1
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Roy S, Pramanik P, Bhattacharya S. Exploring the role of G-quadruplex DNA, and their structural polymorphism, in targeting small molecules for the design of anticancer therapeutics: Progress, challenges, and future directions. Biochimie 2025; 234:120-145. [PMID: 40250703 DOI: 10.1016/j.biochi.2025.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2024] [Revised: 04/13/2025] [Accepted: 04/15/2025] [Indexed: 04/20/2025]
Abstract
Selective stabilization of non-canonical G-quadruplex DNA structures by small molecules can be a potential target for anticancer therapeutics. The primary motivation for the molecular design of these G-quadruplex binders is to restrict the transcriptional machinery, which can impede cancer cell progression. This review article comprises the structural diversity of different G-quadruplex DNA, the design strategy for targeting these structures with small molecules, and various G-quadruplex binding ligands which have been expanded by the chemists and biologists over the past few decades. Further, the existence of G-quadruplex structures inside human cells, the significant challenges for designing these selective G-quadruplex binding ligands, current status, and progress towards achieving this goal have also been discussed.
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Affiliation(s)
- Soma Roy
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012, India; School of Applied & Interdisciplinary Sciences, Indian Association for the Cultivation of Science, Kolkata, 700032, India
| | - Pulakesh Pramanik
- School of Applied & Interdisciplinary Sciences, Indian Association for the Cultivation of Science, Kolkata, 700032, India
| | - Santanu Bhattacharya
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012, India; School of Applied & Interdisciplinary Sciences, Indian Association for the Cultivation of Science, Kolkata, 700032, India; Technical Research Centre, Indian Association for the Cultivation of Science, Kolkata, 700032, India; Department of Chemistry, Indian Institute of Science Education and Research Tirupati, Tirupati, 517619, India.
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2
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Moura NMM, Guedes S, Salvador D, Oliveira H, Neves MGPMS, Ramos CIV. Is Silver a Precious Metal for G-Quadruplex Stabilization Mediated by Porphyrins? Int J Mol Sci 2024; 25:13556. [PMID: 39769320 PMCID: PMC11678824 DOI: 10.3390/ijms252413556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2024] [Revised: 12/08/2024] [Accepted: 12/13/2024] [Indexed: 01/11/2025] Open
Abstract
Cancer is a leading cause of death, so continuous efforts into cancer therapy are imperative. In tumor cells, telomerase and oncogene activity are key points for uncontrolled cell growth. Targeting these processes with ligands that inhibit telomerase and/or reduce oncogene expression has been identified as a promising cancer therapy. This study evaluated the selectivity and affinity of the silverII complex of 5,10,15,20-tetrakis(N-methyl-4-pyridinium)porphyrin (AgTMPyP) to stabilize DNA sequences capable of forming G4 structures mimicking the telomeric and oncogene regions, using spectroscopic, biochemical methods and in vitro assays. The tetracationic silver complex was compared with the free base, H2TMPyP, and the zincII complex, ZnTMPyP. The results obtained from UV-Vis and fluorescence methods pointed to a great affinity and good selectivity of AgTMPyP to G4 structures, especially for the oncogene MYC. In general, an increase in the ability of the studied ligands for 1O2 generation when interacting with oncogenic and telomeric G4 sequences was found. The results of the PCR stop assays proved that AgTMPyP has the ability to inhibit Taq polymerase. Additionally, in vitro assays demonstrated that the silverII complex exhibits low cytotoxicity against HaCaT- an immortalized, non-tumorigenic, skin keratinocytes cell line-and, although nonexclusive, AgTMPyP shows nuclear co-localization.
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Affiliation(s)
- Nuno M. M. Moura
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (N.M.M.M.); (S.G.)
| | - Sofia Guedes
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (N.M.M.M.); (S.G.)
| | - Diana Salvador
- CESAM-Centre for Environmental and Marine Studies, Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal; (D.S.); (H.O.)
- CICECO, Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Helena Oliveira
- CESAM-Centre for Environmental and Marine Studies, Department of Biology and CESAM, University of Aveiro, 3810-193 Aveiro, Portugal; (D.S.); (H.O.)
| | - M. Graça P. M. S. Neves
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (N.M.M.M.); (S.G.)
| | - Catarina I. V. Ramos
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (N.M.M.M.); (S.G.)
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3
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Chakraborty G, Balinin K, Villar-Guerra RD, Emondts M, Portale G, Loznik M, Niels Klement WJ, Zheng L, Weil T, Chaires JB, Herrmann A. Supramolecular DNA-based catalysis in organic solvents. iScience 2024; 27:109689. [PMID: 38706840 PMCID: PMC11067378 DOI: 10.1016/j.isci.2024.109689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 10/04/2023] [Accepted: 04/05/2024] [Indexed: 05/07/2024] Open
Abstract
The distinct folding accompanied by its polymorphic character renders DNA G-quadruplexes promising biomolecular building blocks to construct novel DNA-based and supramolecular assemblies. However, the highly polar nature of DNA limits the use of G-quadruplexes to water as a solvent. In addition, the archetypical G-quadruplex fold needs to be stabilized by metal-cations, which is usually a potassium ion. Here, we show that a noncovalent PEGylation process enabled by electrostatic interactions allows the first metal-free G-quadruplexes in organic solvents. Strikingly, incorporation of an iron-containing porphyrin renders the self-assembled metal-free G-quadruplex catalytically active in organic solvents. Hence, these "supraG4zymes" enable DNA-based catalysis in organic media. The results will allow the broad utilization of DNA G-quadruplexes in nonaqueous environments.
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Affiliation(s)
- Gurudas Chakraborty
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, the Netherlands
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, 52056 Aachen, Germany
| | - Konstantin Balinin
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, the Netherlands
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, 52056 Aachen, Germany
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Rafael del Villar-Guerra
- James Graham Brown Cancer Center, University of Louisville, 505 S. Hancock St., Louisville, KY 40202, USA
| | - Meike Emondts
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, 52056 Aachen, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany
| | - Giuseppe Portale
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, the Netherlands
| | - Mark Loznik
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, the Netherlands
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, 52056 Aachen, Germany
| | - Wiebe Jacob Niels Klement
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, the Netherlands
| | - Lifei Zheng
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, 52056 Aachen, Germany
| | - Tanja Weil
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Jonathan B. Chaires
- James Graham Brown Cancer Center, University of Louisville, 505 S. Hancock St., Louisville, KY 40202, USA
| | - Andreas Herrmann
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, Groningen 9747 AG, the Netherlands
- DWI-Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, 52056 Aachen, Germany
- Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany
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4
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Zheng YY, Dartawan R, Wu Y, Wu C, Zhang H, Lu J, Hu A, Vangaveti S, Sheng J. Structural effects of inosine substitution in telomeric DNA quadruplex. Front Chem 2024; 12:1330378. [PMID: 38312345 PMCID: PMC10834636 DOI: 10.3389/fchem.2024.1330378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 01/08/2024] [Indexed: 02/06/2024] Open
Abstract
The telomeric DNA, a distal region of eukaryotic chromosome containing guanine-rich repetitive sequence of (TTAGGG)n, has been shown to adopt higher-order structures, specifically G-quadruplexes (G4s). Previous studies have demonstrated the implication of G4 in tumor inhibition through chromosome maintenance and manipulation of oncogene expression featuring their G-rich promoter regions. Besides higher order structures, several regulatory roles are attributed to DNA epigenetic markers. In this work, we investigated how the structural dynamics of a G-quadruplex, formed by the telomeric sequence, is affected by inosine, a prevalent modified nucleotide. We used the standard (TTAGGG)n telomere repeats with guanosine mutated to inosine at each G position. Sequences (GGG)4, (IGG)4, (GIG)4, (GGI)4, (IGI)4, (IIG)4, (GII)4, and (III)4, bridged by TTA linker, are studied using biophysical experiments and molecular modeling. The effects of metal cations in quadruplex folding were explored in both Na+ and K+ containing buffers using CD and UV-melting studies. Our results show that antiparallel quadruplex topology forms with the native sequence (GGG)4 and the terminal modified DNAs (IGG)4 and (GGI)4 in both Na+ and K+ containing buffers. Specifically, quadruplex hybrid was observed for (GGG)4 in K+ buffer. Among the other modified sequences, (GIG)4, (IGI)4 and (GII)4 show parallel features, while (IIG)4 and (III)4 show no detectable conformation in the presence of either Na+ or K+. Our studies indicate that terminal lesions (IGG)4 and (GGI)4 may induce certain unknown conformations. The folding dynamics become undetectable in the presence of more than one inosine substitution except (IGI)4 in both buffer ions. In addition, both UV melting and CD melting studies implied that in most cases the K+ cation confers more thermodynamic stability compared to Na+. Collectively, our conformational studies revealed the diverse structural polymorphisms of G4 with position dependent G-to-I mutations in different ion conditions.
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Affiliation(s)
- Ya Ying Zheng
- Department of Chemistry, Albany, NY, United States
- The RNA Institute, University at Albany, State University of New York, Albany, NY, United States
| | - Ricky Dartawan
- Department of Chemistry, Albany, NY, United States
- The RNA Institute, University at Albany, State University of New York, Albany, NY, United States
| | - Yuhan Wu
- Department of Chemistry, Albany, NY, United States
- The RNA Institute, University at Albany, State University of New York, Albany, NY, United States
| | - Chengze Wu
- Department of Chemistry, Albany, NY, United States
- The RNA Institute, University at Albany, State University of New York, Albany, NY, United States
| | - Hope Zhang
- Department of Chemistry, Albany, NY, United States
- The RNA Institute, University at Albany, State University of New York, Albany, NY, United States
| | - Jeanne Lu
- Department of Chemistry, Albany, NY, United States
- The RNA Institute, University at Albany, State University of New York, Albany, NY, United States
| | - Ashley Hu
- Department of Chemistry, Albany, NY, United States
- The RNA Institute, University at Albany, State University of New York, Albany, NY, United States
| | - Sweta Vangaveti
- The RNA Institute, University at Albany, State University of New York, Albany, NY, United States
| | - Jia Sheng
- Department of Chemistry, Albany, NY, United States
- The RNA Institute, University at Albany, State University of New York, Albany, NY, United States
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5
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Robinson J, Stenspil SG, Maleckaite K, Bartlett M, Di Antonio M, Vilar R, Kuimova MK. Cellular Visualization of G-Quadruplex RNA via Fluorescence- Lifetime Imaging Microscopy. J Am Chem Soc 2024; 146:1009-1018. [PMID: 38151240 PMCID: PMC10786036 DOI: 10.1021/jacs.3c11908] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 12/29/2023]
Abstract
Over the past decade, appreciation of the roles of G-quadruplex (G4) structures in cellular regulation and maintenance has rapidly grown, making the establishment of robust methods to visualize G4s increasingly important. Fluorescent probes are commonly used for G4 detection in vitro; however, achieving sufficient selectivity to detect G4s in a dense and structurally diverse cellular environment is challenging. The use of fluorescent probes for G4 detection is further complicated by variations of probe uptake into cells, which may affect fluorescence intensity independently of G4 abundance. In this work, we report an alternative small-molecule approach to visualize G4s that does not rely on fluorescence intensity switch-on and, thus, does not require the use of molecules with exclusive G4 binding selectivity. Specifically, we have developed a novel thiazole orange derivative, TOR-G4, that exhibits a unique fluorescence lifetime when bound to G4s compared to other structures, allowing G4 binding to be sensitively distinguished from non-G4 binding, independent of the local probe concentration. Furthermore, TOR-G4 primarily colocalizes with RNA in the cytoplasm and nucleoli of cells, making it the first lifetime-based probe validated for exploring the emerging roles of RNA G4s in cellulo.
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Affiliation(s)
- Jenna Robinson
- Department
of Chemistry, Molecular Science Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, U.K.
- Molecular
Science Research Hub, Institute of Chemical
Biology, 82 Wood Lane, London W12 0BZ, U.K.
- The
Francis Crick Institute, 1 Midland Road, London NW1 1AT, U.K.
| | - Stine G. Stenspil
- Department
of Chemistry, Molecular Science Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, U.K.
| | - Karolina Maleckaite
- Department
of Chemistry, Molecular Science Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, U.K.
| | - Molly Bartlett
- Department
of Chemistry, Molecular Science Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, U.K.
| | - Marco Di Antonio
- Department
of Chemistry, Molecular Science Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, U.K.
- Molecular
Science Research Hub, Institute of Chemical
Biology, 82 Wood Lane, London W12 0BZ, U.K.
- The
Francis Crick Institute, 1 Midland Road, London NW1 1AT, U.K.
| | - Ramon Vilar
- Department
of Chemistry, Molecular Science Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, U.K.
- Molecular
Science Research Hub, Institute of Chemical
Biology, 82 Wood Lane, London W12 0BZ, U.K.
| | - Marina K. Kuimova
- Department
of Chemistry, Molecular Science Research Hub, Imperial College London, 82 Wood Lane, London W12
0BZ, U.K.
- Molecular
Science Research Hub, Institute of Chemical
Biology, 82 Wood Lane, London W12 0BZ, U.K.
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6
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Shiekh S, Kodikara SG, Balci H. Structure, Topology, and Stability of Multiple G-quadruplexes in Long Telomeric Overhangs. J Mol Biol 2024; 436:168205. [PMID: 37481156 PMCID: PMC10799177 DOI: 10.1016/j.jmb.2023.168205] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/05/2023] [Accepted: 07/12/2023] [Indexed: 07/24/2023]
Abstract
Telomeres and their single stranded overhangs gradually shorten with successive cell divisions, as part of the natural aging process, but can be elongated by telomerase, a nucleoprotein complex which is activated in the majority of cancers. This prominent implication in cancer and aging has made the repetitive telomeric sequences (TTAGGG repeats) and the G-quadruplex structures that form in their overhangs the focus of intense research in the past several decades. However, until recently most in vitro efforts to understand the structure, stability, dynamics, and interactions of telomeric overhangs had been focused on short sequences that are not representative of longer sequences encountered in a physiological setting. In this review, we will provide a broad perspective about telomeres and associated factors, and introduce the agents and structural characteristics involved in organizing, maintaining, and protecting telomeric DNA. We will also present a summary of recent research performed on long telomeric sequences, nominally defined as those that can form two or more tandem G-quadruplexes, i.e., which contain eight or more TTAGGG repeats. Results of experimental studies using a broad array of experimental tools, in addition to recent computational efforts will be discussed, particularly in terms of their implications for the stability, folding topology, and compactness of the tandem G-quadruplexes that form in long telomeric overhangs.
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Affiliation(s)
- Sajad Shiekh
- Department of Physics, Kent State University, Kent, OH 44242, USA
| | | | - Hamza Balci
- Department of Physics, Kent State University, Kent, OH 44242, USA.
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7
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Nain N, Singh A, Khan S, Kukreti S. G-quadruplex formation at human DAT1 gene promoter: Effect of cytosine methylation. Biochem Biophys Rep 2023; 34:101464. [PMID: 37096205 PMCID: PMC10121379 DOI: 10.1016/j.bbrep.2023.101464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/28/2023] [Accepted: 03/31/2023] [Indexed: 04/26/2023] Open
Abstract
The dopamine transporter gene (DAT1), a recognized genetic risk factor for attention deficit hyperactivity disorder (ADHD) is principally responsible for the regulation of dopamine synaptic levels and serves as a key target in many psychostimulants drugs. DAT1 gene methylation has been considered an epigenetic marker in ADHD. The identification of G-rich sequence motifs potential to form G-quadruplexes is correlated with functionally important genomic regions. Herein, biophysical and biochemical techniques are employed to investigate the structural polymorphism along with the effect of cytosine methylation on a 26-nt G-rich sequence present in the promoter region of the DAT1 gene. The gel electrophoresis, circular dichroism spectroscopy, and UV-thermal melting data are well correlated and conclude the formation of a parallel (bimolecular), as well as antiparallel (tetramolecular) G-quadruplex in Na+ solution. Interestingly, the existence of uni-, bi-, tri-, and tetramolecular quadruplex structures in K+ solution exhibited only the parallel type G-quadruplex. The results demonstrate that in presence of either cation (Na+ or K+) the cytosine methylation reserved the structural topologies unaltered. However, methylation lowers the thermal stability of G-quadruplexes and the duplex structures, as well. These findings provide insights to understand the regulatory mechanisms underlying the formation of the G-quadruplex structure induced by DNA methylation.
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Affiliation(s)
- Nishu Nain
- Nucleic Acids Research Lab, Department of Chemistry, University of Delhi, Delhi, 110007, India
| | - Anju Singh
- Nucleic Acids Research Lab, Department of Chemistry, University of Delhi, Delhi, 110007, India
- Department of Chemistry, Ramjas College, University of Delhi, Delhi, 110007, India
| | - Shoaib Khan
- Nucleic Acids Research Lab, Department of Chemistry, University of Delhi, Delhi, 110007, India
| | - Shrikant Kukreti
- Nucleic Acids Research Lab, Department of Chemistry, University of Delhi, Delhi, 110007, India
- Corresponding author.
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8
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Dey A, Pandav K, Nath M, Barthwal R, Prasad R. Molecular rec§ognition of telomere DNA sequence by 2, 6 anthraquinone derivatives leads to thermal stabilization and induces apoptosis in cancer cells. Int J Biol Macromol 2022; 221:355-370. [PMID: 36041576 DOI: 10.1016/j.ijbiomac.2022.08.156] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 11/25/2022]
Abstract
According to current research, anti-cancer anthraquinones impact telomere disruption and may interact with G-quadruplex DNA that triggers signaling to apoptosis. The present study represents the biophysical investigation of oxidative stress, late apoptosis, and induced senescence among cancer cells after binding laboratory synthesized piperidine-based anthraquinone derivatives, 2, 6- Bis [(3-piperidino)acetamido)]anthracene-9,10-dione (N1P) and 2, 6-Bis [piperidino)propionamido]anthracene-9,10-dione (N2P), with G-quadruplex DNA. We employed biophysical approaches to explore the interaction of synthetic anthraquinone derivatives with quadruplex DNA sequences to influence biological activities in the presence of K+ and Na+ cations. The binding affinity for N2P and N1P are Kb = 5.8 × 106 M-1 and Kb = 1.0 × 106 M-1, respectively, leading to hypo-/hyper-chromism with 5-7 nm red shift and significant fluorescence quenching and changes in ellipticity resulting in external binding of both the ligands to G-quadruplex DNA. Ligand binding induced enhancement of thermostability of G4 DNA is greater in Na+ environment (ΔTm = 34 °C) as compared to that in K+ environment (ΔTm = 21 °C), thereby restricting telomerase binding access to telomeres. Microscopic images of treated cells indicated cellular shape, nuclear condensation, and fragmentation alterations. The findings pave the path for therapeutic research, given the great potential of modifying anthraquinone substituent groups towards improved efficacy, ROS generation, and G-quadruplex DNA selectivity.
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Affiliation(s)
- Arpita Dey
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
| | - Kumud Pandav
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
| | - Mala Nath
- Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India
| | - Ritu Barthwal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India.
| | - Ramasare Prasad
- Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667, India.
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9
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Zaug AJ, Goodrich KJ, Song JJ, Sullivan AE, Cech TR. Reconstitution of a telomeric replicon organized by CST. Nature 2022; 608:819-825. [PMID: 35831508 PMCID: PMC9402439 DOI: 10.1038/s41586-022-04930-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 06/06/2022] [Indexed: 11/20/2022]
Abstract
Telomeres, the natural ends of linear chromosomes, comprise repeat-sequence DNA and associated proteins1. Replication of telomeres allows continued proliferation of human stem cells and immortality of cancer cells2. This replication requires telomerase3 extension of the single-stranded DNA (ssDNA) of the telomeric G-strand ((TTAGGG)n); the synthesis of the complementary C-strand ((CCCTAA)n) is much less well characterized. The CST (CTC1–STN1–TEN1) protein complex, a DNA polymerase α-primase accessory factor4,5, is known to be required for telomere replication in vivo6–9, and the molecular analysis presented here reveals key features of its mechanism. We find that human CST uses its ssDNA-binding activity to specify the origins for telomeric C-strand synthesis by bound Polα-primase. CST-organized DNA polymerization can copy a telomeric DNA template that folds into G-quadruplex structures, but the challenges presented by this template probably contribute to telomere replication problems observed in vivo. Combining telomerase, a short telomeric ssDNA primer and CST–Polα–primase gives complete telomeric DNA replication, resulting in the same sort of ssDNA 3′ overhang found naturally on human telomeres. We conclude that the CST complex not only terminates telomerase extension10,11 and recruits Polα–primase to telomeric ssDNA4,12,13 but also orchestrates C-strand synthesis. Because replication of the telomere has features distinct from replication of the rest of the genome, targeting telomere-replication components including CST holds promise for cancer therapeutics. The Polα–primase-associated CST complex organizes telomeric C-strand DNA synthesis, and, in combination with telomerase, it carries out complete replication of the single-stranded DNA overhang found at human telomeres.
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Affiliation(s)
- Arthur J Zaug
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.,BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA.,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA
| | - Karen J Goodrich
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.,BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA.,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA
| | - Jessica J Song
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Ashley E Sullivan
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
| | - Thomas R Cech
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA. .,BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA. .,Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA.
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10
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Lena A, Benassi A, Stasi M, Saint‐Pierre C, Freccero M, Gasparutto D, Bombard S, Doria F, Verga D. Photoactivatable V-Shaped Bifunctional Quinone Methide Precursors as a New Class of Selective G-quadruplex Alkylating Agents. Chemistry 2022; 28:e202200734. [PMID: 35441438 PMCID: PMC9322314 DOI: 10.1002/chem.202200734] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Indexed: 12/22/2022]
Abstract
Combining the selectivity of G-quadruplex (G4) ligands with the spatial and temporal control of photochemistry is an emerging strategy to elucidate the biological relevance of these structures. In this work, we developed six novel V-shaped G4 ligands that can, upon irradiation, form stable covalent adducts with G4 structures via the reactive intermediate, quinone methide (QM). We thoroughly investigated the photochemical properties of the ligands and their ability to generate QMs. Subsequently, we analyzed their specificity for various topologies of G4 and discovered a preferential binding towards the human telomeric sequence. Finally, we tested the ligand ability to act as photochemical alkylating agents, identifying the covalent adducts with G4 structures. This work introduces a novel molecular tool in the chemical biology toolkit for G4s.
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Affiliation(s)
- Alberto Lena
- Department of ChemistryUniversity of PaviaViale Taramelli 1027100PaviaItaly
| | - Alessandra Benassi
- Department of ChemistryUniversity of PaviaViale Taramelli 1027100PaviaItaly
| | - Michele Stasi
- Department of ChemistryUniversity of PaviaViale Taramelli 1027100PaviaItaly
- Present Address: Department of ChemistryTechnical University of MunichLichtenbergstraße 485748GarchingGermany
| | | | - Mauro Freccero
- Department of ChemistryUniversity of PaviaViale Taramelli 1027100PaviaItaly
| | - Didier Gasparutto
- University Grenoble AlpesCEACNRSIRIGSyMMES-UMR581938054GrenobleFrance
| | - Sophie Bombard
- CNRS UMR9187INSERM U1196Institut CuriePSL Research University91405OrsayFrance
- CNRS UMR9187INSERM U1196Université Paris-Saclay91405OrsayFrance
| | - Filippo Doria
- Department of ChemistryUniversity of PaviaViale Taramelli 1027100PaviaItaly
| | - Daniela Verga
- CNRS UMR9187INSERM U1196Institut CuriePSL Research University91405OrsayFrance
- CNRS UMR9187INSERM U1196Université Paris-Saclay91405OrsayFrance
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11
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Jiang J, Teunens T, Tisaun J, Denuit L, Moucheron C. Ruthenium(II) Polypyridyl Complexes and Their Use as Probes and Photoreactive Agents for G-quadruplexes Labelling. Molecules 2022; 27:1541. [PMID: 35268640 PMCID: PMC8912042 DOI: 10.3390/molecules27051541] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 02/01/2023] Open
Abstract
Due to their optical and electrochemical properties, ruthenium(II) polypyridyl complexes have been used in a wide array of applications. Since the discovery of the light-switch ON effect of [Ru(bpy)2dppz]2+ when interacting with DNA, the design of new Ru(II) complexes as light-up probes for specific regions of DNA has been intensively explored. Amongst them, G-quadruplexes (G4s) are of particular interest. These structures formed by guanine-rich parts of DNA and RNA may be associated with a wide range of biological events. However, locating them and understanding their implications in biological pathways has proven challenging. Elegant approaches to tackle this challenge relies on the use of photoprobes capable of marking, reversibly or irreversibly, these G4s. Indeed, Ru(II) complexes containing ancillary π-deficient TAP ligands can create a covalently linked adduct with G4s after a photoinduced electron transfer from a guanine residue to the excited complex. Through careful design of the ligands, high selectivity of interaction with G4 structures can be achieved. This allows the creation of specific Ru(II) light-up probes and photoreactive agents for G4 labelling, which is at the core of this review composed of an introduction dedicated to a brief description of G-quadruplex structures and two main sections. The first one will provide a general picture of ligands and metal complexes interacting with G4s. The second one will focus on an exhaustive and comprehensive overview of the interactions and (photo)reactions of Ru(II) complexes with G4s.
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Affiliation(s)
- Julie Jiang
- Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université Libre de Bruxelles, Avenue F. D. Roosevelt 50-CP 160/08, 1050 Brussels, Belgium; (J.J.); (T.T.); (J.T.); (L.D.)
| | - Titouan Teunens
- Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université Libre de Bruxelles, Avenue F. D. Roosevelt 50-CP 160/08, 1050 Brussels, Belgium; (J.J.); (T.T.); (J.T.); (L.D.)
- Laboratoire de Chimie des Matériaux Nouveaux, Université de Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Jérôme Tisaun
- Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université Libre de Bruxelles, Avenue F. D. Roosevelt 50-CP 160/08, 1050 Brussels, Belgium; (J.J.); (T.T.); (J.T.); (L.D.)
| | - Laura Denuit
- Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université Libre de Bruxelles, Avenue F. D. Roosevelt 50-CP 160/08, 1050 Brussels, Belgium; (J.J.); (T.T.); (J.T.); (L.D.)
| | - Cécile Moucheron
- Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université Libre de Bruxelles, Avenue F. D. Roosevelt 50-CP 160/08, 1050 Brussels, Belgium; (J.J.); (T.T.); (J.T.); (L.D.)
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12
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Liu YC, Yang DY, Sheu SY. Insights into the free energy landscape and salt-controlled mechanism of the conformational conversions between human telomeric G-quadruplex structures. Int J Biol Macromol 2021; 191:230-242. [PMID: 34536474 DOI: 10.1016/j.ijbiomac.2021.09.057] [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: 06/29/2021] [Revised: 08/23/2021] [Accepted: 09/10/2021] [Indexed: 12/16/2022]
Abstract
G-quadruplexes have become attractive drug targets in cancer therapy. However, due to the polymorphism of G-quadruplex structures, it is difficult to experimentally verify the relevant structures of multiple intermediates and transition states in dynamic equilibrium. Hence, understanding the mechanism by which structural conversions of G-quadruplexes occur is still challenging. We conducted targeted molecular dynamics simulation with umbrella sampling to investigate how salt affects the conformational conversion of human telomeric G-quadruplex. Our results explore a unique view into the structures and energy barrier of the intermediates and transition states in the interconversion process. The pathway of G-quadruplex conformational interconversion was mapped out by a free energy landscape, consisting of branched parallel pathways with multiple energy basins. We propose a salt-controlled mechanism that as the salt concentration increases, the conformational conversion mechanism switches from multi-pathway folding to sequential folding pathways. The hybrid-I and hybrid-II structures are intermediates in the basket-propeller transformation. In high-salt solutions, the conformational conversion upon K+ binding is more feasible than upon Na+ binding. The free energy barrier for conformational conversions ranges from 1.6 to 4.6 kcal/mol. Our work will be beneficial in developing anticancer agents.
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Affiliation(s)
- Yu-Cheng Liu
- Institute of Biomedical Informatics, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Dah-Yen Yang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
| | - Sheh-Yi Sheu
- Institute of Biomedical Informatics, National Yang Ming Chiao Tung University, Taipei 112, Taiwan; Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei 112, Taiwan.
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13
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Zhu Y, Liu W, Zhang C. G-Quadruplexes Formation at the Upstream Region of Replication Origin (OriL) of the Pseudorabies Virus: Implications for Antiviral Targets. Viruses 2021; 13:v13112219. [PMID: 34835025 PMCID: PMC8623188 DOI: 10.3390/v13112219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 10/28/2021] [Accepted: 11/01/2021] [Indexed: 11/16/2022] Open
Abstract
Pseudorabies virus (PRV) is the causative agent of Aujeszky's disease, which still causes large economic losses for the swine industry. Therefore, it is urgent to find a new strategy to prevent and control PRV infection. Previous studies have proven that guanine (G)-rich DNA or RNA sequences in some other viruses' genomes have the potential to form G-quadruplex (G4), which serve as promising antivirus targets. In this study, we identified two novel G4-forming sequences, OriL-A and OriL-S, which are located at the upstream origin of replication (OriL) in the PRV genome and conserved across 32 PRV strains. Circular dichroism (CD) spectroscopy and a gel electrophoresis assay showed that the two G-rich sequences can fold into parallel G4 structures in vitro. Moreover, fluorescence resonance energy transfer (FRET) melting and a Taq polymerase stop assay indicated that the G4 ligand PhenDC3 has the capacity to bind and stabilize the G4. Notably, the treatment of PRV-infected cells with G4-stabilizer PhenDC3 significantly inhibited PRV DNA replication in host cells but did not affect PRV's attachment and entry. These results not only expand our knowledge about the G4 characteristics in the PRV genome but also suggest that G4 may serve as an innovative therapeutic target against PRV.
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14
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Salsbury AM, Lemkul JA. Cation competition and recruitment around the c-kit1 G-quadruplex using polarizable simulations. Biophys J 2021; 120:2249-2261. [PMID: 33794153 PMCID: PMC8390831 DOI: 10.1016/j.bpj.2021.03.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/22/2021] [Accepted: 03/25/2021] [Indexed: 11/24/2022] Open
Abstract
Nucleic acid-ion interactions are fundamentally important to the physical, energetic, and conformational properties of DNA and RNA. These interactions help fold and stabilize highly ordered secondary and tertiary structures, such as G-quadruplexes (GQs), which are functionally relevant in telomeres, replication initiation sites, and promoter sequences. The c-kit proto-oncogene encodes for a receptor tyrosine kinase and is linked to gastrointestinal stromal tumors, mast cell disease, and leukemia. This gene contains three unique GQ-forming sequences that have proposed antagonistic effects on gene expression. The dominant GQ, denoted c-kit1, has been shown to decrease expression of c-kit transcripts, making the c-kit1 GQ a promising drug target. Toward disease intervention, more information is needed regarding its conformational dynamics and ion binding properties. Therefore, we performed molecular dynamics simulations of the c-kit1 GQ with K+, Na+, Li+, and mixed salt solutions using the Drude-2017 polarizable force field. We evaluated GQ structure, ion sampling, core energetics, ion dehydration and binding, and ion competition and found that each analysis supported the known GQ-ion specificity trend (K+ > Na+ > Li+). We also found that K+ ions coordinate in the tetrad core antiprismatically, whereas Na+ and Li+ align coplanar to guanine tetrads, partially because of their attraction to surrounding water. Further, we showed that K+ occupancy is higher around the c-kit1 GQ and its nucleobases than Na+ and Li+, which tend to interact with backbone and sugar moieties. Finally, we showed that K+ binding to the c-kit1 GQ is faster and more frequent than Na+ and Li+. Such descriptions of GQ-ion dynamics suggest the rate of dehydration as the dominant factor for preference of K+ by DNA GQs and provide insight into noncanonical nucleic acids for which little experimental data exist.
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Affiliation(s)
| | - Justin A Lemkul
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia; Center for Drug Discovery, Virginia Tech, Blacksburg, Virginia.
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15
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Podder A, Lee HJ, Kim BH. Fluorescent Nucleic Acid Systems for Biosensors. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2021. [DOI: 10.1246/bcsj.20200351] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Arup Podder
- Department of Chemistry, Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
| | - Ha Jung Lee
- Department of Chemistry, Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
| | - Byeang Hyean Kim
- Department of Chemistry, Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang 37673, Korea
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16
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Active and Passive Destabilization of G-Quadruplex DNA by the Telomere POT1-TPP1 Complex. J Mol Biol 2021; 433:166846. [PMID: 33549587 DOI: 10.1016/j.jmb.2021.166846] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 01/05/2021] [Accepted: 01/22/2021] [Indexed: 11/23/2022]
Abstract
Chromosome ends are protected by guanosine-rich telomere DNA that forms stable G-quadruplex (G4) structures. The heterodimeric POT1-TPP1 complex interacts specifically with telomere DNA to shield it from illicit DNA damage repair and to resolve secondary structure that impedes telomere extension. The mechanism by which POT1-TPP1 accomplishes these tasks is poorly understood. Here, we establish the kinetic framework for POT1-TPP1 binding and unfolding of telomere G4 DNA. Our data identify two modes of POT1-TPP1 destabilization of G4 DNA that are governed by protein concentration. At low concentrations, POT1-TPP1 passively captures transiently unfolded G4s. At higher concentrations, POT1-TPP1 proteins bind to G4s to actively destabilize the DNA structures. Cancer-associated POT1-TPP1 mutations impair multiple reaction steps in this process, resulting in less efficient destabilization of G4 structures. The mechanistic insight highlights the importance of cell cycle dependent expression and localization of the POT1-TPP1 complex and distinguishes diverse functions of this complex in telomere maintenance.
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17
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Sengupta A, Roy SS, Chowdhury S. Non-duplex G-Quadruplex DNA Structure: A Developing Story from Predicted Sequences to DNA Structure-Dependent Epigenetics and Beyond. Acc Chem Res 2021; 54:46-56. [PMID: 33347280 DOI: 10.1021/acs.accounts.0c00431] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The story of the non-duplex DNA form known as the G-quadruplex (G4) has traversed a winding path. From initial skepticism followed by debate to a surge in interest, the G4 story intertwines many threads. Starting with computational predictions of a gene regulatory role, which now include epigenetic functions, our group was involved in many of these advances along with many other laboratories. Following a brief background, set in the latter half of the last century when the concept of the G4 as a structure took ground, here we account the developments. This is through a lens that though focused on our groups' research presents work from many other groups that played significant roles. Together these provide a broad perspective to the G4 story. Initially we were intrigued on seeing potential G4 (pG4)-forming sequences, then known to be found primarily at the telomeres and immunoglobin switch regions, occurring throughout the genome and being particularly prevalent in promoters of bacteria. We further observed that pG4s were not only prevalent but also conserved through evolution in promoters of human, chimpanzee, mouse and rat genomes. This was between 2005 and 2007. Encouraged by these partly and partly in response to the view held by many that genome-wide presence of G4s were genomic "accidents", the focus shifted to seeking experimental evidence.In the next year, 2008, two independent findings showed promise. First, on treating human cancer cells with G4-binding ligands, we observed widespread change in gene expression. Second, our search for the missing G4-specific transcription factor, without which, importantly, G4s in promoters posed only half the story, yielded results. We determined how NM23-H2 (also known as NME2 or NDPK-B) interacts with G4s and how interaction of NM23-H2 with a G4 in the promoter of the oncogene c-myc was important for regulation of c-myc transcription. NM23-H2, and subsequently many other similar factors discovered by multiple groups, is possibly giving shape to what might be the "G4-transcriptome". Later, a close look at NM23-H2-G4 interaction in regulation of the human reverse transcriptase gene (hTERT) revealed the role of G4s in local epigenetic modifications. Meanwhile work from others showed how G4s impact histone modifications following replication. Together these show the intrinsic role of DNA sequence, through formation of DNA structure, in epigenetics.More recent work, however, was waiting to reveal aspects that tend to bring forth a completely new understanding of G4s. We observed that the telomere-repeat-binding-factor-2 (TRF2), known canonically to be telomere-associated, binds extensively outside telomeres throughout the genome. Moreover, a large fraction of the non-telomeric TRF2 sites comprise G4s. Second, the extent of non-telomeric TRF2 binding at promoters was dependent on telomere length. Thereby TRF2-induced epigenetic gene regulation was telomere-dependent. Together these implicate underlying connections that show signs of addressing an intriguing unanswered question that takes us back to the beginning: Why are G4s prevalent in two distinct regions, the telomeres and gene promoters?
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Affiliation(s)
- Antara Sengupta
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Shuvra Shekhar Roy
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Shantanu Chowdhury
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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18
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Ranjan N, Andreasen KF, Arora Y, Xue L, Arya DP. Surface Dependent Dual Recognition of a G-quadruplex DNA With Neomycin-Intercalator Conjugates. Front Chem 2020; 8:60. [PMID: 32117884 PMCID: PMC7028757 DOI: 10.3389/fchem.2020.00060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Accepted: 01/20/2020] [Indexed: 01/17/2023] Open
Abstract
G-quadruplexes have been characterized as structures of vital importance in the cellular functioning of several life forms. They have subsequently been established to serve as a therapeutic target of several diseases including cancer, HIV, tuberculosis and malaria. In this paper, we report the binding of aminosugar-intercalator conjugates with a well-studied anti-parallel G-quadruplex derived from Oxytricha Nova G-quadruplex DNA. Of the four neomycin-intercalator conjugates studied with varying surface areas, BQQ-neomycin conjugate displayed the best binding to this DNA G-quadruplex structure with an association constant of Ka = (1.01 ±0.03) × 107 M−1 which is nearly 100-fold higher than the binding of neomycin to this quadruplex. The binding of BQQ-neomycin displays a binding stoichiometry of 1:1 indicating the presence of a single and unique binding site for this G-quadruplex. In contrast, the BQQ-neomycin displays very weak binding to the bacterial A-site rRNA sequence showing that BQQ-does not enhance the neomycin binding to its natural target, the bacterial rRNA A-site. The BQQ-neomycin conjugate is prone to aggregation even at low micromolar concentrations (4 μM) leading to some ambiguities in the analysis of thermal denaturation profiles. Circular dichroism experiments showed that binding of BQQ-neomycin conjugate causes some structural changes in the quadruplex while still maintaining the overall anti-parallel structure. Finally, the molecular docking experiments suggest that molecular surface plays an important role in the recognition of a second site on the G-quadruplex. Overall, these results show that molecules with more than one binding moieties can be made to specifically recognize G-quadruplexes with high affinities. The dual binding molecules comprise of quadruplex groove binding and intercalator units, and the molecular surface of the intercalator plays an important part in enhancing binding interaction to the G-quadruplex structure.
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Affiliation(s)
- Nihar Ranjan
- Laboratory for Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC, United States.,Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Raebareli, India
| | - Katrine F Andreasen
- Laboratory for Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC, United States
| | - Yashaswina Arora
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Raebareli, India
| | - Liang Xue
- Laboratory for Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC, United States
| | - Dev P Arya
- Laboratory for Medicinal Chemistry, Department of Chemistry, Clemson University, Clemson, SC, United States
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19
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Conformational rearrangements of G-quadruplex topology promoted by Cu(II) 12-MC Cu(II)PyrAcHA-4 metallacrown. Int J Biol Macromol 2019; 156:1258-1269. [PMID: 31759020 DOI: 10.1016/j.ijbiomac.2019.11.163] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 11/18/2019] [Accepted: 11/19/2019] [Indexed: 11/20/2022]
Abstract
Cu(II) 12-MCCu(II)PyrAcHA-4 metallacrown was studied by several spectroscopic techniques as an interacting ligand with G-quadruplex DNA structures. Investigations were performed on oligonucleotides bearing human telomeric and protooncogenic c-myc sequences in buffered solution mimicking ionic conditions in cellular environment. The planar square-based Cu(II) 12-MC-4 metallacrown interacts with GQ via an end-stacking mode with 1:1 stoichiometry. Circular dichroism (CD) titration revealed capability of this metallacrown to induce transformation of the GQ hybrid topology into the parallel form. Thermal melting experiment indicated higher thermal stability of both antiparallel (ΔTm = +15 °C) and parallel (ΔTm = ≥27 °C) G-quadruplexes in the presence of Cu (II) 12-MC-4. Indirect GQ FID assay let to determine high binding affinity of the Cu(II) 12-MC-4 to antiparallel 22Htel/Na+ GQ (KMC = 3.9 (±0.4) x 106 M-1). Comparing with lower binding constants previously reported for Ln (III) 15-MC-5 and Sm (III) 12-MC-4, one can conclude that the square planar geometry and the positive charge of metallacrown play an important role in MC/GQ interactions.
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20
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Nakano SI, Ayusawa T, Tanino Y, Sugimoto N. Stabilization of DNA Loop Structures by Large Cations. J Phys Chem B 2019; 123:7687-7694. [PMID: 31465227 DOI: 10.1021/acs.jpcb.9b06074] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The DNA-binding properties of large cations differ from those of metal ions due to steric exclusion from base-paired regions. In this study, the thermal stability of DNA secondary structures, including duplexes, internal loops, bulge loops, hairpin loops, dangling ends, and G-quadruplexes, was investigated in the presence of cations of different sizes. Large cations, such as tetrabutylammonium and tetrapentylammonium ions, reduced the stability of fully matched duplexes but increased the stability of duplexes with a long loop. The cations also increased the stability of G-quadruplexes with a long loop, and the degree of stabilization was greater for low-stability G-quadruplexes. Analysis of the salt concentration dependence indicates that large cations bind to the loop nucleotides, leading to counteracting the destabilization effect on base pairing. It is likely that binding occurs when loop nucleotides are sufficiently flexible to allow for greater accessibility for large cations. These results provide insight into nucleic acid interactions with large cationic molecules and suggest a potential method for stabilizing noncanonical DNA structures under intracellular conditions.
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Affiliation(s)
- Shu-Ichi Nakano
- Department of Nanobiochemistry, Faculty of Frontiers of Innovative Research in Science and Technology (FIRST) , Konan University , 7-1-20, Minatojima-minamimachi, Chuo-ku, Kobe , 650-0047 , Japan
| | - Toshiya Ayusawa
- 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
| | - Yuichi Tanino
- 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
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21
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He Y, Chen D, Huang PJJ, Zhou Y, Ma L, Xu K, Yang R, Liu J. Misfolding of a DNAzyme for ultrahigh sodium selectivity over potassium. Nucleic Acids Res 2019; 46:10262-10271. [PMID: 30215808 PMCID: PMC6212836 DOI: 10.1093/nar/gky807] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 09/08/2018] [Indexed: 02/07/2023] Open
Abstract
Herein, the excellent Na+ selectivity of a few RNA-cleaving DNAzymes was exploited, where Na+ can be around 3000-fold more effective than K+ for promoting catalysis. By using a double mutant based on the Ce13d DNAzyme, and by lowering the temperature, increased 2-aminopurine (2AP) fluorescence was observed with addition of both Na+ and K+. The fluorescence increase was similar for these two metals at below 10 mM, after which K+ took a different pathway. Since 2AP probes its local base stacking environment, K+ can be considered to induce misfolding. Binding of both Na+ and K+ was specific, since single base mutations could fully inhibit 2AP fluorescence for both metals. The binding thermodynamics was measured by temperature-dependent experiments revealing enthalpy-driven binding for both metals and less coordination sites compared to G-quadruplex DNA. Cleavage activity assays indicated a moderate cleavage activity with 10 mM K+, while further increase of K+ inhibited the activity, also supporting its misfolding of the DNAzyme. For comparison, a G-quadruplex DNA was also studied using the same system, where Na+ and K+ led to the same final state with only around 8-fold difference in Kd. This study provides interesting insights into strategies for discriminating Na+ and K+.
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Affiliation(s)
- Yanping He
- State Key Laboratory of Precision Measurement Technology and Instruments, University of Tianjin, Tianjin 300072, China.,Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Da Chen
- State Key Laboratory of Precision Measurement Technology and Instruments, University of Tianjin, Tianjin 300072, China
| | - Po-Jung Jimmy Huang
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Yibo Zhou
- School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114, P. R. China
| | - Lingzi Ma
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
| | - Kexin Xu
- State Key Laboratory of Precision Measurement Technology and Instruments, University of Tianjin, Tianjin 300072, China
| | - Ronghua Yang
- School of Chemistry and Biological Engineering, Changsha University of Science and Technology, Changsha 410114, P. R. China
| | - Juewen Liu
- Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON N2L 3G1, Canada
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22
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Small Molecule Fluorescent Probes for G- Quadruplex Visualization as Potential Cancer Theranostic Agents. Molecules 2019; 24:molecules24040752. [PMID: 30791494 PMCID: PMC6412342 DOI: 10.3390/molecules24040752] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/10/2019] [Accepted: 01/22/2019] [Indexed: 11/25/2022] Open
Abstract
G-quadruplexes have gained prominence over the past two decades for their role in gene regulation, control of anti-tumour activity and ageing. The physiological relevance and significance of these non-canonical structures in the context of cancer has been reviewed several times. Putative roles of G-quadruplexes in cancer prognosis and pathogenesis have spurred the search for small molecule ligands that are capable of binding and modulating the effect of such structures. On a related theme, small molecule fluorescent probes have emerged that are capable of selective recognition of G-quadruplex structures. These have opened up the possibility of direct visualization and tracking of such structures. In this review we outline recent developments on G-quadruplex specific small molecule fluorescent probes for visualizing G-quadruplexes. The molecules represent a variety of structural scaffolds, mechanism of quadruplex-recognition and fluorescence signal transduction. Quadruplex selectivity and in vivo imaging potential of these molecules places them uniquely as quadruplex-theranostic agents in the predominantly cancer therapeutic context of quadruplex-selective ligands.
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23
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Sengupta A, Ganguly A, Chowdhury S. Promise of G-Quadruplex Structure Binding Ligands as Epigenetic Modifiers with Anti-Cancer Effects. Molecules 2019; 24:E582. [PMID: 30736345 PMCID: PMC6384772 DOI: 10.3390/molecules24030582] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 11/16/2022] Open
Abstract
Evidences from more than three decades of work support the function of non-duplex DNA structures called G-quadruplex (G4) in important processes like transcription and replication. In addition, G4 structures have been studied in connection with DNA base modifications and chromatin/nucleosome arrangements. Recent work, interestingly, shows promise of G4 structures, through interaction with G4 structure-interacting proteins, in epigenetics-in both DNA and histone modification. Epigenetic changes are found to be intricately associated with initiation as well as progression of cancer. Multiple oncogenes have been reported to harbor the G4 structure at regulatory regions. In this context, G4 structure-binding ligands attain significance as molecules with potential to modify the epigenetic state of chromatin. Here, using examples from recent studies we discuss the emerging role of G4 structures in epigenetic modifications and, therefore, the promise of G4 structure-binding ligands in epigenetic therapy.
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Affiliation(s)
- Antara Sengupta
- Integrative and Functional Biology Unit, CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi-110025, India.
- Academy of Scientific and Innovative Research, Rafi Marg, New Delhi-110001, India.
| | - Akansha Ganguly
- Integrative and Functional Biology Unit, CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi-110025, India.
| | - Shantanu Chowdhury
- Integrative and Functional Biology Unit, CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi-110025, India.
- Academy of Scientific and Innovative Research, Rafi Marg, New Delhi-110001, India.
- GNR Knowledge Centre for Genome Informatics, CSIR Institute of Genomics and Integrative Biology, Mathura Road, New Delhi-110025, India.
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Non-duplex G-Quadruplex Structures Emerge as Mediators of Epigenetic Modifications. Trends Genet 2018; 35:129-144. [PMID: 30527765 DOI: 10.1016/j.tig.2018.11.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 10/10/2018] [Accepted: 11/02/2018] [Indexed: 12/16/2022]
Abstract
The role of non-duplex DNA, the guanine-quadruplex structure in particular, is becoming widely appreciated. Increasing evidence in the last decade implicates quadruplexes in important processes such as transcription and replication. Interestingly, more recent work suggests roles for quadruplexes, in association with quadruplex-interacting proteins, in epigenetics through both DNA and histone modifications. Here, we review the effect of the quadruplex structure on post-replication epigenetic memory and quadruplex-induced promoter DNA/histone modifications. Furthermore, we highlight the epigenetic state of the telomerase promoter where quadruplexes could play a key regulatory role. Finally, we discuss the possibility that DNA structures such as quadruplexes, within a largely duplex DNA background, could act as molecular anchors for locally induced epigenetic modifications.
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25
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Tariq Z, Barthwal R. Binding of anticancer drug daunomycin to parallel G-quadruplex DNA [d-(TTGGGGT)]4 leads to thermal stabilization: A multispectroscopic investigation. Int J Biol Macromol 2018; 120:1965-1974. [DOI: 10.1016/j.ijbiomac.2018.09.154] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 09/21/2018] [Accepted: 09/24/2018] [Indexed: 10/28/2022]
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26
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Label-free fluorescent and electrochemical biosensors based on defective G-quadruplexes. Biosens Bioelectron 2018; 118:1-8. [DOI: 10.1016/j.bios.2018.07.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/13/2018] [Accepted: 07/16/2018] [Indexed: 12/14/2022]
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27
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Identification and characterization of G-quadruplex formation within the EP0 promoter of pseudorabies virus. Sci Rep 2018; 8:14029. [PMID: 30232344 PMCID: PMC6145870 DOI: 10.1038/s41598-018-32222-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 09/04/2018] [Indexed: 12/19/2022] Open
Abstract
EP0 is an important early gene that modulates the life cycle of pseudorabies virus (PRV). A guanine-rich sequence overlapping with three Sp1 binding sites is located upstream of the transcription start site (TSS) in the EP0 promoter. Using native polyacrylamide gel electrophoresis (PAGE) and circular dichroism (CD), we verified that the G-rich region in the EP0 promoter forms an intramolecular parallel G-quadruplex (G4) in the presence of K+ ions. Further dimethyl sulphate (DMS) footprinting and Taq polymerase stop assays indicates the potential polymorphic folding of G4. In addition, a small chemical ligand, pyridostatin (PDS), promotes and stabilizes the formation of G4. Interestingly, based on the results of electrophoretic mobility shift assays (EMSA), the Sp1 protein bound to G4-bearing DNA with more affinity than DNA lacking the G4 structure. According to the luciferase reporter assay, G4 negatively regulates the EP0 promoter activity. These results demonstrate that Sp1 and G4 cooperate to regulate EP0 promoter activity.
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Oxadiazole/Pyridine-Based Ligands: A Structural Tuning for Enhancing G-Quadruplex Binding. Molecules 2018; 23:molecules23092162. [PMID: 30154319 PMCID: PMC6225118 DOI: 10.3390/molecules23092162] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 08/16/2018] [Accepted: 08/20/2018] [Indexed: 11/16/2022] Open
Abstract
Non-macrocyclic heteroaryls represent a valuable class of ligands for nucleic acid recognition. In this regard, non-macrocyclic pyridyl polyoxazoles and polyoxadiazoles were recently identified as selective G-quadruplex stabilizing compounds with high cytotoxicity and promising anticancer activity. Herein, we describe the synthesis of a new family of heteroaryls containing oxadiazole and pyridine moieties targeting DNA G-quadruplexes. To perform a structure–activity analysis identifying determinants of activity and selectivity, we followed a convergent synthetic pathway to modulate the nature and number of the heterocycles (1,3-oxazole vs. 1,2,4-oxadiazole and pyridine vs. benzene). Each ligand was evaluated towards secondary nucleic acid structures, which have been chosen as a prototype to mimic cancer-associated G-quadruplex structures (e.g., the human telomeric sequence, c-myc and c-kit promoters). Interestingly, heptapyridyl-oxadiazole compounds showed preferential binding towards the telomeric sequence (22AG) in competitive conditions vs. duplex DNA. In addition, G4-FID assays suggest a different binding mode from the classical stacking on the external G-quartet. Additionally, CD titrations in the presence of the two most promising compounds for affinity, TOxAzaPy and TOxAzaPhen, display a structural transition of 22AG in K-rich buffer. This investigation suggests that the pyridyl-oxadiazole motif is a promising recognition element for G-quadruplexes, combining seven heteroaryls in a single binding unit.
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DU ZH, LI XY, TIAN JJ, Zhang YZ, TIAN HT, XU WT. Progress on Detection of Metals Ions by Functional Nucleic Acids Biosensor. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2018. [DOI: 10.1016/s1872-2040(18)61094-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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30
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Kovalev VI, Vekshin NL. Fluorescence Analysis of 7-Aminoactinomycin–Telomeric Oligonucleotide d[AGGG(TTAGGG)3] Complexes. Biophysics (Nagoya-shi) 2018. [DOI: 10.1134/s0006350918010062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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31
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Peng P, Du Y, Sun Y, Liu S, Mi L, Li T. Probing the propeller-like loops of DNA G-quadruplexes with looped-out 2-aminopurine for label-free switchable molecular sensing. Analyst 2018; 143:3814-3820. [DOI: 10.1039/c8an00914g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report a novel ligand-free signal readout mechanism for probing the propeller-like loops of DNA G-quadruplexes with looped-out 2-aminopurine.
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Affiliation(s)
- Pai Peng
- Department of Chemistry
- University of Science and Technology of China
- Hefei
- P.R. China
| | - Yi Du
- Department of Chemistry
- University of Science and Technology of China
- Hefei
- P.R. China
| | - Yudie Sun
- Department of Chemistry
- University of Science and Technology of China
- Hefei
- P.R. China
| | - Shuangna Liu
- Department of Chemistry
- University of Science and Technology of China
- Hefei
- P.R. China
| | - Lan Mi
- Department of Chemistry
- University of Science and Technology of China
- Hefei
- P.R. China
| | - Tao Li
- Department of Chemistry
- University of Science and Technology of China
- Hefei
- P.R. China
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32
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McRae EKS, Booy EP, Padilla-Meier GP, McKenna SA. On Characterizing the Interactions between Proteins and Guanine Quadruplex Structures of Nucleic Acids. J Nucleic Acids 2017; 2017:9675348. [PMID: 29250441 PMCID: PMC5700478 DOI: 10.1155/2017/9675348] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 10/08/2017] [Indexed: 01/07/2023] Open
Abstract
Guanine quadruplexes (G4s) are four-stranded secondary structures of nucleic acids which are stabilized by noncanonical hydrogen bonding systems between the nitrogenous bases as well as extensive base stacking, or pi-pi, interactions. Formation of these structures in either genomic DNA or cellular RNA has the potential to affect cell biology in many facets including telomere maintenance, transcription, alternate splicing, and translation. Consequently, G4s have become therapeutic targets and several small molecule compounds have been developed which can bind such structures, yet little is known about how G4s interact with their native protein binding partners. This review focuses on the recognition of G4s by proteins and small peptides, comparing the modes of recognition that have thus far been observed. Emphasis will be placed on the information that has been gained through high-resolution crystallographic and NMR structures of G4/peptide complexes as well as biochemical investigations of binding specificity. By understanding the molecular features that lead to specificity of G4 binding by native proteins, we will be better equipped to target protein/G4 interactions for therapeutic purposes.
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Affiliation(s)
- Ewan K. S. McRae
- Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada
| | - Evan P. Booy
- Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada
| | | | - Sean A. McKenna
- Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada
- Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, MB, Canada
- Manitoba Institute for Materials, University of Manitoba, Winnipeg, MB, Canada
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33
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Singh A, Kukreti S. A triple stranded G-quadruplex formation in the promoter region of human myosin β(Myh7) gene. J Biomol Struct Dyn 2017; 36:2773-2786. [PMID: 28927343 DOI: 10.1080/07391102.2017.1374211] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Regulatory regions in human genome, enriched in guanine-rich DNA sequences have the propensity to fold into G-quadruplex structures. On exploring the genome for search of G-tracts, it was interesting to find that promoter of Human Myosin Gene (MYH7) contains a conserved 23-mer G-rich sequence (HM-23). Mutations in this gene are associated with familial cardiomyopathy. Enrichment of MYH7 gene in G-rich sequences could possibly play a critical role in its regulation. We used polyacrylamide gel electrophoresis (PAGE), UV-Thermal denaturation (UV-Tm) and Circular Dichroism (CD), to demonstrate the formation of a G-quadruplex by 23-mer G-rich sequence HM23 in promoter location of MYH7 gene. We observed that the wild G-rich sequence HM23 containing consecutive G5 stretch in two stacks adopt G-quadruplexes of diverse molecularity by involvement of four-strand, three-strand and two-strands with same parallel topology. Interestingly, the mutated sequence in the absence of continuous G5 stretch obstructs the formation of three-stranded G-quadruplex. We demonstrated that continuous G5 stretch is mandatory for the formation of a unique three-stranded G-quadruplex. Presence of various transcription factors (TF) in vicinity of the sequence HM23 leave fair possibility of recognition by TF binding sites, and so modulate gene expression. These findings may add on our understanding about the effect of base change in the formation of varied structural species in similar solution condition. This study may give insight about structural polymorphism arising due to recognition of non-Watson-Crick G-quadruplex structures by cellular proteins and designing structure specific molecules.
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Affiliation(s)
- Anju Singh
- a Nucleic Acids Research Laboratory, Department of Chemistry , University of Delhi , North Campus, Delhi 110007 , India
| | - Shrikant Kukreti
- a Nucleic Acids Research Laboratory, Department of Chemistry , University of Delhi , North Campus, Delhi 110007 , India
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Siebenmorgen T, Zacharias M. Origin of Ion Specificity of Telomeric DNA G-Quadruplexes Investigated by Free-Energy Simulations. Biophys J 2017; 112:2280-2290. [PMID: 28591601 DOI: 10.1016/j.bpj.2017.04.036] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/12/2017] [Accepted: 04/24/2017] [Indexed: 11/29/2022] Open
Abstract
Telomeric DNA consists of tandem repeats of the sequence d(TTAGGG) that form G-quadruplex structures made of stacked guanines with monovalent cations bound at a central cavity. Although different ions can stabilize a G-quadruplex structure, the preferred bound ions are typically K+ or Na+. Several different strand-folding topologies have been reported for Q-quadruplexes formed from telomeric repeats depending on DNA length and ion solution condition. This suggests a possible dependence of the ion selectivity of the central pore on the folding topology of the quadruplex. Molecular dynamics free energy perturbation has been employed to systematically study the relative affinity of the central quadruplex pore for different cation types and the associated energetic and solvation contributions to ion selectivity. The calculations have been performed on two different common quadruplex folding topologies. For both topologies, the same ion selectivity was found with a preference for K+ followed by Rb+ and Na+, which agrees with the experimentally determined preference for most investigated quadruplexes. The selectivity is determined by a balance between attractive Coulomb interactions and loss of hydration but also modulated by van der Waals contributions. Specificity is mediated by the central guanines and no significant contribution of the nucleic acid backbone. The simulations indicate that different topologies might be stabilized by ions bound at the surface or alternative sites of the quadruplex because the ion specificity of the central pore does not depend on the strand folding topology.
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Affiliation(s)
- Till Siebenmorgen
- Physics Department, Technical University of Munich, Garching, Germany
| | - Martin Zacharias
- Physics Department, Technical University of Munich, Garching, Germany.
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35
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Structural insight for the recognition of G-quadruplex structure at human c-myc promoter sequence by flavonoid Quercetin. Sci Rep 2017; 7:3600. [PMID: 28620169 PMCID: PMC5472631 DOI: 10.1038/s41598-017-03906-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 05/11/2017] [Indexed: 12/21/2022] Open
Abstract
Small molecule ligands that could stabilize G-quadruplex structure formed at the promoter region of human c-myc oncogene will regulate its expression in cancer cells. Flavonoids, a group of naturally available small molecule, have been known for their various promising effects on human health. In present study, we have performed detailed biophysical studies for the interaction of human c-myc G-quadruplex DNA with nine representative flavonoids: Luteolin, Quercetin, Rutin, Genistein, Kaempferol, Puerarin, Hesperidin, Myricetin and Daidzein. We found by using fluorescence titration that Quercetin interacts with c-myc G-quadruplex DNA sequence Pu24T with highest affinity. This interaction was further explored by using NMR spectroscopy and we have derived the first solution structure for the complex formed between Quercetin and biologically significant c-myc promoter DNA sequence forming G-quadruplex structure. In present solution structure, Quercetin stacks at 5' and 3' G-tetrads of Pu24T G-quadruplex structure and stabilize it via π-π stacking interactions. Furthermore, in vitro studies on HeLa cells suggested that Quercetin induces apoptosis-mediated cell death and down-regulated c-myc gene expression. This study emphasizes the potential of flavonoids as a promising candidate for targeting c-myc promoter region and thus, could act as a potential anti-cancer agent.
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36
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Recent advances in DNA-based electrochemical biosensors for heavy metal ion detection: A review. Biosens Bioelectron 2017; 90:125-139. [DOI: 10.1016/j.bios.2016.11.039] [Citation(s) in RCA: 188] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 11/03/2016] [Accepted: 11/15/2016] [Indexed: 12/20/2022]
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37
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Miljanić S, Ratkaj M, Matković M, Piantanida I, Gratteri P, Bazzicalupi C. Assessment of human telomeric G-quadruplex structures using surface-enhanced Raman spectroscopy. Anal Bioanal Chem 2017; 409:2285-2295. [DOI: 10.1007/s00216-016-0172-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/13/2016] [Accepted: 12/20/2016] [Indexed: 10/20/2022]
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38
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Rajczak E, Pecoraro VL, Juskowiak B. Sm(iii)[12-MCGa(III)shi-4] as a luminescent probe for G-quadruplex structures. Metallomics 2017; 9:1735-1744. [DOI: 10.1039/c7mt00232g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The luminescent anionic metallacrown Sm12-MC-4 exhibits similarity in shape and size to the guanine tetrad and is able to form complexes with G-quadruplex assembly.
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Affiliation(s)
- Ewa Rajczak
- Faculty of Chemistry
- Adam Mickiewicz University in Poznan
- 61-614 Poznan
- Poland
| | | | - Bernard Juskowiak
- Faculty of Chemistry
- Adam Mickiewicz University in Poznan
- 61-614 Poznan
- Poland
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39
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Biswas B, Kandpal M, Jauhari UK, Vivekanandan P. Genome-wide analysis of G-quadruplexes in herpesvirus genomes. BMC Genomics 2016; 17:949. [PMID: 27871228 PMCID: PMC5117502 DOI: 10.1186/s12864-016-3282-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/09/2016] [Indexed: 11/10/2022] Open
Abstract
Background G-quadruplexes are increasingly recognized as regulatory elements in human, animal, bacterial and plant genomes. The presence and function of G-quadruplexes are not well studied among herpesviruses; in particular, there are no systematic genome-wide analysis of these important secondary structures in herpesvirus genomes. Results We performed genome-wide analysis of putative quadruplex sequences (PQS) in human herpesviruses. We found unusually high PQS densities among human herpesviruses. PQS are enriched in the repeat regions and regulatory regions of human herpesviruses. Interestingly, PQS densities are higher in regulatory regions of immediate early genes compared to early and late genes in most herpesviruses. In addition, the majority of genes functionally conserved across human herpesviruses contain one or more PQS within the regulatory regions. We also describe the existence of unique intramolecular PQS repeats or repetitive G-quadruplex motifs in herpesviruses. Functional studies confirm a role for G-quadruplexes in regulating the gene expression of human herpesviruses. Conclusion The pervasiveness of PQS, their enrichment and conservation at specific genomic locations suggest that these structural entities may represent a novel class of functional elements in herpesviruses. Our findings provide the necessary framework for studies on the biological role of G-quadruplexes in herpesviruses. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3282-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Banhi Biswas
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - Manish Kandpal
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - Utkarsh Kumar Jauhari
- Department of Civil Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - Perumal Vivekanandan
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, 110016, India.
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40
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Lei H, Liu J, Yan J, Quan J, Fang Y. Luminescent Helical Nanofiber Self-Assembled from a Cholesterol-Based Metalloamphiphile and Its Application in DNA Conformation Recognition. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:10350-10357. [PMID: 27648676 DOI: 10.1021/acs.langmuir.6b03181] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Compared to pure organic amphiphiles, metalloamphiphiles display distinctive features, including luminescence, magnetism and catalytic properties. However, the self-organization of metalloamphiphiles is commonly driven by solvophobic effects. Alkyl chains and oligomeric ethylene glycol moieties are thus the most frequently used aggregation units to drive the self-assembly of metalloamphiphiles. We expect novel metallo-supramolecular structures with exciting functions to be created if additional noncovalent interaction modes are incorporated. In this work, a new type of metalloamphiphile, consisting of a Tb(III) complex head and a cholesteryl unit (TbL3+(I)), was designed and synthesized. TbL3+(I) spontaneously self-assembles into helical nanofibers (d = 6 nm) in water. This synthetic multivalent nanoscale binding array displays powerful capability for the recognition of DNA conformations through a turn-on luminescence sensing mechanism. ssDNA-kit1 triggered a 26-fold increase in the luminescence intensity of TbL3+(I). Its corresponding G-quadruplex structure (G-quadruplex-kit1), however, induced a 6.6-fold enhancement under the same conditions. Consequently, TbL3+(I) nanofibers can monitor DNA folding. In contrast, neither ssDNA-kit1 nor G-quadruplex-kit1 markedly promoted the luminescence of molecularly dispersed TbL3+(II), illustrating that the multivalent electrostatic interactions between the phosphate groups on the backbone of DNA and TbL3+(I) self-assembled into nanofibers could greatly improve the efficiency of the energy transfer between the guanine units and the organized TbL3+(I). The TbL3+(I) nanofibers could bind and distinguish not only the kit1-ssDNA/G-quadruplex but also the conformations of other G-rich DNA, such as spb1, htelo, and intermolec-htelo. The self-assembly of luminescent metalloamphiphiles thus provides a general and convenient strategy for the efficient recognition and conversion of molecular information.
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Affiliation(s)
- Hairui Lei
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an 710062, People's Republic of China
| | - Jing Liu
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an 710062, People's Republic of China
| | - Junlin Yan
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an 710062, People's Republic of China
| | - Jingmiao Quan
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an 710062, People's Republic of China
| | - Yu Fang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry & Chemical Engineering, Shaanxi Normal University , Xi'an 710062, People's Republic of China
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41
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Zhao A, Zhao C, Ren J, Qu X. Enantioselective targeting left-handed Z-G-quadruplex. Chem Commun (Camb) 2016; 52:1365-8. [PMID: 26616287 DOI: 10.1039/c5cc08401f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Herein, we report the first example where an M-enantiomer of a chiral metal complex can selectively stabilize a left-handed G-quadruplex, but its P-enantiomer cannot. The interactions between the chiral metal complexes and the left-handed G-quadruplex were evaluated by UV melting, circular dichroism, isothermal titration calorimetry, gel electrophoresis and NMR titrations.
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Affiliation(s)
- Andong Zhao
- Laboratory of Chemical Biology and State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Graduate School of the Chinese Academy of Sciences, Changchun, Jilin 130022, China.
| | - Chuanqi Zhao
- Laboratory of Chemical Biology and State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Graduate School of the Chinese Academy of Sciences, Changchun, Jilin 130022, China.
| | - Jinsong Ren
- Laboratory of Chemical Biology and State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Graduate School of the Chinese Academy of Sciences, Changchun, Jilin 130022, China.
| | - Xiaogang Qu
- Laboratory of Chemical Biology and State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Graduate School of the Chinese Academy of Sciences, Changchun, Jilin 130022, China.
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42
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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: 424] [Impact Index Per Article: 47.1] [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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43
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Wu CG, Spies M. G-quadruplex recognition and remodeling by the FANCJ helicase. Nucleic Acids Res 2016; 44:8742-8753. [PMID: 27342280 PMCID: PMC5062972 DOI: 10.1093/nar/gkw574] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 06/15/2016] [Indexed: 12/16/2022] Open
Abstract
Guanine rich nucleic acid sequences can form G-quadruplex (G4) structures that interfere with DNA replication, repair and RNA transcription. The human FANCJ helicase contributes to maintaining genomic integrity by promoting DNA replication through G4-forming DNA regions. Here, we combined single-molecule and ensemble biochemical analysis to show that FANCJ possesses a G4-specific recognition site. Through this interaction, FANCJ targets G4-containing DNA where its helicase and G4-binding activities enable repeated rounds of stepwise G4-unfolding and refolding. In contrast to other G4-remodeling enzymes, FANCJ partially stabilizes the G-quadruplex. This would preserve the substrate for the REV1 translesion DNA synthesis polymerase to incorporate cytosine across from a replication-stalling G-quadruplex. The residues responsible for G-quadruplex recognition also participate in interaction with MLH1 mismatch-repair protein, suggesting that the FANCJ activity supporting replication and its participation in DNA interstrand crosslink repair and/or heteroduplex rejection are mutually exclusive. Our findings not only describe the mechanism by which FANCJ recognizes G-quadruplexes and mediates their stepwise unfolding, but also explain how FANCJ chooses between supporting DNA repair versus promoting DNA replication through G-rich sequences.
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Affiliation(s)
- Colin G Wu
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Rd., 4-532 BSB, Iowa City, IA 52242, USA
| | - Maria Spies
- Department of Biochemistry, University of Iowa Carver College of Medicine, 51 Newton Rd., 4-532 BSB, Iowa City, IA 52242, USA
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44
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Sherlock ME, Rumble CA, Kwok CK, Breffke J, Maroncelli M, Bevilacqua PC. Steady-State and Time-Resolved Studies into the Origin of the Intrinsic Fluorescence of G-Quadruplexes. J Phys Chem B 2016; 120:5146-58. [PMID: 27267433 DOI: 10.1021/acs.jpcb.6b03790] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Stretches of guanines in DNA and RNA can fold into guanine quadruplex structures (GQSs). These structures protect telomeres in DNA and regulate gene expression in RNA. GQSs have an intrinsic fluorescence that is sensitive to different parameters, including loop sequence and length. However, the dependence of GQS fluorescence on solution and sequence parameters and the origin of this fluorescence are poorly understood. Herein we examine effects of dangling nucleotides and cosolute conditions on GQS fluorescence using both steady-state and time-resolved fluorescence spectroscopy. The quantum yield of dGGGTGGGTGGGTGGG, termed "dG3T", is found to be modest at ∼2 × 10(-3). Nevertheless, dG3T and its variants are significantly brighter than the common nucleic acid fluorophore 2-aminopurine (2AP) largely due to their sizable extinction coefficients. Dangling 5'-end nucleotides generally reduce emission and blue-shift the resultant spectrum, whereas dangling 3'-end nucleotides slightly enhance fluorescence, particularly on the red side of the emission band. Time-resolved fluorescence decays are broadly distributed in time and require three exponential components for accurate fits. Time-resolved emission spectra suggest the presence of two emitting populations centered at ∼330 and ∼390 nm, with the redder component being a well-defined long-lived (∼1 ns) entity. Insights into GQS fluorescence obtained here should be useful in designing brighter intrinsic RNA and DNA quadruplexes for use in label-free biotechnological applications.
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Affiliation(s)
- Madeline E Sherlock
- Department of Chemistry, ‡Center for RNA Molecular Biology, and §Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Christopher A Rumble
- Department of Chemistry, ‡Center for RNA Molecular Biology, and §Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Chun Kit Kwok
- Department of Chemistry, ‡Center for RNA Molecular Biology, and §Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Jens Breffke
- Department of Chemistry, ‡Center for RNA Molecular Biology, and §Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Mark Maroncelli
- Department of Chemistry, ‡Center for RNA Molecular Biology, and §Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
| | - Philip C Bevilacqua
- Department of Chemistry, ‡Center for RNA Molecular Biology, and §Department of Biochemistry and Molecular Biology, Pennsylvania State University , University Park, Pennsylvania 16802, United States
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45
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Yamada H, Nagase S, Takahashi K, Sakoda Y, Kida H, Okamoto S. Toll-like receptor 9 ligand D-type oligodeoxynucleotide D35 as a broad inhibitor for influenza A virus replication that is associated with suppression of neuraminidase activity. Antiviral Res 2016; 129:81-92. [PMID: 26923882 PMCID: PMC7113795 DOI: 10.1016/j.antiviral.2016.02.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 02/09/2016] [Accepted: 02/17/2016] [Indexed: 12/18/2022]
Abstract
The most effective drugs available to treat influenza are neuraminidase (NA) inhibitors, which provide important additional measures for the control of influenza virus infections. However, since the emergence of NA inhibitor-resistant viruses may compromise the clinical utility of this class of anti-influenza agents, it is very important to develop new anti-influenza agents which target a different region in NA responsible for its sensitivity from that for NA inhibitors and could be used to treat NA inhibitors-resistant isolates. The oligodeoxynucleotide D35, multimerized and aggregated, suppressed replication of influenza A viruses except A/WSN/33 (WSN). The suppressive viral replication by D35 depended on G-terad and multimer formation. The range of the suppressive viral replication at the late stage, including virus assembly and release from infected cells, was much larger than that at the initial stage, viral attachment and entry. D35 suppressed NA activity of influenza A viruses. Furthermore, replacing the NA gene of A/Puerto Rico/8/34 (PR8), in which viral replication was inhibited by D35 at the late stage, with the NA gene from WSN, in which viral replication was not inhibited, eliminated the D35-dependent suppression. D35 showed an additive anti-influenza effect with oseltamivir. It was also effective in vivo. These results suggest that the influenza virus NA mainly contributse to the D35-suppressible virus release from infected cells at the late stage. In addition, because administration of D35 into the virus-infected mice suppressed viral replication and weight loss, clinical application of D35 could be considered. The oligodeoxynucleotide D35 suppressed replication of some influenza A viruses. D35 inhibits viral replication at the late step which is dependent on NA activity. Antiviral mechanism by D35 is different from that by oseltamivir.
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Affiliation(s)
- Hiroshi Yamada
- Laboratory of Virology and Vaccinology, National Institute of Biomedical Innovation, Ibaraki, Osaka, Japan
| | - Satoshi Nagase
- Department of Laboratory Sciences, Division of Health Sciences, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Kazuo Takahashi
- Department of Infectious Diseases, Osaka Prefectural Institute of Public Health, Osaka, Japan
| | - Yoshihiro Sakoda
- Laboratory of Microbiology, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroshi Kida
- Laboratory of Microbiology, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan; Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan
| | - Shigefumi Okamoto
- Department of Laboratory Sciences, Division of Health Sciences, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan.
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46
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Li YY, Abu-Ghazalah R, Zamiri B, Macgregor RB. Concentration-dependent conformational changes in GQ-forming ODNs. Biophys Chem 2016; 211:70-5. [PMID: 26943018 DOI: 10.1016/j.bpc.2016.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 02/11/2016] [Accepted: 02/11/2016] [Indexed: 01/02/2023]
Abstract
Guanine-rich oligodeoxyribonucleotides (ODNs) can form non-canonical DNA structures known as G-quadruplexes, which are four stranded structures stabilized by sodium or potassium cations. The topologies of G-quadruplexes are highly polymorphic. H-Tel, an ODN with four consecutive repeats of the human telomeric sequence, [d(AGGGTTAGGGTTAGGGTTAGGG)], can assume different monomolecular G-quadruplex topologies depending on the type of cation present in solution. Our previous work demonstrated that at high concentrations of H-Tel, the monomolecular G-quadruplexes formed by H-Tel self-associate to form higher order structures. The aggregates display circular dichroism (CD) spectra similar to that of an all-parallel structure. In the current work, we present data for 19 ODNs for which we have modified the loop sequences of H-Tel in order to learn if concentration-dependent self-aggregation is a general phenomenon and to probe the contribution of the loops to the self-association of these ODNs. Our studies use CD spectroscopy and spectroscopically monitored heat denaturation. Our data show that the concentration-dependent formation of parallel G-quadruplex aggregates is a general phenomenon. We propose that one of the factors that might affect this process is the association of partially unfolded antiparallel structures.
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Affiliation(s)
- Yang Yun Li
- Department of Pharmaceutical Sciences, University of Toronto, Canada
| | | | - Bita Zamiri
- Department of Pharmaceutical Sciences, University of Toronto, Canada
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47
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Interaction of metallacrown complexes with G-quadruplex DNA. J Inorg Biochem 2016; 155:105-14. [DOI: 10.1016/j.jinorgbio.2015.11.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 11/06/2015] [Accepted: 11/30/2015] [Indexed: 11/19/2022]
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48
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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: 111] [Impact Index Per Article: 12.3] [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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49
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Zhang X, Xu CX, Di Felice R, Sponer J, Islam B, Stadlbauer P, Ding Y, Mao L, Mao ZW, Qin PZ. Conformations of Human Telomeric G-Quadruplex Studied Using a Nucleotide-Independent Nitroxide Label. Biochemistry 2015; 55:360-72. [PMID: 26678746 DOI: 10.1021/acs.biochem.5b01189] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Guanine-rich oligonucleotides can form a unique G-quadruplex (GQ) structure with stacking units of four guanine bases organized in a plane through Hoogsteen bonding. GQ structures have been detected in vivo and shown to exert their roles in maintaining genome integrity and regulating gene expression. Understanding GQ conformation is important for understanding its inherent biological role and for devising strategies to control and manipulate functions based on targeting GQ. Although a number of biophysical methods have been used to investigate structure and dynamics of GQs, our understanding is far from complete. As such, this work explores the use of the site-directed spin labeling technique, complemented by molecular dynamics simulations, for investigating GQ conformations. A nucleotide-independent nitroxide label (R5), which has been previously applied for probing conformations of noncoding RNA and DNA duplexes, is attached to multiple sites in a 22-nucleotide DNA strand derived from the human telomeric sequence (hTel-22) that is known to form GQ. The R5 labels are shown to minimally impact GQ folding, and inter-R5 distances measured using double electron-electron resonance spectroscopy are shown to adequately distinguish the different topological conformations of hTel-22 and report variations in their occupancies in response to changes of the environment variables such as salt, crowding agent, and small molecule ligand. The work demonstrates that the R5 label is able to probe GQ conformation and establishes the base for using R5 to study more complex sequences, such as those that may potentially form multimeric GQs in long telomeric repeats.
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Affiliation(s)
- Xiaojun Zhang
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
| | - Cui-Xia Xu
- School of Chemistry and Chemical Engineering, Sun Yat-Sen University , Guangzhou 510275, China
| | - Rosa Di Felice
- Department of Physics and Astronomy, University of Southern California , Los Angeles, California 90089, United States.,Center S3, CNR institute of Nanoscience , Modena, Italy
| | - Jiri Sponer
- Central European Institute of Technology (CEITEC), Masaryk University , Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic.,Institute of Biophysics, Academy of Sciences of the Czech Republic , Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Barira Islam
- Central European Institute of Technology (CEITEC), Masaryk University , Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Petr Stadlbauer
- Institute of Biophysics, Academy of Sciences of the Czech Republic , Kralovopolska 135, 612 65 Brno, Czech Republic
| | - Yuan Ding
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
| | - Lingling Mao
- School of Chemistry and Chemical Engineering, Sun Yat-Sen University , Guangzhou 510275, China
| | - Zong-Wan Mao
- School of Chemistry and Chemical Engineering, Sun Yat-Sen University , Guangzhou 510275, China
| | - Peter Z Qin
- Department of Chemistry, University of Southern California , Los Angeles, California 90089, United States
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50
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Chen Q, Zuo J, Chen J, Tong P, Mo X, Zhang L, Li J. A label-free fluorescent biosensor for ultratrace detection of terbium (ш) based on structural conversion of G-quadruplex DNA mediated by ThT and terbium (ш). Biosens Bioelectron 2015; 72:326-31. [DOI: 10.1016/j.bios.2015.04.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 04/02/2015] [Accepted: 04/13/2015] [Indexed: 10/23/2022]
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