1
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Chaillou S, Stamou PE, Torres LL, Riesco AB, Hazelton W, Pinheiro VB. Directed evolution of colE1 plasmid replication compatibility: a fast tractable tunable model for investigating biological orthogonality. Nucleic Acids Res 2022; 50:9568-9579. [PMID: 36018798 PMCID: PMC9458437 DOI: 10.1093/nar/gkac682] [Citation(s) in RCA: 2] [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: 01/06/2022] [Revised: 06/02/2022] [Accepted: 08/03/2022] [Indexed: 12/24/2022] Open
Abstract
Plasmids of the ColE1 family are among the most frequently used in molecular biology. They were adopted early for many biotechnology applications, and as models to study plasmid biology. Their mechanism of replication is well understood, involving specific interactions between a plasmid encoded sense-antisense gene pair (RNAI and RNAII). Due to such mechanism, two plasmids with the same origin cannot be stably maintained in cells-a process known as incompatibility. While mutations in RNAI and RNAII can make colE1 more compatible, there has been no systematic effort to engineer new compatible colE1 origins, which could bypass technical design constraints for multi-plasmid applications. Here, we show that by diversifying loop regions in RNAI (and RNAII), it is possible to select new viable colE1 origins compatible with the wild-type one. We demonstrate that sequence divergence is not sufficient to enable compatibility and pairwise interactions are not an accurate guide for higher order interactions. We identify potential principles to engineer plasmid copy number independently from other regulatory strategies and we propose plasmid compatibility as a tractable model to study biological orthogonality.
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Affiliation(s)
| | | | - Leticia L Torres
- University College London, Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Ana B Riesco
- University College London, Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Warren Hazelton
- University College London, Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Vitor B Pinheiro
- To whom correspondence should be addressed. Tel: +32 16 330 257;
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2
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Guo P, Farahat AA, Paul A, Boykin DW, Wilson WD. Engineered modular heterocyclic-diamidines for sequence-specific recognition of mixed AT/GC base pairs at the DNA minor groove. Chem Sci 2021; 12:15849-15861. [PMID: 35024109 PMCID: PMC8672716 DOI: 10.1039/d1sc04720e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/28/2021] [Indexed: 12/20/2022] Open
Abstract
This report describes a breakthrough in a project to design minor groove binders to recognize any sequence of DNA. A key goal is to invent synthetic chemistry for compound preparation to recognize an adjacent GG sequence that has been difficult to target. After trying several unsuccessful compound designs, an N-alkyl-benzodiimidazole structure was selected to provide two H-bond acceptors for the adjacent GG-NH groups. Flanking thiophenes provide a preorganized structure with strong affinity, DB2831, and the structure is terminated by phenyl-amidines. The binding experimental results for DB2831 with a target AAAGGTTT sequence were successful and include a high ΔT m, biosensor SPR with a K D of 4 nM, a similar K D from fluorescence titrations and supporting competition mass spectrometry. MD analysis of DB2831 bound to an AAAGGTTT site reveals that the two unprotonated N of the benzodiimidazole group form strong H-bonds (based on distance) with the two central G-NH while the central -CH of the benzodiimidazole is close to the -C[double bond, length as m-dash]O of a C base. These three interactions account for the strong preference of DB2831 for a -GG- sequence. Surprisingly, a complex with one dynamic, interfacial water is favored with 75% occupancy.
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Affiliation(s)
- Pu Guo
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University 50 Decatur St SE Atlanta GA 30303 USA +1 404-413-5503
| | - Abdelbasset A Farahat
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University 50 Decatur St SE Atlanta GA 30303 USA +1 404-413-5503
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Mansoura University Mansoura 35516 Egypt
| | - Ananya Paul
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University 50 Decatur St SE Atlanta GA 30303 USA +1 404-413-5503
| | - David W Boykin
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University 50 Decatur St SE Atlanta GA 30303 USA +1 404-413-5503
| | - W David Wilson
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University 50 Decatur St SE Atlanta GA 30303 USA +1 404-413-5503
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3
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Goiriz L, Rodrigo G. Nonequilibrium thermodynamics of the RNA-RNA interaction underlying a genetic transposition program. Phys Rev E 2021; 103:042410. [PMID: 34005948 DOI: 10.1103/physreve.103.042410] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 03/19/2021] [Indexed: 11/07/2022]
Abstract
Thermodynamic descriptions are powerful tools to formally study complex gene expression programs evolved in living cells on the basis of macromolecular interactions. While transcriptional regulations are often modeled in the equilibrium, other interactions that occur in the cell follow a more complex pattern. Here, we adopt a nonequilibrium thermodynamic scheme to explain the RNA-RNA interaction underlying IS10 transposition. We determine the energy landscape associated with such an interaction at the base-pair resolution, and we present an original scaling law for expression prediction that depends on different free energies characterizing that landscape. Then, we show that massive experimental data of the IS10 RNA-controlled expression are better explained by this thermodynamic description in nonequilibrium. Overall, these results contribute to better comprehend the kinetics of post-transcriptional regulations and, more broadly, the functional consequences of processes out of the equilibrium in biology.
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Affiliation(s)
- Lucas Goiriz
- Institute for Integrative Systems Biology (I2SysBio), CSIC - University of Valencia, Paterna 46980, Spain
| | - Guillermo Rodrigo
- Institute for Integrative Systems Biology (I2SysBio), CSIC - University of Valencia, Paterna 46980, Spain
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4
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Nesterov-Mueller A, Popov R, Seligmann H. Combinatorial Fusion Rules to Describe Codon Assignment in the Standard Genetic Code. Life (Basel) 2020; 11:life11010004. [PMID: 33374866 PMCID: PMC7824455 DOI: 10.3390/life11010004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/15/2020] [Accepted: 12/21/2020] [Indexed: 11/16/2022] Open
Abstract
We propose combinatorial fusion rules that describe the codon assignment in the standard genetic code simply and uniformly for all canonical amino acids. These rules become obvious if the origin of the standard genetic code is considered as a result of a fusion of four protocodes: Two dominant AU and GC protocodes and two recessive AU and GC protocodes. The biochemical meaning of the fusion rules consists of retaining the complementarity between cognate codons of the small hydrophobic amino acids and large charged or polar amino acids within the protocodes. The proto tRNAs were assembled in form of two kissing hairpins with 9-base and 10-base loops in the case of dominant protocodes and two 9-base loops in the case of recessive protocodes. The fusion rules reveal the connection between the stop codons, the non-canonical amino acids, pyrrolysine and selenocysteine, and deviations in the translation of mitochondria. Using fusion rules, we predicted the existence of additional amino acids that are essential for the development of the standard genetic code. The validity of the proposed partition of the genetic code into dominant and recessive protocodes is considered referring to state-of-the-art hypotheses. The formation of two aminoacyl-tRNA synthetase classes is compatible with four-protocode partition.
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Affiliation(s)
- Alexander Nesterov-Mueller
- Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany; (R.P.); (H.S.)
- Correspondence:
| | - Roman Popov
- Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany; (R.P.); (H.S.)
| | - Hervé Seligmann
- Institute of Microstructure Technology, Karlsruhe Institute of Technology (KIT), 76344 Eggenstein-Leopoldshafen, Germany; (R.P.); (H.S.)
- The National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- Laboratory AGEIS EA 7407, Team Tools for e-GnosisMedical & LabcomCNRS/UGA/OrangeLabs Telecoms4Health, Faculty of Medicine, Université Grenoble Alpes, F-38700 La Tronche, France
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5
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Velema WA, Park HS, Kadina A, Orbai L, Kool ET. Trapping Transient RNA Complexes by Chemically Reversible Acylation. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202010861] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Willem A. Velema
- Institute for Molecules and Materials Radboud University Nijmegen 6525 AJ The Netherlands
| | - Hyun Shin Park
- Department of Chemistry Stanford University Stanford CA 94305 USA
| | - Anastasia Kadina
- Department of Chemistry Stanford University Stanford CA 94305 USA
| | - Lucian Orbai
- Cell Data Sciences 46127 Landing Pkwy Fremont CA 94538 USA
| | - Eric T. Kool
- Department of Chemistry Stanford University Stanford CA 94305 USA
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6
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Velema WA, Park HS, Kadina A, Orbai L, Kool ET. Trapping Transient RNA Complexes by Chemically Reversible Acylation. Angew Chem Int Ed Engl 2020; 59:22017-22022. [PMID: 32845055 DOI: 10.1002/anie.202010861] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Indexed: 01/01/2023]
Abstract
RNA-RNA interactions are essential for biology, but they can be difficult to study due to their transient nature. While crosslinking strategies can in principle be used to trap such interactions, virtually all existing strategies for crosslinking are poorly reversible, chemically modifying the RNA and hindering molecular analysis. We describe a soluble crosslinker design (BINARI) that reacts with RNA through acylation. We show that it efficiently crosslinks noncovalent RNA complexes with mimimal sequence bias and establish that the crosslink can be reversed by phosphine reduction of azide trigger groups, thereby liberating the individual RNA components for further analysis. The utility of the new approach is demonstrated by reversible protection against nuclease degradation and trapping transient RNA complexes of E. coli DsrA-rpoS derived bulge-loop interactions, which underlines the potential of BINARI crosslinkers to probe RNA regulatory networks.
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Affiliation(s)
- Willem A Velema
- Institute for Molecules and Materials, Radboud University, Nijmegen, 6525, AJ, The Netherlands
| | - Hyun Shin Park
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Anastasia Kadina
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Lucian Orbai
- Cell Data Sciences, 46127 Landing Pkwy, Fremont, CA, 94538, USA
| | - Eric T Kool
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
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7
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Steffen FD, Khier M, Kowerko D, Cunha RA, Börner R, Sigel RKO. Metal ions and sugar puckering balance single-molecule kinetic heterogeneity in RNA and DNA tertiary contacts. Nat Commun 2020; 11:104. [PMID: 31913262 PMCID: PMC6949254 DOI: 10.1038/s41467-019-13683-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 11/15/2019] [Indexed: 11/13/2022] Open
Abstract
The fidelity of group II intron self-splicing and retrohoming relies on long-range tertiary interactions between the intron and its flanking exons. By single-molecule FRET, we explore the binding kinetics of the most important, structurally conserved contact, the exon and intron binding site 1 (EBS1/IBS1). A comparison of RNA-RNA and RNA-DNA hybrid contacts identifies transient metal ion binding as a major source of kinetic heterogeneity which typically appears in the form of degenerate FRET states. Molecular dynamics simulations suggest a structural link between heterogeneity and the sugar conformation at the exon-intron binding interface. While Mg2+ ions lock the exon in place and give rise to long dwell times in the exon bound FRET state, sugar puckering alleviates this structural rigidity and likely promotes exon release. The interplay of sugar puckering and metal ion coordination may be an important mechanism to balance binding affinities of RNA and DNA interactions in general.
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Affiliation(s)
- Fabio D Steffen
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Mokrane Khier
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Danny Kowerko
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
- Department of Informatics, Technical University Chemnitz, Straße der Nationen 62, 09111, Chemnitz, Germany
| | - Richard A Cunha
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Richard Börner
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
- Laserinstitut Hochschule Mittweida, University of Applied Sciences Mittweida, Technikumplatz 17, 09648, Mittweida, Germany.
| | - Roland K O Sigel
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
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8
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Murata A, Nakamori M, Nakatani K. Modulating RNA secondary and tertiary structures by mismatch binding ligands. Methods 2019; 167:78-91. [DOI: 10.1016/j.ymeth.2019.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 05/05/2019] [Accepted: 05/07/2019] [Indexed: 12/21/2022] Open
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9
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Abstract
Many years of research in RNA biology have soundly established the importance of RNA-based regulation far beyond most early traditional presumptions. Importantly, the advances in "wet" laboratory techniques have produced unprecedented amounts of data that require efficient and precise computational analysis schemes and algorithms. Hence, many in silico methods that attempt topological and functional classification of novel putative RNA-based regulators are available. In this review, we technically outline thermodynamics-based standard RNA secondary structure and RNA-RNA interaction prediction approaches that have proven valuable to the RNA research community in the past and present. For these, we highlight their usability with a special focus on prokaryotic organisms and also briefly mention recent advances in whole-genome interactomics and how this may influence the field of predictive RNA research.
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10
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Thermodynamic investigation of kissing-loop interactions. Biochimie 2018; 157:177-183. [PMID: 30502370 DOI: 10.1016/j.biochi.2018.11.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/20/2018] [Indexed: 01/01/2023]
Abstract
Kissing loop interactions (KLIs) are a common motif that is critical in retroviral dimerization, viroid replication, mRNA, and riboswitches. In addition, KLIs are currently used in a variety of biotechnology applications, such as in aptamer sensors, RNA scaffolds and to stabilize vaccines for therapeutics. Here we describe the thermodynamics of a basic intramolecular DNA capable of engaging in a KLI, consisting of two hairpins connected by a flexible linker. Each hairpin loop has a five-nucleotide complementary sequence theoretically capable of engaging in a KLI. On either side of each loop is two thymines which will not engage in kissing but are present to provide more flexibility and optimal KLI positioning. Our results suggest that the KLI occurs even at physiological salt levels, and that the KLI does not alter the thermodynamics and stability of the two stem structures. The KLI does not involve all five nucleotides, or at least each base-pair stack is not making full contact. Adding a second strand complementary to the bottom of the kissing complex removes flexibility and causes destabilization of the stems. The KLI of this less flexible complex is maintained but the TM is reduced, indicating an entopic penalty to its formation.
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11
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Rodrigo G. Post-transcriptional bursting in genes regulated by small RNA molecules. Phys Rev E 2018; 97:032401. [PMID: 29776125 DOI: 10.1103/physreve.97.032401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Indexed: 11/07/2022]
Abstract
Gene expression programs in living cells are highly dynamic due to spatiotemporal molecular signaling and inherent biochemical stochasticity. Here we study a mechanism based on molecule-to-molecule variability at the RNA level for the generation of bursts of protein production, which can lead to heterogeneity in a cell population. We develop a mathematical framework to show numerically and analytically that genes regulated post transcriptionally by small RNA molecules can exhibit such bursts due to different states of translation activity (on or off), mostly revealed in a regime of few molecules. We exploit this framework to compare transcriptional and post-transcriptional bursting and also to illustrate how to tune the resulting protein distribution with additional post-transcriptional regulations. Moreover, because RNA-RNA interactions are predictable with an energy model, we define the kinetic constants of on-off switching as functions of the two characteristic free-energy differences of the system, activation and formation, with a nonequilibrium scheme. Overall, post-transcriptional bursting represents a distinctive principle linking gene regulation to gene expression noise, which highlights the importance of the RNA layer beyond the simple information transfer paradigm and significantly contributes to the understanding of the intracellular processes from a first-principles perspective.
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Affiliation(s)
- Guillermo Rodrigo
- Institute for Integrative Systems Biology, CSIC, Universidad de Valencia, 46980 Paterna, Spain
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12
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Ray S, Widom JR, Walter NG. Life under the Microscope: Single-Molecule Fluorescence Highlights the RNA World. Chem Rev 2018; 118:4120-4155. [PMID: 29363314 PMCID: PMC5918467 DOI: 10.1021/acs.chemrev.7b00519] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The emergence of single-molecule (SM) fluorescence techniques has opened up a vast new toolbox for exploring the molecular basis of life. The ability to monitor individual biomolecules in real time enables complex, dynamic folding pathways to be interrogated without the averaging effect of ensemble measurements. In parallel, modern biology has been revolutionized by our emerging understanding of the many functions of RNA. In this comprehensive review, we survey SM fluorescence approaches and discuss how the application of these tools to RNA and RNA-containing macromolecular complexes in vitro has yielded significant insights into the underlying biology. Topics covered include the three-dimensional folding landscapes of a plethora of isolated RNA molecules, their assembly and interactions in RNA-protein complexes, and the relation of these properties to their biological functions. In all of these examples, the use of SM fluorescence methods has revealed critical information beyond the reach of ensemble averages.
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Affiliation(s)
| | | | - Nils G. Walter
- Department of Chemistry, Single Molecule Analysis Group, University of Michigan, Ann Arbor, MI 48109, USA
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13
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Börner R, Kowerko D, Miserachs HG, Schaffer MF, Sigel RK. Metal ion induced heterogeneity in RNA folding studied by smFRET. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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14
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Isothermal Titration Calorimetry: Assisted Crystallization of RNA-Ligand Complexes. Methods Mol Biol 2016; 1320:127-43. [PMID: 26227041 DOI: 10.1007/978-1-4939-2763-0_9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
The success rate of nucleic acids/ligands co-crystallization can be significantly improved by performing preliminary biophysical analyses. Among suitable biophysical approaches, isothermal titration calorimetry (ITC) is certainly a method of choice. ITC can be used in a wide range of experimental conditions to monitor in real time the formation of the RNA- or DNA-ligand complex, with the advantage of providing in addition the complete binding profile of the interaction. Following the ITC experiment, the complex is ready to be concentrated for crystallization trials. This chapter describes a detailed experimental protocol for using ITC as a tool for monitoring RNA/small molecule binding, followed by co-crystallization.
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15
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Li H, Lee T, Dziubla T, Pi F, Guo S, Xu J, Li C, Haque F, Liang XJ, Guo P. RNA as a stable polymer to build controllable and defined nanostructures for material and biomedical applications. NANO TODAY 2015; 10:631-655. [PMID: 26770259 PMCID: PMC4707685 DOI: 10.1016/j.nantod.2015.09.003] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The value of polymers is manifested in their vital use as building blocks in material and life sciences. Ribonucleic acid (RNA) is a polynucleic acid, but its polymeric nature in materials and technological applications is often overlooked due to an impression that RNA is seemingly unstable. Recent findings that certain modifications can make RNA resistant to RNase degradation while retaining its authentic folding property and biological function, and the discovery of ultra-thermostable RNA motifs have adequately addressed the concerns of RNA unstability. RNA can serve as a unique polymeric material to build varieties of nanostructures including nanoparticles, polygons, arrays, bundles, membrane, and microsponges that have potential applications in biomedical and material sciences. Since 2005, more than a thousand publications on RNA nanostructures have been published in diverse fields, indicating a remarkable increase of interest in the emerging field of RNA nanotechnology. In this review, we aim to: delineate the physical and chemical properties of polymers that can be applied to RNA; introduce the unique properties of RNA as a polymer; review the current methods for the construction of RNA nanostructures; describe its applications in material, biomedical and computer sciences; and, discuss the challenges and future prospects in this field.
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Affiliation(s)
- Hui Li
- Nanobiotechnology Center, Markey Cancer Center, and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Taek Lee
- Nanobiotechnology Center, Markey Cancer Center, and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea
| | - Thomas Dziubla
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506, USA
| | - Fengmei Pi
- Nanobiotechnology Center, Markey Cancer Center, and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Sijin Guo
- Nanobiotechnology Center, Markey Cancer Center, and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
- Department of Chemistry, University of Kentucky, Lexington, KY 40506, USA
| | - Jing Xu
- Laboratory of Nanomedicine and Nanosafety, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology of China, Beijing 100190, China
| | - Chan Li
- Laboratory of Nanomedicine and Nanosafety, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology of China, Beijing 100190, China
| | - Farzin Haque
- Nanobiotechnology Center, Markey Cancer Center, and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
| | - Xing-Jie Liang
- Laboratory of Nanomedicine and Nanosafety, CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology of China, Beijing 100190, China
| | - Peixuan Guo
- Nanobiotechnology Center, Markey Cancer Center, and Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536, USA
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16
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Di Palma F, Bottaro S, Bussi G. Kissing loop interaction in adenine riboswitch: insights from umbrella sampling simulations. BMC Bioinformatics 2015; 16 Suppl 9:S6. [PMID: 26051557 PMCID: PMC4464220 DOI: 10.1186/1471-2105-16-s9-s6] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
INTRODUCTION Riboswitches are cis-acting regulatory RNA elements prevalently located in the leader sequences of bacterial mRNA. An adenine sensing riboswitch cis-regulates adeninosine deaminase gene (add) in Vibrio vulnificus. The structural mechanism regulating its conformational changes upon ligand binding mostly remains to be elucidated. In this open framework it has been suggested that the ligand stabilizes the interaction of the distal "kissing loop" complex. Using accurate full-atom molecular dynamics with explicit solvent in combination with enhanced sampling techniques and advanced analysis methods it could be possible to provide a more detailed perspective on the formation of these tertiary contacts. METHODS In this work, we used umbrella sampling simulations to study the thermodynamics of the kissing loop complex in the presence and in the absence of the cognate ligand. We enforced the breaking/formation of the loop-loop interaction restraining the distance between the two loops. We also assessed the convergence of the results by using two alternative initialization protocols. A structural analysis was performed using a novel approach to analyze base contacts. RESULTS Contacts between the two loops were progressively lost when larger inter-loop distances were enforced. Inter-loop Watson-Crick contacts survived at larger separation when compared with non-canonical pairing and stacking interactions. Intra-loop stacking contacts remained formed upon loop undocking. Our simulations qualitatively indicated that the ligand could stabilize the kissing loop complex. We also compared with previously published simulation studies. DISCUSSION AND CONCLUSIONS Kissing complex stabilization given by the ligand was compatible with available experimental data. However, the dependence of its value on the initialization protocol of the umbrella sampling simulations posed some questions on the quantitative interpretation of the results and called for better converged enhanced sampling simulations.
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17
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Šulc P, Romano F, Ouldridge TE, Doye JPK, Louis AA. A nucleotide-level coarse-grained model of RNA. J Chem Phys 2015; 140:235102. [PMID: 24952569 DOI: 10.1063/1.4881424] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We present a new, nucleotide-level model for RNA, oxRNA, based on the coarse-graining methodology recently developed for the oxDNA model of DNA. The model is designed to reproduce structural, mechanical, and thermodynamic properties of RNA, and the coarse-graining level aims to retain the relevant physics for RNA hybridization and the structure of single- and double-stranded RNA. In order to explore its strengths and weaknesses, we test the model in a range of nanotechnological and biological settings. Applications explored include the folding thermodynamics of a pseudoknot, the formation of a kissing loop complex, the structure of a hexagonal RNA nanoring, and the unzipping of a hairpin motif. We argue that the model can be used for efficient simulations of the structure of systems with thousands of base pairs, and for the assembly of systems of up to hundreds of base pairs. The source code implementing the model is released for public use.
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Affiliation(s)
- Petr Šulc
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, United Kingdom
| | - Flavio Romano
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Thomas E Ouldridge
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, United Kingdom
| | - Jonathan P K Doye
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Ard A Louis
- Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, United Kingdom
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18
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Paul A, Chai Y, Boykin DW, Wilson WD. Understanding mixed sequence DNA recognition by novel designed compounds: the kinetic and thermodynamic behavior of azabenzimidazole diamidines. Biochemistry 2014; 54:577-87. [PMID: 25495885 PMCID: PMC4303320 DOI: 10.1021/bi500989r] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Sequence-specific recognition of DNA by small organic molecules offers a potentially effective approach for the external regulation of gene expression and is an important goal in cell biochemistry. Rational design of compounds from established modules can potentially yield compounds that bind strongly and selectively with specific DNA sequences. An initial approach is to start with common A·T bp recognition molecules and build in G·C recognition units. Here we report on the DNA interaction of a synthetic compound that specifically binds to a G·C bp in the minor groove of DNA by using an azabenzimidazole moiety. The detailed interactions were evaluated with biosensor-surface plasmon resonance (SPR), isothermal calorimetric (ITC), and mass spectrometry (ESI-MS) methods. The compound, DB2277, binds with single G·C bp containing sequences with sub-nanomolar potency and displays slow dissociation kinetics and high selectivity. A detailed thermodynamic and kinetic study at different experimental salt concentrations and temperatures shows that the binding free energy is salt concentration dependent but essentially temperature independent under our experimental conditions, and binding enthalpy is temperature dependent but salt concentration independent. The results show that in the proper compound structural context novel heterocyclic cations can be designed to strongly recognize complex DNA sequences.
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Affiliation(s)
- Ananya Paul
- Department of Chemistry and Center for Diagnostics and Therapeutics, Georgia State University , Atlanta, Georgia 30303-3083, United States
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19
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Holmstrom ED, Polaski JT, Batey RT, Nesbitt DJ. Single-molecule conformational dynamics of a biologically functional hydroxocobalamin riboswitch. J Am Chem Soc 2014; 136:16832-43. [PMID: 25325398 PMCID: PMC4277777 DOI: 10.1021/ja5076184] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
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Riboswitches
represent a family of highly structured regulatory
elements found primarily in the leader sequences of bacterial mRNAs.
They function as molecular switches capable of altering gene expression;
commonly, this occurs via a conformational change in a regulatory
element of a riboswitch that results from ligand binding in the aptamer
domain. Numerous studies have investigated the ligand binding process,
but little is known about the structural changes in the regulatory
element. A mechanistic description of both processes is essential
for deeply understanding how riboswitches modulate gene expression.
This task is greatly facilitated by studying all aspects of riboswitch
structure/dynamics/function in the same model system. To this end,
single-molecule fluorescence resonance energy transfer (smFRET) techniques
have been used to directly observe the conformational dynamics of
a hydroxocobalamin (HyCbl) binding riboswitch (env8HyCbl) with a known crystallographic structure.1 The single-molecule RNA construct studied in this work
is unique in that it contains all of the structural elements both
necessary and sufficient for regulation of gene expression in a biological
context. The results of this investigation reveal that the undocking
rate constant associated with the disruption of a long-range kissing-loop
(KL) interaction is substantially decreased when the ligand is bound
to the RNA, resulting in a preferential stabilization of the docked
conformation. Notably, the formation of this tertiary KL interaction
directly sequesters the Shine-Dalgarno sequence (i.e., the ribosome
binding site) via base-pairing, thus preventing translation initiation.
These results reveal that the conformational dynamics of this regulatory
switch are quantitatively described by a four-state kinetic model,
whereby ligand binding promotes formation of the KL interaction. The
results of complementary cell-based gene expression experiments conducted
in Escherichia coli are highly correlated
with the smFRET results, suggesting that KL formation is directly
responsible for regulating gene expression.
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Affiliation(s)
- Erik D Holmstrom
- JILA, University of Colorado and National Institute of Standards and Technology, and ‡Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309-0440, United States
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20
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Sloane JL, Greenberg MM. Interstrand cross-link and bioconjugate formation in RNA from a modified nucleotide. J Org Chem 2014; 79:9792-8. [PMID: 25295850 PMCID: PMC4201359 DOI: 10.1021/jo501982r] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
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RNA
oligonucleotides containing a phenyl selenide derivative of
5-methyluridine were chemically synthesized by solid-phase synthesis.
The phenyl selenide is rapidly converted to an electrophilic, allylic
phenyl seleneate under mild oxidative conditions. The phenyl seleneate
yields interstrand cross-links when part of a duplex and is useful
for synthesizing oligonucleotide conjugates. Formation of the latter
is illustrated by reaction of an oligonucleotide containing the phenyl
selenide with amino acids in the presence of mild oxidant. The products
formed are analogous to those observed in tRNA that are believed to
be formed posttranslationally via a biosynthetic intermediate that
is chemically homologous to the phenyl seleneate.
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Affiliation(s)
- Jack L Sloane
- Department of Chemistry, Johns Hopkins University , 3400 N. Charles Street, Baltimore, Maryland 21218, United States
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21
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Blond A, Ennifar E, Tisné C, Micouin L. The design of RNA binders: targeting the HIV replication cycle as a case study. ChemMedChem 2014; 9:1982-96. [PMID: 25100137 DOI: 10.1002/cmdc.201402259] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Indexed: 01/08/2023]
Abstract
The human immunodeficiency virus 1 (HIV-1) replication cycle is finely tuned with many important steps involving RNA-RNA or protein-RNA interactions, all of them being potential targets for the development of new antiviral compounds. This cycle can also be considered as a good benchmark for the evaluation of early-stage strategies aiming at designing drugs that bind to RNA, with the possibility to correlate in vitro activities with antiviral properties. In this review, we highlight different approaches developed to interfere with four important steps of the HIV-1 replication cycle: the early stage of reverse transcription, the transactivation of viral transcription, the nuclear export of partially spliced transcripts and the dimerization step.
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Affiliation(s)
- Aurélie Blond
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, UMR 8601, CNRS, Université Paris Descartes, Sorbonne Paris Cité, Faculté des Sciences Fondamentales et Biomédicales, 45 Rue des Saints Pères, 75006 Paris (France)
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22
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Mundigala H, Michaux JB, Feig AL, Ennifar E, Rueda D. HIV-1 DIS stem loop forms an obligatory bent kissing intermediate in the dimerization pathway. Nucleic Acids Res 2014; 42:7281-9. [PMID: 24813449 PMCID: PMC4066764 DOI: 10.1093/nar/gku332] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The HIV-1 dimerization initiation sequence (DIS) is a conserved palindrome in the apical loop of a conserved hairpin motif in the 5′-untranslated region of its RNA genome. DIS hairpin plays an important role in genome dimerization by forming a ‘kissing complex’ between two complementary hairpins. Understanding the kinetics of this interaction is key to exploiting DIS as a possible human immunodeficiency virus (HIV) drug target. Here, we present a single-molecule Förster resonance energy transfer (smFRET) study of the dimerization reaction kinetics. Our data show the real-time formation and dissociation dynamics of individual kissing complexes, as well as the formation of the mature extended duplex complex that is ultimately required for virion packaging. Interestingly, the single-molecule trajectories reveal the presence of a previously unobserved bent intermediate required for extended duplex formation. The universally conserved A272 is essential for the formation of this intermediate, which is stabilized by Mg2+, but not by K+ cations. We propose a 3D model of a possible bent intermediate and a minimal dimerization pathway consisting of three steps with two obligatory intermediates (kissing complex and bent intermediate) and driven by Mg2+ ions.
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Affiliation(s)
- Hansini Mundigala
- Department of Chemistry, Wayne State University, Detroit, MI 48236, USA
| | | | - Andrew L Feig
- Department of Chemistry, Wayne State University, Detroit, MI 48236, USA
| | - Eric Ennifar
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire du CNRS, F-67084 Strasbourg, France
| | - David Rueda
- Department of Chemistry, Wayne State University, Detroit, MI 48236, USA Department of Medicine, Section of Virology, Imperial College, London W12 0NN, UK Single Molecule Imaging Group, MRC Clinical Sciences Center, Imperial College, London W12 0NN, UK
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23
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Paudel B, Rueda D. RNA folding dynamics using laser-assisted single-molecule refolding. Methods Mol Biol 2014; 1086:289-307. [PMID: 24136611 DOI: 10.1007/978-1-62703-667-2_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
RNA folding pathways can be complex and even include kinetic traps or misfolded intermediates that can be slow to resolve. Characterizing these pathways is critical to understanding how RNA molecules acquire their biological function. We have previously developed a novel approach to help characterize such misfolded intermediates. Laser-assisted single-molecule refolding (LASR) is a powerful technique that combines temperature-jump (T-jump) kinetics with single-molecule detection. In a typical LASR experiment, the temperature is rapidly increased and conformational dynamics are characterized, in real-time, at the single-molecule level using single-molecule fluorescence resonance energy transfer (smFRET). Here, we provide detailed protocols for performing LASR experiments including sample preparation, temperature calibration, and data analysis.
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Affiliation(s)
- Bishnu Paudel
- Department of Medicine, Section of Virology, Imperial College, London, UK
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24
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Hong C, Otabe T, Matsumoto S, Dohno C, Murata A, Hagihara M, Nakatani K. Formation of a Ligand-Assisted Complex of Two RNA Hairpin Loops. Chemistry 2014; 20:5282-7. [DOI: 10.1002/chem.201304683] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Indexed: 01/16/2023]
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25
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Wang S, Kumar A, Aston K, Nguyen B, Bashkin JK, Boykin DW, Wilson WD. Different thermodynamic signatures for DNA minor groove binding with changes in salt concentration and temperature. Chem Commun (Camb) 2013; 49:8543-5. [PMID: 23945614 PMCID: PMC3791883 DOI: 10.1039/c3cc44569k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The effects of salt concentration and temperature on the thermodynamics of DNA minor groove binding have quite different signatures: binding enthalpy is salt concentration independent but temperature dependent. Conversely, binding free energy is salt dependent but essentially temperature independent through enthalpy-entropy compensation.
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Affiliation(s)
- Shuo Wang
- Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA.
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26
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Allnér O, Nilsson L, Villa A. Loop-loop interaction in an adenine-sensing riboswitch: a molecular dynamics study. RNA (NEW YORK, N.Y.) 2013; 19:916-926. [PMID: 23716711 PMCID: PMC3683926 DOI: 10.1261/rna.037549.112] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 03/28/2013] [Indexed: 06/01/2023]
Abstract
Riboswitches are mRNA-based molecules capable of controlling the expression of genes. They undergo conformational changes upon ligand binding, and as a result, they inhibit or promote the expression of the associated gene. The close connection between structural rearrangement and function makes a detailed knowledge of the molecular interactions an important step to understand the riboswitch mechanism and efficiency. We have performed all-atom molecular dynamics simulations of the adenine-sensing add A-riboswitch to study the breaking of the kissing loop, one key tertiary element in the aptamer structure. We investigated the aptamer domain of the add A-riboswitch in complex with its cognate ligand and in the absence of the ligand. The opening of the hairpins was simulated using umbrella sampling using the distance between two loops as the reaction coordinate. A two-step process was observed in all the simulated systems. First, a general loss of stacking and hydrogen bond interactions is seen. The last interactions that break are the two base pairs G37-C61 and G38-C60, but the break does not affect the energy profile, indicating their pivotal role in the tertiary structure formation but not in the structure stabilization. The junction area is partially organized before the kissing loop formation and residue A24 anchors together the loop helices. Moreover, when the distance between the loops is increased, one of the hairpins showed more flexibility by changing its orientation in the structure, while the other conserved its coaxial arrangement with the rest of the structure.
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Affiliation(s)
- Olof Allnér
- Department of Biosciences and Nutrition, Karolinska Institutet, Center for Biosciences, SE-14183 Huddinge, Sweden.
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27
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Cragnolini T, Derreumaux P, Pasquali S. Coarse-grained simulations of RNA and DNA duplexes. J Phys Chem B 2013; 117:8047-60. [PMID: 23730911 DOI: 10.1021/jp400786b] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Although RNAs play many cellular functions, little is known about the dynamics and thermodynamics of these molecules. In principle, all-atom molecular dynamics simulations can investigate these issues, but with current computer facilities, these simulations have been limited to small RNAs and to short times. HiRe-RNA, a recently proposed high-resolution coarse-grained RNA that captures many geometric details such as base pairing and stacking, is able to fold RNA molecules to near-native structures in a short computational time. So far, it had been applied to simple hairpins, and here we present its application to duplexes of a couple dozen nucleotides and show how with replica exchange molecular dynamics (REMD) we can easily predict the correct double helix from a completely random configuration and study the dissociation curve. To show the versatility of our model, we present an application to a double stranded DNA molecule as well. A reconstruction algorithm allows us to obtain full atom structures from the coarse-grained model. Through atomistic molecular dynamics (MD), we can compare the dynamics starting from a representative structure of a low temperature replica or from the experimental structure, and show how the two are statistically identical, highlighting the validity of a coarse-grained approach for structured RNAs and DNAs.
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Affiliation(s)
- Tristan Cragnolini
- Laboratoire de Biochimie Théorique UPR 9080 CNRS, Université Paris Diderot, Sorbonne, Paris Citè, IBPC 13 rue Pierre et Marie Curie, 75005 Paris, France
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