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Gajarsky M, Stadlbauer P, Sponer J, Cucchiarini A, Dobrovolna M, Brazda V, Mergny JL, Trantirek L, Lenarcic Zivkovic M. DNA Quadruplex Structure with a Unique Cation Dependency. Angew Chem Int Ed Engl 2024; 63:e202313226. [PMID: 38143239 DOI: 10.1002/anie.202313226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 12/11/2023] [Accepted: 12/22/2023] [Indexed: 12/26/2023]
Abstract
DNA quadruplex structures provide an additional layer of regulatory control in genome maintenance and gene expression and are widely used in nanotechnology. We report the discovery of an unprecedented tetrastranded structure formed from a native G-rich DNA sequence originating from the telomeric region of Caenorhabditis elegans. The structure is defined by multiple properties that distinguish it from all other known DNA quadruplexes. Most notably, the formation of a stable so-called KNa-quadruplex (KNaQ) requires concurrent coordination of K+ and Na+ ions at two distinct binding sites. This structure provides novel insight into G-rich DNA folding under ionic conditions relevant to eukaryotic cell physiology and the structural evolution of telomeric DNA. It highlights the differences between the structural organization of human and nematode telomeric DNA, which should be considered when using C. elegans as a model in telomere biology, particularly in drug screening applications. Additionally, the absence/presence of KNaQ motifs in the host/parasite introduces an intriguing possibility of exploiting the KNaQ fold as a plausible antiparasitic drug target. The structure's unique shape and ion dependency and the possibility of controlling its folding by using low-molecular-weight ligands can be used for the design or discovery of novel recognition DNA elements and sensors.
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Affiliation(s)
- Martin Gajarsky
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 753/5, 62500, Brno, Czech Republic
- Current address: Center for Molecular Medicine Cologne, University of Cologne, 50931, Cologne, Germany
| | - Petr Stadlbauer
- Institute of Biophysics, Czech Academy of Sciences, Kralovopolska 135, 61265, Brno, Czech Republic
| | - Jiri Sponer
- Institute of Biophysics, Czech Academy of Sciences, Kralovopolska 135, 61265, Brno, Czech Republic
| | - Anne Cucchiarini
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 753/5, 62500, Brno, Czech Republic
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, Inserm, Institut Polytechnique de Paris, 91120, Palaiseau, France
| | - Michaela Dobrovolna
- Institute of Biophysics, Czech Academy of Sciences, Kralovopolska 135, 61265, Brno, Czech Republic
- Faculty of Chemistry, Brno University of Technology, Purkynova 464, 61200, Brno, Czech Republic
| | - Vaclav Brazda
- Institute of Biophysics, Czech Academy of Sciences, Kralovopolska 135, 61265, Brno, Czech Republic
- Faculty of Chemistry, Brno University of Technology, Purkynova 464, 61200, Brno, Czech Republic
| | - Jean-Louis Mergny
- Institute of Biophysics, Czech Academy of Sciences, Kralovopolska 135, 61265, Brno, Czech Republic
- Laboratoire d'Optique et Biosciences, Ecole Polytechnique, CNRS, Inserm, Institut Polytechnique de Paris, 91120, Palaiseau, France
| | - Lukas Trantirek
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 753/5, 62500, Brno, Czech Republic
| | - Martina Lenarcic Zivkovic
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 753/5, 62500, Brno, Czech Republic
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, 1000, Ljubljana, Slovenia
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2
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Zalar M, Wang B, Plavec J, Šket P. Insight into Tetramolecular DNA G-Quadruplexes Associated with ALS and FTLD: Cation Interactions and Formation of Higher-Ordered Structure. Int J Mol Sci 2023; 24:13437. [PMID: 37686239 PMCID: PMC10487854 DOI: 10.3390/ijms241713437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 09/10/2023] Open
Abstract
The G4C2 hexanucleotide repeat expansion in the c9orf72 gene is a major genetic cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), with the formation of G-quadruplexes directly linked to the development of these diseases. Cations play a crucial role in the formation and structure of G-quadruplexes. In this study, we investigated the impact of biologically relevant potassium ions on G-quadruplex structures and utilized 15N-labeled ammonium cations as a substitute for K+ ions to gain further insights into cation binding and exchange dynamics. Through nuclear magnetic resonance spectroscopy and molecular dynamics simulations, we demonstrate that the single d(G4C2) repeat, in the presence of 15NH4+ ions, adopts a tetramolecular G-quadruplex with an all-syn quartet at the 5'-end. The movement of 15NH4+ ions through the central channel of the G-quadruplex, as well as to the bulk solution, is governed by the vacant cation binding site, in addition to the all-syn quartet at the 5'-end. Furthermore, the addition of K+ ions to G-quadruplexes folded in the presence of 15NH4+ ions induces stacking of G-quadruplexes via their 5'-end G-quartets, leading to the formation of stable higher-ordered species.
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Affiliation(s)
- Matja Zalar
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia; (M.Z.); (B.W.); (J.P.)
| | - Baifan Wang
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia; (M.Z.); (B.W.); (J.P.)
| | - Janez Plavec
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia; (M.Z.); (B.W.); (J.P.)
- EN-FIST Center of Excellence, Trg OF 13, SI-1000 Ljubljana, Slovenia
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
| | - Primož Šket
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia; (M.Z.); (B.W.); (J.P.)
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3
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Bağda E, Kızılyar Y, İnci ÖG, Ghaffarlou M, Barsbay M. One-pot modification of oleate-capped UCNPs with AS1411 G-quadruplex DNA in a fully aqueous medium. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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4
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Largy E, König A, Ghosh A, Ghosh D, Benabou S, Rosu F, Gabelica V. Mass Spectrometry of Nucleic Acid Noncovalent Complexes. Chem Rev 2021; 122:7720-7839. [PMID: 34587741 DOI: 10.1021/acs.chemrev.1c00386] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nucleic acids have been among the first targets for antitumor drugs and antibiotics. With the unveiling of new biological roles in regulation of gene expression, specific DNA and RNA structures have become very attractive targets, especially when the corresponding proteins are undruggable. Biophysical assays to assess target structure as well as ligand binding stoichiometry, affinity, specificity, and binding modes are part of the drug development process. Mass spectrometry offers unique advantages as a biophysical method owing to its ability to distinguish each stoichiometry present in a mixture. In addition, advanced mass spectrometry approaches (reactive probing, fragmentation techniques, ion mobility spectrometry, ion spectroscopy) provide more detailed information on the complexes. Here, we review the fundamentals of mass spectrometry and all its particularities when studying noncovalent nucleic acid structures, and then review what has been learned thanks to mass spectrometry on nucleic acid structures, self-assemblies (e.g., duplexes or G-quadruplexes), and their complexes with ligands.
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Affiliation(s)
- Eric Largy
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Alexander König
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Anirban Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Debasmita Ghosh
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Sanae Benabou
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
| | - Frédéric Rosu
- Univ. Bordeaux, CNRS, INSERM, IECB, UMS 3033, F-33600 Pessac, France
| | - Valérie Gabelica
- Univ. Bordeaux, CNRS, INSERM, ARNA, UMR 5320, U1212, IECB, F-33600 Pessac, France
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5
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Winnerdy FR, Bakalar B, Das P, Heddi B, Marchand A, Rosu F, Gabelica V, Phan AT. Unprecedented hour-long residence time of a cation in a left-handed G-quadruplex. Chem Sci 2021; 12:7151-7157. [PMID: 34123342 PMCID: PMC8153214 DOI: 10.1039/d1sc00515d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/06/2021] [Indexed: 11/21/2022] Open
Abstract
Cations are critical for the folding and assembly of nucleic acids. In G-quadruplex structures, cations can bind between stacked G-tetrads and coordinate with negatively charged guanine carbonyl oxygens. They usually exchange between binding sites and with the bulk in solution with time constants ranging from sub-millisecond to seconds. Here we report the first observation of extremely long-lived K+ and NH4 + ions, with an exchange time constant on the order of an hour, when coordinated at the center of a left-handed G-quadruplex DNA. A single-base mutation, that switched one half of the structure from left- to right-handed conformation resulting in a right-left hybrid G-quadruplex, was shown to remove this long-lived behaviour of the central cation.
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Affiliation(s)
- Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University Singapore 637371 Singapore
| | - Blaž Bakalar
- School of Physical and Mathematical Sciences, Nanyang Technological University Singapore 637371 Singapore
| | - Poulomi Das
- School of Physical and Mathematical Sciences, Nanyang Technological University Singapore 637371 Singapore
| | - Brahim Heddi
- School of Physical and Mathematical Sciences, Nanyang Technological University Singapore 637371 Singapore
- Laboratoire de Biologie et de Pharmacologie Appliquée, CNRS, Ecole Normale Supérieure Paris-Saclay Gif-sur-Yvette 91190 France
| | - Adrien Marchand
- Laboratoire Acides Nucléiques: Régulations Naturelle et Artificielle, Université de Bordeaux, Inserm & CNRS (ARNA, U1212, UMR5320), IECB Pessac 33600 France
| | - Frédéric Rosu
- Institut Européen de Chimie et Biologie, Université de Bordeaux, CNRS & Inserm (IECB, UMS3033, US001) Pessac 33607 France
| | - Valérie Gabelica
- Laboratoire Acides Nucléiques: Régulations Naturelle et Artificielle, Université de Bordeaux, Inserm & CNRS (ARNA, U1212, UMR5320), IECB Pessac 33600 France
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University Singapore 637371 Singapore
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6
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Chen F, Lu Q, Huang L, Liu B, Liu M, Zhang Y, Liu J. DNA Triplex and Quadruplex Assembled Nanosensors for Correlating K
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and pH in Lysosomes. Angew Chem Int Ed Engl 2021; 60:5453-5458. [PMID: 33244829 DOI: 10.1002/anie.202013302] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Indexed: 12/24/2022]
Affiliation(s)
- Feng Chen
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research College of Chemistry and Chemical Engineering Hunan Normal University Changsha Hunan Province China
| | - Qiujun Lu
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research College of Chemistry and Chemical Engineering Hunan Normal University Changsha Hunan Province China
| | - Linna Huang
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research College of Chemistry and Chemical Engineering Hunan Normal University Changsha Hunan Province China
| | - Biwu Liu
- Department of Chemistry Waterloo Institute for Nanotechnology University of Waterloo 200 University Avenue West Waterloo Ontario N2L 3G1 Canada
| | - Meiling Liu
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research College of Chemistry and Chemical Engineering Hunan Normal University Changsha Hunan Province China
| | - Youyu Zhang
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research College of Chemistry and Chemical Engineering Hunan Normal University Changsha Hunan Province China
| | - Juewen Liu
- Department of Chemistry Waterloo Institute for Nanotechnology University of Waterloo 200 University Avenue West Waterloo Ontario N2L 3G1 Canada
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7
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DNA Triplex and Quadruplex Assembled Nanosensors for Correlating K
+
and pH in Lysosomes. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202013302] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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8
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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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9
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Sharawy M, Consta S. Effect of the chemical environment of the DNA guanine quadruplex on the free energy of binding of Na and K ions. J Chem Phys 2019; 149:225102. [PMID: 30553268 DOI: 10.1063/1.5050534] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Guanine quadruplex (G-quadruplex) structures play a vital role in stabilizing the DNA genome and in protecting healthy cells from transforming into cancer cells. The structural stability of G-quadruplexes is greatly enhanced by the binding of monovalent cations such as Na+ or K+ into the interior axial channel. We computationally study the free energy of binding of Na+ and K+ ions to two intramolecular G-quadruplexes that differ considerably in their degree of rigidity and the presence or absence of terminal nucleotides. The goal of our study is two-fold. On the one hand, we study the free energy of binding every ion, which complements the experimental findings that report the average free energy for replacing Na+ with K+ ions. On the other hand, we examine the role of the G-quadruplex structure in the binding free energy. In the study, we employ all-atom molecular dynamics simulations and the alchemical transformation method for the computation of the free energies. To compare the cation-dependent contribution to the structural stability of G-quadruplexes, we use a two-step approach to calculate the individual free energy difference ΔG of binding two Na+ and two K+ to two G-quadruplexes: the unimolecular DNA d[T2GT2(G3T)3] (Protein Data Bank ID 2M4P) and the human telomeric DNA d[AGGG(TTAGGG)3] (PDB ID 1KF1). In contrast to the experimental studies that estimate the average free energy of binding, we find a varying difference of approximately 2-9 kcal/mol between the free energy contribution of binding the first and second cation, Na+ or K+. Furthermore, we found that the free energy of binding K+ is not affected by the chemical nature of the two quadruplexes. By contrast, Na+ showed dependency on the G-quadruplex structure; the relatively small size allows Na+ to explore larger configurational space than K+. Numerical results presented here may offer reference values for future design of cationic drug-like ligands that replace the metal ions in G-quadruplexes.
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Affiliation(s)
- Mahmoud Sharawy
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Styliani Consta
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
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10
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Mandal P, Sahoo D, Saha S, Chowdhury J. Sensing of Different Human Telomeric G-Quadruplex DNA Topologies by Natural Alkaloid Allocryptopine Using Spectroscopic Techniques. J Phys Chem B 2018; 122:10279-10290. [PMID: 30346761 DOI: 10.1021/acs.jpcb.8b07856] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Paulami Mandal
- Department of Physics, Jadavpur University, 188, Raja S. C. Mallick Road, Kolkata, West Bengal 700032, India
| | - Dibakar Sahoo
- School of Physics, Sambalpur University, Jyoti Vihar, Burla, Odisha 768 019, India
| | - Saumen Saha
- Department of Physics, Jadavpur University, 188, Raja S. C. Mallick Road, Kolkata, West Bengal 700032, India
| | - Joydeep Chowdhury
- Department of Physics, Jadavpur University, 188, Raja S. C. Mallick Road, Kolkata, West Bengal 700032, India
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11
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Yu Z, Zhou W, Ma G, Li Y, Fan L, Li X, Lu Y. Insights into the Competition between K+ and Pb2+ Binding to a G-Quadruplex and Discovery of a Novel K+–Pb2+–Quadruplex Intermediate. J Phys Chem B 2018; 122:9382-9388. [DOI: 10.1021/acs.jpcb.8b08161] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Ze Yu
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Wei Zhou
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Ge Ma
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Yunchao Li
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Louzhen Fan
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Xiaohong Li
- College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Yi Lu
- Department of Chemistry, Department of Materials Science and Engineering, University of Illinois at Urbana and Champaign, Urbana, Illinois 61801, United States
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12
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Kumar M, Kaushik M, Kukreti S. A topological transition from bimolecular quadruplex to G-triplex/tri-G-quadruplex exhibited by truncated double repeats of human telomere. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2018; 47:903-915. [PMID: 29934676 DOI: 10.1007/s00249-018-1312-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 04/11/2018] [Accepted: 05/21/2018] [Indexed: 12/12/2022]
Abstract
Human telomeric G-rich sequences can fold back into various conformations depending upon the salt (Na+ or K+) at physiological pH. On the basis of results obtained by native PAGE electrophoresis, circular dichroism, and UV-melting experiments, we report here that truncated sequences of human telomere (d-GGGTTAGGG; GM9, d-AGGGTTAGGG; GM10, d-TAGGGTTAGGG; GM11) adopt a varied range of quadruplex conformations as a function of the cation present. By correlating CD and gel electrophoresis experiments; it was concluded that the GM9 oligonucleotide can self-associate to form a tetramer quadruplex (antiparallel; AP) in Na+ solution and a mixture of G-triplex (AP) or tri-G-quadruplex (parallel; P) along with a tetramer G-quadruplex structure (AP) in K+. The GM10 oligonucleotide formed a bimolecular G-quadruplex in both Na+ and K+ solutions, while GM11 associated to form a bimolecular G-quadruplex (AP) structure in Na+ solution and a mixture of bimolecular G-quadruplex (AP) and bimolecular G-quadruplex (P) along with parallel G-triplex or antiparallel tri-G-quadruplex in K+. All the UV-melting profiles, thermal difference spectra, and CD melting curves suggested the formation of a variety of G-quadruplex conformations by the DNA sequences studied in Na+ and K+ ions. Hypothetical models for different conformations adopted by these DNA molecules have also been proposed, which may further enhance our knowledge about the divergent topologies of guanine quadruplexes.
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Affiliation(s)
- Mohan Kumar
- Nucleic Acid Research Laboratory, Department of Chemistry, University of Delhi, Delhi, India
| | - Mahima Kaushik
- Nucleic Acid Research Laboratory, Department of Chemistry, University of Delhi, Delhi, India.,Cluster Innovation Centre, University of Delhi, Delhi, India
| | - Shrikant Kukreti
- Nucleic Acid Research Laboratory, Department of Chemistry, University of Delhi, Delhi, India.
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13
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Akhshi P, Wu G. Umbrella sampling molecular dynamics simulations reveal concerted ion movement through G-quadruplex DNA channels. Phys Chem Chem Phys 2018; 19:11017-11025. [PMID: 28327752 DOI: 10.1039/c7cp01028a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We have applied the umbrella sampling (US) method in all-atom molecular dynamics (MD) simulations to obtain potential of mean force (PMF) profiles for ion transport through three representative G-quadruplex DNA channels: [d(TG4T)]4, [d(G3T4G4)]2, and d[G4(T4G4)3]. The US MD results are in excellent agreement with those obtained previously with the adaptive biasing force (ABF) method. We then utilized the unique features in the US MD method to investigate multi-ion effects in [d(G3T4G4)]2 and discovered that the concerted ion movement is crucial for fully explaining the unusual experimental results on ion movement in this particular G-quadruplex system. We anticipate that these modern free-energy methods will be useful tools in evaluating ion transport properties of other G-quadruplex DNA channels.
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Affiliation(s)
- Parisa Akhshi
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada.
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14
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Analysis of Cation-Dependent DNA (G3T1)4 Shape Change Using Fluorescence Correlation Spectroscopy. J Fluoresc 2017; 27:2037-2043. [DOI: 10.1007/s10895-017-2142-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 07/18/2017] [Indexed: 10/19/2022]
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15
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Harkness RW, Mittermaier AK. G-quadruplex dynamics. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017. [PMID: 28642152 DOI: 10.1016/j.bbapap.2017.06.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
G-quadruplexes (GQs) are four-stranded nucleic acid secondary structures formed by guanosine (G)-rich DNA and RNA sequences. It is becoming increasingly clear that cellular processes including gene expression and mRNA translation are regulated by GQs. GQ structures have been extensively characterized, however little attention to date has been paid to their conformational dynamics, despite the fact that many biological GQ sequences populate multiple structures of similar free energies, leading to an ensemble of exchanging conformations. The impact of these dynamics on biological function is currently not well understood. Recently, structural dynamics have been demonstrated to entropically stabilize GQ ensembles, potentially modulating gene expression. Transient, low-populated states in GQ ensembles may additionally regulate nucleic acid interactions and function. This review will underscore the interplay of GQ dynamics and biological function, focusing on several dynamic processes for biological GQs and the characterization of GQ dynamics by nuclear magnetic resonance (NMR) spectroscopy in conjunction with other biophysical techniques. This article is part of a Special Issue entitled: Biophysics in Canada, edited by Lewis Kay, John Baenziger, Albert Berghuis and Peter Tieleman.
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Affiliation(s)
- Robert W Harkness
- McGill University Department of Chemistry, 801 Sherbrooke St. W., Montreal, QC H3A 0B8, Canada
| | - Anthony K Mittermaier
- McGill University Department of Chemistry, 801 Sherbrooke St. W., Montreal, QC H3A 0B8, Canada.
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16
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He L, Meng Z, Xie YQ, Chen X, Li T, Shao F. Aza-bridged bisphenanthrolinyl Pt(II) complexes: Efficient stabilization and topological selectivity on telomeric G-quadruplexes. J Inorg Biochem 2017; 166:135-140. [DOI: 10.1016/j.jinorgbio.2016.11.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 09/30/2016] [Accepted: 11/03/2016] [Indexed: 12/15/2022]
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17
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Bhattacharyya D, Mirihana Arachchilage G, Basu S. Metal Cations in G-Quadruplex Folding and Stability. Front Chem 2016; 4:38. [PMID: 27668212 PMCID: PMC5016522 DOI: 10.3389/fchem.2016.00038] [Citation(s) in RCA: 381] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 08/25/2016] [Indexed: 12/23/2022] Open
Abstract
This review is focused on the structural and physicochemical aspects of metal cation coordination to G-Quadruplexes (GQ) and their effects on GQ stability and conformation. G-quadruplex structures are non-canonical secondary structures formed by both DNA and RNA. G-quadruplexes regulate a wide range of important biochemical processes. Besides the sequence requirements, the coordination of monovalent cations in the GQ is essential for its formation and determines the stability and polymorphism of GQ structures. The nature, location, and dynamics of the cation coordination and their impact on the overall GQ stability are dependent on several factors such as the ionic radii, hydration energy, and the bonding strength to the O6 of guanines. The intracellular monovalent cation concentration and the localized ion concentrations determine the formation of GQs and can potentially dictate their regulatory roles. A wide range of biochemical and biophysical studies on an array of GQ enabling sequences have generated at a minimum the knowledge base that allows us to often predict the stability of GQs in the presence of the physiologically relevant metal ions, however, prediction of conformation of such GQs is still out of the realm.
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Affiliation(s)
| | | | - Soumitra Basu
- Department of Chemistry and Biochemistry, Kent State UniversityKent, OH, USA
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18
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Largy E, Marchand A, Amrane S, Gabelica V, Mergny JL. Quadruplex Turncoats: Cation-Dependent Folding and Stability of Quadruplex-DNA Double Switches. J Am Chem Soc 2016; 138:2780-92. [PMID: 26837276 DOI: 10.1021/jacs.5b13130] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Quadruplex (G4) nucleic acids, a family of secondary structures formed by guanine-rich sequences, exhibit an important structural polymorphism. We demonstrate here that G-rich DNA sequences may function as a double switch based on different triggers, provided that their quadruplex structures and stability display a high dependence on cation nature and concentration. A first switch is based on a remarkable antiparallel-to-parallel conversion, taking place in a few seconds at room temperature by addition of low KCl amounts to a sodium-rich sample. The second switch involves the conversion of alternative antiparallel quadruplex structures binding only one cation, formed in the presence of sub-millimolar potassium or strontium concentrations, to parallel structures by increasing the cation concentration. Incidentally, extremely low K(+) or Sr(2+) concentrations (≤5 equiv) are sufficient to induce G4 formation in a buffer devoid of other G4-promoting cations, and we suggest that the alternative structures observed contain only two tetrads. Such DNA systems are biological relevant targets, can be used in nanotechnology applications, and are valuable methodological tools for understanding DNA quadruplex folding, notably at low cation concentrations. We demonstrate that this behavior is not restricted to a narrow set of sequences but can also be found for other G-quadruplex-forming motifs, arguing for widespread applications.
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Affiliation(s)
- Eric Largy
- U1212, ARNA Laboratory, Inserm , F-33000 Bordeaux, France.,IECB, ARNA Laboratory, Université de Bordeaux , F-33600 Pessac, France.,UMR 5320, ARNA Laboratory, CNRS , F-33600 Pessac, France
| | - Adrien Marchand
- U1212, ARNA Laboratory, Inserm , F-33000 Bordeaux, France.,IECB, ARNA Laboratory, Université de Bordeaux , F-33600 Pessac, France.,UMR 5320, ARNA Laboratory, CNRS , F-33600 Pessac, France
| | - Samir Amrane
- U1212, ARNA Laboratory, Inserm , F-33000 Bordeaux, France.,IECB, ARNA Laboratory, Université de Bordeaux , F-33600 Pessac, France.,UMR 5320, ARNA Laboratory, CNRS , F-33600 Pessac, France
| | - Valérie Gabelica
- U1212, ARNA Laboratory, Inserm , F-33000 Bordeaux, France.,IECB, ARNA Laboratory, Université de Bordeaux , F-33600 Pessac, France.,UMR 5320, ARNA Laboratory, CNRS , F-33600 Pessac, France
| | - Jean-Louis Mergny
- U1212, ARNA Laboratory, Inserm , F-33000 Bordeaux, France.,IECB, ARNA Laboratory, Université de Bordeaux , F-33600 Pessac, France.,UMR 5320, ARNA Laboratory, CNRS , F-33600 Pessac, France
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19
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Largy E, Mergny JL, Gabelica V. Role of Alkali Metal Ions in G-Quadruplex Nucleic Acid Structure and Stability. Met Ions Life Sci 2016; 16:203-58. [PMID: 26860303 DOI: 10.1007/978-3-319-21756-7_7] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
G-quadruplexes are guanine-rich nucleic acids that fold by forming successive quartets of guanines (the G-tetrads), stabilized by intra-quartet hydrogen bonds, inter-quartet stacking, and cation coordination. This specific although highly polymorphic type of secondary structure deviates significantly from the classical B-DNA duplex. G-quadruplexes are detectable in human cells and are strongly suspected to be involved in a number of biological processes at the DNA and RNA levels. The vast structural polymorphism exhibited by G-quadruplexes, together with their putative biological relevance, makes them attractive therapeutic targets compared to canonical duplex DNA. This chapter focuses on the essential and specific coordination of alkali metal cations by G-quadruplex nucleic acids, and most notably on studies highlighting cation-dependent dissimilarities in their stability, structure, formation, and interconversion. Section 1 surveys G-quadruplex structures and their interactions with alkali metal ions while Section 2 presents analytical methods used to study G-quadruplexes. The influence of alkali cations on the stability, structure, and kinetics of formation of G-quadruplex structures of quadruplexes will be discussed in Sections 3 and 4. Section 5 focuses on the cation-induced interconversion of G-quadruplex structures. In Sections 3 to 5, we will particularly emphasize the comparisons between cations, most often K(+) and Na(+) because of their prevalence in the literature and in cells.
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Affiliation(s)
- Eric Largy
- ARNA Laboratory, Université Bordeaux, IECB, 2, rue Robert Escarpit, F-33600, Pessac, France.,ARNA Laboratory, INSERM, U869, F-33000, Bordeaux, France
| | - Jean-Louis Mergny
- ARNA Laboratory, Université Bordeaux, IECB, 2, rue Robert Escarpit, F-33600, Pessac, France. .,ARNA Laboratory, INSERM, U869, F-33000, Bordeaux, France.
| | - Valérie Gabelica
- ARNA Laboratory, Université Bordeaux, IECB, 2, rue Robert Escarpit, F-33600, Pessac, France. .,ARNA Laboratory, INSERM, U869, F-33000, Bordeaux, France.
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20
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Trajkovski M, Morel E, Hamon F, Bombard S, Teulade-Fichou MP, Plavec J. Interactions of Pt-ttpy with G-Quadruplexes Originating from Promoter Region of the c-myc Gene Deciphered by NMR and Gel Electrophoresis Analysis. Chemistry 2015; 21:7798-807. [DOI: 10.1002/chem.201500347] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Indexed: 12/20/2022]
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21
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Zhu H, Xiao S, Wang L, Liang H. Communication: Asymmetrical cation movements through G-quadruplex DNA. J Chem Phys 2014; 141:041103. [DOI: 10.1063/1.4891218] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Hong Zhu
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Shiyan Xiao
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Lei Wang
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Haojun Liang
- CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
- Hefei National Laboratory for Physical Sciences at Microscale, Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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22
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Wang ZF, Li MH, Hsu STD, Chang TC. Structural basis of sodium-potassium exchange of a human telomeric DNA quadruplex without topological conversion. Nucleic Acids Res 2014; 42:4723-33. [PMID: 24476914 PMCID: PMC3985656 DOI: 10.1093/nar/gku083] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Understanding the mechanism of Na(+)/K(+)-dependent spectral conversion of human telomeric G-quadruplex (G4) sequences has been limited not only because of the structural polymorphism but also the lack of sufficient structural information at different stages along the conversion process for one given oligonucleotide. In this work, we have determined the topology of the Na(+) form of Tel23 G4, which is the same hybrid form as the K(+) form of Tel23 G4 despite the distinct spectral patterns in their respective nuclear magnetic resonance (NMR) and circular dichroism spectra. The spectral difference, particularly the well-resolved imino proton NMR signals, allows us to monitor the structural conversion from Na(+) form to K(+) form during Na(+)/K(+) exchange. Time-resolved NMR experiments of hydrogen-deuterium exchange and hybridization clearly exclude involvement of the global unfolding for the fast Na(+)/K(+) spectral conversion. In addition, the K(+) titration monitored by NMR reveals that the Na(+)/K(+) exchange in Tel23 G4 is a two-step process. The addition of K(+) significantly stabilizes the unfolding kinetics of Tel23 G4. These results offer a possible explanation of rapid spectral conversion of Na(+)/K(+) exchange and insight into the mechanism of Na(+)/K(+) structural conversion in human telomeric G4s.
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Affiliation(s)
- Zi-Fu Wang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan, Republic of China, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, Republic of China, Institute of Biophotonics, National Yang-Ming University, Taipei 112, Taiwan, Republic of China, Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan, Republic of China and Department of Biochemical Sciences, National Taiwan University, Taipei 106, Taiwan, Republic of China
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Sjoberg J. Ammonium ion binding to DNA G-quadruplexes: do electrospray mass spectra faithfully reflect the solution-phase species? JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013; 24:1-8. [PMID: 23132414 PMCID: PMC5110665 DOI: 10.1007/s13361-012-0499-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Revised: 09/04/2012] [Accepted: 09/04/2012] [Indexed: 06/01/2023]
Abstract
G-quadruplex nucleic acids can bind ammonium ions in solution, and these complexes can be detected by electrospray mass spectrometry (ESI-MS). However, because ammonium ions are volatile, the extent to which ESI-MS quantitatively could provide an accurate reflection of such solution-phase equilibria is unclear. Here we studied five G-quadruplexes having known solution-phase structure and ammonium ion binding constants: the bimolecular G-quadruplexes (dG(4)T(4)G(4))(2), (dG(4)T(3)G(4))(2), and (dG(3)T(4)G(4))(2), and the intramolecular G-quadruplexes dG(4)(T(4)G(4))(3) and dG(2)T(2)G(2)TGTG(2)T(2)G(2) (thrombin binding aptamer). We found that not all mass spectrometers are equally suited to reflect the solution phase species. Ion activation can occur in the electrospray source, or in a high-pressure traveling wave ion mobility cell. When the softest instrumental conditions are used, ammonium ions bound between G-quartets, but also additional ammonium ions bound at specific sites outside the external G-quartets, can be observed. However, even specifically bound ammonium ions are in some instances too labile to be fully retained in the gas phase structures, and although the ammonium ion distribution observed by ESI-MS shows biases at specific stoichiometries, the relative abundances in solution are not always faithfully reflected. Ion mobility spectrometry results show that all inter-quartet ammonium ions are necessary to preserve the G-quadruplex fold in the gas phase. Ion mobility experiments, therefore, help assign the number of inner ammonium ions in the solution phase structure.
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24
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Sjoberg J. Ammonium ion binding to DNA G-quadruplexes: do electrospray mass spectra faithfully reflect the solution-phase species? JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013. [PMID: 23132414 PMCID: PMC5110665 DOI: 10.1007/s13361-013-0649-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
G-quadruplex nucleic acids can bind ammonium ions in solution, and these complexes can be detected by electrospray mass spectrometry (ESI-MS). However, because ammonium ions are volatile, the extent to which ESI-MS quantitatively could provide an accurate reflection of such solution-phase equilibria is unclear. Here we studied five G-quadruplexes having known solution-phase structure and ammonium ion binding constants: the bimolecular G-quadruplexes (dG(4)T(4)G(4))(2), (dG(4)T(3)G(4))(2), and (dG(3)T(4)G(4))(2), and the intramolecular G-quadruplexes dG(4)(T(4)G(4))(3) and dG(2)T(2)G(2)TGTG(2)T(2)G(2) (thrombin binding aptamer). We found that not all mass spectrometers are equally suited to reflect the solution phase species. Ion activation can occur in the electrospray source, or in a high-pressure traveling wave ion mobility cell. When the softest instrumental conditions are used, ammonium ions bound between G-quartets, but also additional ammonium ions bound at specific sites outside the external G-quartets, can be observed. However, even specifically bound ammonium ions are in some instances too labile to be fully retained in the gas phase structures, and although the ammonium ion distribution observed by ESI-MS shows biases at specific stoichiometries, the relative abundances in solution are not always faithfully reflected. Ion mobility spectrometry results show that all inter-quartet ammonium ions are necessary to preserve the G-quadruplex fold in the gas phase. Ion mobility experiments, therefore, help assign the number of inner ammonium ions in the solution phase structure.
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25
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Šket P, Virgilio A, Esposito V, Galeone A, Plavec J. Strand directionality affects cation binding and movement within tetramolecular G-quadruplexes. Nucleic Acids Res 2012; 40:11047-57. [PMID: 22977177 PMCID: PMC3510487 DOI: 10.1093/nar/gks851] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Nuclear magnetic resonance study of G-quadruplex structures formed by d(TG3T) and its modified analogs containing a 5′-5′ or 3′-3′ inversion of polarity sites, namely d(3′TG5′-5′G2T3′), d(3′T5′-5′G3T3′) and d(5′TG3′-3′G2T5’) demonstrates formation of G-quadruplex structures with tetrameric topology and distinct cation-binding preferences. All oligonucleotides are able to form quadruplex structures with two binding sites, although the modified oligonucleotides also form, in variable amounts, quadruplex structures with only one bound cation. The inter-quartet cavities at the inversion of polarity sites bind ammonium ions less tightly than a naturally occurring 5′-3′ backbone. Exchange of 15 ions between G-quadruplex and bulk solution is faster at the 3′-end in comparison to the 5′-end. In addition to strand directionality, cation movement is influenced by formation of an all-syn G-quartet. Formation of such quartet has been observed also for the parent d(TG3T) that besides the canonical quadruplex with only all-anti G-quartets, forms a tetramolecular parallel quadruplex containing one all-syn G-quartet, never observed before in unmodified quadruplex structures.
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Affiliation(s)
- Primoz Šket
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, Ljubljana SI-1000, Slovenia
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26
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Akhshi P, Acton G, Wu G. Molecular dynamics simulations to provide new insights into the asymmetrical ammonium ion movement inside of the [d(G3T4G4)]2 G-quadruplex DNA structure. J Phys Chem B 2012; 116:9363-70. [PMID: 22780684 DOI: 10.1021/jp304760k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have used both adaptive biasing force (ABF) and regular molecular dynamics (MD) simulations to investigate the asymmetrical NH(4)(+) ion movement inside of a bimolecular G-quadruplex DNA structure [d(G(3)T(4)G(4))](2). The free-energy landscapes obtained from ABF MD simulations suggest that the NH(4)(+) ion exiting the [d(G(3)T(4)G(4))](2) G-quadruplex stem in the direction toward the edge-type loop (denoted as the upper direction) experiences a lower free-energy barrier than that toward the diagonal loop (denoted as the lower direction) by approximately 3-4 kcal mol(-1). This result is in qualitative agreement with the previous discovery made by Šket and Plavec on the same G-quadruplex structure from (15)N NMR experiments (J. Am. Chem. Soc. 2007, 129, 8794). In the Na(+) form of the same G-quadruplex, Na(+) ion movement was found to be symmetrical, with a free-energy barrier of only 5-7 kcal mol(-1) to cross all three G-quartets, that is, [d(G(3)T(4)G(4))](2) still exhibits ion-channel-like behaviors for Na(+) ions. On the basis of the new computational results, we hypothesize that the stiffness of a G-quartet is primarily determined by the base stacking interactions within the G-quadruplex stem. Therefore, the structural origin for the asymmetrical NH(4)(+) ion movement in [d(G(3)T(4)G(4))](2) is the presence of two different modes of base stacking around the NH(4)(+) binding sites, a more stable 5'-syn-anti mode between lower and central G-quartets and a less stable 5'-anti-anti mode between upper and central G-quartets. Simulations also suggest that loop topology at the end of a G-quadruplex stem only controls the direction at which an exiting NH(4)(+) ion reaches bulk solution but does not impose significant free-energy barriers.
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Affiliation(s)
- Parisa Akhshi
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6
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27
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Adrian M, Heddi B, Phan AT. NMR spectroscopy of G-quadruplexes. Methods 2012; 57:11-24. [DOI: 10.1016/j.ymeth.2012.05.003] [Citation(s) in RCA: 184] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 05/15/2012] [Accepted: 05/16/2012] [Indexed: 12/24/2022] Open
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Akhshi P, Mosey NJ, Wu G. Free-Energy Landscapes of Ion Movement through a G-Quadruplex DNA Channel. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201107700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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29
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Akhshi P, Mosey NJ, Wu G. Free-Energy Landscapes of Ion Movement through a G-Quadruplex DNA Channel. Angew Chem Int Ed Engl 2012; 51:2850-4. [DOI: 10.1002/anie.201107700] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Indexed: 11/09/2022]
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30
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Rosu F, Gabelica V, Poncelet H, De Pauw E. Tetramolecular G-quadruplex formation pathways studied by electrospray mass spectrometry. Nucleic Acids Res 2010; 38:5217-25. [PMID: 20400500 PMCID: PMC2926595 DOI: 10.1093/nar/gkq208] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Electrospray mass spectrometry was used to investigate the mechanism of tetramolecular G-quadruplex formation by the DNA oligonucleotide dTG5T, in ammonium acetate. The intermediates and products were separated according to their mass (number of strands and inner cations) and quantified. The study of the temporal evolution of each species allows us to propose the following formation mechanism. (i) Monomers, dimers and trimers are present at equilibrium already in the absence of ammonium acetate. (ii) The addition of cations promotes the formation of tetramers and pentamers that incorporate ammonium ions and therefore presumably have stacked guanine quartets in their structure. (iii) The pentamers eventually disappear and tetramers become predominant. However, these tetramers do not have their four strands perfectly aligned to give five G-quartets: the structures contain one ammonium ion too few, and ion mobility spectrometry shows that their conformation is more extended. (iv) At 4°C, the rearrangement of the kinetically trapped tetramers with presumably slipped strand(s) into the perfect G-quadruplex structure is extremely slow (not complete after 4 months). We also show that the addition of methanol to the monomer solution significantly accelerates the cation-induced G-quadruplex assembly.
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Affiliation(s)
- Frédéric Rosu
- Department of Chemistry B6c, University of Liège, Liège, Belgium.
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Cesare Marincola F, Virno A, Randazzo A, Mocci F, Saba G, Lai A. Competitive binding exchange between alkali metal ions (K+, Rb+, and Cs+) and Na+ ions bound to the dimeric quadruplex [d(G4T4G4)]2: a 23Na and 1H NMR study. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2009; 47:1036-1042. [PMID: 19757406 DOI: 10.1002/mrc.2509] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A comparative study of the competitive cation exchange between the alkali metal ions K+, Rb+, and Cs+ and the Na+ ions bound to the dimeric quadruplex [d(G4T4G4)]2 was performed in aqueous solution by a combined use of the 23Na and 1H NMR spectroscopy. The titration data confirm the different binding affinities of these ions for the G-quadruplex and, in particular, major differences in the behavior of Cs+ as compared to the other ions were found. Accordingly, Cs+ competes with Na+ only for the binding sites at the quadruplex surface (primarily phosphate groups), while K+ and Rb+ are also able to replace sodium ions located inside the quadruplex. Furthermore, the 1H NMR results relative to the CsCl titration evidence a close approach of Cs+ ions to the phosphate groups in the narrow groove of [d(G4T4G4)]2. Based on a three-site exchange model, the 23Na NMR relaxation data lead to an estimate of the relative binding affinity of Cs+ versus Na+ for the quadruplex surface of 0.5 at 298 K. Comparing this value to those reported in the literature for the surface of the G-quadruplex formed by 5'-guanosinemonophosphate and for the surface of double-helical DNA suggests that topology factors may have an important influence on the cation affinity for the phosphate groups on DNA.
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Affiliation(s)
- Flaminia Cesare Marincola
- Dipartimento di Scienze Chimiche, Università di Cagliari, Cittadella Universitaria di Monserrato, S.S. 554 (bivio per Sestu), I-09042, Monserrato, Cagliari, Italy.
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32
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Trajkovski M, Sket P, Plavec J. Cation localization and movement within DNA thrombin binding aptamer in solution. Org Biomol Chem 2009; 7:4677-84. [PMID: 19865704 DOI: 10.1039/b914783g] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The thrombin binding aptamer, 15-mer oligonucleotide d[G(2)T(2)G(2)TGTG(2)T(2)G(2)], was folded into the well known antiparallel unimolecular G-quadruplex in the presence of (15)NH(4)(+) ions. Although the formed G-quadruplex is thermodynamically less stable than in the presence of K(+) ions, the loop conformations and folding topology are the same. On the other hand, titration of Na(+) ions into an aqueous solution of TBA resulted in the formation of one major and several minor species of G-quadruplexes. Solution-state NMR was used to localize (15)NH(4)(+) ions between the two G-quartets within the core of the structure, and to determine the equilibrium binding constant, which equals 190 M(-1). No other potential cation binding sites were resolved on the time-scale of NMR spectrometer. Exchange of (15)NH(4)(+) ions between the inner binding site and bulk solution is characterized by the exchange rate constant of 1.0 s(-1) at 15 degrees C. T4 and T13 form a noncanonical base pair, which greatly affects access of bulk ions into the cation binding site in the G-quadruplex core. G2 and G11 exhibit out of plane bending towards the two TT loops away from the bound (15)NH(4)(+) ions, which in turn exposes them to more efficient chemical exchange processes with bulk ions and water.
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Affiliation(s)
- Marko Trajkovski
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, SI-1000, Ljubljana, Slovenia
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33
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Fadrná E, Špačková N, Sarzyñska J, Koča J, Orozco M, Cheatham TE, Kulinski T, Šponer J. Single Stranded Loops of Quadruplex DNA As Key Benchmark for Testing Nucleic Acids Force Fields. J Chem Theory Comput 2009; 5:2514-30. [DOI: 10.1021/ct900200k] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Eva Fadrná
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic, Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61 704 Poznań, Poland, Joint IRB-BSC program on Computational Biology, Institute for Research in Biomedicine, Baldiri Reixac 10-12, 08028 Barcelona, Spain, Barcelona Supercomputing
| | - Nad’a Špačková
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic, Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61 704 Poznań, Poland, Joint IRB-BSC program on Computational Biology, Institute for Research in Biomedicine, Baldiri Reixac 10-12, 08028 Barcelona, Spain, Barcelona Supercomputing
| | - Joanna Sarzyñska
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic, Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61 704 Poznań, Poland, Joint IRB-BSC program on Computational Biology, Institute for Research in Biomedicine, Baldiri Reixac 10-12, 08028 Barcelona, Spain, Barcelona Supercomputing
| | - Jaroslav Koča
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic, Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61 704 Poznań, Poland, Joint IRB-BSC program on Computational Biology, Institute for Research in Biomedicine, Baldiri Reixac 10-12, 08028 Barcelona, Spain, Barcelona Supercomputing
| | - Modesto Orozco
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic, Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61 704 Poznań, Poland, Joint IRB-BSC program on Computational Biology, Institute for Research in Biomedicine, Baldiri Reixac 10-12, 08028 Barcelona, Spain, Barcelona Supercomputing
| | - Thomas E. Cheatham
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic, Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61 704 Poznań, Poland, Joint IRB-BSC program on Computational Biology, Institute for Research in Biomedicine, Baldiri Reixac 10-12, 08028 Barcelona, Spain, Barcelona Supercomputing
| | - Tadeusz Kulinski
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic, Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61 704 Poznań, Poland, Joint IRB-BSC program on Computational Biology, Institute for Research in Biomedicine, Baldiri Reixac 10-12, 08028 Barcelona, Spain, Barcelona Supercomputing
| | - Jiří Šponer
- National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic, Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61 704 Poznań, Poland, Joint IRB-BSC program on Computational Biology, Institute for Research in Biomedicine, Baldiri Reixac 10-12, 08028 Barcelona, Spain, Barcelona Supercomputing
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34
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Nikan M, Sherman JC. Cation-Complexation Behavior of Template-Assembled Synthetic G-Quartets. J Org Chem 2009; 74:5211-8. [DOI: 10.1021/jo9001245] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mehran Nikan
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, Canada V6T 1Z1
| | - John C. Sherman
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, Canada V6T 1Z1
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35
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Podbevsek P, Sket P, Plavec J. Stacking and not solely topology of T3 loops controls rigidity and ammonium ion movement within d(G4T3G4)2 G-quadruplex. J Am Chem Soc 2008; 130:14287-93. [PMID: 18834130 DOI: 10.1021/ja8048282] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A solution state NMR study has shown that d(G4T3G4) in the presence of (15)NH4(+) ions folds into a single bimolecular G-quadruplex structure in which its G-tracts are antiparallel and the two T3 loops span along the edges of the outer G-quartets on the opposite sides of the G-quadruplex core. This head-to-tail topology is in agreement with the topology of the G-quadruplex recently found in the X-ray crystal structure formed by d(G4T3G4) in the presence of K(+) ions [Neidle et al. J. Am. Chem. Soc. 2006, 128, 5480]. In contrast, the presence of K(+) ions in solution resulted in a complex ensemble of G-quadruplex structures. Molecular models based on NMR data demonstrate that thymine loop residues efficiently base-base stack on the outer G-quartets and in this way stabilize a single structure in the presence of (15)NH4(+) ions. The use of heteronuclear NMR enabled us to localize three (15)NH4(+) ion binding sites between pairs of adjacent G-quartets and study the kinetics of their movement. Interestingly, no (15)NH4(+) ion movement within the G-quadruplex was detected at 25 degrees C. At 35 degrees C we were able to observe slow movement of (15)NH4(+) ions from the outer binding sites to bulk solution with the characteristic residence lifetime of 1.2 s. The slow movement of (15)NH4(+) ions from the outer binding sites into bulk solution and the absence of movement from the inner binding site were attributed to steric hindrance imposed by the T3 loops and the rigidity of the G-quadruplex.
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Affiliation(s)
- Peter Podbevsek
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia
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36
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Podbevsek P, Sket P, Plavec J. NMR study of ammonium ion binding to d[G3T4G4]2 and d[G4(T4G4)3] G-quadruplexes. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2008; 26:1547-51. [PMID: 18066824 DOI: 10.1080/15257770701545358] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Quantitative NMR study has shown a significant difference in affinity of (15)NH(4)(+) ions for cation binding sites within G-quadruplexes adopted by d[G3T4G4]2 and d[G4(T4G4)3].
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Affiliation(s)
- Peter Podbevsek
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, SI 1001 Ljubljana, Slovenia
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37
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Ida R, Wu G. Direct NMR detection of alkali metal ions bound to G-quadruplex DNA. J Am Chem Soc 2008; 130:3590-602. [PMID: 18293981 DOI: 10.1021/ja709975z] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe a general multinuclear (1H, 23Na, 87Rb) NMR approach for direct detection of alkali metal ions bound to G-quadruplex DNA. This study is motivated by our recent discovery that alkali metal ions (Na+, K+, Rb+) tightly bound to G-quadruplex DNA are actually "NMR visible" in solution (Wong, A.; Ida, R.; Wu, G. Biochem. Biophys. Res. Commun. 2005, 337, 363). Here solution and solid-state NMR methods are developed for studying ion binding to the classic G-quadruplex structures formed by three DNA oligomers: d(TG4T), d(G4T3G4), and d(G4T4G4). The present study yields the following major findings. (1) Alkali metal ions tightly bound to G-quadruplex DNA can be directly observed by NMR in solution. (2) Competitive ion binding to the G-quadruplex channel site can be directly monitored by simultaneous NMR detection of the two competing ions. (3) Na+ ions are found to locate in the diagonal T4 loop region of the G-quadruplex formed by two strands of d(G4T4G4). This is the first time that direct NMR evidence has been found for alkali metal ion binding to the diagonal T4 loop in solution. We propose that the loop Na+ ion is located above the terminal G-quartet, coordinating to four guanine O6 atoms from the terminal G-quartet and one O2 atom from a loop thymine base and one water molecule. This Na+ ion coordination is supported by quantum chemical calculations on 23Na chemical shifts. Variable-temperature 23Na NMR results have revealed that the channel and loop Na+ ions in d(G4T4G4) exhibit very different ion mobilities. The loop Na+ ions have a residence lifetime of 220 micros at 15 degrees C, whereas the residence lifetime of Na+ ions residing inside the G-quadruplex channel is 2 orders of magnitude longer. (4) We have found direct 23Na NMR evidence that mixed K+ and Na+ ions occupy the d(G4T4G4) G-quadruplex channel when both Na+ and K+ ions are present in solution. (5) The high spectral resolution observed in this study is unprecedented in solution 23Na NMR studies of biological macromolecules. Our results strongly suggest that multinuclear NMR is a viable technique for studying ion binding to G-quadruplex DNA.
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Affiliation(s)
- Ramsey Ida
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6
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38
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Webba da Silva M. NMR methods for studying quadruplex nucleic acids. Methods 2008; 43:264-77. [PMID: 17967697 DOI: 10.1016/j.ymeth.2007.05.007] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 05/16/2007] [Indexed: 12/22/2022] Open
Abstract
Solution NMR spectroscopy has traditionally played a central role in examining quadruplex structure, dynamics, and interactions. Here, an overview is given of the methods currently applied to structural, dynamics, thermodynamics, and kinetics studies of nucleic acid quadruplexes and associated cations.
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Affiliation(s)
- Mateus Webba da Silva
- School of Biomedical Sciences, University of Ulster, Cromore Road, Coleraine BT52 1SA, UK.
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39
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Wei C, Tang Q, Li C. Structural transition from the random coil to quadruplex of AG(3)(T(2)AG(3))(3) induced by Zn(2+). Biophys Chem 2007; 132:110-3. [PMID: 18031921 DOI: 10.1016/j.bpc.2007.10.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 10/29/2007] [Accepted: 10/30/2007] [Indexed: 10/22/2022]
Abstract
Structures of G-quadruplex DNAs can be typically stabilized by monovalent cations such as K(+), Na(+). Some divalent and trivalent cations, such as Sr(2+), Pb(2+), Tb(3+) and Eu(3+), can also induce the formation of G-quadruplex DNA. Here we show that Zn(2+) can induce the human telomeric sequence AG(3)(T(2)AG(3))(3) to fold the G-quadruplex structure by UV absorbance difference spectra and circular dichroism (CD) spectroscopy. At micromolar concentrations, the Zn(2+)-induced changes in the UV absorbance difference spectra and CD spectra are the characteristics of antiparallel G-quadruplexes although the long wavelength CD maximum is around 285 nm rather than the typical value of 295 nm. The binding stoichometry of Zn(2+) per one AG(3)(T(2)AG(3))(3) molecule is four. To our knowledge, the structural transition of human telomeric sequence induced by Zn(2+) was observed for the first time.
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Affiliation(s)
- Chunying Wei
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Institute of Molecular Science, Shanxi University, Taiyuan China.
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40
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Sket P, Plavec J. Not All G-Quadruplexes Exhibit Ion-Channel-like Properties: NMR Study of Ammonium Ion (Non)movement within the d(G3T4G4)2 Quadruplex. J Am Chem Soc 2007; 129:8794-800. [PMID: 17580943 DOI: 10.1021/ja0710003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A solution-state NMR study on 15NH4(+) ion movement within d(G(3)T(4)G(4))(2), a dimeric G-quadruplex consisting of three G-quartets and two T(4) loops, rather unexpectedly demonstrated the absence of 15NH4(+) ion movement between the binding sites U and L along the central axis of the G-quadruplex. Distinct temperature dependences of autocorrelation signals for U and L binding sites have been observed in 15N-1H NzExHSQC spectra which correlate with the local stiffness of the G-quadruplex. The volumes of the cross-peaks, which are the result of 15NH4(+) ion movement, have been interpreted in terms of rate constants, T(1) relaxation, and proton exchange. 15NH4(+) ion movements from the binding sites U and L into the bulk solution are characterized by lifetimes of 139 ms and 1.7 s at 298 K, respectively. The 12 times faster movement from the binding site U demonstrates that 15NH4(+) ion movement is controlled by the structure of T4 loop residues, which through diagonal- vs edge-type orientations impose distinct steric restraints for cations to leave or enter the G-quadruplex. Arrhenius-type analysis has afforded an activation energy of 66 kJ mol(-)1 for the UB process, while it could not be determined for the LB process due to slow rates at temperatures below 298 K. We further the use of the 15NH4(+) ion as an NMR probe to gain insight into the occupancy of binding sites by cations and kinetics of ion movement which are intrinsically correlated with the structural details, dynamic fluctuations, and local flexibility of the DNA structure.
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Affiliation(s)
- Primoz Sket
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia
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41
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Podbevšek P, Hud NV, Plavec J. NMR evaluation of ammonium ion movement within a unimolecular G-quadruplex in solution. Nucleic Acids Res 2007; 35:2554-63. [PMID: 17412708 PMCID: PMC1895886 DOI: 10.1093/nar/gkm138] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
d[G4(T4G4)3] has been folded into a unimolecular G-quadruplex in the presence of 15NH4+ ions. NMR spectroscopy confirmed that its topology is the same as the solution state structure determined earlier by Wang and Patel (J. Mol. Biol., 1995; 251: 76-94) in the presence of Na+ ions. The d[G4(T4G4)3] G-quadruplex exhibits four G-quartets with three 15NH4+-ion-binding sites (O1, I and O2). Quantitative analysis utilizing 15NH4+ ions as a NMR probe clearly demonstrates that there is no unidirectional 15NH4+ ion movement through the central cavity of the G-quadruplex. 15NH4+ ions move back and forth between the binding sites within the G-quadruplex and exchange with ions in bulk solution. 15NH4+ ion movement is controlled by the thermodynamic preferences of individual binding sites, steric restraints of the G-quartets for 15NH4+ ion passage and diagonal versus edge-type arrangement of the T4 loops. The movement of 15NH4+ ions from the interior of the G-quadruplex to bulk solution is faster than exchange within the G-quadruplex. The structural details of the G-quadruplex define stiffness of individual G-quartets that intimately affects 15NH4+ ion movement. The stiffness of G-quartets and steric hindrance imposed by thymine residues in the loops contribute to the 5-fold difference in the exchange rate constants through the outer G-quartets.
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Affiliation(s)
- Peter Podbevšek
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Nicholas V. Hud
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Janez Plavec
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana, Slovenia and School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
- *To whom correspondence should be addressed +1-386 1-47-60-353+386 1-47-60-300
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42
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Yu HQ, Miyoshi D, Sugimoto N. Characterization of structure and stability of long telomeric DNA G-quadruplexes. J Am Chem Soc 2007; 128:15461-8. [PMID: 17132013 DOI: 10.1021/ja064536h] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the current study, we used a combination of gel electrophoresis, circular dichroism, and UV melting analysis to investigate the structure and stability of G-quadruplexes formed by long telomeric DNAs from Oxytricha and human, where the length of the repeat (n)=4 to 12. We found that the Oxytricha telomeric DNAs, which have the sequence (TTTTGGGG)n, folded into intramolecular and intermolecular G-quadruplexes depending on the ionic conditions, whereas human telomeric DNAs, which have the sequence (TTAGGG)n, formed only intramolecular G-quadruplexes in all the tested conditions. We further estimated the thermodynamic parameters of the intramolecular G-quadruplex. We found that thermodynamic stabilities of G-quadruplex structures of long telomeric DNAs (n=5 to 12) are mostly independent of sequence length, although telomeric DNAs are more stable when n=4 than when n>or=5. Most importantly, when n is a multiple of four, the change in enthalpy and entropy for G-quadruplex formation increased gradually, demonstrating that the individual G-quadruplex units are composed of four repeats and that the individual units do not interact. Therefore, we propose that the G-quadruplexes formed by long telomeric DNAs (n>or=8) are bead-on-a-string structures in which the G-quadruplex units are connected by one TTTT (Oxytricha) or TTA (human) linker. These results should be useful for understanding the structure and function of telomeres and for developing improved therapeutic agents targeting telomeric DNAs.
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Affiliation(s)
- Hai-Qing Yu
- Frontier Institute for Biomolecular Engineering Research (FIBER) and Department of Chemistry, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashinada-ku, Kobe 658-8501, Japan
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43
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Ida R, Kwan ICM, Wu G. Direct23Na NMR observation of mixed cations residing inside a G-quadruplex channel. Chem Commun (Camb) 2007:795-7. [PMID: 17308634 DOI: 10.1039/b613105k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report direct (23)Na NMR observation for the presence of mixed cations (Na(+)/K(+), Na(+)/Rb(+), Na(+)/Sr(2+)) inside the G-quadruplex channel formed by the self-association of guanosine 5'-monophosphate at pH 8.
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Affiliation(s)
- Ramsey Ida
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada
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44
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Ma L, Iezzi M, Kaucher MS, Lam YF, Davis JT. Cation Exchange in Lipophilic G-Quadruplexes: Not All Ion Binding Sites Are Equal. J Am Chem Soc 2006; 128:15269-77. [PMID: 17117879 DOI: 10.1021/ja064878n] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lipophilic guanosine derivatives that form G-quadruplexes are promising building blocks for ionophores and ion channels. Herein, cation exchange between solvated cations (K+ and NH4+) and bound cations in the G-quadruplex [G1]16.4Na+.4DNP- was studied by electrospray ionization mass spectrometry and solution 1H, 15N NMR spectroscopy. The ESI-MS and 1H NMR data provided evidence for the formation of mixed-cationic Na+, K+ G-quadruplexes. The use of 15NH4+ cations in NMR titrations, along with 15N-filtered 1H NMR and selective NOE experiments, identified two mixed-cationic intermediates in the cation exchange pathway from [G1]16.4Na+.4DNP- to [G1]16.4NH4+.4DNP-. The central Na+, bound between the two symmetry-related G8-Na+ octamers, exchanges with either K+ or NH4+ before the two outer Na+ ions situated within the C4 symmetric G8 octamers. A structural rationale, based on differences in the cations' octahedral coordination geometries, is proposed to explain the differences in site exchange for these lipophilic G-quadruplexes. Large cations such as Cs+ can be exchanged into the central cation binding site that holds the two symmetry-related C4 symmetric G8 octamer units together. The potential relevance of these findings to both supramolecular chemistry and DNA G-quadruplex structure are discussed.
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Affiliation(s)
- Ling Ma
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
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45
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Burge S, Parkinson GN, Hazel P, Todd AK, Neidle S. Quadruplex DNA: sequence, topology and structure. Nucleic Acids Res 2006; 34:5402-15. [PMID: 17012276 PMCID: PMC1636468 DOI: 10.1093/nar/gkl655] [Citation(s) in RCA: 1824] [Impact Index Per Article: 101.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
G-quadruplexes are higher-order DNA and RNA structures formed from G-rich sequences that are built around tetrads of hydrogen-bonded guanine bases. Potential quadruplex sequences have been identified in G-rich eukaryotic telomeres, and more recently in non-telomeric genomic DNA, e.g. in nuclease-hypersensitive promoter regions. The natural role and biological validation of these structures is starting to be explored, and there is particular interest in them as targets for therapeutic intervention. This survey focuses on the folding and structural features on quadruplexes formed from telomeric and non-telomeric DNA sequences, and examines fundamental aspects of topology and the emerging relationships with sequence. Emphasis is placed on information from the high-resolution methods of X-ray crystallography and NMR, and their scope and current limitations are discussed. Such information, together with biological insights, will be important for the discovery of drugs targeting quadruplexes from particular genes.
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Affiliation(s)
| | | | | | | | - Stephen Neidle
- To whom correspondence should be addressed. Tel: +44 207 753 5969; Fax: +44 207 753 5970;
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