1
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Napolitano E, Criscuolo A, Riccardi C, Esposito CL, Catuogno S, Coppola G, Roviello GN, Montesarchio D, Musumeci D. Directing in Vitro Selection towards G-quadruplex-forming Aptamers to Inhibit HMGB1 Pathological Activity. Angew Chem Int Ed Engl 2024; 63:e202319828. [PMID: 38358301 DOI: 10.1002/anie.202319828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/09/2024] [Accepted: 02/14/2024] [Indexed: 02/16/2024]
Abstract
In the search for novel, effective inhibitors of High-Mobility Group Box1 (HMGB1)-a protein involved in various inflammatory and autoimmune diseases as well as in cancer-we herein discovered a set of anti-HMGB1 G-quadruplex(G4)-forming aptamers by using an in vitro selection procedure applied to a doped library of guanine-rich oligonucleotides. The selected DNA sequences were then studied in a pseudo-physiological buffer mimicking the extracellular medium, where HMGB1 exerts its pathological activity, using spectroscopic, electrophoretic, and chromatographic techniques. All the oligonucleotides proved to fold into monomeric G4s and in some cases also dimeric species, stable at physiological temperature. Remarkably, the protein preferentially recognized the sequences forming dimeric parallel G4 structures, as evidenced by a properly designed chemiluminescent binding assay which also highlighted a good selectivity of these aptamers for HMGB1. Moreover, all aptamers showed anti-HMGB1 activity, inhibiting protein-induced cell migration. The acquired data allowed identifying L12 as the best anti-HMGB1 aptamer, featured by high thermal and enzymatic stability, no toxicity at least up to 5 μM concentration on healthy cells, along with potent anti-HMGB1 activity (IC50 ca. 28 nM) and good binding affinity for the protein, thus indicating it as a very promising lead candidate for in vivo studies.
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Affiliation(s)
- Ettore Napolitano
- Department of Chemical Sciences, University of Napoli Federico II, via Cintia 21, 80126, Napoli, Italy
| | - Andrea Criscuolo
- Department of Chemical Sciences, University of Napoli Federico II, via Cintia 21, 80126, Napoli, Italy
| | - Claudia Riccardi
- Department of Chemical Sciences, University of Napoli Federico II, via Cintia 21, 80126, Napoli, Italy
| | - Carla L Esposito
- Institute of Experimental Endocrinology and Oncology "Gaetano Salvatore" (IEOS), National Research Council (CNR), Via Sergio Pansini 5, 80131, Napoli, Italy
| | - Silvia Catuogno
- Institute of Experimental Endocrinology and Oncology "Gaetano Salvatore" (IEOS), National Research Council (CNR), Via Sergio Pansini 5, 80131, Napoli, Italy
| | - Gabriele Coppola
- Institute of Experimental Endocrinology and Oncology "Gaetano Salvatore" (IEOS), National Research Council (CNR), Via Sergio Pansini 5, 80131, Napoli, Italy
| | - Giovanni N Roviello
- Institute of Biostructures and Bioimaging (IBB), National Research Council of Italy (CNR), 80145, Napoli, Italy
| | - Daniela Montesarchio
- Department of Chemical Sciences, University of Napoli Federico II, via Cintia 21, 80126, Napoli, Italy
| | - Domenica Musumeci
- Department of Chemical Sciences, University of Napoli Federico II, via Cintia 21, 80126, Napoli, Italy
- Institute of Biostructures and Bioimaging (IBB), National Research Council of Italy (CNR), 80145, Napoli, Italy
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2
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Hu W, Jing H, Fu W, Wang Z, Zhou J, Zhang N. Conversion to Trimolecular G-Quadruplex by Spontaneous Hoogsteen Pairing-Based Strand Displacement Reaction between Bimolecular G-Quadruplex and Double G-Rich Probes. J Am Chem Soc 2023; 145:18578-18590. [PMID: 37553999 DOI: 10.1021/jacs.3c05617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2023]
Abstract
Bimolecular or tetramolecular G-quadruplexes (GQs) are predominantly self-assembled by the same sequence-identical G-rich oligonucleotides and usually remain inert to the strand displacement reaction (SDR) with other short G-rich invading fragments of DNA or RNA. Appealingly, in this study, we demonstrate that a parallel homomeric bimolecular GQ target of Tub10 d(CAGGGAGGGT) as the starting reactant, although completely folded in K+ solution and sufficiently stable (melting temperature of 57.7 °C), can still spontaneously accept strand invasion by a pair of short G-rich invading probes of P1 d(TGGGA) near room temperature. The final SDR product is a novel parallel heteromeric trimolecular GQ (tri-GQ) of Tub10/2P1 reassembled between one Tub10 strand and two P1 strands. Here we present, to the best of our knowledge, the first NMR solution structure of such a discrete heteromeric tri-GQ and unveil a unique mode of two probes vs one target in mutual recognition among G-rich canonical DNA oligomers. As a model system, the short invading probe P1 can spontaneously trap G-rich target Tub10 from a Watson-Crick duplex completely hybridized between Tub10 and its fully complementary strand d(ACCCTCCCTG). The Tub10 sequence of d(CAGGGAGGGT) is a fragment from the G-rich promoter region of the human β2-tubulin gene. Our findings provide new insights into the Hoogsteen pairing-based SDR between a GQ target and double invading probes of short G-rich DNA fragments and are expected to grant access to increasingly complex architectures in GQ-based DNA nanotechnology.
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Affiliation(s)
- Wenxuan Hu
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- University of Science and Technology of China, Hefei 230026, China
| | - Haitao Jing
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Wenqiang Fu
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
| | - Zengrong Wang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- University of Science and Technology of China, Hefei 230026, China
| | - Jiang Zhou
- Analytical Instrumentation Center, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Na Zhang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
- Key Laboratory of Anhui Province for High Field Magnetic Resonance Imaging, Hefei 230031, China
- High Magnetic Field Laboratory of Anhui Province, Hefei 230031, China
- Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China
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3
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Roxo C, Pasternak A. Changes in physicochemical and anticancer properties modulated by chemically modified sugar moieties within sequence-related G-quadruplex structures. PLoS One 2022; 17:e0273528. [PMID: 35998148 PMCID: PMC9397905 DOI: 10.1371/journal.pone.0273528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 08/09/2022] [Indexed: 11/18/2022] Open
Abstract
We systematically investigated the influence of locked nucleic acid (LNA), unlock nucleic acid (UNA), and 2’-O-methyl-RNA (2’-O-Me-RNA) residues on the thermal stability, structure folding topology, biological activity and enzymatic resistance of three sequence-related DNA G-quadruplexes. In order to better understand the mechanism of action of the studied modifications, a single-position substitution in the loops or G-tetrads was performed and their influence was analyzed for a total of twenty-seven modified G-quadruplex variants. The studies show that the influence of each modification on the physicochemical properties of G-quadruplexes is position-dependent, due to mutual interactions between G-tetrads, loops, and additional guanosine at 5’ or 3’ end. Nevertheless, the anticancer activity of the modified G-quadruplexes is determined by their structure, thus also by the local changes of chemical character of sugar moieties, what might influence the specific interactions with therapeutic targets. In general, UNA modifications are efficient modulators of the G-quadruplex thermodynamic stability, however they are poor tools to improve the anticancer properties. In contrast, LNA and 2’-O-Me-RNA modified G-quadruplexes demonstrated certain antiproliferative potential and might be used as molecular tools for designing novel G-quadruplex-based therapeutics.
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Affiliation(s)
- Carolina Roxo
- Department of Nucleic Acids Bioengineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | - Anna Pasternak
- Department of Nucleic Acids Bioengineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
- * E-mail:
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4
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Pal R, Deb I, Sarzynska J, Lahiri A. LNA-induced dynamic stability in a therapeutic aptamer: insights from molecular dynamics simulations. J Biomol Struct Dyn 2022; 41:2221-2230. [PMID: 35100936 DOI: 10.1080/07391102.2022.2029567] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Modulation of structural and thermodynamic properties of nucleic acids with synthetic modifications is a promising area of research with possible applications in nanotechnology and nanotherapeutics. Locked nucleic acid (LNA) is one such modification in which the C4' and O2' atoms of the sugar moiety are connected through a methylene bridge. The LNA modified DNA aptamer RNV66, and its unmodified counterpart V7t1, both of which target the vascular endothelial growth factor (VEGF) implicated in oncogenic angiogenesis, have a G-rich tract that can fold into G-quadruplex structures. However, it is not understood why V7t1 has a polymorphic structure while its LNA modified counterpart RNV66 has a unique quadruplex fold with higher nuclease resistance, thermal stability and greater binding affinity for VEGF. In this work, we have performed extensive molecular dynamics simulations of RNV66 and V7t1 to study and compare the structural and dynamic consequences of the insertion of LNAs. It was observed that the increase in dynamic stability was significant in the presence of LNA residues and our protocol for combining different torsional parameters using OL15 for the DNA aptamer and parm99_LNA along with parmbsc0 and βOL15 for the LNAs nicely reproduced the experimentally observed conformational features of RNV66. Our observations would help in further theoretical studies in understanding the lack of frustration in the folding of the LNA modified aptamer and its higher affinity for VEGF.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Rupak Pal
- Department of Biophysics, Molecular Biology, and Bioinformatics, University of Calcutta, Kolkata, India
| | - Indrajit Deb
- Department of Biophysics, Molecular Biology, and Bioinformatics, University of Calcutta, Kolkata, India
| | - Joanna Sarzynska
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
| | - Ansuman Lahiri
- Department of Biophysics, Molecular Biology, and Bioinformatics, University of Calcutta, Kolkata, India
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5
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Roxo C, Kotkowiak W, Pasternak A. G4 Matters-The Influence of G-Quadruplex Structural Elements on the Antiproliferative Properties of G-Rich Oligonucleotides. Int J Mol Sci 2021; 22:4941. [PMID: 34066551 PMCID: PMC8125755 DOI: 10.3390/ijms22094941] [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: 04/08/2021] [Revised: 05/03/2021] [Accepted: 05/04/2021] [Indexed: 12/28/2022] Open
Abstract
G-quadruplexes (G4s) are non-canonical structures formed by guanine-rich sequences of DNA or RNA that have attracted increased attention as anticancer agents. This systematic study aimed to investigate the anticancer potential of five G4-forming, sequence-related DNA molecules in terms of their thermodynamic and structural properties, biostability and cellular uptake. The antiproliferative studies revealed that less thermodynamically stable G4s with three G-tetrads in the core and longer loops are more predisposed to effectively inhibit cancer cell growth. By contrast, highly structured G4s with an extended core containing four G-tetrads and longer loops are characterized by more efficient cellular uptake and improved biostability. Various analyses have indicated that the G4 structural elements are intrinsic to the biological activity of these molecules. Importantly, the structural requirements are different for efficient cancer cell line inhibition and favorable G4 cellular uptake. Thus, the ultimate antiproliferative potential of G4s is a net result of the specific balance among the structural features that are favorable for efficient uptake and those that increase the inhibitory activity of the studied molecules. Understanding the G4 structural features and their role in the biological activity of G-rich molecules might facilitate the development of novel, more potent G4-based therapeutics with unprecedented anticancer properties.
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Affiliation(s)
| | - Weronika Kotkowiak
- Department of Nucleic Acids Bioengineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland;
| | - Anna Pasternak
- Department of Nucleic Acids Bioengineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland;
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6
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Jana J, Mohr S, Vianney YM, Weisz K. Structural motifs and intramolecular interactions in non-canonical G-quadruplexes. RSC Chem Biol 2021; 2:338-353. [PMID: 34458788 PMCID: PMC8341446 DOI: 10.1039/d0cb00211a] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 01/14/2021] [Indexed: 12/12/2022] Open
Abstract
Guanine(G)-rich DNA or RNA sequences can assemble or intramolecularly fold into G-quadruplexes formed through the stacking of planar G·G·G·G tetrads in the presence of monovalent cations. These secondary nucleic acid structures have convincingly been shown to also exist within a cellular environment exerting important regulatory functions in physiological processes. For identifying nucleic acid segments prone to quadruplex formation, a putative quadruplex sequence motif encompassing closely spaced tracts of three or more guanosines is frequently employed for bioinformatic search algorithms. Depending on the number and type of intervening residues as well as on solution conditions, such sequences may fold into various canonical G4 topologies with continuous G-columns. On the other hand, a growing number of sequences capable of quadruplex formation feature G-deficient guanine tracts, escaping the conservative consensus motif. By folding into non-canonical quadruplex structures, they adopt unique topologies depending on their specific sequence context. These include G-columns with only two guanines, bulges, snapback loops, D- and V-shaped loops as well as interlocked structures. This review focuses on G-quadruplex species carrying such distinct structural motifs. It evaluates characteristic features of their non-conventional scaffold and highlights principles of stabilizing interactions that also allow for their folding into stable G-quadruplex structures.
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Affiliation(s)
- Jagannath Jana
- Institute of Biochemistry, Universität Greifswald Felix-Hausdorff-Str. 4 D-17487 Greifswald Germany +49 3834 420-4427 +49 3834 420-4426
| | - Swantje Mohr
- Institute of Biochemistry, Universität Greifswald Felix-Hausdorff-Str. 4 D-17487 Greifswald Germany +49 3834 420-4427 +49 3834 420-4426
| | - Yoanes Maria Vianney
- Institute of Biochemistry, Universität Greifswald Felix-Hausdorff-Str. 4 D-17487 Greifswald Germany +49 3834 420-4427 +49 3834 420-4426
| | - Klaus Weisz
- Institute of Biochemistry, Universität Greifswald Felix-Hausdorff-Str. 4 D-17487 Greifswald Germany +49 3834 420-4427 +49 3834 420-4426
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7
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Das P, Winnerdy FR, Maity A, Mechulam Y, Phan AT. A novel minimal motif for left-handed G-quadruplex formation. Chem Commun (Camb) 2021; 57:2527-2530. [PMID: 33690751 DOI: 10.1039/d0cc08146a] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A recent study on the left-handed G-quadruplex (LHG4) DNA revealed a 12-nt minimal motif GTGGTGGTGGTG with the ability to independently form an LHG4 and to drive an adjacent sequence to LHG4 formation. Here we have identified a second LHG4-forming motif, GGTGGTGGTGTG, and determined the X-ray crystal structure of an LHG4 involving this motif. Our structural analysis indicated the role of split guanines and single thymine loops in promoting LHG4 formation.
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Affiliation(s)
- Poulomi Das
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore. and NTU Institute of Structural Biology, Nanyang Technological University, Singapore 636921, Singapore
| | - Arijit Maity
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
| | - Yves Mechulam
- Laboratoire de Biologie Structurale de la Cellule (BIOC), Ecole Polytechnique, CNRS-UMR7654, Institut Polytechnique de Paris, Palaiseau 91128, France
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore. and NTU Institute of Structural Biology, Nanyang Technological University, Singapore 636921, Singapore
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8
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Das P, Ngo KH, Winnerdy FR, Maity A, Bakalar B, Mechulam Y, Schmitt E, Phan AT. Bulges in left-handed G-quadruplexes. Nucleic Acids Res 2021; 49:1724-1736. [PMID: 33503265 PMCID: PMC7897477 DOI: 10.1093/nar/gkaa1259] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/10/2020] [Accepted: 12/18/2020] [Indexed: 12/03/2022] Open
Abstract
G-quadruplex (G4) DNA structures with a left-handed backbone progression have unique and conserved structural features. Studies on sequence dependency of the structures revealed the prerequisites and some minimal motifs required for left-handed G4 formation. To extend the boundaries, we explore the adaptability of left-handed G4s towards the existence of bulges. Here we present two X-ray crystal structures and an NMR solution structure of left-handed G4s accommodating one, two and three bulges. Bulges in left-handed G4s show distinct characteristics as compared to those in right-handed G4s. The elucidation of intricate structural details will help in understanding the possible roles and limitations of these unique structures.
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Affiliation(s)
- Poulomi Das
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Khac Huy Ngo
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Arijit Maity
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Blaž Bakalar
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Yves Mechulam
- Laboratoire de Biologie Structurale de la Cellule (BIOC), Ecole Polytechnique, CNRS-UMR7654, Institut Polytechnique de Paris, Palaiseau 91128, France
| | - Emmanuelle Schmitt
- Laboratoire de Biologie Structurale de la Cellule (BIOC), Ecole Polytechnique, CNRS-UMR7654, Institut Polytechnique de Paris, Palaiseau 91128, France
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, Singapore 636921, Singapore
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9
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Jing S, Liu Q, Jin Y, Li B. Dimeric G-Quadruplex: An Effective Nucleic Acid Scaffold for Lighting Up Thioflavin T. Anal Chem 2020; 93:1333-1341. [PMID: 33347269 DOI: 10.1021/acs.analchem.0c02637] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
As a recently identified higher-order quadruplex (G4) structure, the G4 dimer possesses unique structure and biological functions. In this work, we found accidentally that two tandem PW17 (one known G4-forming DNA) sequences can fold into a stable G4 dimer, and the G4 dimer can enhance dramatically the fluorescence intensity of thioflavin T (ThT). The G4 dimer/ThT fluorescence intensity is about ninefold that of the corresponding G4 monomer/ThT. Meanwhile, compared with the common G4/ThT system, G4 dimer/ThT exhibited more stable fluorescence emission in the media with various concentrations of Na+ and K+. On the basis of these findings, G4 dimer/ThT was used as a fluorescence indicator to construct one arched DNA probe for label-free detection of DNA. By incorporating a G4 dimer sequence in amplified products, we further designed one rolling circle amplification-based biosensing strategy to show the utility of this G4 dimer/ThT fluorescence indicator. This study demonstrates that dimeric G4 is an effective nucleic acid scaffold for lighting up ThT, showing promising applications in a label-free bioassay.
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Affiliation(s)
- Shaochun Jing
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Shaanxi Normal University, Xi'an 710062, China.,Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China
| | - Qiang Liu
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Shaanxi Normal University, Xi'an 710062, China.,Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China
| | - Yan Jin
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Shaanxi Normal University, Xi'an 710062, China.,Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China
| | - Baoxin Li
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, Shaanxi Normal University, Xi'an 710062, China.,Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China
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10
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Reddy Sannapureddi RK, Mohanty MK, Gautam AK, Sathyamoorthy B. Characterization of DNA G-quadruplex Topologies with NMR Chemical Shifts. J Phys Chem Lett 2020; 11:10016-10022. [PMID: 33179931 DOI: 10.1021/acs.jpclett.0c02969] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
G-quadruplexes are nucleic acid motifs formed by stacking of guanosine-tetrad pseudoplanes. They perform varied biological roles, and their distinctive structural features enable diverse applications. High-resolution structural characterization of G-quadruplexes is often time-consuming and expensive, calling for effective methods. Herein, we develop NMR chemical shifts and machine learning-based methodology that allows direct, rapid, and reliable analysis of canonical three-plane DNA G-quadruplexes sans isotopic enrichment. We show, for the first time, that each unique topology enforces a specific distribution of glycosidic torsion angles. Newly acquired carbon chemical shifts are exquisite probes for the dihedral angle distribution and provide immediate and unambiguous backbone topology assignment. The support vector machine learning methodology aids resonance assignment by providing plane indices for tetrad-forming guanosines. We further demonstrate the robustness by successful application of the methodology to a sequence that folds in two dissimilar topologies under different ionic conditions, providing its first atomic-level characterization.
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Affiliation(s)
| | - Manish Kumar Mohanty
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Anoop Kumar Gautam
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
| | - Bharathwaj Sathyamoorthy
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Madhya Pradesh 462066, India
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11
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Haase L, Weisz K. Locked nucleic acid building blocks as versatile tools for advanced G-quadruplex design. Nucleic Acids Res 2020; 48:10555-10566. [PMID: 32890406 PMCID: PMC7544228 DOI: 10.1093/nar/gkaa720] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/24/2020] [Accepted: 08/20/2020] [Indexed: 01/21/2023] Open
Abstract
A hybrid-type G-quadruplex is modified with LNA (locked nucleic acid) and 2′-F-riboguanosine in various combinations at the two syn positions of its third antiparallel G-tract. LNA substitution in the central tetrad causes a complete rearrangement to either a V-loop or antiparallel structure, depending on further modifications at the 5′-neighboring site. In the two distinct structural contexts, LNA-induced stabilization is most effective compared to modifications with other G surrogates, highlighting a potential use of LNA residues for designing not only parallel but various more complex G4 structures. For instance, the conventional V-loop is a structural element strongly favored by an LNA modification at the V-loop 3′-end in contrast with an alternative V-loop, clearly distinguishable by altered conformational properties and base-backbone interactions as shown in a detailed analysis of V-loop structures.
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Affiliation(s)
- Linn Haase
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17489 Greifswald, Germany
| | - Klaus Weisz
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Str. 4, D-17489 Greifswald, Germany
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12
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Maity A, Winnerdy FR, Chang WD, Chen G, Phan AT. Intra-locked G-quadruplex structures formed by irregular DNA G-rich motifs. Nucleic Acids Res 2020; 48:3315-3327. [PMID: 32100003 PMCID: PMC7102960 DOI: 10.1093/nar/gkaa008] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 12/30/2019] [Accepted: 02/24/2020] [Indexed: 12/14/2022] Open
Abstract
G-rich DNA sequences with tracts of three or more continuous guanines (G≥3) are known to have high propensity to adopt stable G-quadruplex (G4) structures. Bioinformatic analyses suggest high prevalence of G-rich sequences with short G-tracts (G≤2) in the human genome. However, due to limited structural studies, the folding principles of such sequences remain largely unexplored and hence poorly understood. Here, we present the solution NMR structure of a sequence named AT26 consisting of irregularly spaced G2 tracts and two isolated single guanines. The structure is a four-layered G4 featuring two bi-layered blocks, locked between themselves in an unprecedented fashion making it a stable scaffold. In addition to edgewise and propeller-type loops, AT26 also harbors two V-shaped loops: a 2-nt V-shaped loop spanning two G-tetrad layers and a 0-nt V-shaped loop spanning three G-tetrad layers, which are named as VS- and VR-loop respectively, based on their distinct structural features. The intra-lock motif can be a basis for extending the G-tetrad core and a very stable intra-locked G4 can be formed by a sequence with G-tracts of various lengths including several G2 tracts. Findings from this study will aid in understanding the folding of G4 topologies from sequences containing irregularly spaced multiple short G-tracts.
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Affiliation(s)
- Arijit Maity
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Weili Denyse Chang
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Gang Chen
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, Singapore 636921, Singapore
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13
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Pavc D, Wang B, Spindler L, Drevenšek-Olenik I, Plavec J, Šket P. GC ends control topology of DNA G-quadruplexes and their cation-dependent assembly. Nucleic Acids Res 2020; 48:2749-2761. [PMID: 31996902 PMCID: PMC7049726 DOI: 10.1093/nar/gkaa058] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/17/2020] [Accepted: 01/21/2020] [Indexed: 01/22/2023] Open
Abstract
GCn and GCnCG, where n = (G2AG4AG2), fold into well-defined, dimeric G-quadruplexes with unprecedented folding topologies in the presence of Na+ ions as revealed by nuclear magnetic resonance spectroscopy. Both G-quadruplexes exhibit unique combination of structural elements among which are two G-quartets, A(GGGG)A hexad and GCGC-quartet. Detailed structural characterization uncovered the crucial role of 5'-GC ends in formation of GCn and GCnCG G-quadruplexes. Folding in the presence of 15NH4+ and K+ ions leads to 3'-3' stacking of terminal G-quartets of GCn G-quadruplexes, while 3'-GC overhangs in GCnCG prevent dimerization. Results of the present study expand repertoire of possible G-quadruplex structures. This knowledge will be useful in DNA sequence design for nanotechnological applications that may require specific folding topology and multimerization properties.
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Affiliation(s)
- Daša Pavc
- Slovenian NMR Center, National Institute of Chemistry, 1000 Ljubljana, Slovenia
- University of Ljubljana, Faculty of Chemistry and Chemical Technology, 1000 Ljubljana, Slovenia
| | - Baifan Wang
- Slovenian NMR Center, National Institute of Chemistry, 1000 Ljubljana, Slovenia
| | - Lea Spindler
- University of Maribor, Faculty of Mechanical Engineering, 2000 Maribor, Slovenia
- Department of Complex Matter, Jozef Stefan Institute, 1000 Ljubljana, Slovenia
| | - Irena Drevenšek-Olenik
- Department of Complex Matter, Jozef Stefan Institute, 1000 Ljubljana, Slovenia
- University of Ljubljana, Faculty of Mathematics and Physics, 1000 Ljubljana, Slovenia
| | - Janez Plavec
- Slovenian NMR Center, National Institute of Chemistry, 1000 Ljubljana, Slovenia
- University of Ljubljana, Faculty of Chemistry and Chemical Technology, 1000 Ljubljana, Slovenia
- EN-FIST Center of Excellence, 1000 Ljubljana, Slovenia
| | - Primož Šket
- Slovenian NMR Center, National Institute of Chemistry, 1000 Ljubljana, Slovenia
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14
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Roy S, Ali A, Kamra M, Muniyappa K, Bhattacharya S. Specific stabilization of promoter G-Quadruplex DNA by 2,6-disubstituted amidoanthracene-9,10-dione based dimeric distamycin analogues and their selective cancer cell cytotoxicity. Eur J Med Chem 2020; 195:112202. [PMID: 32302880 DOI: 10.1016/j.ejmech.2020.112202] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/19/2020] [Accepted: 03/01/2020] [Indexed: 10/24/2022]
Abstract
We have designed and synthesized anthraquinone containing compounds which have oligopyrrole side chains of varying lengths. These compounds stabilized the G-quadruplex DNA formed in the promoter regions of c-MYC oncogenes selectively over the duplex DNA. These observations were recorded using UV-vis spectroscopic titrations, fluorescence measurements and circular dichroism (CD) spectral titrations. The potency of the compounds to stabilize the G4 DNA has been shown from the thermal denaturation experiments. The compound interacts with c-MYC G-quadruplex DNA through stacking mode as obtained from ethidium bromide displacement assay, cyclic voltammetric titration, and docking experiments. Molecular modeling studies suggested that the stacking of the anthraquinone moiety over the G-tetrad of the G4 structures are responsible for the stability of such quadruplex secondary structure. Furthermore, polymerase stop assay also supported the formation of stable G4 structures in the presence of the above-mentioned compounds. The compounds have shown selective cancer cell (HeLa and HEK293T) cytotoxicity over normal cells (NIH3T3 and HDFa) under in vitro conditions as determined from MTT based cell viability assay. Apoptosis was found to be the mechanistic pathway underlying the cancer cell cytotoxicity as obtained from Annexin V-FITC and PI dual staining assay which was further substantiated by nuclear morphological changes as observed by AO/EB dual staining assay. Cellular morphological changes, as well as nuclear condensation and fragmentation upon treatment with these compounds, were observed under bright field and confocal microscopy.
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Affiliation(s)
- Soma Roy
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Asfa Ali
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Mohini Kamra
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Kalappa Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, 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.
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15
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Haase L, Dickerhoff J, Weisz K. Sugar Puckering Drives G-Quadruplex Refolding: Implications for V-Shaped Loops. Chemistry 2020; 26:524-533. [PMID: 31609483 PMCID: PMC6973071 DOI: 10.1002/chem.201904044] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/10/2019] [Indexed: 01/04/2023]
Abstract
A DNA G-quadruplex adopting a (3+1) hybrid structure was modified in two adjacent syn positions of the antiparallel strand with anti-favoring 2'-deoxy-2'-fluoro-riboguanosine (F rG) analogues. The two substitutions promoted a structural rearrangement to a topology with the 5'-terminal G residue located in the central tetrad and the two modified residues linked by a V-shaped zero-nucleotide loop. Strikingly, whereas a sugar pucker in the preferred north domain is found for both modified nucleotides, the F rG analogue preceding the V-loop is forced to adopt the unfavored syn conformation in the new quadruplex fold. Apparently, a preferred C3'-endo sugar pucker within the V-loop architecture outweighs the propensity of the F rG analogue to adopt an anti glycosidic conformation. Refolding into a V-loop topology is likewise observed for a sequence modified at corresponding positions with two riboguanosine substitutions. In contrast, 2'-F-arabinoguanosine analogues with their favored south-east sugar conformation do not support formation of the V-loop topology. Examination of known G-quadruplexes with a V-shaped loop highlights the critical role of the sugar conformation for this distinct structural motif.
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Affiliation(s)
- Linn Haase
- Institute of BiochemistryUniversity of GreifswaldFelix-Hausdorff-Str. 417487GreifswaldGermany
| | - Jonathan Dickerhoff
- Institute of BiochemistryUniversity of GreifswaldFelix-Hausdorff-Str. 417487GreifswaldGermany
- Present address: Department of Medicinal Chemistry and Molecular PharmacologyCollege of PharmacyPurdue UniversityWest LafayetteIN47907USA
| | - Klaus Weisz
- Institute of BiochemistryUniversity of GreifswaldFelix-Hausdorff-Str. 417487GreifswaldGermany
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16
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Haase L, Weisz K. Switching the type of V-loop in sugar-modified G-quadruplexes through altered fluorine interactions. Chem Commun (Camb) 2020; 56:4539-4542. [DOI: 10.1039/d0cc01285h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The interplay of specific fluoro interactions determines conformational features of G-quadruplexes with two different 2′-fluoro-substituted residues.
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Affiliation(s)
- Linn Haase
- Institut für Biochemie
- Universität Greifswald
- D-17489 Greifswald
- Germany
| | - Klaus Weisz
- Institut für Biochemie
- Universität Greifswald
- D-17489 Greifswald
- Germany
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17
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Winnerdy FR, Bakalar B, Maity A, Vandana JJ, Mechulam Y, Schmitt E, Phan AT. NMR solution and X-ray crystal structures of a DNA molecule containing both right- and left-handed parallel-stranded G-quadruplexes. Nucleic Acids Res 2019; 47:8272-8281. [PMID: 31216034 PMCID: PMC6735952 DOI: 10.1093/nar/gkz349] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/16/2019] [Accepted: 06/13/2019] [Indexed: 01/29/2023] Open
Abstract
Analogous to the B- and Z-DNA structures in double-helix DNA, there exist both right- and left-handed quadruple-helix (G-quadruplex) DNA. Numerous conformations of right-handed and a few left-handed G-quadruplexes were previously observed, yet they were always identified separately. Here, we present the NMR solution and X-ray crystal structures of a right- and left-handed hybrid G-quadruplex. The structure reveals a stacking interaction between two G-quadruplex blocks with different helical orientations and displays features of both right- and left-handed G-quadruplexes. An analysis of loop mutations suggests that single-nucleotide loops are preferred or even required for the left-handed G-quadruplex formation. The discovery of a right- and left-handed hybrid G-quadruplex further expands the polymorphism of G-quadruplexes and is potentially useful in designing a left-to-right junction in G-quadruplex engineering.
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Affiliation(s)
- Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Blaž Bakalar
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Arijit Maity
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - J Jeya Vandana
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Yves Mechulam
- Laboratoire de Biochimie, UMR 7654, CNRS, Ecole Polytechnique, Palaiseau 91128, France
| | - Emmanuelle Schmitt
- Laboratoire de Biochimie, UMR 7654, CNRS, Ecole Polytechnique, Palaiseau 91128, France
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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18
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Wan C, Fu W, Jing H, Zhang N. NMR solution structure of an asymmetric intermolecular leaped V-shape G-quadruplex: selective recognition of the d(G2NG3NG4) sequence motif by a short linear G-rich DNA probe. Nucleic Acids Res 2019; 47:1544-1556. [PMID: 30445650 PMCID: PMC6379650 DOI: 10.1093/nar/gky1167] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 11/01/2018] [Accepted: 11/04/2018] [Indexed: 02/07/2023] Open
Abstract
Aside from classical loops among G-quadruplexes, the unique leaped V-shape scaffold spans over three G-tetrads, without any intervening residues. This scaffold enables a sharp reversal of two adjacent strand directions and simultaneously participates in forming the G-tetrad core. These features make this scaffold itself distinctive and thus an essentially more accessible target. As an alternative to the conventional antisense method using a complementary chain, forming an intermolecular G-quadruplex from two different oligomers, in which the longer one as the target is captured by a short G-rich fragment, could be helpful for recognizing G-rich sequences and structural motifs. However, such an intermolecular leaped V-shape G-quadruplex consisting of DNA oligomers of quite different lengths has not been evaluated. Here, we present the first nuclear magnetic resonance (NMR) study of an asymmetric intermolecular leaped V-shape G-quadruplex assembled between an Oxytricha nova telomeric sequence d(G2T4G4T4G4) and a single G-tract fragment d(TG4A). Furthermore, we explored the selectivity of this short fragment as a potential probe, examined the kinetic discrimination for probing a specific mutant, and proposed the key sequence motif d(G2NG3NG4) essential for building the leaped V-shape G-quadruplexes.
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Affiliation(s)
- Chanjuan Wan
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China.,University of Science and Technology of China, Hefei 230026, China
| | - Wenqiang Fu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China.,University of Science and Technology of China, Hefei 230026, China
| | - Haitao Jing
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China.,University of Science and Technology of China, Hefei 230026, China
| | - Na Zhang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China.,Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China.,Key Laboratory of Anhui Province for High Field Magnetic Resonance Imaging, Hefei 230031, China
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19
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Trajkovski M, Endoh T, Tateishi-Karimata H, Ohyama T, Tanaka S, Plavec J, Sugimoto N. Pursuing origins of (poly)ethylene glycol-induced G-quadruplex structural modulations. Nucleic Acids Res 2019; 46:4301-4315. [PMID: 29648656 PMCID: PMC5934638 DOI: 10.1093/nar/gky250] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/28/2018] [Indexed: 01/18/2023] Open
Abstract
Molecular crowding conditions provided by high concentration of cosolutes are utilized for characterization of biomolecules in cell-mimicking environment and development of drug-delivery systems. In this context, (poly)ethylene glycols are often used for studying non-canonical DNA structures termed G-quadruplexes, which came into focus by emerging structural biology findings and new therapeutic drug design approaches. Recently, several reports were made arguing against using (poly)ethylene glycols in role of molecular crowding agents due to their direct impact on DNA G-quadruplex stability and topology. However, the available data on structural details underlying DNA interaction is very scarce and thus limits in-depth comprehension. Herein, structural and thermodynamic analyses were strategically combined to assess G-quadruplex-cosolute interactions and address previously reported variances regarding the driving forces of G-rich DNA structural transformations under molecular crowding conditions. With the use of complementary (CD, NMR and UV) spectroscopic methods and model approach we characterized DNA G-quadruplex in the presence of the smallest and one of the largest typically used (poly)ethylene glycols. Dehydration effect is the key contributor to ethylene-glycol-induced increased stability of the G-quadruplex, which is in the case of the large cosolute mainly guided by the subtle direct interactions between PEG 8000 and the outer G-quartet regions.
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Affiliation(s)
- Marko Trajkovski
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, Ljubljana, SI-1000, Slovenia
| | - Tamaki Endoh
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Hisae Tateishi-Karimata
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Tatsuya Ohyama
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Shigenori Tanaka
- Department of Computational Science, Graduate School of System Informatics, Kobe University, 1-1, Rokkodai, Nada-ku, Kobe 657-8501, Japan
| | - Janez Plavec
- Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, Ljubljana, SI-1000, Slovenia.,EN→FIST Centre of Excellence, Trg OF 13, SI-1000 Ljubljana, Slovenia.,Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, p. p. 537, SI-1000 Ljubljana, Slovenia
| | - Naoki Sugimoto
- Frontier Institute for Biomolecular Engineering Research (FIBER), Konan University, 7-1-20 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan.,Graduate School of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20 Minatojima-Minamimachi, Kobe 650-0047, Japan
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20
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Lightfoot HL, Hagen T, Tatum NJ, Hall J. The diverse structural landscape of quadruplexes. FEBS Lett 2019; 593:2083-2102. [PMID: 31325371 DOI: 10.1002/1873-3468.13547] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 07/09/2019] [Accepted: 07/15/2019] [Indexed: 12/15/2022]
Abstract
G-quadruplexes are secondary structures formed in G-rich sequences in DNA and RNA. Considerable research over the past three decades has led to in-depth insight into these unusual structures in DNA. Since the more recent exploration into RNA G-quadruplexes, such structures have demonstrated their in cellulo existence, function and roles in pathology. In comparison to Watson-Crick-based secondary structures, most G-quadruplexes display highly redundant structural characteristics. However, numerous reports of G-quadruplex motifs/structures with unique features (e.g. bulges, long loops, vacancy) have recently surfaced, expanding the repertoire of G-quadruplex scaffolds. This review addresses G-quadruplex formation and structure, including recent reports of non-canonical G-quadruplex structures. Improved methods of detection will likely further expand this collection of novel structures and ultimately change the face of quadruplex-RNA targeting as a therapeutic strategy.
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Affiliation(s)
- Helen L Lightfoot
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Switzerland
| | - Timo Hagen
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Switzerland
| | - Natalie J Tatum
- Newcastle Cancer Centre, Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Jonathan Hall
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, ETH Zurich, Switzerland
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21
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Liu H, Wang R, Yu X, Shen F, Lan W, Haruehanroengra P, Yao Q, Zhang J, Chen Y, Li S, Wu B, Zheng L, Ma J, Lin J, Cao C, Li J, Sheng J, Gan J. High-resolution DNA quadruplex structure containing all the A-, G-, C-, T-tetrads. Nucleic Acids Res 2019; 46:11627-11638. [PMID: 30285239 PMCID: PMC6265469 DOI: 10.1093/nar/gky902] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 09/24/2018] [Indexed: 12/18/2022] Open
Abstract
DNA can form diverse structures, which predefine their physiological functions. Besides duplexes that carry the genetic information, quadruplexes are the most well-studied DNA structures. In addition to their important roles in recombination, replication, transcription and translation, DNA quadruplexes have also been applied as diagnostic aptamers and antidisease therapeutics. Herein we further expand the sequence and structure complexity of DNA quadruplex by presenting a high-resolution crystal structure of DNA1 (5′-AGAGAGATGGGTGCGTT-3′). This is the first quadruplex structure that contains all the internal A-, G-, C-, T-tetrads, A:T:A:T tetrads and bulged nucleotides in one single structure; as revealed by site-specific mutagenesis and biophysical studies, the central ATGGG motif plays important role in the quadruplex formation. Interestingly, our structure also provides great new insights into cation recognition, including the first-time reported Pb2+, by tetrad structures.
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Affiliation(s)
- Hehua Liu
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200433, China.,State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Rui Wang
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Xiang Yu
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200433, China.,State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Fusheng Shen
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Wenxian Lan
- State Key Laboratory of Bioorganic and Natural Product Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Shanghai 200032, China
| | - Phensinee Haruehanroengra
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Qingqing Yao
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Jing Zhang
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Yiqing Chen
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Suhua Li
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Baixing Wu
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Lina Zheng
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Jinbiao Ma
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Jinzhong Lin
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Chunyang Cao
- State Key Laboratory of Bioorganic and Natural Product Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, Shanghai 200032, China
| | - Jixi Li
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200433, China.,Department of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Jia Sheng
- Department of Chemistry and The RNA Institute, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Jianhua Gan
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200433, China
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22
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Towards Understanding of Polymorphism of the G-rich Region of Human Papillomavirus Type 52. Molecules 2019; 24:molecules24071294. [PMID: 30987050 PMCID: PMC6479982 DOI: 10.3390/molecules24071294] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 03/29/2019] [Accepted: 03/31/2019] [Indexed: 11/17/2022] Open
Abstract
The potential to affect gene expression via G-quadruplex stabilization has been extended to all domains of life, including viruses. Here, we investigate the polymorphism and structures of G-quadruplexes of the human papillomavirus type 52 with UV, CD and NMR spectroscopy and gel electrophoresis. We show that oligonucleotide with five G-tracts folds into several structures and that naturally occurring single nucleotide polymorphisms (SNPs) have profound effects on the structural polymorphism in the context of G-quadruplex forming propensity, conformational heterogeneity and folding stability. With help of SNP analysis, we were able to select one of the predominant forms, formed by G-rich sequence d(G₃TAG₃CAG₄ACACAG₃T). This oligonucleotide termed HPV52(1-4) adopts a three G-quartet snap back (3 + 1) type scaffold with four syn guanine residues, two edgewise loops spanning the same groove, a no-residue V loop and a propeller type loop. The first guanine residue is incorporated in the central G-quartet and all four-guanine residues from G4 stretch are included in the three quartet G-quadruplex core. Modification studies identified several structural elements that are important for stabilization of the described G-quadruplex fold. Our results expand set of G-rich targets in viral genomes and address the fundamental questions regarding folding of G-rich sequences.
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23
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Lenarčič Živković M, Rozman J, Plavec J. Adenine-Driven Structural Switch from a Two- to Three-Quartet DNA G-Quadruplex. Angew Chem Int Ed Engl 2018; 57:15395-15399. [PMID: 30222243 PMCID: PMC6563693 DOI: 10.1002/anie.201809328] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Indexed: 12/15/2022]
Abstract
A G-rich sequence found in the regulatory region of the RANKL gene, which is associated with homeostasis of bone metabolism, folds into a two-quartet basket-type G-quadruplex stabilized by A⋅G⋅A and G⋅G⋅G base-triads. Perusal of local structural features together with G/A-to-T modifications uncovered the critical role of A5 for the formation of a distinct antiparallel two-quartet topology and not the three-quartet topology that would be expected based on the sequence with four GGG-tracts alone. The structural changes induced by the A5-to-T5 modification include a switch in orientation and relative positions of G-strands that together with anti to syn reorientation of G12 provide insights into the complexity of the interactions that influence the folding of G-rich DNA. Understanding the impact of loop residues on the stability and formation of G-quadruplexes advances our knowledge and ability to predict structures adopted by G-rich sequences, which are involved in regulatory mechanisms in the cell, and may also facilitate drug design.
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Affiliation(s)
| | - Jan Rozman
- Slovenian NMR CentreNational Institute of ChemistryHajdrihova 9LjubljanaSlovenia
| | - Janez Plavec
- Slovenian NMR CentreNational Institute of ChemistryHajdrihova 9LjubljanaSlovenia
- EN- FIST Centre of ExcellenceTrg OF 13LjubljanaSlovenia
- Faculty of Chemistry and Chemical TechnologyUniversity of LjubljanaVečna pot 113LjubljanaSlovenia
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24
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Lenarčič Živković M, Rozman J, Plavec J. Adenine‐Driven Structural Switch from a Two‐ to Three‐Quartet DNA G‐Quadruplex. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201809328] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | - Jan Rozman
- Slovenian NMR CentreNational Institute of Chemistry Hajdrihova 9 Ljubljana Slovenia
| | - Janez Plavec
- Slovenian NMR CentreNational Institute of Chemistry Hajdrihova 9 Ljubljana Slovenia
- EN- FIST Centre of Excellence Trg OF 13 Ljubljana Slovenia
- Faculty of Chemistry and Chemical TechnologyUniversity of Ljubljana Večna pot 113 Ljubljana Slovenia
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25
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Liu Y, Lan W, Wang C, Cao C. A putative G-quadruplex structure in the proximal promoter of VEGFR-2 has implications for drug design to inhibit tumor angiogenesis. J Biol Chem 2018; 293:8947-8955. [PMID: 29666187 DOI: 10.1074/jbc.ra118.002666] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 04/03/2018] [Indexed: 01/11/2023] Open
Abstract
Tumor angiogenesis is mainly regulated by vascular endothelial growth factor (VEGF) produced by cancer cells. It is active on the endothelium via VEGF receptor 2 (VEGFR-2). G-quadruplexes are DNA secondary structures formed by guanine-rich sequences, for example, within gene promoters where they may contribute to transcriptional activity. The proximal promoter of VEGFR-2 contains a G-quadruplex, which has been suggested to interact with small molecules that inhibit VEGFR-2 expression and thereby tumor angiogenesis. However, its structure is not known. Here, we determined its NMR solution structure, which is composed of three stacked G-tetrads containing three syn guanines. The first guanine (G1) is positioned within the central G-tetrad. We also observed that a noncanonical, V-shaped loop spans three G-tetrad planes, including no bridging nucleotides. A long and diagonal loop, which includes six nucleotides, connects reversal double chains. With a melting temperature of 54.51 °C, the scaffold of this quadruplex is stabilized by one G-tetrad plane stacking with one nonstandard bp, G3-C8, whose bases interact with each other through only one hydrogen bond. In summary, the NMR solution structure of the G-quadruplex in the proximal promoter region of the VEGFR-2 gene reported here has uncovered its key features as a potential anticancer drug target.
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Affiliation(s)
- Yaping Liu
- From the State Key Laboratory of Bioorganic and Natural Product Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry and.,University of Chinese Academy of Sciences, Number 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China.,Collaborative Innovation Center of Chemistry for Life Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China and
| | - Wenxian Lan
- From the State Key Laboratory of Bioorganic and Natural Product Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry and.,University of Chinese Academy of Sciences, Number 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Chunxi Wang
- From the State Key Laboratory of Bioorganic and Natural Product Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry and.,University of Chinese Academy of Sciences, Number 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Chunyang Cao
- From the State Key Laboratory of Bioorganic and Natural Product Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry and .,University of Chinese Academy of Sciences, Number 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China.,Collaborative Innovation Center of Chemistry for Life Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China and
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Adrian M, Winnerdy FR, Heddi B, Phan AT. Rotation of Guanine Amino Groups in G-Quadruplexes: A Probe for Local Structure and Ligand Binding. Biophys J 2017; 113:775-784. [PMID: 28834714 DOI: 10.1016/j.bpj.2017.05.053] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/22/2017] [Accepted: 05/25/2017] [Indexed: 12/25/2022] Open
Abstract
Nucleic acids are dynamic molecules whose functions may depend on their conformational fluctuations and local motions. In particular, amino groups are dynamic components of nucleic acids that participate in the formation of various secondary structures such as G-quadruplexes. Here, we present a cost-efficient NMR method to quantify the rotational dynamics of guanine amino groups in G-quadruplex nucleic acids. An isolated spectrum of amino protons from a specific tetrad-bound guanine can be extracted from the nuclear Overhauser effect spectroscopy spectrum based on the close proximity between the intra-residue imino and amino protons. We apply the method in different structural contexts of G-quadruplexes and their complexes. Our results highlight the role of stacking and hydrogen-bond interactions in restraining amino-group rotation. The measurement of the rotation rate of individual amino groups could give insight into the dynamic processes occurring at specific locations within G-quadruplex nucleic acids, providing valuable probes for local structure, dynamics, and ligand binding.
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Affiliation(s)
- Michael Adrian
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Fernaldo Richtia Winnerdy
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Brahim Heddi
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Anh Tuân Phan
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore.
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27
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Brčić J, Plavec J. G-quadruplex formation of oligonucleotides containing ALS and FTD related GGGGCC repeat. Front Chem Sci Eng 2016. [DOI: 10.1007/s11705-016-1556-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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28
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Largy E, Mergny JL, Gabelica V. Role of Alkali Metal Ions in G-Quadruplex Nucleic Acid Structure and Stability. Met Ions Life Sci 2016; 16:203-58. [PMID: 26860303 DOI: 10.1007/978-3-319-21756-7_7] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
G-quadruplexes are guanine-rich nucleic acids that fold by forming successive quartets of guanines (the G-tetrads), stabilized by intra-quartet hydrogen bonds, inter-quartet stacking, and cation coordination. This specific although highly polymorphic type of secondary structure deviates significantly from the classical B-DNA duplex. G-quadruplexes are detectable in human cells and are strongly suspected to be involved in a number of biological processes at the DNA and RNA levels. The vast structural polymorphism exhibited by G-quadruplexes, together with their putative biological relevance, makes them attractive therapeutic targets compared to canonical duplex DNA. This chapter focuses on the essential and specific coordination of alkali metal cations by G-quadruplex nucleic acids, and most notably on studies highlighting cation-dependent dissimilarities in their stability, structure, formation, and interconversion. Section 1 surveys G-quadruplex structures and their interactions with alkali metal ions while Section 2 presents analytical methods used to study G-quadruplexes. The influence of alkali cations on the stability, structure, and kinetics of formation of G-quadruplex structures of quadruplexes will be discussed in Sections 3 and 4. Section 5 focuses on the cation-induced interconversion of G-quadruplex structures. In Sections 3 to 5, we will particularly emphasize the comparisons between cations, most often K(+) and Na(+) because of their prevalence in the literature and in cells.
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Affiliation(s)
- Eric Largy
- ARNA Laboratory, Université Bordeaux, IECB, 2, rue Robert Escarpit, F-33600, Pessac, France.,ARNA Laboratory, INSERM, U869, F-33000, Bordeaux, France
| | - Jean-Louis Mergny
- ARNA Laboratory, Université Bordeaux, IECB, 2, rue Robert Escarpit, F-33600, Pessac, France. .,ARNA Laboratory, INSERM, U869, F-33000, Bordeaux, France.
| | - Valérie Gabelica
- ARNA Laboratory, Université Bordeaux, IECB, 2, rue Robert Escarpit, F-33600, Pessac, France. .,ARNA Laboratory, INSERM, U869, F-33000, Bordeaux, France.
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29
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Cheong VV, Lech CJ, Heddi B, Phan AT. Inverting the G-Tetrad Polarity of a G-Quadruplex by Using Xanthine and 8-Oxoguanine. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201507034] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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30
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Cheong VV, Lech CJ, Heddi B, Phan AT. Inverting the G-Tetrad Polarity of a G-Quadruplex by Using Xanthine and 8-Oxoguanine. Angew Chem Int Ed Engl 2015; 55:160-3. [PMID: 26563582 DOI: 10.1002/anie.201507034] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 09/04/2015] [Indexed: 01/24/2023]
Abstract
G-quadruplexes are four-stranded nucleic acid structures that are built from consecutively stacked guanine tetrad (G-tetrad) assemblies. The simultaneous incorporation of two guanine base lesions, xanthine (X) and 8-oxoguanine (O), within a single G-tetrad of a G-quadruplex was recently shown to lead to the formation of a stable G⋅G⋅X⋅O tetrad. Herein, a judicious introduction of X and O into a human telomeric G-quadruplex-forming sequence is shown to reverse the hydrogen-bond polarity of the modified G-tetrad while preserving the original folding topology. The control exerted over G-tetrad polarity by joint X⋅O modification will be valuable for the design and programming of G-quadruplex structures and their properties.
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Affiliation(s)
- Vee Vee Cheong
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)
| | - Christopher Jacques Lech
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)
| | - Brahim Heddi
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore)
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore).
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31
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Marušič M, Plavec J. The Effect of DNA Sequence Directionality on G-Quadruplex Folding. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201505348] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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32
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Marušič M, Plavec J. The Effect of DNA Sequence Directionality on G‐Quadruplex Folding. Angew Chem Int Ed Engl 2015; 54:11716-9. [DOI: 10.1002/anie.201505348] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 07/20/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Maja Marušič
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia)
| | - Janez Plavec
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana (Slovenia)
- EN‐FIST Center of Excellence, 1000 Ljubljana (Slovenia)
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, 1000 Ljubljana (Slovenia)
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33
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Brčić J, Plavec J. Solution structure of a DNA quadruplex containing ALS and FTD related GGGGCC repeat stabilized by 8-bromodeoxyguanosine substitution. Nucleic Acids Res 2015; 43:8590-600. [PMID: 26253741 PMCID: PMC4787828 DOI: 10.1093/nar/gkv815] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 07/30/2015] [Indexed: 12/13/2022] Open
Abstract
A prolonged expansion of GGGGCC repeat within non-coding region of C9orf72 gene has been identified as the most common cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), which are devastating neurodegenerative disorders. Formation of unusual secondary structures within expanded GGGGCC repeat, including DNA and RNA G-quadruplexes and R-loops was proposed to drive ALS and FTD pathogenesis. Initial NMR investigation on DNA oligonucleotides with four repeat units as the shortest model with the ability to form an unimolecular G-quadruplex indicated their folding into multiple G-quadruplex structures in the presence of K+ ions. Single dG to 8Br-dG substitution at position 21 in oligonucleotide d[(G4C2)3G4] and careful optimization of folding conditions enabled formation of mostly a single G-quadruplex species, which enabled determination of a high-resolution structure with NMR. G-quadruplex structure adopted by d[(G4C2)3GGBrGG] is composed of four G-quartets, which are connected by three edgewise C-C loops. All four strands adopt antiparallel orientation to one another and have alternating syn-anti progression of glycosidic conformation of guanine residues. One of the cytosines in every loop is stacked upon the G-quartet contributing to a very compact and stable structure.
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Affiliation(s)
- Jasna Brčić
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, SI-1000, Ljubljana, Slovenia
| | - Janez Plavec
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, SI-1000, Ljubljana, Slovenia Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia EN-FIST Center of Excellence, Ljubljana, Slovenia
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34
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Kreig A, Calvert J, Sanoica J, Cullum E, Tipanna R, Myong S. G-quadruplex formation in double strand DNA probed by NMM and CV fluorescence. Nucleic Acids Res 2015. [PMID: 26202971 PMCID: PMC4652765 DOI: 10.1093/nar/gkv749] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
G-quadruplexes (GQs) are alternative DNA secondary structures that can form throughout the human genome and control the replication and transcription of important regulatory genes. Here, we established an ensemble fluorescence assay by employing two GQ-interacting compounds, N-methyl mesoporphyrin IX (NMM) and Crystal Violet (CV). This enables quantitative measurement of the GQ folding propensity and conformation specificity in both single strand (ss) and double strand (ds) DNA. Our GQ mapping indicates that the likelihood of GQ formation is substantially diminished in dsDNA, likely due to the competition from the Watson-Crick base pairing. Unlike GQ folding sequence in ssDNA which forms both parallel and antiparallel GQs, dsDNA displays only parallel folding. Additionally, we employed single molecule FRET to obtain a direct quantitation of stably formed-, weakly folded and unfolded GQ conformations. The findings of this study and the method developed here will enable identifying and classifying potential GQ-forming sequences in human genome.
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Affiliation(s)
- Alex Kreig
- Bioengineering Department, University of Illinois; 1304 W. Springfield Ave. Urbana, IL 61801, USA
| | - Jacob Calvert
- Bioengineering Department, University of Illinois; 1304 W. Springfield Ave. Urbana, IL 61801, USA
| | - Janet Sanoica
- Bioengineering Department, University of Illinois; 1304 W. Springfield Ave. Urbana, IL 61801, USA
| | - Emily Cullum
- Bioengineering Department, University of Illinois; 1304 W. Springfield Ave. Urbana, IL 61801, USA
| | - Ramreddy Tipanna
- Bioengineering Department, University of Illinois; 1304 W. Springfield Ave. Urbana, IL 61801, USA
| | - Sua Myong
- Bioengineering Department, University of Illinois; 1304 W. Springfield Ave. Urbana, IL 61801, USA Biophysics and Computational Biology; 1110 W. Green St. Urbana, IL 61801, USA Institute for Genomic Biology; 1206 Gregory Drive, Urbana, IL 61801, USA Physics Frontier Center (Center of Physics for Living Cells), University of Illinois; 1110 W. Green St. Urbana, IL 61801, USA
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35
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König SLB, Evans AC, Huppert JL. Seven essential questions on G-quadruplexes. Biomol Concepts 2015; 1:197-213. [PMID: 25961997 DOI: 10.1515/bmc.2010.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The helical duplex architecture of DNA was discovered by Francis Crick and James Watson in 1951 and is well known and understood. However, nucleic acids can also adopt alternative structural conformations that are less familiar, although no less biologically relevant, such as the G-quadruplex. G-quadruplexes continue to be the subject of a rapidly expanding area of research, owing to their significant potential as therapeutic targets and their unique biophysical properties. This review begins by focusing on G-quadruplex structure, elucidating the intermolecular and intramolecular interactions underlying its formation and highlighting several substructural variants. A variety of methods used to characterize these structures are also outlined. The current state of G-quadruplex research is then addressed by proffering seven pertinent questions for discussion. This review concludes with an overview of possible directions for future research trajectories in this exciting and relevant field.
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36
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Lim KW, Jenjaroenpun P, Low ZJ, Khong ZJ, Ng YS, Kuznetsov VA, Phan AT. Duplex stem-loop-containing quadruplex motifs in the human genome: a combined genomic and structural study. Nucleic Acids Res 2015; 43:5630-46. [PMID: 25958397 PMCID: PMC4477648 DOI: 10.1093/nar/gkv355] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 04/02/2015] [Indexed: 12/12/2022] Open
Abstract
Duplex stem-loops and four-stranded G-quadruplexes have been implicated in (patho)biological processes. Overlap of stem-loop- and quadruplex-forming sequences could give rise to quadruplex-duplex hybrids (QDH), which combine features of both structural forms and could exhibit unique properties. Here, we present a combined genomic and structural study of stem-loop-containing quadruplex sequences (SLQS) in the human genome. Based on a maximum loop length of 20 nt, our survey identified 80 307 SLQS, embedded within 60 172 unique clusters. Our analysis suggested that these should cover close to half of total SLQS in the entire genome. Among these, 48 508 SLQS were strand-specifically located in genic/promoter regions, with the majority of genes displaying a low number of SLQS. Notably, genes containing abundant SLQS clusters were strongly associated with brain tissues. Enrichment analysis of SLQS-positive genes and mapping of SLQS onto transcriptional/mutagenesis hotspots and cancer-associated genes, provided a statistical framework supporting the biological involvements of SLQS. In vitro formation of diverse QDH by selective SLQS hits were successfully verified by nuclear magnetic resonance spectroscopy. Folding topologies of two SLQS were elucidated in detail. We also demonstrated that sequence changes at mutation/single-nucleotide polymorphism loci could affect the structural conformations adopted by SLQS. Thus, our predicted SLQS offer novel insights into the potential involvement of QDH in diverse (patho)biological processes and could represent novel regulatory signals.
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Affiliation(s)
- Kah Wai Lim
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Piroon Jenjaroenpun
- Department of Genome and Gene Expression Data Analysis, Bioinformatics Institute, 138671, Singapore
| | - Zhen Jie Low
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore School of Biological Sciences, Nanyang Technological University, 637551, Singapore
| | - Zi Jian Khong
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
| | - Yi Siang Ng
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
| | | | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore
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37
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A tetrahelical DNA fold adopted by tandem repeats of alternating GGG and GCG tracts. Nat Commun 2014; 5:5831. [PMID: 25500730 PMCID: PMC4275592 DOI: 10.1038/ncomms6831] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 11/12/2014] [Indexed: 01/21/2023] Open
Abstract
DNA can form diverse higher-order structures, whose details are greatly dependent on nucleotide sequence. G-rich sequences containing four or more repeats of three guanines are expected to form G-quadruplexes. Here we show that DNA sequences with GGGAGCG repeats found in the regulatory region of the PLEKHG3 gene are capable of forming tetrahelical DNA structures that are distinct from G-quadruplexes. The d(GGGAGCGAGGGAGCG) sequence, VK1, forms a dimer. Two VK1 sequences connected by an adenine residue, VK2, fold into a monomer, which shares identical structural characteristics with the VK1 fold. Their four-stranded architectures are stabilized by four G-C, four G-A and six G-G base pairs. No G-quartets or Hoogsteen-type hydrogen-bonded guanine residues are present and the overall topology is conserved in the presence of Li(+), Na(+), K(+) and NH4(+) ions. Unique structural features include two edgewise loops on each side of the structure stabilized by three G-G base pairs in N1-carbonyl symmetric geometry.
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38
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Triplex intermediates in folding of human telomeric quadruplexes probed by microsecond-scale molecular dynamics simulations. Biochimie 2014; 105:22-35. [DOI: 10.1016/j.biochi.2014.07.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 07/01/2014] [Indexed: 11/23/2022]
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Tippana R, Xiao W, Myong S. G-quadruplex conformation and dynamics are determined by loop length and sequence. Nucleic Acids Res 2014; 42:8106-14. [PMID: 24920827 PMCID: PMC4081081 DOI: 10.1093/nar/gku464] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The quadruplex forming G-rich sequences are unevenly distributed throughout the human genome. Their enrichment in oncogenic promoters and telomeres has generated interest in targeting G-quadruplex (GQ) for an anticancer therapy. Here, we present a quantitative analysis on the conformations and dynamics of GQ forming sequences measured by single molecule fluorescence. Additionally, we relate these properties to GQ targeting ligands and G4 resolvase 1 (G4R1) protein binding. Our result shows that both the loop (non-G components) length and sequence contribute to the conformation of the GQ. Real time single molecule traces reveal that the folding dynamics also depend on the loop composition. We demonstrate that GQ-stabilizing small molecules, N-methyl mesoporphyrin IX (NMM), its analog, NMP and the G4R1 protein bind selectively to the parallel GQ conformation. Our findings point to the complexity of GQ folding governed by the loop length and sequence and how the GQ conformation determines the small molecule and protein binding propensity.
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Affiliation(s)
- Ramreddy Tippana
- Bioengineering Department, University of Illinois, 1304 W. Springfield Ave., Urbana, IL 61801, USA
| | - Weikun Xiao
- Bioengineering Department, University of Illinois, 1304 W. Springfield Ave., Urbana, IL 61801, USA
| | - Sua Myong
- Bioengineering Department, University of Illinois, 1304 W. Springfield Ave., Urbana, IL 61801, USA Biophysics and Computational Biology, 1110 W. Green St., Urbana, IL 61801, USA Institute for Genomic Biology, 1206 Gregory Drive, Urbana, IL 61801, USA Physics Frontier Center (Center of Physics for Living Cells), University of Illinois, 1110 W. Green St., Urbana, IL 61801, USA
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40
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Adrian M, Ang DJ, Lech CJ, Heddi B, Nicolas A, Phan AT. Structure and conformational dynamics of a stacked dimeric G-quadruplex formed by the human CEB1 minisatellite. J Am Chem Soc 2014; 136:6297-305. [PMID: 24742225 DOI: 10.1021/ja4125274] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
CEB1 is a highly polymorphic human minisatellite. In yeast, the size variation of CEB1 tandem arrays has been associated with the capacity of the motif to form G-quadruplexes. Here we report on the NMR solution structure of a G-quadruplex formed by the CEB1 DNA G-rich fragment d(AGGGGGGAGGGAGGGTGG), harboring several G-tracts including one with six continuous guanines. This sequence forms a dimeric G-quadruplex involving the stacking of two subunits, each being a unique snapback parallel-stranded scaffold with three G-tetrad layers, three double-chain-reversal loops, and a V-shaped loop. The two subunits are stacked at their 5'-end tetrads, and multiple stacking rotamers may be present due to a high symmetry at the stacking interface. There is a conformational exchange in the millisecond time scale involving a swapping motion between two bases of the six-guanine tract. Our results not only add to the understanding of how the G-quadruplex formation in human minisatellite leads to genetic instability but also address the fundamental questions regarding stacking of G-quadruplexes and how a long continuous G-tract participates in the structure and conformational dynamics of G-quadruplexes.
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Affiliation(s)
- Michael Adrian
- School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore
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41
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Li Z, Lech CJ, Phan AT. Sugar-modified G-quadruplexes: effects of LNA-, 2'F-RNA- and 2'F-ANA-guanosine chemistries on G-quadruplex structure and stability. Nucleic Acids Res 2013; 42:4068-79. [PMID: 24371274 PMCID: PMC3973314 DOI: 10.1093/nar/gkt1312] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
G-quadruplex-forming oligonucleotides containing modified nucleotide chemistries have demonstrated promising pharmaceutical potential. In this work, we systematically investigate the effects of sugar-modified guanosines on the structure and stability of a (4+0) parallel and a (3+1) hybrid G-quadruplex using over 60 modified sequences containing a single-position substitution of 2′-O-4′-C-methylene-guanosine (LNAG), 2′-deoxy-2′-fluoro-riboguanosine (FG) or 2′-deoxy-2′-fluoro-arabinoguanosine (FANAG). Our results are summarized in two parts: (I) Generally, LNAG substitutions into ‘anti’ position guanines within a guanine-tetrad lead to a more stable G-quadruplex, while substitutions into ‘syn’ positions disrupt the native G-quadruplex conformation. However, some interesting exceptions to this trend are observed. We discover that a LNAG modification upstream of a short propeller loop hinders G-quadruplex formation. (II) A single substitution of either FG or FANAG into a ‘syn’ position is powerful enough to perturb the (3+1) G-quadruplex. Substitution of either FG or FANAG into any ‘anti’ position is well tolerated in the two G-quadruplex scaffolds. FANAG substitutions to ‘anti’ positions are better tolerated than their FG counterparts. In both scaffolds, FANAG substitutions to the central tetrad layer are observed to be the most stabilizing. The observations reported herein on the effects of LNAG, FG and FANAG modifications on G-quadruplex structure and stability will enable the future design of pharmaceutically relevant oligonucleotides.
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Affiliation(s)
- Zhe Li
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
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42
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Lim KW, Ng VCM, Martín-Pintado N, Heddi B, Phan AT. Structure of the human telomere in Na+ solution: an antiparallel (2+2) G-quadruplex scaffold reveals additional diversity. Nucleic Acids Res 2013; 41:10556-62. [PMID: 23999095 PMCID: PMC3905899 DOI: 10.1093/nar/gkt771] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Single-stranded DNA overhangs at the ends of human telomeric repeats are capable of adopting four-stranded G-quadruplex structures, which could serve as potential anticancer targets. Out of the five reported intramolecular human telomeric G-quadruplex structures, four were formed in the presence of K+ ions and only one in the presence of Na+ ions, leading often to a perception that this structural polymorphism occurs exclusively in the presence of K+ but not Na+. Here we present the structure of a new antiparallel (2+2) G-quadruplex formed by a derivative of a 27-nt human telomeric sequence in Na+ solution, which comprises a novel core arrangement distinct from the known topologies. This structure complements the previously elucidated basket-type human telomeric G-quadruplex to serve as reference structures in Na+-containing environment. These structures, together with the coexistence of other conformations in Na+ solution as observed by nuclear magnetic resonance spectroscopy, establish the polymorphic nature of human telomeric repeats beyond the influence of K+ ions.
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Affiliation(s)
- Kah Wai Lim
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore, School of Biological Sciences, Nanyang Technological University, 637551 Singapore and Instituto de Química Física Rocasolano, CSIC, 28006 Madrid, Spain
| | - Veronica Chinn Min Ng
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore, School of Biological Sciences, Nanyang Technological University, 637551 Singapore and Instituto de Química Física Rocasolano, CSIC, 28006 Madrid, Spain
| | - Nerea Martín-Pintado
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore, School of Biological Sciences, Nanyang Technological University, 637551 Singapore and Instituto de Química Física Rocasolano, CSIC, 28006 Madrid, Spain
| | - Brahim Heddi
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore, School of Biological Sciences, Nanyang Technological University, 637551 Singapore and Instituto de Química Física Rocasolano, CSIC, 28006 Madrid, Spain
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore, School of Biological Sciences, Nanyang Technological University, 637551 Singapore and Instituto de Química Física Rocasolano, CSIC, 28006 Madrid, Spain
- *To whom correspondence should be addressed. Tel: +65 6514 1915; Fax: +65 6795 7981;
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Marušič M, Veedu RN, Wengel J, Plavec J. G-rich VEGF aptamer with locked and unlocked nucleic acid modifications exhibits a unique G-quadruplex fold. Nucleic Acids Res 2013; 41:9524-36. [PMID: 23935071 PMCID: PMC3814366 DOI: 10.1093/nar/gkt697] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The formation of a single G-quadruplex structure adopted by a promising 25 nt G-rich vascular endothelial growth factor aptamer in a K+ rich environment was facilitated by locked nucleic acid modifications. An unprecedented all parallel-stranded monomeric G-quadruplex with three G-quartet planes exhibits several unique structural features. Five consecutive guanine residues are all involved in G-quartet formation and occupy positions in adjacent DNA strands, which are bridged with a no-residue propeller-type loop. A two-residue D-shaped loop facilitates inclusion of an isolated guanine residue into the vacant spot within the G-quartet. The remaining two G-rich tracts of three residues each adopt parallel orientation and are linked with edgewise and propeller loops. Both 5′ with 3 nt and 3′ with 4 nt overhangs display well-defined conformations, with latter adopting a basket handle topology. Locked residues contribute to thermal stabilization of the adopted structure and formation of structurally pre-organized intermediates that facilitate folding into a single G-quadruplex. Understanding the impact of chemical modifications on folding, thermal stability and structural polymorphism of G-quadruplexes provides means for the improvement of vascular endothelial growth factor aptamers and advances our insights into driving nucleic acid structure by locking or unlocking the conformation of sugar moieties of nucleotides in general.
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Affiliation(s)
- Maja Marušič
- Slovenian NMR Center, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia, School of Chemistry & Molecular Biosciences, University of Queensland, St Lucia, Brisbane, 4072 Australia, Nucleic Acid Center, Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, 5230 Odense M, Denmark, EN-FIST Center of Excellence, SI-1000 Ljubljana, Slovenia and Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia
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Stadlbauer P, Krepl M, Cheatham TE, Koča J, Šponer J. Structural dynamics of possible late-stage intermediates in folding of quadruplex DNA studied by molecular simulations. Nucleic Acids Res 2013; 41:7128-43. [PMID: 23700306 PMCID: PMC3737530 DOI: 10.1093/nar/gkt412] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 04/18/2013] [Accepted: 04/24/2013] [Indexed: 12/31/2022] Open
Abstract
Explicit solvent molecular dynamics simulations have been used to complement preceding experimental and computational studies of folding of guanine quadruplexes (G-DNA). We initiate early stages of unfolding of several G-DNAs by simulating them under no-salt conditions and then try to fold them back using standard excess salt simulations. There is a significant difference between G-DNAs with all-anti parallel stranded stems and those with stems containing mixtures of syn and anti guanosines. The most natural rearrangement for all-anti stems is a vertical mutual slippage of the strands. This leads to stems with reduced numbers of tetrads during unfolding and a reduction of strand slippage during refolding. The presence of syn nucleotides prevents mutual strand slippage; therefore, the antiparallel and hybrid quadruplexes initiate unfolding via separation of the individual strands. The simulations confirm the capability of G-DNA molecules to adopt numerous stable locally and globally misfolded structures. The key point for a proper individual folding attempt appears to be correct prior distribution of syn and anti nucleotides in all four G-strands. The results suggest that at the level of individual molecules, G-DNA folding is an extremely multi-pathway process that is slowed by numerous misfolding arrangements stabilized on highly variable timescales.
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Affiliation(s)
- Petr Stadlbauer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, UT 84124, USA and CEITEC – Central European Institute of Technology, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Miroslav Krepl
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, UT 84124, USA and CEITEC – Central European Institute of Technology, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Thomas E. Cheatham
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, UT 84124, USA and CEITEC – Central European Institute of Technology, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Jaroslav Koča
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, UT 84124, USA and CEITEC – Central European Institute of Technology, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Jiří Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic, Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, UT 84124, USA and CEITEC – Central European Institute of Technology, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
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Abstract
The oxazole homodimer YOYO-1 has served as a valuable tool for the detection and quantification of nucleic acids. While the base specificity and selectivity of binding of YOYO-1 has been researched to some extent, the effect of unorthodox nucleic acid conformations on dye binding has received relatively less attention. In this work, we attempt to correlate the quadruplex-forming ability of G-rich sequences with binding of YOYO-1. Oligonucleotides differing in the number of tandem G repeats, total length, and length of loop sequence were evaluated for their ability to form quadruplexes in presence of sodium (Na(+)) or potassium (K(+)) ions. The fluorescence behavior of YOYO-1 upon binding such G-rich sequences was also ascertained. A distinct correlation was observed between the strength and propensity of quadruplex formation, and the affinity of YOYO-1 to bind such sequences. Specifically, as exemplified by the oligonucleotides 5'-G4T2G4-3' and 5'-G3TG3TG3-3', sequences possessing longer G-rich regions and shorter loop sequences formed stronger quadruplexes in presence of K(+) which translated to weaker binding of YOYO-1. The dependence of binding of YOYO-1 on sequence and structural features of G-rich DNA has not been explored previously and such studies are expected to aid in more effective interpretation of applications involving the fluorophore.
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Affiliation(s)
- Shohini Ghosh Datta
- a Department of Chemistry , Indian Institute of Technology Gandhinagar , VGEC Complex Chandkheda, Ahmedabad , 382424 , India
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Šponer J, Mládek A, Špačková N, Cang X, Cheatham TE, Grimme S. Relative stability of different DNA guanine quadruplex stem topologies derived using large-scale quantum-chemical computations. J Am Chem Soc 2013; 135:9785-96. [PMID: 23742743 PMCID: PMC3775466 DOI: 10.1021/ja402525c] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We provide theoretical predictions of the intrinsic stability of different arrangements of guanine quadruplex (G-DNA) stems. Most computational studies of nucleic acids have applied Molecular Mechanics (MM) approaches using simple pairwise-additive force fields. The principle limitation of such calculations is the highly approximate nature of the force fields. In this study, we for the first time apply accurate QM computations (DFT-D3 with large atomic orbital basis sets) to essentially complete DNA building blocks, seven different folds of the cation-stabilized two-quartet G-DNA stem, each having more than 250 atoms. The solvent effects are approximated by COSMO continuum solvent. We reveal sizable differences between MM and QM descriptions of relative energies of different G-DNA stems, which apparently reflect approximations of the DNA force field. Using the QM energy data, we propose correction to earlier free energy estimates of relative stabilities of different parallel, hybrid, and antiparallel G-stem folds based on classical simulations. The new energy ranking visibly improves the agreement between theory and experiment. We predict the 5'-anti-anti-3' GpG dinucleotide step to be the most stable one, closely followed by the 5'-syn-anti-3' step. The results are in good agreement with known experimental structures of 2-, 3-, and 4-quartet G-DNA stems. Besides providing specific results for G-DNA, our study highlights basic limitations of force field modeling of nucleic acids. Although QM computations have their own limitations, mainly the lack of conformational sampling and the approximate description of the solvent, they can substantially improve the quality of calculations currently relying exclusively on force fields.
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Affiliation(s)
- Jiří Šponer
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic
- CEITEC - Central European Institute of Technology, Masaryk University, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Arnošt Mládek
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic
- CEITEC - Central European Institute of Technology, Masaryk University, Campus Bohunice, Kamenice 5, 625 00 Brno, Czech Republic
| | - Nad’a Špačková
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65 Brno, Czech Republic
- Department of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic
| | - Xiaohui Cang
- Institute of Genetics, School of Life Science, Zhejiang University, Hangzhou, China 310058
| | - Thomas E. Cheatham
- Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, UT 84124, USA
| | - Stefan Grimme
- Mulliken Center for Theoretical Chemistry, Institute of Physical & Theoretical Chemistry, University of Bonn, Beringstrasse. 4, D-53115 Bonn, Germany
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McManus SA, Li Y. Assessing the amount of quadruplex structures present within G₂-tract synthetic random-sequence DNA libraries. PLoS One 2013; 8:e64131. [PMID: 23717551 PMCID: PMC3663748 DOI: 10.1371/journal.pone.0064131] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Accepted: 04/11/2013] [Indexed: 11/23/2022] Open
Abstract
The process of in vitro selection has led to the discovery of many aptamers with potential to be developed into inhibitors and biosensors, but problems in isolating aptamers against certain targets with desired affinity and specificity still remain. One possible improvement is to use libraries enhanced for motifs repeatedly isolated in aptamer molecules. One such frequently observed motif is the two-tiered guanine quadruplex. In this study we investigated whether DNA libraries could be designed to contain a large fraction of molecules capable of folding into two-tiered guanine quadruplexes. Using comprehensive circular dichroism analysis, we found that DNA libraries could be designed to contain a large proportion of sequences that adopt guanine quadruplex structures. Analysis of individual sequences from a small library revealed a mixture of quadruplexes of different topologies providing the diversity desired for an in vitro selection. We also found that primer-binding sites are detrimental to quadruplex formation and devised a method for post-selection amplification of primer-less quadruplex libraries. With the development of guanine quadruplex enriched DNA libraries, it should be possible to improve the chances of isolating aptamers that utilize a quadruplex scaffold and enhance the success of in vitro selection experiments.
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Affiliation(s)
- Simon A. McManus
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Yingfu Li
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
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Mukundan VT, Phan AT. Bulges in G-Quadruplexes: Broadening the Definition of G-Quadruplex-Forming Sequences. J Am Chem Soc 2013; 135:5017-28. [DOI: 10.1021/ja310251r] [Citation(s) in RCA: 213] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
| | - Anh Tuân Phan
- School of
Physical and Mathematical Sciences, Nanyang Technological University, Singapore
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49
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Sjoberg J. Ammonium ion binding to DNA G-quadruplexes: do electrospray mass spectra faithfully reflect the solution-phase species? JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013; 24:1-8. [PMID: 23132414 PMCID: PMC5110665 DOI: 10.1007/s13361-012-0499-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2012] [Revised: 09/04/2012] [Accepted: 09/04/2012] [Indexed: 06/01/2023]
Abstract
G-quadruplex nucleic acids can bind ammonium ions in solution, and these complexes can be detected by electrospray mass spectrometry (ESI-MS). However, because ammonium ions are volatile, the extent to which ESI-MS quantitatively could provide an accurate reflection of such solution-phase equilibria is unclear. Here we studied five G-quadruplexes having known solution-phase structure and ammonium ion binding constants: the bimolecular G-quadruplexes (dG(4)T(4)G(4))(2), (dG(4)T(3)G(4))(2), and (dG(3)T(4)G(4))(2), and the intramolecular G-quadruplexes dG(4)(T(4)G(4))(3) and dG(2)T(2)G(2)TGTG(2)T(2)G(2) (thrombin binding aptamer). We found that not all mass spectrometers are equally suited to reflect the solution phase species. Ion activation can occur in the electrospray source, or in a high-pressure traveling wave ion mobility cell. When the softest instrumental conditions are used, ammonium ions bound between G-quartets, but also additional ammonium ions bound at specific sites outside the external G-quartets, can be observed. However, even specifically bound ammonium ions are in some instances too labile to be fully retained in the gas phase structures, and although the ammonium ion distribution observed by ESI-MS shows biases at specific stoichiometries, the relative abundances in solution are not always faithfully reflected. Ion mobility spectrometry results show that all inter-quartet ammonium ions are necessary to preserve the G-quadruplex fold in the gas phase. Ion mobility experiments, therefore, help assign the number of inner ammonium ions in the solution phase structure.
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50
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Abu-Ghazalah RM, Rutledge S, Lau LWY, Dubins DN, Macgregor RB, Helmy AS. Concentration-dependent structural transitions of human telomeric DNA sequences. Biochemistry 2012; 51:7357-66. [PMID: 22931349 DOI: 10.1021/bi300689t] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Oligodeoxyribonucleotides (ODNs) that have four repeats of the human telomeric sequence d(TTAGGG)(n) can assume multiple monomolecular G-quadruplex topologies. These are determined by the cation species present, the bases at the 5' or 3' end, and the sample preparation technique. In this work, we report our studies of the concentration dependence of the circular dichroism (CD) and the vibrational modes probed by Raman scattering of three previously characterized monomolecular G-quadruplexes: H-Tel, d[5'-A(GGGTTA)(3)GGG-3']; hybrid-1, d[5'-AAA(GGGTTA)(3)GGGAA-3']; and hybrid-2, d[5'-TTA(GGGTTA)(3)GGGTT-3']. At high (millimolar) ODN concentrations, we observed a transformation of the CD spectrum of H-Tel, with a relaxation time on the order of 10 h. Analysis of the kinetics of this process is consistent with the formation of an aggregated complex of folded H-Tel monomers. Upon dilution, the aggregates dissociate rapidly, yielding spectra identical to those of monomeric H-Tel. Both hybrid sequences undergo a similar transition under high-salt (1 M) conditions. The measurements suggest that for these ODN concentrations, which are typically used in high-resolution spectroscopies, the monomolecular G-quadruplex structures undergo a transition to multimolecular structures at room temperature. Guided by our findings, we propose that the terminal bases of the hybrid-1 and hybrid-2 ODNs impede the formation of these aggregates; however, in solutions containing 1 M salt, the hybrid oligonucleotides aggregate.
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Affiliation(s)
- Rashid M Abu-Ghazalah
- Edward S. Rogers Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
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