01/18/2023] Open
Abstract
In bacteria, the regulation of gene expression by cis-acting transcriptional riboswitches located in the 5'-untranslated regions of messenger RNA requires the temporal synchronization of RNA synthesis and ligand binding-dependent conformational refolding. Ligand binding to the aptamer domain of the riboswitch induces premature termination of the mRNA synthesis of ligand-associated genes due to the coupled formation of 3'-structural elements acting as terminators. To date, there has been no high resolution structural description of the concerted process of synthesis and ligand-induced restructuring of the regulatory RNA element. Here, we show that for the guanine-sensing xpt-pbuX riboswitch from Bacillus subtilis, the conformation of the full-length transcripts is static: it exclusively populates the functional off-state but cannot switch to the on-state, regardless of the presence or absence of ligand. We show that only the combined matching of transcription rates and ligand binding enables transcription intermediates to undergo ligand-dependent conformational refolding. DOI:http://dx.doi.org/10.7554/eLife.21297.001
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Affiliation(s)
- Hannah Steinert
- Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Florian Sochor
- Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Anna Wacker
- Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Janina Buck
- Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Christina Helmling
- Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Fabian Hiller
- Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Sara Keyhani
- Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Jonas Noeske
- Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Steffen Grimm
- Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Martin M Rudolph
- Department of Biology, Technical University Darmstadt, Darmstadt, Germany
| | - Heiko Keller
- Center for Biomolecular Magnetic Resonance, Institute of Molecular Biosciences, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Rachel Anne Mooney
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States
| | - Beatrix Suess
- Department of Biology, Technical University Darmstadt, Darmstadt, Germany
| | - Boris Fürtig
- Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Jens Wöhnert
- Center for Biomolecular Magnetic Resonance, Institute of Molecular Biosciences, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
| | - Harald Schwalbe
- Center for Biomolecular Magnetic Resonance, Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe-University Frankfurt am Main, Frankfurt am Main, Germany
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40
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Jones CP, Ferré-D'Amaré AR. Long-Range Interactions in Riboswitch Control of Gene Expression. Annu Rev Biophys 2017; 46:455-481. [PMID: 28375729 DOI: 10.1146/annurev-biophys-070816-034042] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Riboswitches are widespread RNA motifs that regulate gene expression in response to fluctuating metabolite concentrations. Known primarily from bacteria, riboswitches couple specific ligand binding and changes in RNA structure to mRNA expression in cis. Crystal structures of the ligand binding domains of most of the phylogenetically widespread classes of riboswitches, each specific to a particular metabolite or ion, are now available. Thus, the bound states-one end point-have been thoroughly characterized, but the unbound states have been more elusive. Consequently, it is less clear how the unbound, sensing riboswitch refolds into the ligand binding-induced output state. The ligand recognition mechanisms of riboswitches are diverse, but we find that they share a common structural strategy in positioning their binding sites at the point of the RNA three-dimensional fold where the residues farthest from one another in sequence meet. We review how riboswitch folds adhere to this fundamental strategy and propose future research directions for understanding and harnessing their ability to specifically control gene expression.
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Affiliation(s)
- Christopher P Jones
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20824;
| | - Adrian R Ferré-D'Amaré
- Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20824;
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