1
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Hou Q, Chatterjee S, Lund PE, Suddala KC, Walter NG. Single-molecule FRET observes opposing effects of urea and TMAO on structurally similar meso- and thermophilic riboswitch RNAs. Nucleic Acids Res 2023; 51:11345-11357. [PMID: 37855661 PMCID: PMC10639078 DOI: 10.1093/nar/gkad866] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 09/17/2023] [Accepted: 09/27/2023] [Indexed: 10/20/2023] Open
Abstract
Bacteria live in a broad range of environmental temperatures that require adaptations of their RNA sequences to maintain function. Riboswitches are regulatory RNAs that change conformation upon typically binding metabolite ligands to control bacterial gene expression. The paradigmatic small class-I preQ1 riboswitches from the mesophile Bacillus subtilis (Bsu) and the thermophile Thermoanaerobacter tengcongensis (Tte) adopt similar pseudoknot structures when bound to preQ1. Here, we use UV-melting analysis combined with single-molecule detected chemical denaturation by urea to compare the thermodynamic and kinetic folding properties of the two riboswitches, and the urea-countering effects of trimethylamine N-oxide (TMAO). Our results show that, first, the Tte riboswitch is more thermotolerant than the Bsu riboswitch, despite only subtle sequence differences. Second, using single-molecule FRET, we find that urea destabilizes the folded pseudoknot structure of both riboswitches, yet has a lower impact on the unfolding kinetics of the thermodynamically less stable Bsu riboswitch. Third, our analysis shows that TMAO counteracts urea denaturation and promotes folding of both the riboswitches, albeit with a smaller effect on the more stable Tte riboswitch. Together, these findings elucidate how subtle sequence adaptations in a thermophilic bacterium can stabilize a common RNA structure when a new ecological niche is conquered.
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Affiliation(s)
- Qian Hou
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
- Tri-Institutional PhD Program in Chemical Biology, Weill Cornell Medicine, The Rockefeller University, Memorial Sloan Kettering Cancer Center, NY, NY 10021, USA
| | - Surajit Chatterjee
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Physics, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Paul E Lund
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Krishna C Suddala
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Nils G Walter
- Single Molecule Analysis Group, Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
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2
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Cho SS, Green AT, Hyeon C, Thirumalai D. TMAO Destabilizes RNA Secondary Structure via Direct Hydrogen Bond Interactions. J Phys Chem B 2023; 127:438-445. [PMID: 36602908 DOI: 10.1021/acs.jpcb.2c05434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Trimethylamine N-oxide (TMAO) is an osmolyte that accumulates in cells in response to osmotic stress. TMAO stabilizes proteins by the entropic stabilization mechanism, which pictures TMAO as a nanocrowder that predominantly destabilizes the unfolded state. However, the mechanism of action of TMAO on RNA is much less understood. Here, we use all-atom molecular dynamics simulations to investigate how TMAO interacts with a 12-nt RNA hairpin with a high melting temperature, and an 8-nt RNA hairpin, which has a relatively fluid native basin in the absence of TMAO. The use of the two hairpins with different free energy of stabilization allows us to probe the origin of the destabilization effect of TMAO on RNA molecules without the possibility of forming tertiary interactions. We generated multiple trajectories using all-atom molecular dynamics (MD) simulations in explicit water by employing AMBER and CHARMM force fields, both in the absence and presence of TMAO. We observed qualitatively similar RNA-TMAO interaction profiles from the simulations using the two force fields. TMAO hydrogen bond interactions are largely depleted around the paired RNA bases and ribose sugars. In contrast, we show that the oxygen atom in TMAO, the hydrogen bond acceptor, preferentially interacts with the hydrogen bond donors in the solvent exposed bases, such as those in the stem-loop and the destabilized base stacks in the unfolded state, especially in the marginally stable 8-nt RNA hairpin. The predicted destabilization mechanism through TMAO-RNA hydrogen bond interactions could be tested using two-dimensional IR spectroscopy. Since TMAO does not significantly interact with the hydroxyl group of the ribose sugars, we predict that similar results must also hold for DNA.
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Affiliation(s)
- Samuel S Cho
- Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109, United States.,Department of Computer Science, Wake Forest University, Winston-Salem, North Carolina 27109, United States
| | - Adam T Green
- Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109, United States
| | - Changbong Hyeon
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul 02455, Republic of Korea
| | - D Thirumalai
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States.,Department of Physics, University of Texas at Austin, Austin, Texas 78712, United States
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3
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Costa Dos Santos G, Renovato-Martins M, de Brito NM. The remodel of the "central dogma": a metabolomics interaction perspective. Metabolomics 2021; 17:48. [PMID: 33969452 PMCID: PMC8106972 DOI: 10.1007/s11306-021-01800-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 04/30/2021] [Indexed: 12/30/2022]
Abstract
BACKGROUND In 1957, Francis Crick drew a linear diagram on a blackboard. This diagram is often called the "central dogma." Subsequently, the relationships between different steps of the "central dogma" have been shown to be considerably complex, mostly because of the emerging world of small molecules. It is noteworthy that metabolites can be generated from the diet through gut microbiome metabolism, serve as substrates for epigenetic modifications, destabilize DNA quadruplexes, and follow Lamarckian inheritance. Small molecules were once considered the missing link in the "central dogma"; however, recently they have acquired a central role, and their general perception as downstream products has become reductionist. Metabolomics is a large-scale analysis of metabolites, and this emerging field has been shown to be the closest omics associated with the phenotype and concomitantly, the basis for all omics. AIM OF REVIEW Herein, we propose a broad updated perspective for the flux of information diagram centered in metabolomics, including the influence of other factors, such as epigenomics, diet, nutrition, and the gut- microbiome. KEY SCIENTIFIC CONCEPTS OF REVIEW Metabolites are the beginning and the end of the flux of information.
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Affiliation(s)
- Gilson Costa Dos Santos
- Laboratory of NMR Metabolomics, IBRAG, Department of Genetics, State University of Rio de Janeiro, Rio de Janeiro, 20551-030, Brazil.
| | - Mariana Renovato-Martins
- Department of Cellular and Molecular Biology, IB, Federal Fluminense University, Niterói, 24210-200, Brazil
| | - Natália Mesquita de Brito
- Laboratory of Cellular and Molecular Pharmacology, IBRAG, Department of Cell Biology, State University of Rio de Janeiro, Rio de Janeiro, 20551-030, Brazil.
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4
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Maiti A, Daschakraborty S. Effect of TMAO on the Structure and Phase Transition of Lipid Membranes: Potential Role of TMAO in Stabilizing Cell Membranes under Osmotic Stress. J Phys Chem B 2021; 125:1167-1180. [PMID: 33481606 DOI: 10.1021/acs.jpcb.0c08335] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Extremophiles adopt strategies to deal with different environmental stresses, some of which are severely damaging to their cell membrane. To combat high osmotic stress, deep-sea organisms synthesize osmolytes, small polar organic molecules, like trimethylamine-N-oxide (TMAO), and incorporate them in the cell. TMAO is known to protect cells from high osmotic or hydrostatic pressure. Several experimental and simulation studies have revealed the roles of such osmolytes on stabilizing proteins. In contrast, the effect of osmolytes on the lipid membrane is poorly understood and broadly debated. A recent experiment has found strong evidence of the possible role of TMAO in stabilizing lipid membranes. Using the molecular dynamics (MD) simulation technique, we have demonstrated the effect of TMAO on two saturated fully hydrated lipid membranes in their fluid and gel phases. We have captured the impact of TMAO's concentration on the membrane's structural properties along with the fluid/gel phase transition temperatures. On increasing the concentration of TMAO, we see a substantial increase in the packing density of the membrane (estimated by area, thickness, and volume) and enhancement in the orientational order of lipid molecules. Having repulsive interaction with the lipid head group, the TMAO molecules are expelled away from the membrane surface, which induces dehydration of the lipid head groups, increasing the packing density. The addition of TMAO also increases the fluid/gel phase transition temperature of the membrane. All of these results are in close agreement with the experimental observations. This study, therefore, provides a molecular-level understanding of how TMAO can influence the cell membrane of deep-sea organisms and help in combating the osmotic stress condition.
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Affiliation(s)
- Archita Maiti
- Department of Chemistry, Indian Institute of Technology Patna, Patna, Bihar 801106, India
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5
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Abstract
RNA enzymes or ribozymes catalyze some of the most important reactions in biology and are thought to have played a central role in the origin and evolution of life on earth. Catalytic function in RNA has evolved in crowded cellular environments that are different from dilute solutions in which most in vitro assays are performed. The presence of molecules such as amino acids, polypeptides, alcohols, and sugars in the cell introduces forces that modify the kinetics and thermodynamics of ribozyme-catalyzed reactions. Synthetic molecules are routinely used in in vitro studies to better approximate the properties of biomolecules under in vivo conditions. This review discusses the various forces that operate within simulated crowded solutions in the context of RNA structure, folding, and catalysis. It also explores ideas about how crowding could have been beneficial to the evolution of functional RNAs and the development of primitive cellular systems in a prebiotic milieu.
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Affiliation(s)
- Saurja DasGupta
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
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6
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Raghunathan S, Jaganade T, Priyakumar UD. Urea-aromatic interactions in biology. Biophys Rev 2020; 12:65-84. [PMID: 32067192 PMCID: PMC7040157 DOI: 10.1007/s12551-020-00620-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 01/08/2020] [Indexed: 02/06/2023] Open
Abstract
Noncovalent interactions are key determinants in both chemical and biological processes. Among such processes, the hydrophobic interactions play an eminent role in folding of proteins, nucleic acids, formation of membranes, protein-ligand recognition, etc.. Though this interaction is mediated through the aqueous solvent, the stability of the above biomolecules can be highly sensitive to any small external perturbations, such as temperature, pressure, pH, or even cosolvent additives, like, urea-a highly soluble small organic molecule utilized by various living organisms to regulate osmotic pressure. A plethora of detailed studies exist covering both experimental and theoretical regimes, to understand how urea modulates the stability of biological macromolecules. While experimentalists have been primarily focusing on the thermodynamic and kinetic aspects, theoretical modeling predominantly involves mechanistic information at the molecular level, calculating atomistic details applying the force field approach to the high level electronic details using the quantum mechanical methods. The review focuses mainly on examples with biological relevance, such as (1) urea-assisted protein unfolding, (2) urea-assisted RNA unfolding, (3) urea lesion interaction within damaged DNA, (4) urea conduction through membrane proteins, and (5) protein-ligand interactions those explicitly address the vitality of hydrophobic interactions involving exclusively the urea-aromatic moiety.
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Affiliation(s)
- Shampa Raghunathan
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad, 500032, India
| | - Tanashree Jaganade
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad, 500032, India
| | - U Deva Priyakumar
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Hyderabad, 500032, India.
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7
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Sung HL, Nesbitt DJ. Correction: High pressure single-molecule FRET studies of the lysine riboswitch: cationic and osmolytic effects on pressure induced denaturation. Phys Chem Chem Phys 2020; 22:17008-17009. [DOI: 10.1039/d0cp90155e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Correction for ‘High pressure single-molecule FRET studies of the lysine riboswitch: cationic and osmolytic effects on pressure induced denaturation’ by Hsuan-Lei Sung et al., Phys. Chem. Chem. Phys., 2020, DOI: 10.1039/d0cp01921f.
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Affiliation(s)
- Hsuan-Lei Sung
- JILA
- National Institute of Standards and Technology and University of Colorado
- Boulder
- USA
- Department of Chemistry and Biochemistry
| | - David J. Nesbitt
- JILA
- National Institute of Standards and Technology and University of Colorado
- Boulder
- USA
- Department of Chemistry and Biochemistry
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8
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Welty R, Rau M, Pabit S, Dunstan MS, Conn GL, Pollack L, Hall KB. Ribosomal Protein L11 Selectively Stabilizes a Tertiary Structure of the GTPase Center rRNA Domain. J Mol Biol 2019; 432:991-1007. [PMID: 31874150 DOI: 10.1016/j.jmb.2019.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 12/03/2019] [Accepted: 12/04/2019] [Indexed: 01/14/2023]
Abstract
The GTPase Center (GAC) RNA domain in bacterial 23S rRNA is directly bound by ribosomal protein L11, and this complex is essential to ribosome function. Previous cocrystal structures of the 58-nucleotide GAC RNA bound to L11 revealed the intricate tertiary fold of the RNA domain, with one monovalent and several divalent ions located in specific sites within the structure. Here, we report a new crystal structure of the free GAC that is essentially identical to the L11-bound structure, which retains many common sites of divalent ion occupation. This new structure demonstrates that RNA alone folds into its tertiary structure with bound divalent ions. In solution, we find that this tertiary structure is not static, but rather is best described as an ensemble of states. While L11 protein cannot bind to the GAC until the RNA has adopted its tertiary structure, new experimental data show that L11 binds to Mg2+-dependent folded states, which we suggest lie along the folding pathway of the RNA. We propose that L11 stabilizes a specific GAC RNA tertiary state, corresponding to the crystal structure, and that this structure reflects the functionally critical conformation of the rRNA domain in the fully assembled ribosome.
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Affiliation(s)
- Robb Welty
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S Euclid Ave, St Louis, MO, 63110, USA; Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Michael Rau
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S Euclid Ave, St Louis, MO, 63110, USA
| | - Suzette Pabit
- School of Applied and Engineering Physics, Cornell University, Clark Hall, Ithaca, NY, 14853, USA
| | - Mark S Dunstan
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Graeme L Conn
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta GA, 30322, USA
| | - Lois Pollack
- School of Applied and Engineering Physics, Cornell University, Clark Hall, Ithaca, NY, 14853, USA
| | - Kathleen B Hall
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 S Euclid Ave, St Louis, MO, 63110, USA.
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9
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Venkata Subbaiah KC, Hedaya O, Wu J, Jiang F, Yao P. Mammalian RNA switches: Molecular rheostats in gene regulation, disease, and medicine. Comput Struct Biotechnol J 2019; 17:1326-1338. [PMID: 31741723 PMCID: PMC6849081 DOI: 10.1016/j.csbj.2019.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 09/30/2019] [Accepted: 10/07/2019] [Indexed: 01/12/2023] Open
Abstract
Alteration of RNA structure by environmental signals is a fundamental mechanism of gene regulation. For example, the riboswitch is a noncoding RNA regulatory element that binds a small molecule and causes a structural change in the RNA, thereby regulating transcription, splicing, or translation of an mRNA. The role of riboswitches in metabolite sensing and gene regulation in bacteria and other lower species was reported almost two decades ago, but riboswitches have not yet been discovered in mammals. An analog of the riboswitch, the protein-directed RNA switch (PDRS), has been identified as an important regulatory mechanism of gene expression in mammalian cells. RNA-binding proteins and microRNAs are two major executors of PDRS via their interaction with target transcripts in mammals. These protein-RNA interactions influence cellular functions by integrating environmental signals and intracellular pathways from disparate stimuli to modulate stability or translation of specific mRNAs. The discovery of a riboswitch in eukaryotes that is composed of a single class of thiamine pyrophosphate (TPP) suggests that additional ligand-sensing RNAs may be present to control eukaryotic or mammalian gene expression. In this review, we focus on protein-directed RNA switch mechanisms in mammals. We offer perspectives on the potential discovery of mammalian protein-directed and compound-dependent RNA switches that are related to human disease and medicine.
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Affiliation(s)
- Kadiam C Venkata Subbaiah
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY 14586, United States
| | - Omar Hedaya
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY 14586, United States.,Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, NY 14586, United States
| | - Jiangbin Wu
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY 14586, United States
| | - Feng Jiang
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY 14586, United States.,Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, NY 14586, United States
| | - Peng Yao
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY 14586, United States.,Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, NY 14586, United States.,The Center for RNA Biology, University of Rochester School of Medicine & Dentistry, Rochester, NY 14586, United States.,The Center for Biomedical Informatics, University of Rochester School of Medicine & Dentistry, Rochester, NY 14586, United States
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10
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Patra S, Schuabb V, Kiesel I, Knop JM, Oliva R, Winter R. Exploring the effects of cosolutes and crowding on the volumetric and kinetic profile of the conformational dynamics of a poly dA loop DNA hairpin: a single-molecule FRET study. Nucleic Acids Res 2019; 47:981-996. [PMID: 30418613 PMCID: PMC6344865 DOI: 10.1093/nar/gky1122] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 10/23/2018] [Indexed: 12/19/2022] Open
Abstract
We investigated the volumetric and kinetic profile of the conformational landscape of a poly dA loop DNA hairpin (Hp) in the presence of salts, osmolytes and crowding media, mimicking the intracellular milieu, using single-molecule FRET methodology. Pressure modulation was applied to explore the volumetric and hydrational characteristics of the free-energy landscape of the DNA Hp, but also because pressure is a stress factor many organisms have to cope with, e.g. in the deep sea where pressures even up to the kbar level are encountered. Urea and pressure synergistically destabilize the closed conformation of the DNA Hp due to a lower molar partial volume in the unfolded state. Conversely, multivalent salts, trimethylamine-N-oxide and Ficoll strongly populate the closed state and counteract deteriorating effects of pressure. Complementary smFRET measurements under immobilized conditions at ambient pressure allowed us to dissect the equilibrium data in terms of folding and unfolding rate constants of the conformational transitions, leading to a deeper understanding of the stabilization mechanisms of the cosolutes. Our results show that the free-energy landscape of the DNA Hp is a rugged one, which is markedly affected by the ionic strength of the solution, by preferential interaction and exclusion of cosolvents as well as by pressure.
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Affiliation(s)
- Satyajit Patra
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Street 4a, 44227 Dortmund, Germany
| | - Vitor Schuabb
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Street 4a, 44227 Dortmund, Germany
| | - Irena Kiesel
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Street 4a, 44227 Dortmund, Germany
| | - Jim-Marcel Knop
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Street 4a, 44227 Dortmund, Germany
| | - Rosario Oliva
- Department of Chemical Sciences, University of Naples Federico II, Via Cinita, 80126 Naples, Italy
| | - Roland Winter
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn Street 4a, 44227 Dortmund, Germany
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11
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Trajkovski M, Endoh T, Tateishi-Karimata H, Ohyama T, Tanaka S, Plavec J, Sugimoto N. Pursuing origins of (poly)ethylene glycol-induced G-quadruplex structural modulations. Nucleic Acids Res 2019; 46:4301-4315. [PMID: 29648656 PMCID: PMC5934638 DOI: 10.1093/nar/gky250] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/28/2018] [Indexed: 01/18/2023] Open
Abstract
Molecular crowding conditions provided by high concentration of cosolutes are utilized for characterization of biomolecules in cell-mimicking environment and development of drug-delivery systems. In this context, (poly)ethylene glycols are often used for studying non-canonical DNA structures termed G-quadruplexes, which came into focus by emerging structural biology findings and new therapeutic drug design approaches. Recently, several reports were made arguing against using (poly)ethylene glycols in role of molecular crowding agents due to their direct impact on DNA G-quadruplex stability and topology. However, the available data on structural details underlying DNA interaction is very scarce and thus limits in-depth comprehension. Herein, structural and thermodynamic analyses were strategically combined to assess G-quadruplex-cosolute interactions and address previously reported variances regarding the driving forces of G-rich DNA structural transformations under molecular crowding conditions. With the use of complementary (CD, NMR and UV) spectroscopic methods and model approach we characterized DNA G-quadruplex in the presence of the smallest and one of the largest typically used (poly)ethylene glycols. Dehydration effect is the key contributor to ethylene-glycol-induced increased stability of the G-quadruplex, which is in the case of the large cosolute mainly guided by the subtle direct interactions between PEG 8000 and the outer G-quartet regions.
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Affiliation(s)
- Marko Trajkovski
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, Ljubljana, SI-1000, Slovenia
| | - Tamaki Endoh
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Hisae Tateishi-Karimata
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Tatsuya Ohyama
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Shigenori Tanaka
- Department of Computational Science, Graduate School of System Informatics, Kobe University, 1-1, Rokkodai, Nada-ku, Kobe 657-8501, Japan
| | - Janez Plavec
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, Ljubljana, SI-1000, Slovenia.,EN→FIST Centre of Excellence, Trg OF 13, SI-1000 Ljubljana, Slovenia.,Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, p. p. 537, SI-1000 Ljubljana, Slovenia
| | - Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan.,Graduate School of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20 Minatojima-Minamimachi, Kobe 650-0047, Japan
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12
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Arns L, Knop JM, Patra S, Anders C, Winter R. Single-molecule insights into the temperature and pressure dependent conformational dynamics of nucleic acids in the presence of crowders and osmolytes. Biophys Chem 2019; 251:106190. [PMID: 31146215 DOI: 10.1016/j.bpc.2019.106190] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 05/20/2019] [Accepted: 05/20/2019] [Indexed: 11/19/2022]
Abstract
In this review we discuss results from temperature and pressure dependent single-molecule Förster resonance energy transfer (smFRET) studies on nucleic acids in the presence of macromolecular crowders and organic osmolytes. As representative examples, we have chosen fragments of both DNAs and RNAs, i.e., a synthetic DNA hairpin, a human telomeric G-quadruplex and the microROSE RNA hairpin. To mimic the effects of intracellular components, our studies include the macromolecular crowding agent Ficoll, a copolymer of sucrose and epichlorohydrin, and the organic osmolytes trimethylamine N-oxide, urea and glycine as well as natural occurring osmolyte mixtures from deep sea organisms. Furthermore, the impact of mutations in an RNA sequence on the conformational dynamics is examined. Different from proteins, the effects of the osmolytes and crowding agents seem to strongly dependent on the structure and chemical make-up of the nucleic acid.
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Affiliation(s)
- Loana Arns
- TU Dortmund University, Faculty of Chemistry and Chemical Biology, Physical Chemistry, Otto-Hahn-Str. 4a, D-44227 Dortmund, Germany
| | - Jim-Marcel Knop
- TU Dortmund University, Faculty of Chemistry and Chemical Biology, Physical Chemistry, Otto-Hahn-Str. 4a, D-44227 Dortmund, Germany
| | - Satyajit Patra
- Aix Marseille Université, CNRS, Centralle Marseille, Institut Fresnel, F-13013 Marseille, France
| | - Christian Anders
- TU Dortmund University, Faculty of Chemistry and Chemical Biology, Physical Chemistry, Otto-Hahn-Str. 4a, D-44227 Dortmund, Germany
| | - Roland Winter
- TU Dortmund University, Faculty of Chemistry and Chemical Biology, Physical Chemistry, Otto-Hahn-Str. 4a, D-44227 Dortmund, Germany.
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13
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Takahashi S, Okura H, Sugimoto N. Bisubstrate Function of RNA Polymerases Triggered by Molecular Crowding Conditions. Biochemistry 2019; 58:1081-1093. [DOI: 10.1021/acs.biochem.8b01204] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Shuntaro Takahashi
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 minatojima-Minamimachi, Kobe 650-0047, Japan
| | - Hiromichi Okura
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 minatojima-Minamimachi, Kobe 650-0047, Japan
| | - Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 minatojima-Minamimachi, Kobe 650-0047, Japan
- Graduate School of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20 minatojima-Minamimachi, Kobe 650-0047, Japan
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14
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Knop JM, Patra S, Harish B, Royer CA, Winter R. The Deep Sea Osmolyte Trimethylamine N-Oxide and Macromolecular Crowders Rescue the Antiparallel Conformation of the Human Telomeric G-Quadruplex from Urea and Pressure Stress. Chemistry 2018; 24:14346-14351. [PMID: 29993151 DOI: 10.1002/chem.201802444] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/04/2018] [Indexed: 11/10/2022]
Abstract
Organisms are thriving in the deep sea at pressures up to the 1 kbar level, which imposes severe stress on the conformational dynamics and stability of their biomolecules. The impact of osmolytes and macromolecular crowders, mimicking intracellular conditions, on the effect of pressure on the conformational dynamics of a human telomeric G-quadruplex (G4) DNA is explored in this study employing single-molecule Förster resonance energy transfer (FRET) experiments. In neat buffer, pressurization favors the parallel/hybrid state of the G4-DNA over the antiparallel conformation at ≈400 bar, finally leading to unfolding beyond 1000 bar. High-pressure NMR data support these findings. The folded topological conformers have different solvent accessible surface areas and cavity volumes, leading to different volumetric properties and hence pressure stabilities. The deep-sea osmolyte trimethylamine N-oxide (TMAO) and macromolecular crowding agents are able to effectively rescue the G4-DNA from unfolding in the whole pressure range encountered on Earth.
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Affiliation(s)
- Jim-Marcel Knop
- Physikalische Chemie I-Biophysikalische Chemie, Fakultät für Chemie und Chemische Biologie, TU Dortmund, Otto-Hahn Str. 4a, 44227, Dortmund, Germany
| | - Satyajit Patra
- Physikalische Chemie I-Biophysikalische Chemie, Fakultät für Chemie und Chemische Biologie, TU Dortmund, Otto-Hahn Str. 4a, 44227, Dortmund, Germany
| | - Balasubramanian Harish
- Center for Biotechnology & Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, 12180, NY, USA
| | - Catherine A Royer
- Center for Biotechnology & Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, 12180, NY, USA
| | - Roland Winter
- Physikalische Chemie I-Biophysikalische Chemie, Fakultät für Chemie und Chemische Biologie, TU Dortmund, Otto-Hahn Str. 4a, 44227, Dortmund, Germany
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15
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Heldt CL, Saksule A, Joshi PU, Ghafarian M. A generalized purification step for viral particles using mannitol flocculation. Biotechnol Prog 2018; 34:1027-1035. [DOI: 10.1002/btpr.2651] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/17/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Caryn L. Heldt
- Dept. of Chemical Engineering; Michigan Technological Univ., 1400 Townsend Dr.; Houghton MI 49931
- Dept. of Biological Sciences; Michigan Technological Univ., 1400 Townsend Dr.; Houghton MI 49931
| | - Ashish Saksule
- Dept. of Chemical Engineering; Michigan Technological Univ., 1400 Townsend Dr.; Houghton MI 49931
| | - Pratik U. Joshi
- Dept. of Chemical Engineering; Michigan Technological Univ., 1400 Townsend Dr.; Houghton MI 49931
| | - Majid Ghafarian
- Dept. of Biological Sciences; Michigan Technological Univ., 1400 Townsend Dr.; Houghton MI 49931
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16
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Leonard KN, Blose JM. Effects of osmolytes and macromolecular crowders on stable GAAA tetraloops and their preference for a CG closing base pair. PeerJ 2018; 6:e4236. [PMID: 29456882 PMCID: PMC5815330 DOI: 10.7717/peerj.4236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/15/2017] [Indexed: 11/20/2022] Open
Abstract
Osmolytes and macromolecular crowders have the potential to influence the stability of secondary structure motifs and alter preferences for conserved nucleic acid sequences in vivo. To further understand the cellular function of RNA we observed the effects of a model osmolyte, polyethylene glycol (PEG) 200, and a model macromolecular crowding agent, PEG 8000, on the GAAA tetraloop motif. GAAA tetraloops are conserved, stable tetraloops, and are critical participants in RNA tertiary structure. They also have a thermodynamic preference for a CG closing base pair. The thermal denaturation of model hairpins containing GAAA loops was monitored using UV-Vis spectroscopy in the presence and absence of PEG 200 or PEG 8000. Both of the cosolutes tested influenced the thermodynamic preference for a CG base pair by destabilizing the loop with a CG closing base pair relative to the loop with a GC closing base pair. This result also extended to a related DNA triloop, which provides further evidence that the interactions between the loop and closing base pair are identical for the d(GCA) triloop and the GAAA tetraloop. Our results suggest that in the presence of model PEG molecules, loops with a GC closing base pair may retain some preferential interactions with the cosolutes that are lost in the presence of the CG closing base pair. These results reveal that relatively small structural changes could influence how neutral cosolutes tune the stability and function of secondary structure motifs in vivo.
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Affiliation(s)
- Kaethe N. Leonard
- Department of Chemistry and Biochemistry, State University of New York, The College at Brockport, Brockport, NY, United States of America
| | - Joshua M. Blose
- Department of Chemistry and Biochemistry, State University of New York, The College at Brockport, Brockport, NY, United States of America
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17
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Rani A, Venkatesu P. Changing relations between proteins and osmolytes: a choice of nature. Phys Chem Chem Phys 2018; 20:20315-20333. [DOI: 10.1039/c8cp02949k] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The stabilization and destabilization of the protein in the presence of any additive is mainly attributed to its preferential exclusion from protein surface and its preferential binding to the protein surface, respectively.
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Affiliation(s)
- Anjeeta Rani
- Department of Chemistry
- University of Delhi
- Delhi 110 007
- India
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18
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Patra S, Anders C, Schummel PH, Winter R. Antagonistic effects of natural osmolyte mixtures and hydrostatic pressure on the conformational dynamics of a DNA hairpin probed at the single-molecule level. Phys Chem Chem Phys 2018; 20:13159-13170. [DOI: 10.1039/c8cp00907d] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Osmolyte mixtures from deep sea organisms are able to rescue nucleic acids from pressure-induced unfolding.
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Affiliation(s)
- Satyajit Patra
- Physical Chemistry I – Biophysical Chemistry
- Faculty of Chemistry and Chemical Biology
- TU Dortmund University
- D-44227 Dortmund
- Germany
| | - Christian Anders
- Physical Chemistry I – Biophysical Chemistry
- Faculty of Chemistry and Chemical Biology
- TU Dortmund University
- D-44227 Dortmund
- Germany
| | - Paul Hendrik Schummel
- Physical Chemistry I – Biophysical Chemistry
- Faculty of Chemistry and Chemical Biology
- TU Dortmund University
- D-44227 Dortmund
- Germany
| | - Roland Winter
- Physical Chemistry I – Biophysical Chemistry
- Faculty of Chemistry and Chemical Biology
- TU Dortmund University
- D-44227 Dortmund
- Germany
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19
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Holmstrom ED, Nesbitt DJ. Biophysical Insights from Temperature-Dependent Single-Molecule Förster Resonance Energy Transfer. Annu Rev Phys Chem 2017; 67:441-65. [PMID: 27215819 DOI: 10.1146/annurev-physchem-040215-112544] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Single-molecule fluorescence microscopy techniques can be used in combination with micrometer length-scale temperature control and Förster resonance energy transfer (FRET) in order to gain detailed information about fundamental biophysical phenomena. In particular, this combination of techniques has helped foster the development of remarkable quantitative tools for studying both time- and temperature-dependent structural kinetics of biopolymers. Over the past decade, multiple research efforts have successfully incorporated precise spatial and temporal control of temperature into single-molecule FRET (smFRET)-based experiments, which have uncovered critical thermodynamic information on a wide range of biological systems such as conformational dynamics of nucleic acids. This review provides an overview of various temperature-dependent smFRET approaches from our laboratory and others, highlighting efforts in which such methods have been successfully applied to studies of single-molecule nucleic acid folding.
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Affiliation(s)
- Erik D Holmstrom
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309;
| | - David J Nesbitt
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309;
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20
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Whittum ME, Blose JM. Effects of osmolytes on stable UUCG tetraloops and their preference for a CG closing base pair. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2017; 36:583-597. [PMID: 29035162 DOI: 10.1080/15257770.2017.1375518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Osmolytes have the potential to affect the stability of secondary structure motifs and alter preferences for conserved nucleic acid sequences in the cell. To contribute to the understanding of the in vivo function of RNA we observed the effects of different classes of osmolytes on the UNCG tetraloop motif. UNCG tetraloops are the most common and stable of the RNA tetraloops and are nucleation sites for RNA folding. They also have a significant thermodynamic preference for a CG closing base pair. The thermal denaturation of model hairpins containing UUCG loops was monitored using UV-Vis spectroscopy in the presence of osmolytes with different chemical properties. Interestingly, all of the osmolytes tested destabilized the hairpins, but all had little effect on the thermodynamic preference for a CG base pair, except for polyethylene glycol (PEG) 200. PEG 200 destabilized the loop with the CG closing base pair relative to the loop with a GC closing base pair. The destabilization was linear with increasing concentrations of PEG 200, and the slope of this relationship was not perturbed by changes in the hairpin stem outside of the closing pair. This result suggests that in the presence of PEG 200, the UUCG loop with a GC closing base pair may retain some preferential interactions with the cosolute that are lost in the presence of the CG closing base pair. These results reveal that relatively small structural changes may influence how osmolytes tune the stability, and thus the function of a secondary structure motif in vivo.
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Affiliation(s)
- Michelle E Whittum
- a Department of Chemistry and Biochemistry, The College at Brockport , State University of New York , Brockport , New York , USA
| | - Joshua M Blose
- a Department of Chemistry and Biochemistry, The College at Brockport , State University of New York , Brockport , New York , USA
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21
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Gao M, Held C, Patra S, Arns L, Sadowski G, Winter R. Crowders and Cosolvents-Major Contributors to the Cellular Milieu and Efficient Means to Counteract Environmental Stresses. Chemphyschem 2017; 18:2951-2972. [DOI: 10.1002/cphc.201700762] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 08/15/2017] [Indexed: 01/27/2023]
Affiliation(s)
- Mimi Gao
- TU Dortmund University; Faculty of Chemistry and Chemical Biology; Physical Chemistry I-Biophysical Chemistry; Otto Hahn Str. 4a 44227 Dortmund Germany
| | - Christoph Held
- TU Dortmund University; Department of Biochemical and Chemical Engineering; Emil-Figge-Str. 70 44227 Dortmund Germany
| | - Satyajit Patra
- TU Dortmund University; Faculty of Chemistry and Chemical Biology; Physical Chemistry I-Biophysical Chemistry; Otto Hahn Str. 4a 44227 Dortmund Germany
| | - Loana Arns
- TU Dortmund University; Faculty of Chemistry and Chemical Biology; Physical Chemistry I-Biophysical Chemistry; Otto Hahn Str. 4a 44227 Dortmund Germany
| | - Gabriele Sadowski
- TU Dortmund University; Department of Biochemical and Chemical Engineering; Emil-Figge-Str. 70 44227 Dortmund Germany
| | - Roland Winter
- TU Dortmund University; Faculty of Chemistry and Chemical Biology; Physical Chemistry I-Biophysical Chemistry; Otto Hahn Str. 4a 44227 Dortmund Germany
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22
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Nakano SI, Sugimoto N. Model studies of the effects of intracellular crowding on nucleic acid interactions. MOLECULAR BIOSYSTEMS 2017; 13:32-41. [PMID: 27819369 DOI: 10.1039/c6mb00654j] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Molecular interactions and reactions in living cells occur with high concentrations of background molecules and ions. Many research studies have shown that intracellular molecules have characteristics different from those obtained using simple aqueous solutions. To better understand the behavior of biomolecules in intracellular environments, biophysical experiments were conducted under cell-mimicking conditions in a test tube. It has been shown that the molecular environments at the physiological level of macromolecular crowding, spatial confinement, water activity and dielectric constant, have significant effects on the interactions of DNA and RNA for hybridization, higher-order folding, and catalytic activity. The experimental approaches using in vitro model systems are useful to reveal the origin of the environmental effects and to bridge the gap between the behaviors of nucleic acids in vitro and in vivo. This paper highlights the model experiments used to evaluate the influences of intracellular environment on nucleic acid interactions.
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Affiliation(s)
- Shu-Ichi Nakano
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan.
| | - Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan. and Graduate School of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan
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23
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The 2D Structure of the T. brucei Preedited RPS12 mRNA Is Not Affected by Macromolecular Crowding. J Nucleic Acids 2017; 2017:6067345. [PMID: 28698807 PMCID: PMC5494072 DOI: 10.1155/2017/6067345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 04/04/2017] [Indexed: 11/17/2022] Open
Abstract
Mitochondrial transcript maturation in African trypanosomes requires RNA editing to convert sequence-deficient pre-mRNAs into translatable mRNAs. The different pre-mRNAs have been shown to adopt highly stable 2D folds; however, it is not known whether these structures resemble the in vivo folds given the extreme "crowding" conditions within the mitochondrion. Here, we analyze the effects of macromolecular crowding on the structure of the mitochondrial RPS12 pre-mRNA. We use high molecular mass polyethylene glycol as a macromolecular cosolute and monitor the structure of the RNA globally and with nucleotide resolution. We demonstrate that crowding has no impact on the 2D fold and we conclude that the MFE structure in dilute solvent conditions represents a good proxy for the folding of the pre-mRNA in its mitochondrial solvent context.
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24
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Hong J, Xiong S. TMAO-Protein Preferential Interaction Profile Determines TMAO's Conditional In Vivo Compatibility. Biophys J 2017; 111:1866-1875. [PMID: 27806268 DOI: 10.1016/j.bpj.2016.09.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/16/2016] [Accepted: 09/26/2016] [Indexed: 10/20/2022] Open
Abstract
Trimethylamine N-oxide (TMAO) exemplifies how Nature uses the solute effect as a simple chemical strategy to cope with hydrodynamic pressure or urea stress to maintain proteostasis. It is a gut-microbe-generated metabolite that strongly promotes the development of atherosclerosis. It remains unclear how TMAO exerts its effects. In this study, we experimentally characterized the profile of the preferential interaction potential of TMAO with proteins, a thermodynamic key to understanding the effects of TMAO on protein processes and the distinction of TMAO among osmolytes. TMAO is thus found to be highly preferentially excluded from most types of protein surface, which explains why TMAO is a strong globular protein stabilizer and identifies the dominant stabilizing factor as the unfavorable interaction of TMAO with the hydrophobic surface exposed upon unfolding. We dissected the mechanism of the counteracting effects of TMAO and urea: the contrary feature of the interaction profiles of the two solutes maximizes the possibility for them to offset each other's perturbing effect on protein processes. The interaction profile also predicts that TMAO promotes aggregation of amyloidogenic intrinsically disordered peptide, as demonstrated here in Aβ42, and that TMAO has a strong potential to impact protein processes in the absence of stressors. Our data suggest that although TMAO is an evolutionally selected chemical chaperone for some organisms or organs, its compatibility in vivo is conditional and determined by its interaction profile with biopolymers and the nature of the essential biopolymer processes. Our thermodynamic framework plus the TMAO-protein interaction profile provides a basis for exploring the broad biological significance of TMAO, including its pathological impact in the absence of stressors. We argue for the general importance of controlling in vivo background solutes and the pathological significance of a control failure.
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Affiliation(s)
- Jiang Hong
- School of Life Sciences, Shanghai University, Shanghai, China; Experimental Center for Life Sciences, School of Life Sciences, Shanghai University, Shanghai, China.
| | - Shangqin Xiong
- School of Life Sciences, Shanghai University, Shanghai, China
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25
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Nakano SI, Tanino Y, Hirayama H, Sugimoto N. Thermal Stability of RNA Structures with Bulky Cations in Mixed Aqueous Solutions. Biophys J 2017; 111:1350-1360. [PMID: 27705759 DOI: 10.1016/j.bpj.2016.08.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 08/25/2016] [Accepted: 08/29/2016] [Indexed: 11/16/2022] Open
Abstract
Bulky cations are used to develop nucleic-acid-based technologies for medical and technological applications in which nucleic acids function under nonaqueous conditions. In this study, the thermal stability of RNA structures was measured in the presence of various bulky cations in aqueous mixtures with organic solvents or polymer additives. The stability of oligonucleotide, transfer RNA, and polynucleotide structures was decreased in the presence of salts of tetrabutylammonium and tetrapentylammonium ions, and the stability and salt concentration dependences were dependent on cation sizes. The degree to which stability was dependent on salt concentration was correlated with reciprocals of the dielectric constants of mixed solutions, regardless of interactions between the cosolutes and RNA. Our results show that organic solvents affect the strength of electrostatic interactions between RNA and cations. Analysis of ion binding to RNA indicated greater enhancement of cation binding to RNA single strands than to duplexes in media with low dielectric constants. Furthermore, background bulky ions changed the dependence of RNA duplex stability on the concentration of metal ion salts. These unique properties of large tetraalkylammonium ions are useful for controlling the stability of RNA structures and its sensitivity to metal ion salts.
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Affiliation(s)
- Shu-Ichi Nakano
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology, Konan University, Kobe, Japan.
| | - Yuichi Tanino
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology, Konan University, Kobe, Japan
| | - Hidenobu Hirayama
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology, Konan University, Kobe, Japan
| | - Naoki Sugimoto
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology, Konan University, Kobe, Japan; Frontier Institute for Biomolecular Engineering Research, Konan University, Kobe, Japan
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26
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Pathak AK, Bandyopadhyay T. Water isotope effect on the thermostability of a polio viral RNA hairpin: A metadynamics study. J Chem Phys 2017; 146:165104. [DOI: 10.1063/1.4982049] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Arup K. Pathak
- Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
| | - Tusar Bandyopadhyay
- Theoretical Chemistry Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
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27
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Patra S, Anders C, Erwin N, Winter R. Osmolyte Effects on the Conformational Dynamics of a DNA Hairpin at Ambient and Extreme Environmental Conditions. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201701420] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Satyajit Patra
- Physikalische Chemie I - Biophysikalische Chemie; Fakultät für Chemie und Chemische Biologie; TU Dortmund; Otto-Hahn Str. 4a 44227 Dortmund Germany
| | - Christian Anders
- Physikalische Chemie I - Biophysikalische Chemie; Fakultät für Chemie und Chemische Biologie; TU Dortmund; Otto-Hahn Str. 4a 44227 Dortmund Germany
| | - Nelli Erwin
- Physikalische Chemie I - Biophysikalische Chemie; Fakultät für Chemie und Chemische Biologie; TU Dortmund; Otto-Hahn Str. 4a 44227 Dortmund Germany
| | - Roland Winter
- Physikalische Chemie I - Biophysikalische Chemie; Fakultät für Chemie und Chemische Biologie; TU Dortmund; Otto-Hahn Str. 4a 44227 Dortmund Germany
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28
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Patra S, Anders C, Erwin N, Winter R. Osmolyte Effects on the Conformational Dynamics of a DNA Hairpin at Ambient and Extreme Environmental Conditions. Angew Chem Int Ed Engl 2017; 56:5045-5049. [DOI: 10.1002/anie.201701420] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 03/03/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Satyajit Patra
- Physikalische Chemie I - Biophysikalische Chemie; Fakultät für Chemie und Chemische Biologie; TU Dortmund; Otto-Hahn Str. 4a 44227 Dortmund Germany
| | - Christian Anders
- Physikalische Chemie I - Biophysikalische Chemie; Fakultät für Chemie und Chemische Biologie; TU Dortmund; Otto-Hahn Str. 4a 44227 Dortmund Germany
| | - Nelli Erwin
- Physikalische Chemie I - Biophysikalische Chemie; Fakultät für Chemie und Chemische Biologie; TU Dortmund; Otto-Hahn Str. 4a 44227 Dortmund Germany
| | - Roland Winter
- Physikalische Chemie I - Biophysikalische Chemie; Fakultät für Chemie und Chemische Biologie; TU Dortmund; Otto-Hahn Str. 4a 44227 Dortmund Germany
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29
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Miner JC, García AE. Equilibrium Denaturation and Preferential Interactions of an RNA Tetraloop with Urea. J Phys Chem B 2017; 121:3734-3746. [PMID: 28181434 DOI: 10.1021/acs.jpcb.6b10767] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Urea is an important organic cosolute with implications in maintaining osmotic stress in cells and differentially stabilizing ensembles of folded biomolecules. We report an equilibrium study of urea-induced denaturation of a hyperstable RNA tetraloop through unbiased replica exchange molecular dynamics. We find that, in addition to destabilizing the folded state, urea smooths the RNA free energy landscape by destabilizing specific configurations, and forming favorable interactions with RNA nucleobases. A linear concentration-dependence of the free energy (m-value) is observed, in agreement with the results of other RNA hairpins and proteins. Additionally, analysis of the hydrogen-bonding and stacking interactions within RNA primarily show temperature-dependence, while interactions between RNA and urea primarily show concentration-dependence. Our findings provide valuable insight into the effects of urea on RNA folding and describe the thermodynamics of a basic RNA hairpin as a function of solution chemistry.
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Affiliation(s)
- Jacob C Miner
- Theoretical Biology and Biophysics, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States.,Center for Nonlinear Studies, CNLS, MS B258, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
| | - Angel E García
- Center for Nonlinear Studies, CNLS, MS B258, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
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30
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Gao M, Arns L, Winter R. Modulation of the Thermodynamic Signatures of an RNA Thermometer by Osmolytes and Salts. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611843] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Mimi Gao
- Physical Chemistry I-Biophysical Chemistry, Faculty of Chemistry and Chemical Biology; TU Dortmund; Otto-Hahn-Strasse 4a 44227 Dortmund Germany
| | - Loana Arns
- Physical Chemistry I-Biophysical Chemistry, Faculty of Chemistry and Chemical Biology; TU Dortmund; Otto-Hahn-Strasse 4a 44227 Dortmund Germany
| | - Roland Winter
- Physical Chemistry I-Biophysical Chemistry, Faculty of Chemistry and Chemical Biology; TU Dortmund; Otto-Hahn-Strasse 4a 44227 Dortmund Germany
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31
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Gao M, Arns L, Winter R. Modulation of the Thermodynamic Signatures of an RNA Thermometer by Osmolytes and Salts. Angew Chem Int Ed Engl 2017; 56:2302-2306. [PMID: 28102930 DOI: 10.1002/anie.201611843] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Indexed: 12/31/2022]
Abstract
Folding of ribonucleic acids (RNAs) is driven by several factors, such as base pairing and stacking, chain entropy, and ion-mediated electrostatics, which have been studied in great detail. However, the power of background molecules in the cellular milieu is often neglected. Herein, we study the effect of common osmolytes on the folding equilibrium of a hairpin-structured RNA and, using pressure perturbation, provide novel thermodynamic and volumetric insights into the modulation mechanism. The presence of TMAO causes an increased thermal stability and a more positive volume change for the helix-to-coil transition, whereas urea destabilizes the hairpin and leads to an increased expansibility of the unfolded state. Further, we find a strong interplay between water, salt, and osmolyte in driving the thermodynamics and defining the temperature and pressure stability limit of the RNA. Our results support a universal working mechanism of TMAO and urea to (de)stabilize proteins and the RNA.
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Affiliation(s)
- Mimi Gao
- Physical Chemistry I-Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Strasse 4a, 44227, Dortmund, Germany
| | - Loana Arns
- Physical Chemistry I-Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Strasse 4a, 44227, Dortmund, Germany
| | - Roland Winter
- Physical Chemistry I-Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, TU Dortmund, Otto-Hahn-Strasse 4a, 44227, Dortmund, Germany
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32
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Sukenik S, Dunsky S, Barnoy A, Shumilin I, Harries D. TMAO mediates effective attraction between lipid membranes by partitioning unevenly between bulk and lipid domains. Phys Chem Chem Phys 2017; 19:29862-29871. [DOI: 10.1039/c7cp04603k] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
TMAO induces an attractive force between lipid bilayers. The force is traced to the preferential repulsion of the osmolyte from lipid.
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Affiliation(s)
- Shahar Sukenik
- Institute of Chemistry and the Fritz Haber Research Center
- The Hebrew University
- Jerusalem 91904
- Israel
| | - Shaked Dunsky
- Institute of Chemistry and the Fritz Haber Research Center
- The Hebrew University
- Jerusalem 91904
- Israel
| | - Avishai Barnoy
- Institute of Chemistry and the Fritz Haber Research Center
- The Hebrew University
- Jerusalem 91904
- Israel
| | - Ilan Shumilin
- Institute of Chemistry and the Fritz Haber Research Center
- The Hebrew University
- Jerusalem 91904
- Israel
| | - Daniel Harries
- Institute of Chemistry and the Fritz Haber Research Center
- The Hebrew University
- Jerusalem 91904
- Israel
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33
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McPhie P, Brown P, Chen B, Dayie TK, Minton AP. Modulation of Conformational Equilibria in the S-Adenosylmethionine (SAM) II Riboswitch by SAM, Mg(2+), and Trimethylamine N-Oxide. Biochemistry 2016; 55:5010-20. [PMID: 27552169 DOI: 10.1021/acs.biochem.6b00283] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The dependence of the conformation of the S-adenosylmethionine (SAM) II riboswitch on the concentration of added Mg(2+) ions and SAM, individually and in mixtures, was monitored by circular dichroism (CD) spectroscopy and by measurement of the diffusion coefficient. The results are analyzed in the context of two complementary quantitative models, both of which are consistent with a single underlying physical model. Magnesium binding sites in the open state have an affinity on average higher than the affinity of those in the compact state, but formation of the compact state is accompanied by an increase in the number of binding sites. Consequently, at low Mg(2+) concentrations, Mg(2+) binds preferentially to the open state, favoring its formation, but at high concentrations, Mg(2+) binds preferentially to the compact state. The affinity of the riboswitch for SAM increases drastically with an increased level of binding of Mg(2+) to the compact pseudoknot conformation. The effect of increasing concentrations of trimethylamine N-oxide (TMAO), a well-studied molecular crowding agent, on the conformation of the riboswitch and its affinity for SAM were also monitored by CD spectroscopy and measurement of diffusion. In the absence of added Mg(2+), high concentrations of TMAO were found to induce a conformational change compatible with the formation of the pseudoknot form but have only a small effect on the affinity of the RNA for SAM.
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Affiliation(s)
- Peter McPhie
- Section on Physical Biochemistry, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Patrick Brown
- Section on Dynamics of Macromolecular of Assembly, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health , Bethesda, Maryland 20892, United States
| | - Bin Chen
- Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States
| | - Theodore K Dayie
- Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States
| | - Allen P Minton
- Section on Physical Biochemistry, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892, United States
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Abstract
Deciphering the folding pathways and predicting the structures of complex three-dimensional biomolecules is central to elucidating biological function. RNA is single-stranded, which gives it the freedom to fold into complex secondary and tertiary structures. These structures endow RNA with the ability to perform complex chemistries and functions ranging from enzymatic activity to gene regulation. Given that RNA is involved in many essential cellular processes, it is critical to understand how it folds and functions in vivo. Within the last few years, methods have been developed to probe RNA structures in vivo and genome-wide. These studies reveal that RNA often adopts very different structures in vivo and in vitro, and provide profound insights into RNA biology. Nonetheless, both in vitro and in vivo approaches have limitations: studies in the complex and uncontrolled cellular environment make it difficult to obtain insight into RNA folding pathways and thermodynamics, and studies in vitro often lack direct cellular relevance, leaving a gap in our knowledge of RNA folding in vivo. This gap is being bridged by biophysical and mechanistic studies of RNA structure and function under conditions that mimic the cellular environment. To date, most artificial cytoplasms have used various polymers as molecular crowding agents and a series of small molecules as cosolutes. Studies under such in vivo-like conditions are yielding fresh insights, such as cooperative folding of functional RNAs and increased activity of ribozymes. These observations are accounted for in part by molecular crowding effects and interactions with other molecules. In this review, we report milestones in RNA folding in vitro and in vivo and discuss ongoing experimental and computational efforts to bridge the gap between these two conditions in order to understand how RNA folds in the cell.
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35
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Draper DE. Folding of RNA tertiary structure: Linkages between backbone phosphates, ions, and water. Biopolymers 2016; 99:1105-13. [PMID: 23568785 DOI: 10.1002/bip.22249] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 03/14/2013] [Accepted: 03/25/2013] [Indexed: 01/08/2023]
Abstract
The functional forms of many RNAs have compact architectures. The placement of phosphates within such structures must be influenced not only by the strong electrostatic repulsion between phosphates, but also by networks of interactions between phosphates, water, and mobile ions. This review first explores what has been learned of the basic thermodynamic constraints on these arrangements from studies of hydration and ions in simple DNA molecules, and then gives an overview of what is known about ion and water interactions with RNA structures. A brief survey of RNA crystal structures identifies several interesting architectures in which closely spaced phosphates share hydration shells or phosphates are buried in environments that provide intramolecular hydrogen bonds or site-bound cations. Formation of these structures must require strong coupling between the uptake of ions and release of water.
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Affiliation(s)
- David E Draper
- Departments of Chemistry and Biophysics, Johns Hopkins University, Baltimore, MD, 21218
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36
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Holmstrom ED, Dupuis NF, Nesbitt DJ. Kinetic and thermodynamic origins of osmolyte-influenced nucleic acid folding. J Phys Chem B 2015; 119:3687-96. [PMID: 25621404 DOI: 10.1021/jp512491n] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The influential role of monovalent and divalent metal cations in facilitating conformational transitions in both RNA and DNA has been a target of intense biophysical research efforts. However, organic neutrally charged cosolutes can also significantly alter nucleic acid conformational transitions. For example, highly soluble small molecules such as trimethylamine N-oxide (TMAO) and urea are occasionally utilized by organisms to regulate cellular osmotic pressure. Ensemble studies have revealed that these so-called osmolytes can substantially influence the thermodynamics of nucleic acid conformational transitions. In the present work, we exploit single-molecule FRET (smFRET) techniques to measure, for first time, the kinetic origins of these osmolyte-induced changes to the folding free energy. In particular, we focus on smFRET RNA and DNA constructs designed as model systems for secondary and tertiary structure formation. These findings reveal that TMAO preferentially stabilizes both secondary and tertiary interactions by increasing kfold and decreasing kunfold, whereas urea destabilizes both conformational transitions, resulting in the exact opposite shift in kinetic rate constants (i.e., decreasing kfold and increasing kunfold). Complementary temperature-dependent smFRET experiments highlight a thermodynamic distinction between the two different mechanisms responsible for TMAO-facilitated conformational transitions, while only a single mechanism is seen for the destabilizing osmolyte urea. Finally, these results are interpreted in the context of preferential interactions between osmolytes, and the solvent accessible surface area (SASA) associated with the (i) nucleobase, (ii) sugar, and (iii) phosphate groups of nucleic acids in order to map out structural changes that occur during the conformational transitions.
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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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37
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RNA folding: structure prediction, folding kinetics and ion electrostatics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 827:143-83. [PMID: 25387965 DOI: 10.1007/978-94-017-9245-5_11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Beyond the "traditional" functions such as gene storage, transport and protein synthesis, recent discoveries reveal that RNAs have important "new" biological functions including the RNA silence and gene regulation of riboswitch. Such functions of noncoding RNAs are strongly coupled to the RNA structures and proper structure change, which naturally leads to the RNA folding problem including structure prediction and folding kinetics. Due to the polyanionic nature of RNAs, RNA folding structure, stability and kinetics are strongly coupled to the ion condition of solution. The main focus of this chapter is to review the recent progress in the three major aspects in RNA folding problem: structure prediction, folding kinetics and ion electrostatics. This chapter will introduce both the recent experimental and theoretical progress, while emphasize the theoretical modelling on the three aspects in RNA folding.
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38
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Abstract
A diverse population of large RNA molecules controls every aspect of cellular function, and yet we know very little about their molecular structures. However, robust technologies developed for visualizing ribozymes and riboswitches, together with new approaches for mapping RNA inside cells, provide the foundation for visualizing the structures of long noncoding RNAs, mRNAs, and viral RNAs, thereby facilitating new mechanistic insights.
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Affiliation(s)
- Anna Marie Pyle
- Department of Molecular, Cellular and Developmental Biology and Department of Chemistry, Yale University, New Haven, CT 06520, USA.
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39
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Nakano SI, Kitagawa Y, Miyoshi D, Sugimoto N. Hammerhead ribozyme activity and oligonucleotide duplex stability in mixed solutions of water and organic compounds. FEBS Open Bio 2014; 4:643-50. [PMID: 25161873 PMCID: PMC4141205 DOI: 10.1016/j.fob.2014.06.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/13/2014] [Accepted: 06/27/2014] [Indexed: 12/23/2022] Open
Abstract
Nucleic acids are useful for biomedical targeting and sensing applications in which the molecular environment is different from that of a dilute aqueous solution. In this study, the influence of various types of mixed solutions of water and water-soluble organic compounds on RNA was investigated by measuring the catalytic activity of the hammerhead ribozyme and the thermodynamic stability of an oligonucleotide duplex. The compounds with a net neutral charge, such as poly(ethylene glycol), small primary alcohols, amide compounds, and aprotic solvent molecules, added at high concentrations changed the ribozyme-catalyzed RNA cleavage rate, with the magnitude of the effect dependent on the NaCl concentration. These compounds also changed the thermodynamic stability of RNA base pairs of an oligonucleotide duplex and its dependence on the NaCl concentration. Specific interactions with RNA molecules and reduced water activity could account for the inhibiting effects on the ribozyme catalysis and destabilizing effects on the duplex stability. The salt concentration dependence data correlated with the dielectric constant, but not with water activity, viscosity, and the size of organic compounds. This observation suggests the significance of the dielectric constant effects on the RNA reactions under molecular crowding conditions created by organic compounds.
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Affiliation(s)
- Shu-Ichi Nakano
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, Japan
| | - Yuichi Kitagawa
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, Japan ; Department of Chemistry, Faculty of Science and Engineering, Konan University, Kobe, Japan
| | - Daisuke Miyoshi
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, Japan
| | - Naoki Sugimoto
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, Japan ; Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, Kobe, Japan
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40
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Strulson CA, Boyer JA, Whitman EE, Bevilacqua PC. Molecular crowders and cosolutes promote folding cooperativity of RNA under physiological ionic conditions. RNA (NEW YORK, N.Y.) 2014; 20:331-47. [PMID: 24442612 PMCID: PMC3923128 DOI: 10.1261/rna.042747.113] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 11/22/2013] [Indexed: 05/21/2023]
Abstract
Folding mechanisms of functional RNAs under idealized in vitro conditions of dilute solution and high ionic strength have been well studied. Comparatively little is known, however, about mechanisms for folding of RNA in vivo where Mg(2+) ion concentrations are low, K(+) concentrations are modest, and concentrations of macromolecular crowders and low-molecular-weight cosolutes are high. Herein, we apply a combination of biophysical and structure mapping techniques to tRNA to elucidate thermodynamic and functional principles that govern RNA folding under in vivo-like conditions. We show by thermal denaturation and SHAPE studies that tRNA folding cooperativity increases in physiologically low concentrations of Mg(2+) (0.5-2 mM) and K(+) (140 mM) if the solution is supplemented with physiological amounts (∼ 20%) of a water-soluble neutral macromolecular crowding agent such as PEG or dextran. Low-molecular-weight cosolutes show varying effects on tRNA folding cooperativity, increasing or decreasing it based on the identity of the cosolute. For those additives that increase folding cooperativity, the gain is manifested in sharpened two-state-like folding transitions for full-length tRNA over its secondary structural elements. Temperature-dependent SHAPE experiments in the absence and presence of crowders and cosolutes reveal extent of cooperative folding of tRNA on a nucleotide basis and are consistent with the melting studies. Mechanistically, crowding agents appear to promote cooperativity by stabilizing tertiary structure, while those low molecular cosolutes that promote cooperativity stabilize tertiary structure and/or destabilize secondary structure. Cooperative folding of functional RNA under physiological-like conditions parallels the behavior of many proteins and has implications for cellular RNA folding kinetics and evolution.
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Affiliation(s)
- Christopher A. Strulson
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Joshua A. Boyer
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Elisabeth E. Whitman
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Philip C. Bevilacqua
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Center for RNA Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
- Corresponding authorE-mail
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41
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Sugimoto N. Noncanonical structures and their thermodynamics of DNA and RNA under molecular crowding: beyond the Watson-Crick double helix. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 307:205-73. [PMID: 24380597 DOI: 10.1016/b978-0-12-800046-5.00008-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
How does molecular crowding affect the stability of nucleic acid structures inside cells? Water is the major solvent component in living cells, and the properties of water in the highly crowded media inside cells differ from that in buffered solution. As it is difficult to measure the thermodynamic behavior of nucleic acids in cells directly and quantitatively, we recently developed a cell-mimicking system using cosolutes as crowding reagents. The influences of molecular crowding on the structures and thermodynamics of various nucleic acid sequences have been reported. In this chapter, we discuss how the structures and thermodynamic properties of nucleic acids differ under various conditions such as highly crowded environments, compartment environments, and in the presence of ionic liquids, and the major determinants of the crowding effects on nucleic acids are discussed. The effects of molecular crowding on the activities of ribozymes and riboswitches on noncanonical structures of DNA- and RNA-like quadruplexes that play important roles in transcription and translation are also described.
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Affiliation(s)
- Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER) and Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, Kobe, Japan.
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42
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Nakano SI, Miyoshi D, Sugimoto N. Effects of molecular crowding on the structures, interactions, and functions of nucleic acids. Chem Rev 2013; 114:2733-58. [PMID: 24364729 DOI: 10.1021/cr400113m] [Citation(s) in RCA: 369] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Shu-ichi Nakano
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST) and Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University , 7-1-20 Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
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43
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Molecular crowding inhibits U-insertion/deletion RNA editing in vitro: consequences for the in vivo reaction. PLoS One 2013; 8:e83796. [PMID: 24376749 PMCID: PMC3871654 DOI: 10.1371/journal.pone.0083796] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 11/16/2013] [Indexed: 01/02/2023] Open
Abstract
Mitochondrial pre-mRNAs in African trypanosomes are edited to generate functional transcripts. The reaction is typified by the insertion and deletion of U nucleotides and is catalyzed by a macromolecular complex, the editosome. Editosomes bind pre-edited mRNA/gRNA pairs and the reaction can be recapitulated in vitro by using pre-mRNA- and gRNA-mimicking oligoribonucleotides together with enriched editosome preparations. Although the in vitro assay has been instrumental in unraveling the basic steps of the editing cycle it is performed at dilute solvent conditions. This ignores the fact that editing takes place inside the highly crowded mitochondria. Here we investigate the effects of molecular crowding on RNA editing. By using neutral, macromolecular cosolutes we generate defined dilute, semidilute and crowded solvent properties and we demonstrate different thermodynamic stabilities of the pre-mRNA/gRNA hybrid RNAs at these conditions. Crowded conditions stabilize the RNAs by -30 kJ/mol. Furthermore, we show that the rate constants for the association and dissociation (kass/kdiss) of substrate RNAs to editosomes decrease, ultimately inhibiting the in vitro reaction. The data demonstrate that the current RNA editing in vitro system is sensitive to molecular crowding, which suggests that the in vivo reaction cannot rely on a diffusion-controlled, collision-based mechanism. Possible non-diffusional reaction pathways are discussed.
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44
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Nakano M, Tateishi-Karimata H, Tanaka S, Sugimoto N. Choline ion interactions with DNA atoms explain unique stabilization of A-T base pairs in DNA duplexes: a microscopic view. J Phys Chem B 2013; 118:379-89. [PMID: 24171395 DOI: 10.1021/jp406647b] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Under physiological conditions, G-C base pairs are more stable than A-T base pairs. In a previous study, we showed that in the hydrated ionic liquid of choline dihydrogen phosphate, the stabilities of these base pairs are reversed. In the present study, we elucidated the unique binding interactions of choline ions with DNA atoms from a microscopic viewpoint using molecular dynamics simulations. Three times more choline ions bind to the DNA duplex than sodium ions. Sodium ions bind closely but not stably; in contrast, the choline ions bind through multiple hydrogen bonding networks with DNA atoms stably. The affinity of choline ion for the minor groove of A-T base pairs is more than 2 times that for other groove areas. In the narrow A-T minor groove, choline ion has high affinity for the ribose atoms of thymine. Choline ions also destabilize the formation of hydrogen bonds between G-C base pairs by binding to base atoms preferentially for both of duplex and single-strand DNA, which are associated with the bonds between G-C base pairs. Our new finding will not only lead to better control of DNA stability for use in DNA nanodevices, but also provide new insight into the stability of DNA duplexes under crowding conditions found in living cells.
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Affiliation(s)
- Miki Nakano
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University , 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan
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45
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Probing the protein-folding mechanism using denaturant and temperature effects on rate constants. Proc Natl Acad Sci U S A 2013; 110:16784-9. [PMID: 24043778 DOI: 10.1073/pnas.1311948110] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Protein folding has been extensively studied, but many questions remain regarding the mechanism. Characterizing early unstable intermediates and the high-free-energy transition state (TS) will help answer some of these. Here, we use effects of denaturants (urea, guanidinium chloride) and temperature on folding and unfolding rate constants and the overall equilibrium constant as probes of surface area changes in protein folding. We interpret denaturant kinetic m-values and activation heat capacity changes for 13 proteins to determine amounts of hydrocarbon and amide surface buried in folding to and from TS, and for complete folding. Predicted accessible surface area changes for complete folding agree in most cases with structurally determined values. We find that TS is advanced (50-90% of overall surface burial) and that the surface buried is disproportionately amide, demonstrating extensive formation of secondary structure in early intermediates. Models of possible pre-TS intermediates with all elements of the native secondary structure, created for several of these proteins, bury less amide and hydrocarbon surface than predicted for TS. Therefore, we propose that TS generally has both the native secondary structure and sufficient organization of other regions of the backbone to nucleate subsequent (post-TS) formation of tertiary interactions. The approach developed here provides proof of concept for the use of denaturants and other solutes as probes of amount and composition of the surface buried in coupled folding and other large conformational changes in TS and intermediates in protein processes.
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46
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Denning EJ, Thirumalai D, MacKerell AD. Protonation of trimethylamine N-oxide (TMAO) is required for stabilization of RNA tertiary structure. Biophys Chem 2013; 184:8-16. [PMID: 24012912 DOI: 10.1016/j.bpc.2013.08.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 08/08/2013] [Accepted: 08/08/2013] [Indexed: 01/10/2023]
Abstract
The osmolyte trimethylamine N-oxide (TMAO) stabilizes the tertiary but not the secondary structures of RNA. However, molecular dynamics simulations performed on the PreQ1 riboswitch showed that TMAO destabilizes the tertiary riboswitch structure, leading us to hypothesize that the presence of RNA could result in enhanced population of the protonated form, TMAOP. Constant pH replica exchange simulations showed that a percentage of TMAO is indeed protonated, thus contributing to the stability of the tertiary but not the secondary structure of PreQ1. TMAOP results in an unfavorable dehydration of phosphodiester backbone, which is compensated by electrostatic attraction between TMAOP and the phosphate groups. In addition, TMAOP interacts with specific sites in the tertiary RNA structure, mimicking the behavior of positively charged ions and of the PreQ1 ligand in stabilizing RNA. Finally, we predict that TMAO-induced stabilization of RNA tertiary structures should be strongly pH dependent.
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Affiliation(s)
- Elizabeth J Denning
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, USA
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47
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Larini L, Shea JE. Double Resolution Model for Studying TMAO/Water Effective Interactions. J Phys Chem B 2013; 117:13268-77. [DOI: 10.1021/jp403635g] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Luca Larini
- Department of Chemistry
and Biochemistry
and of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, United
States
| | - Joan-Emma Shea
- Department of Chemistry
and Biochemistry
and of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, United
States
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48
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Tan ZJ, Chen SJ. Ion-mediated RNA structural collapse: effect of spatial confinement. Biophys J 2013; 103:827-36. [PMID: 22947944 DOI: 10.1016/j.bpj.2012.06.048] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Revised: 06/25/2012] [Accepted: 06/27/2012] [Indexed: 12/28/2022] Open
Abstract
RNAs are negatively charged molecules that reside in cellular environments with macromolecular crowding. Macromolecular confinement can influence the ion effects in RNA folding. In this work, using the recently developed tightly bound ion model for ion fluctuation and correlation, we investigate the effect of confinement on ion-mediated RNA structural collapse for a simple model system. We find that for both Na(+) and Mg(2+), the ion efficiencies in mediating structural collapse/folding are significantly enhanced by the structural confinement. This enhancement of ion efficiency is attributed to the decreased electrostatic free-energy difference between the compact conformation ensemble and the (restricted) extended conformation ensemble due to the spatial restriction.
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Affiliation(s)
- Zhi-Jie Tan
- Department of Physics and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, People's Republic of China.
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49
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Lambert D, Draper DE. Denaturation of RNA secondary and tertiary structure by urea: simple unfolded state models and free energy parameters account for measured m-values. Biochemistry 2012; 51:9014-26. [PMID: 23088364 PMCID: PMC3505219 DOI: 10.1021/bi301103j] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
To investigate the mechanism by which urea destabilizes RNA structure, urea-induced unfolding of four different RNA secondary and tertiary structures was quantified in terms of an m-value, the rate at which the free energy of unfolding changes with urea molality. From literature data and our osmometric study of a backbone analogue, we derived average interaction potentials (per square angstrom of solvent accessible surface) between urea and three kinds of RNA surfaces: phosphate, ribose, and base. Estimates of the increases in solvent accessible surface areas upon RNA denaturation were based on a simple model of unfolded RNA as a combination of helical and single-strand segments. These estimates, combined with the three interaction potentials and a term to account for interactions of urea with released ions, yield calculated m-values that are in good agreement with experimental values (200 mm monovalent salt). Agreement was obtained only if single-stranded RNAs were modeled in a highly stacked, A-form conformation. The primary driving force for urea-induced denaturation is the strong interaction of urea with the large surface areas of bases that become exposed upon denaturation of either RNA secondary or tertiary structure, though interactions of urea with backbone and released ions may account for up to a third of the m-value. Urea m-values for all four RNAs are salt-dependent, which we attribute to an increased extension (or decreased charge density) of unfolded RNAs with an increased urea concentration. The sensitivity of the urea m-value to base surface exposure makes it a potentially useful probe of the conformations of RNA unfolded states.
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Affiliation(s)
| | - David E. Draper
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218
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50
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Miyoshi D, Fujimoto T, Sugimoto N. Molecular Crowding and Hydration Regulating of G-Quadruplex Formation. Top Curr Chem (Cham) 2012; 330:87-110. [DOI: 10.1007/128_2012_335] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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