1
|
Li Y, Zandieh M, Liu J. Modulation of DNAzyme Activity via Butanol Dehydration. Chem Asian J 2021; 16:4062-4066. [PMID: 34665937 DOI: 10.1002/asia.202101091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/18/2021] [Indexed: 11/07/2022]
Abstract
Understanding the activity of biomolecules in cosolvent systems is important for catalysis, separation and developing biosensors. The majority of previously studied solvents are either phase separated with water or miscible with water. Butanol was recently used to extract water for the conjugation of DNA to gold nanoparticles. In this work, the effect of butanol on the activity of a few RNA-cleaving DNAzymes was studied. A 130-fold improvement in sensitivity for the Na+ -specific EtNa DNAzyme was observed, and butanol also improved the activity of another Na+ -specific DNAzyme, NaA43T by a few folds. However, when divalent metal ions were used for both EtNa and 17E DNAzymes, the activity was inhibited. A main driven force for enhanced DNAzyme activity is the concentration effect due to butanol dehydration. This study provides insights into the interplay between DNA, metal ions and organic solvents, and such an understanding might be useful for developing sensitive biosensors.
Collapse
Affiliation(s)
- Yuqing Li
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - Mohamad Zandieh
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| |
Collapse
|
2
|
Gunawardhana SM, Holmstrom ED. Apolar chemical environments compact unfolded RNAs and can promote folding. BIOPHYSICAL REPORTS 2021; 1. [PMID: 35382036 PMCID: PMC8978554 DOI: 10.1016/j.bpr.2021.100004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It is well documented that the structure, and thus function, of nucleic acids depends on the chemical environment surrounding them, which often includes potential proteinaceous binding partners. The nonpolar amino acid side chains of these proteins will invariably alter the polarity of the local chemical environment around the nucleic acid. However, we are only beginning to understand how environmental polarity generally influences the structural and energetic properties of RNA folding. Here, we use a series of aqueous-organic cosolvent mixtures to systematically modulate the solvent polarity around two different RNA folding constructs that can form either secondary or tertiary structural elements. Using single-molecule Förster resonance energy transfer spectroscopy to simultaneously monitor the structural and energetic properties of these RNAs, we show that the unfolded conformations of both model RNAs become more compact in apolar environments characterized by dielectric constants less than that of pure water. In the case of tertiary structure formation, this compaction also gives rise to more energetically favorable folding. We propose that these physical changes arise from an enhanced accumulation of counterions in the low dielectric environment surrounding the unfolded RNA.
Collapse
Affiliation(s)
| | - Erik D Holmstrom
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas.,Department of Chemistry, University of Kansas, Lawrence, Kansas
| |
Collapse
|
3
|
Ma L, Huang Z, Liu J. Selection of a self-cleaving ribozyme activated in a chemically and thermally denaturing environment. Chem Commun (Camb) 2021; 57:7641-7644. [PMID: 34250983 DOI: 10.1039/d1cc03102c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
A new self-cleaving ribozyme was obtained from in vitro selection, displaying site-specific cleavage activity under denaturing conditions, such as high temperatures up to 95 °C, and denaturing solvents (20 M formamide). Adding salt such as Mg2+ also inhibited its activity. The conserved ribozyme sequence was found in the genome of several extremophiles, suggesting its potential biological relevance. This study provides an example of a ribozyme working under exotic conditions, which may expand the application of ribozymes in non-biological environments.
Collapse
Affiliation(s)
- Lingzi Ma
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
| | - Zhicheng Huang
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
| |
Collapse
|
4
|
Liu Z, Wang S, Tapeinos C, Torrieri G, Känkänen V, El-Sayed N, Python A, Hirvonen JT, Santos HA. Non-viral nanoparticles for RNA interference: Principles of design and practical guidelines. Adv Drug Deliv Rev 2021; 174:576-612. [PMID: 34019958 DOI: 10.1016/j.addr.2021.05.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/04/2021] [Accepted: 05/15/2021] [Indexed: 02/08/2023]
Abstract
Ribonucleic acid interference (RNAi) is an innovative treatment strategy for a myriad of indications. Non-viral synthetic nanoparticles (NPs) have drawn extensive attention as vectors for RNAi due to their potential advantages, including improved safety, high delivery efficiency and economic feasibility. However, the complex natural process of RNAi and the susceptible nature of oligonucleotides render the NPs subject to particular design principles and requirements for practical fabrication. Here, we summarize the requirements and obstacles for fabricating non-viral nano-vectors for efficient RNAi. To address the delivery challenges, we discuss practical guidelines for materials selection and NP synthesis in order to maximize RNA encapsulation efficiency and protection against degradation, and to facilitate the cytosolic release of oligonucleotides. The current status of clinical translation of RNAi-based therapies and further perspectives for reducing the potential side effects are also reviewed.
Collapse
|
5
|
Zhang Y, Narlikar GJ, Kutateladze TG. Enzymatic Reactions inside Biological Condensates. J Mol Biol 2021; 433:166624. [PMID: 32805219 PMCID: PMC9089403 DOI: 10.1016/j.jmb.2020.08.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/06/2020] [Accepted: 08/10/2020] [Indexed: 12/24/2022]
Abstract
Biological enzymes significantly speed up chemical reactions in living organisms. The complex environment within cells has long been appreciated as a major regulator of enzymatic activities. Recent advances in the rapidly evolving field of biological condensates, which are spontaneously formed by macromolecules through phase separation, suggest new possibilities for how enzymatic reactions may be modulated within cells. Here, we review the latest studies of enzymatic reactions in biological condensates focusing on basic concepts in enzymology and discussing some context-dependent roles of phase separation in regulating biochemical reactions.
Collapse
Affiliation(s)
- Yi Zhang
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
| | - Geeta J Narlikar
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158, USA.
| | - Tatiana G Kutateladze
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
| |
Collapse
|
6
|
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.
Collapse
Affiliation(s)
- Saurja DasGupta
- Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
| |
Collapse
|
7
|
Catalytic RNA, ribozyme, and its applications in synthetic biology. Biotechnol Adv 2019; 37:107452. [DOI: 10.1016/j.biotechadv.2019.107452] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 09/16/2019] [Accepted: 09/17/2019] [Indexed: 12/21/2022]
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Nakano SI, Yamashita H, Tanabe K, Sugimoto N. Bulky cations greatly increase the turnover of a native hammerhead ribozyme. RSC Adv 2019; 9:35820-35824. [PMID: 35528091 PMCID: PMC9074697 DOI: 10.1039/c9ra06797c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 10/28/2019] [Indexed: 12/13/2022] Open
Abstract
Methods to facilitate the catalytic turnover of ribozymes are required for advancing oligonucleotide-based technologies. This study examined tetraalkylammonium ions for their ability to increase the efficiency of catalytic turnover of a native hammerhead ribozyme. Kinetic analysis showed that large tetraalkylammonium ions significantly increased the turnover rate of the ribozyme and was much more effective than poly(ethylene glycol) (PEG) and urea. The magnitude of the rate increase depended on the concentrations of Mg2+ and tetrapentylammonium ions, and the rate was enhanced by more than 180-fold at the optimal concentrations of these salts. The results provide physical insights into interactions of ribozymes with large cationic molecules through electrostatic forces and steric hindrance. Large tetraalkylammonium ions increase the turnover rate of the ribozyme derived from an intronic ribozyme in the human genome. The rate can be enhanced by more than a hundred-fold at the optimal concentrations of Mg2+ and TPeA ions.![]()
Collapse
Affiliation(s)
- Shu-ichi Nakano
- Department of Nanobiochemistry
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST)
- Konan University
- Kobe
- Japan
| | - Hirofumi Yamashita
- Department of Nanobiochemistry
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST)
- Konan University
- Kobe
- Japan
| | - Kazuya Tanabe
- 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
| |
Collapse
|
10
|
Paudel BP, Fiorini E, Börner R, Sigel RKO, Rueda DS. Optimal molecular crowding accelerates group II intron folding and maximizes catalysis. Proc Natl Acad Sci U S A 2018; 115:11917-11922. [PMID: 30397128 PMCID: PMC6255197 DOI: 10.1073/pnas.1806685115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
Unlike in vivo conditions, group II intron ribozymes are known to require high magnesium(II) concentrations ([Mg2+]) and high temperatures (42 °C) for folding and catalysis in vitro. A possible explanation for this difference is the highly crowded cellular environment, which can be mimicked in vitro by macromolecular crowding agents. Here, we combined bulk activity assays and single-molecule Förster Resonance Energy Transfer (smFRET) to study the influence of polyethylene glycol (PEG) on catalysis and folding of the ribozyme. Our activity studies reveal that PEG reduces the [Mg2+] required, and we found an "optimum" [PEG] that yields maximum activity. smFRET experiments show that the most compact state population, the putative active state, increases with increasing [PEG]. Dynamic transitions between folded states also increase. Therefore, this study shows that optimal molecular crowding concentrations help the ribozyme not only to reach the native fold but also to increase its in vitro activity to approach that in physiological conditions.
Collapse
Affiliation(s)
- Bishnu P Paudel
- Molecular Virology, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
- Single Molecule Imaging, Medical Research Council London Institute of Medical Sciences, London W12 0NN, United Kingdom
| | - Erica Fiorini
- Department of Chemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Richard Börner
- Department of Chemistry, University of Zurich, 8057 Zurich, Switzerland
| | - Roland K O Sigel
- Department of Chemistry, University of Zurich, 8057 Zurich, Switzerland
| | - David S Rueda
- Molecular Virology, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom;
- Single Molecule Imaging, Medical Research Council London Institute of Medical Sciences, London W12 0NN, United Kingdom
| |
Collapse
|
11
|
Drobot B, Iglesias-Artola JM, Le Vay K, Mayr V, Kar M, Kreysing M, Mutschler H, Tang TYD. Compartmentalised RNA catalysis in membrane-free coacervate protocells. Nat Commun 2018; 9:3643. [PMID: 30194374 PMCID: PMC6128941 DOI: 10.1038/s41467-018-06072-w] [Citation(s) in RCA: 194] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 08/08/2018] [Indexed: 12/20/2022] Open
Abstract
Phase separation of mixtures of oppositely charged polymers provides a simple and direct route to compartmentalisation via complex coacervation, which may have been important for driving primitive reactions as part of the RNA world hypothesis. However, to date, RNA catalysis has not been reconciled with coacervation. Here we demonstrate that RNA catalysis is viable within coacervate microdroplets and further show that these membrane-free droplets can selectively retain longer length RNAs while permitting transfer of lower molecular weight oligonucleotides. Phase separation of mixtures of oppositely charged polymers provides a simple and direct route to compartmentalisation via coacervation. Here authors demonstrate that a coacervate microenvironment supports RNA catalysis whilst selectively sequestering RNA based on length.
Collapse
Affiliation(s)
- Björn Drobot
- Max-Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany
| | - Juan M Iglesias-Artola
- Max-Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany
| | - Kristian Le Vay
- Max-Planck Institute for Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Viktoria Mayr
- Max-Planck Institute for Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - Mrityunjoy Kar
- Max-Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany
| | - Moritz Kreysing
- Max-Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany.
| | - Hannes Mutschler
- Max-Planck Institute for Biochemistry, Am Klopferspitz 18, 82152, Martinsried, Germany.
| | - T-Y Dora Tang
- Max-Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307, Dresden, Germany.
| |
Collapse
|
12
|
Nakano SI, Yamaguchi D, Sugimoto N. Thermal stability and conformation of DNA and proteins under the confined condition in the matrix of hydrogels. Mol Biol Rep 2018; 45:403-411. [PMID: 29626318 DOI: 10.1007/s11033-018-4174-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 03/24/2018] [Indexed: 01/15/2023]
Abstract
Spatially confined environments are seen in biological systems and in the fields of biotechnology and nanotechnology. The confinement restricts the conformational space of polymeric molecules and increasing the degree of molecular crowding. Here, we developed preparation methods for agarose and polyacrylamide gels applicable to UV spectroscopy that can evaluate the confinement effects on DNA and protein structures. Measurements of UV absorbance and CD spectra showed no significant effect of the confinement in the porous media of agarose gels on the base-pair stability of DNA polynucleotides [poly(dA)/poly(dT)] and oligonucleotides (hairpin, duplex, and triplex structures). On the other hand, a highly confined environment created by polyacrylamide gels at high concentrations increased the stability of polynucleotides while leaving that of oligonucleotides unaffected. The changes in the base-pair stability of the polynucleotides were accompanied by the perturbation of the helical conformation. The polyacrylamide gels prepared in this study were also used for the studies on proteins (lysozyme, bovine serum albumin, and myoglobin). The effects on the proteins were different from the effects on DNA structures, suggesting different nature of interactions within the gel. The experimental methods and results are useful to understand the physical properties of nucleic acids and proteins under confined conditions.
Collapse
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.
| | - Daisuke Yamaguchi
- 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
- 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.,Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe, 650-0047, Japan
| |
Collapse
|
13
|
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.
Collapse
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
| |
Collapse
|
14
|
|
15
|
Nakano SI, Watabe T, Sugimoto N. Modulation of Ribozyme and Deoxyribozyme Activities Using Tetraalkylammonium Ions. Chemphyschem 2017; 18:3614-3619. [DOI: 10.1002/cphc.201700882] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/13/2017] [Indexed: 12/31/2022]
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
| | - Takaaki Watabe
- 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
- Department of Chemistry; Faculty of Science and Engineering; Konan University; 8-9-1, Okamoto, Higashinada-ku Kobe 658-8501 Japan
| | - Naoki Sugimoto
- 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
- Frontier Institute for Biomolecular Engineering Research (FIBER); Konan University; 7-1-20, Minatojima-minamimachi, Chuo-ku Kobe 650-0047 Japan
| |
Collapse
|
16
|
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.
Collapse
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
| |
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
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.
Collapse
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
| |
Collapse
|
19
|
Xu L, Zhou W, Liu J. Enhanced DNA sensitized Tb 3+ luminescence in organic solvents for more sensitive detection. Anal Chim Acta 2017; 977:44-51. [PMID: 28577597 DOI: 10.1016/j.aca.2017.04.046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 04/15/2017] [Accepted: 04/21/2017] [Indexed: 12/12/2022]
Abstract
DNA-sensitized Tb3+ luminescence spectroscopy is a powerful method for probing nucleic acids and developing biosensors. Its performance in organic solvents has yet to be explored. In this study, Tb3+ luminescence with nucleosides, nucleotides and DNA oligonucleotides in various organic solvents is studied. Tb3+ emission with single nucleotides is quenched up to 88% in dimethyl formamide (DMF), while its emission with nucleosides is enhanced. For the four 15-mer DNA homopolymers, the strongest absolute emission enhancement was achieved with C15. Similar emission properties are observed in other solvents including DMF, DMSO, acetonitrile methanol, ethanol, isopropanol and ethylene glycol. A few DNAzymes are tested as random DNA sequences all showing 1.4-6.9-fold emission enhancement in ethanol. A previously reported optimized sequence in water (G3T)5 is further enhanced by the solvents. Using this sequence, a detection limit of 5.5 nm Hg2+ is achieved in 25% ethanol solution. A similar Hg2+ sensitivity is also observed in a lake water mixed with ethanol. Luminescence lifetime is longer in DMF than in water. This study indicates that DNA-sensitized Tb3+ luminescence can be measured in water miscible solvents and most likely, with even stronger emission than that in water.
Collapse
Affiliation(s)
- Li Xu
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, China; Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
| | - Wenhu Zhou
- School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, 410013, China; Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Juewen Liu
- Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada.
| |
Collapse
|
20
|
Kilburn D, Behrouzi R, Lee HT, Sarkar K, Briber RM, Woodson SA. Entropic stabilization of folded RNA in crowded solutions measured by SAXS. Nucleic Acids Res 2016; 44:9452-9461. [PMID: 27378777 PMCID: PMC5100557 DOI: 10.1093/nar/gkw597] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 06/21/2016] [Indexed: 01/29/2023] Open
Abstract
Non-coding RNAs must fold into specific structures that are stabilized by metal ions and other co-solutes in the cell's interior. Large crowder molecules such as PEG stabilize a bacterial group I ribozyme so that the RNA folds in low Mg2+ concentrations typical of the cell's interior. To understand the thermodynamic origins of stabilization by crowder molecules, small angle X-ray scattering was used to measure the folding and helix assembly of a bacterial group I ribozyme at different temperatures and in different MgCl2 and polyethylene glycol (PEG) concentrations. The resulting phase diagrams show that perturbations to folding by each variable do not overlap. A favorable enthalpy change drives the formation of compact, native-like structures, but requires Mg2+ ions at all temperatures studied (5–55°C). PEG reduces the entropic cost of helix assembly and increases correlations between RNA segments at all temperatures. The phase diagrams also revealed a semi-compact intermediate between the unfolded and folded ensemble that is locally more flexible than the unfolded state, as judged by SHAPE modification. These results suggest that environmental variables such as temperature and solute density will favor different types of RNA structures.
Collapse
Affiliation(s)
- Duncan Kilburn
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Reza Behrouzi
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Hui-Ting Lee
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Krishnarjun Sarkar
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Robert M Briber
- Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA
| | - Sarah A Woodson
- T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| |
Collapse
|
21
|
The structural stability and catalytic activity of DNA and RNA oligonucleotides in the presence of organic solvents. Biophys Rev 2016; 8:11-23. [PMID: 28510143 DOI: 10.1007/s12551-015-0188-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/03/2015] [Indexed: 01/02/2023] Open
Abstract
Organic solvents and apolar media are used in the studies of nucleic acids to modify the conformation and function of nucleic acids, to improve solubility of hydrophobic ligands, to construct molecular scaffolds for organic synthesis, and to study molecular crowding effects. Understanding how organic solvents affect nucleic acid interactions and identifying the factors that dominate solvent effects are important for the creation of oligonucleotide-based technologies. This review describes the structural and catalytic properties of DNA and RNA oligonucleotides in organic solutions and in aqueous solutions with organic cosolvents. There are several possible mechanisms underlying the effects of organic solvents on nucleic acid interactions. The reported results emphasize the significance of the osmotic pressure effect and the dielectric constant effect in addition to specific interactions with nucleic acid strands. This review will serve as a guide for the selection of solvent systems based on the purpose of the nucleic acid-based experiments.
Collapse
|
22
|
Effects of background anionic compounds on the activity of the hammerhead ribozyme in Mg(2+)-unsaturated solutions. J Biol Inorg Chem 2015. [PMID: 26220274 DOI: 10.1007/s00775-015-1286-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Cellular ribozymes exhibit catalytic activity in media containing large numbers of anionic compounds and macromolecules. In this study, the RNA cleavage activity of the hammerhead ribozyme induced by Mg(2+) was investigated using the solutions containing background nucleic acids, small phosphate and carboxylic acid compounds, and neutral polymers. Analysis of the substrate cleavage kinetics showed that the anionic compounds do not affect the ribozyme activity in Mg(2+)-saturated solutions and there is almost no effect of the anion-Mg(2+) complexes formed. On the other hand, the rate of substrate cleavage in Mg(2+)-unsaturated solutions was reduced under conditions of a high background of anionic compounds found in cells. The extent of the reduction was more with a greater net negative charge, caused by decreased amounts of Mg(2+) that could be used for the ribozyme reaction. It was remarkable that background DNA and RNA molecules having phosphodiester bonds reduced the cleavage rate as much as adenosine monophosphates having a charge of -2 when the effects of the same amount of phosphate groups were compared. Greater reductions in rates than those expected from the molecular charge were also observed in the background of fatty acids that form micelles. An addition of poly(ethylene glycol) to the solutions partially restored the ribozyme activity, suggesting a possible role of macromolecular crowding in counteracting the inhibitory effects of background anions on the ribozyme reaction. The results have biological and practical implications with respect to the effects of molecular environment on the efficiency of ion binding to RNA.
Collapse
|
23
|
Nakano SI, Kitagawa Y, Yamashita H, Miyoshi D, Sugimoto N. Effects of Cosolvents on the Folding and Catalytic Activities of the Hammerhead Ribozyme. Chembiochem 2015; 16:1803-10. [DOI: 10.1002/cbic.201500139] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Indexed: 11/09/2022]
|
24
|
Roles of the amino group of purine bases in the thermodynamic stability of DNA base pairing. Molecules 2014; 19:11613-27. [PMID: 25100254 PMCID: PMC6271411 DOI: 10.3390/molecules190811613] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Revised: 07/28/2014] [Accepted: 07/31/2014] [Indexed: 01/19/2023] Open
Abstract
The energetic aspects of hydrogen-bonded base-pair interactions are important for the design of functional nucleotide analogs and for practical applications of oligonucleotides. The present study investigated the contribution of the 2-amino group of DNA purine bases to the thermodynamic stability of oligonucleotide duplexes under different salt and solvent conditions, using 2'-deoxyriboinosine (I) and 2'-deoxyribo-2,6-diaminopurine (D) as non-canonical nucleotides. The stability of DNA duplexes was changed by substitution of a single base pair in the following order: G•C > D•T ≈ I•C > A•T > G•T > I•T. The apparent stabilization energy due to the presence of the 2-amino group of G and D varied depending on the salt concentration, and decreased in the water-ethanol mixed solvent. The effects of salt concentration on the thermodynamics of DNA duplexes were found to be partially sequence-dependent, and the 2-amino group of the purine bases might have an influence on the binding of ions to DNA through the formation of a stable base-paired structure. Our results also showed that physiological salt conditions were energetically favorable for complementary base recognition, and conversely, low salt concentration media and ethanol-containing solvents were effective for low stringency oligonucleotide hybridization, in the context of conditions employed in this study.
Collapse
|