1
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Dutta S, Srivatsan SG. Enzymatic Functionalization of RNA Oligonucleotides by Terminal Uridylyl Transferase Using Fluorescent and Clickable Nucleotide Analogs. Chem Asian J 2024; 19:e202400475. [PMID: 38949615 DOI: 10.1002/asia.202400475] [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: 04/26/2024] [Revised: 06/27/2024] [Accepted: 07/01/2024] [Indexed: 07/02/2024]
Abstract
We report a systematic study on controlling the enzyme activity of a terminal uridylyl transferase (TUTase) called SpCID1, which provides methods to effect site-specific incorporation of a single modified nucleotide analog at the 3'-end of an RNA oligonucleotide (ON). Responsive heterocycle-modified fluorescent UTP probes that are useful in analyzing non-canonical nucleic acid structures and azide- and alkyne-modified UTP analogs that are compatible for chemoenzymatic functionalization were used as study systems. In the first strategy, we balanced the concentration of essential metal ion cofactors (Mg2+ and Mn2+ ions) to restrict the processivity of the enzyme, which gave a very good control on the incorporation of clickable nucleotide analogs. In the second approach, borate that complexes with 2' and 3' oxygen atoms of a ribose sugar was used as a reversibly binding chelator to block repeated addition of nucleotide analogs. Notably, in the presence of heterocycle-modified fluorescent UTPs, we obtained single-nucleotide incorporated RNA products in reasonable yields, while with clickable nucleotides yields were very good. Further, 3'-end azide- and alkyne-labeled RNA ONs were post-enzymatically functionalized by CuAAC and SPAAC reactions with fluorescent probes. These strategies broaden the scope of TUTase in site-specifically installing modifications of different types onto RNA for various applications.
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Affiliation(s)
- Swagata Dutta
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune, 411008, India
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune, 411008, India
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2
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Ito Y, Tanaka H, Murakami A, Fuchi Y, Hari Y. Synthesis of fluorescent 5-heteroarylpyrimidine-containing oligonucleotides via post-synthetic trifluoromethyl conversion. Org Biomol Chem 2024; 22:3510-3517. [PMID: 38619422 DOI: 10.1039/d4ob00402g] [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: 04/16/2024]
Abstract
Post-synthetic conversion of the trifluoromethyl group to a heteroaryl group at the C5 position of the pyrimidine base in DNA oligonucleotides was achieved. Specifically, the oligonucleotides containing 5-trifluoromethylpyrimidine bases were treated with o-phenylenediamines and o-aminothiophenols as nucleophiles to afford the corresponding 5-(benzimidazol-2-yl)- and 5-(benzothiazol-2-yl)-pyrimidine-modified bases. Furthermore, evaluation of the fluorescence properties of the obtained oligonucleotides revealed that among them the oligonucleotide containing 5-(5-methylbenzimidazol-2-yl)cytosine exhibited the highest fluorescence intensity. These results indicated that post-synthetic trifluoromethyl conversion, which is practical and operationally simple, is a powerful tool for exploring functional oligonucleotides.
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Affiliation(s)
- Yuta Ito
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Nishihama, Yamashiro-cho, Tokushima 770-8514, Japan.
| | - Hisato Tanaka
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Nishihama, Yamashiro-cho, Tokushima 770-8514, Japan.
| | - Ayana Murakami
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Nishihama, Yamashiro-cho, Tokushima 770-8514, Japan.
| | - Yasufumi Fuchi
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Nishihama, Yamashiro-cho, Tokushima 770-8514, Japan.
| | - Yoshiyuki Hari
- Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Nishihama, Yamashiro-cho, Tokushima 770-8514, Japan.
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3
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Khatik SY, Roy S, Srivatsan SG. Synthesis and Enzymatic Incorporation of a Dual-App Nucleotide Probe That Reports Antibiotics-Induced Conformational Change in the Bacterial Ribosomal Decoding Site RNA. ACS Chem Biol 2024; 19:687-695. [PMID: 38407057 DOI: 10.1021/acschembio.3c00676] [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: 02/27/2024]
Abstract
Natural nucleosides are nonfluorescent and do not have intrinsic labels that can be readily utilized for analyzing nucleic acid structure and recognition. In this regard, researchers typically use the so-called "one-label, one-technique" approach to study nucleic acids. However, we envisioned that a responsive dual-app nucleoside system that harnesses the power of two complementing biophysical techniques namely, fluorescence and 19F NMR, will allow the investigation of nucleic acid conformations more comprehensively than before. We recently introduced a nucleoside analogue by tagging trifluoromethyl-benzofuran at the C5 position of 2'-deoxyuridine, which serves as an excellent fluorescent and 19F NMR probe to study G-quadruplex and i-motif structures. Taking forward, here, we report the development of a ribonucleotide version of the dual-app probe to monitor antibiotics-induced conformational changes in RNA. The ribonucleotide analog is derived by conjugating trifluoromethyl-benzofuran at the C5 position of uridine (TFBF-UTP). The analog is efficiently incorporated by T7 RNA polymerase to produce functionalized RNA transcripts. Detailed photophysical and 19F NMR of the nucleoside and nucleotide incorporated into RNA oligonucleotides revealed that the analog is structurally minimally invasive and can be used for probing RNA conformations by fluorescence and 19F NMR techniques. Using the probe, we monitored and estimated aminoglycoside antibiotics binding to the bacterial ribosomal decoding site RNA (A-site, a very important RNA target). While 2-aminopurine, a famous fluorescent nucleic acid probe, fails to detect structurally similar aminoglycoside antibiotics binding to the A-site, our probe reports the binding of different aminoglycosides to the A-site. Taken together, our results demonstrate that TFBF-UTP is a very useful addition to the nucleic acid analysis toolbox and could be used to devise discovery platforms to identify new RNA binders of therapeutic potential.
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Affiliation(s)
- Saddam Y Khatik
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Sarupa Roy
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
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4
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Pandey A, Roy S, Srivatsan SG. Probing the Competition between Duplex, G-Quadruplex and i-Motif Structures of the Oncogenic c-Myc DNA Promoter Region. Chem Asian J 2023; 18:e202300510. [PMID: 37541298 DOI: 10.1002/asia.202300510] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/09/2023] [Indexed: 08/06/2023]
Abstract
Development of probe systems that provide unique spectral signatures for duplex, G-quadruplex (GQ) and i-motif (iM) structures is very important to understand the relative propensity of a G-rich-C-rich promoter region to form these structures. Here, we devise a platform using a combination of two environment-sensitive nucleoside analogs namely, 5-fluorobenzofuran-modified 2'-deoxyuridine (FBF-dU) and 5-fluoro-2'-deoxyuridine (F-dU) to study the structures adopted by a promoter region of the c-Myc oncogene. FBF-dU serves as a dual-purpose probe containing a fluorescent and 19 F NMR label. When incorporated into the C-rich sequence, it reports the formation of different iMs via changes in its fluorescence properties and 19 F signal. F-dU incorporated into the G-rich ON reports the formation of a GQ structure whose 19 F signal is clearly different from the signals obtained for iMs. Rewardingly, the labeled ONs when mixed with respective complementary strands allows us to determine the relative population of different structures formed by the c-Myc promoter by the virtue of the probe's ability to produce distinct and resolved 19 F signatures for different structures. Our results indicate that at physiological pH and temperature the c-Myc promoter forms duplex, random coil and GQ structures, and does not form an iM. Whereas at acidic pH, the mixture largely forms iM and GQ structures. Taken together, our system will complement existing tools and provide unprecedented insights on the population equilibrium and dynamics of nucleic acid structures under different conditions.
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Affiliation(s)
- Akanksha Pandey
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Sarupa Roy
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune, 411008, India
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune, 411008, India
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5
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Johnson RE, Murray MT, Bycraft LJ, Wetmore SD, Manderville RA. A modular aldol approach for internal fluorescent molecular rotor chalcone surrogates for DNA biosensing applications. Chem Sci 2023; 14:4832-4844. [PMID: 37181758 PMCID: PMC10171068 DOI: 10.1039/d3sc00772c] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 04/11/2023] [Indexed: 05/16/2023] Open
Abstract
Fluorescent molecular rotors (FMRs) are critical tools for probing nucleic acid structure and function. Many valuable FMRs have been incorporated into oligonucleotides, although the methods of doing so can be cumbersome. Development of synthetically simple, high yielding modular methods to fine-tune dye performance is crucial to expand the biotechnological applications of oligonucleotides. Herein, we report the utility of 6-hydroxy-indanone (6HI) with a glycol backbone to serve as a handle for on-strand aldehyde capture as a modular aldol approach for site-specific insertion of internal FMR chalcones. Aldol reactions with aromatic aldehydes containing N-donors proceed in high yield to create modified DNA oligonucleotides, which in the duplex match the stability of the fully paired canonical B-form with strong stacking interactions between the planar probe and the flanking base pairs, as evidenced by molecular dynamics (MD) simulations. The FMR chalcones possess remarkable quantum yields (Φfl up to 76%) in duplex DNA, coupled with large Stokes shifts (Δν up to 155 nm), light-up emissions (Irel up to 60-fold) that span the visible region (λem 518-680 nm) with brightness up to 17 480 cm-1 M-1. The library also contains a FRET pair and dual emission probes, suitable for ratiometric sensing. The ease of aldol insertion coupled with the excellent performance of the FMR chalcones permits their future wide-spread use.
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Affiliation(s)
- Ryan E Johnson
- Department of Chemistry & Toxicology, University of Guelph Guelph Ontario N1G 2W1 Canada
| | - Makay T Murray
- Department of Chemistry & Biochemistry, University of Lethbridge Lethbridge Alberta T1K 3M4 Canada
| | - Lucas J Bycraft
- Department of Chemistry & Toxicology, University of Guelph Guelph Ontario N1G 2W1 Canada
| | - Stacey D Wetmore
- Department of Chemistry & Biochemistry, University of Lethbridge Lethbridge Alberta T1K 3M4 Canada
| | - Richard A Manderville
- Department of Chemistry & Toxicology, University of Guelph Guelph Ontario N1G 2W1 Canada
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Reznichenko O, Leclercq D, Franco Pinto J, Mouawad L, Gabelica V, Granzhan A. Optimization of G-Quadruplex Ligands through a SAR Study Combining Parallel Synthesis and Screening of Cationic Bis(acylhydrazones). Chemistry 2023; 29:e202202427. [PMID: 36286608 PMCID: PMC10099395 DOI: 10.1002/chem.202202427] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Indexed: 11/06/2022]
Abstract
G-quadruplexes (G4s), secondary structures adopted by guanine-rich DNA and RNA sequences, are implicated in numerous biological processes and have been suggested as potential drug targets. Accordingly, there is an increasing interest in developing high-throughput methods that allow the generation of congeneric series of G4-targeting molecules ("ligands") and investigating their interactions with the targets. We have developed an operationally simple method of parallel synthesis to generate "ready-to-screen" libraries of cationic acylhydrazones, a motif that we have previously identified as a promising scaffold for potent, biologically active G4 ligands. Combined with well-established screening techniques, such as fluorescence melting, this method enables the rapid synthesis and screening of combinatorial libraries of potential G4 ligands. Following this protocol, we synthesized a combinatorial library of 90 bis(acylhydrazones) and screened it against five different nucleic acid structures. This way, we were able to analyze the structure-activity relationships within this series of G4 ligands, and identified three novel promising ligands whose interactions with G4-DNAs of different topologies were studied in detail by a combination of several biophysical techniques, including native mass spectrometry, and molecular modeling.
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Affiliation(s)
- Oksana Reznichenko
- CMBC, CNRS UMR9187Inserm U1196, Institut CuriePSL Research University91405OrsayFrance
- CMBC, CNRS UMR9187Inserm U1196Université Paris Saclay91405OrsayFrance
| | - Denis Leclercq
- CMBC, CNRS UMR9187Inserm U1196, Institut CuriePSL Research University91405OrsayFrance
- CMBC, CNRS UMR9187Inserm U1196Université Paris Saclay91405OrsayFrance
| | - Jaime Franco Pinto
- CMBC, CNRS UMR9187Inserm U1196, Institut CuriePSL Research University91405OrsayFrance
- CMBC, CNRS UMR9187Inserm U1196Université Paris Saclay91405OrsayFrance
| | - Liliane Mouawad
- CMBC, CNRS UMR9187Inserm U1196, Institut CuriePSL Research University91405OrsayFrance
- CMBC, CNRS UMR9187Inserm U1196Université Paris Saclay91405OrsayFrance
| | - Valérie Gabelica
- Univ. BordeauxCNRS, INSERM, ARNAUMR 5320, U1212, IECB33600PessacFrance
| | - Anton Granzhan
- CMBC, CNRS UMR9187Inserm U1196, Institut CuriePSL Research University91405OrsayFrance
- CMBC, CNRS UMR9187Inserm U1196Université Paris Saclay91405OrsayFrance
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7
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Chung WC, Ravichandran S, Park D, Lee GM, Kim YE, Choi Y, Song MJ, Kim KK, Ahn JH. G-quadruplexes formed by Varicella-Zoster virus reiteration sequences suppress expression of glycoprotein C and regulate viral cell-to-cell spread. PLoS Pathog 2023; 19:e1011095. [PMID: 36630443 PMCID: PMC9873165 DOI: 10.1371/journal.ppat.1011095] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 01/24/2023] [Accepted: 01/02/2023] [Indexed: 01/12/2023] Open
Abstract
G-quadruplex (G4) formed by repetitive guanosine-rich sequences plays important roles in diverse cellular processes; however, its roles in viral infection are not fully understood. In this study, we investigated the genome-wide distribution of G4-forming sequences (G4 motifs) in Varicella-Zoster virus (VZV) and found that G4 motifs are enriched in the internal repeat short and the terminal repeat short regions flanking the unique short region and also in some reiteration (R) sequence regions. A high density of G4 motifs in the R2 region was found on the template strand of ORF14, which encodes glycoprotein C (gC), a virulent factor for viral growth in skin. Analyses such as circular dichroism spectroscopy, thermal difference spectra, and native polyacrylamide gel electrophoresis with oligodeoxynucleotides demonstrated that several G4 motifs in ORF14 form stable G4 structures. In transfection assays, gC expression from the G4-disrupted ORF14 gene was increased at the transcriptional level and became more resistant to suppression by G4-ligand treatment. The recombinant virus containing the G4-disrupted ORF14 gene expressed a higher level of gC mRNA, while it showed a slightly reduced growth. This G4-disrupted ORF14 virus produced smaller plaques than the wild-type virus. Our results demonstrate that G4 formation via reiteration sequences suppresses gC expression during VZV infection and regulates viral cell-to-cell spread.
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Affiliation(s)
- Woo-Chang Chung
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Subramaniyam Ravichandran
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Daegyu Park
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Gwang Myeong Lee
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Young-Eui Kim
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Youngju Choi
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Moon Jung Song
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, Republic of Korea
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
- Biomedical Research Institute, Samsung Medical Center, Seoul, Republic of Korea
| | - Jin-Hyun Ahn
- Department of Microbiology, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
- Biomedical Research Institute, Samsung Medical Center, Seoul, Republic of Korea
- * E-mail:
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8
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Palai BB, Panda SS, Sharma NK. Synthesis of Aminotroponyl-/Difluoroboronyl Aminotroponyl Deoxyuridine Phosphoramidites. Curr Protoc 2022; 2:e609. [PMID: 36541868 DOI: 10.1002/cpz1.609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This report describes the chemical synthesis of aminotroponyl-conjugated deoxyuridine analog (at-dU) and its difluoroboron complex (dfbat-dU) and their phosphoramidites by using the versatile phosphorylating reagent 2-Cyanoethyl N,N-diisopropylchlorophosphoramidite. Tropolone is a non-benzenoid aromatic bioactive natural fluorescent molecule, possessing intramolecular charge transfer and metal chelating properties with transition metal ions such as Cu2+/ Zn2+/ Ni2+ . Its synthetic derivatives, 2-aminotropones also exhibit unique bioactivities and are considered potential therapeutic drug candidate. Recently, the fluorescence properties of aminotropone has improved by complexing with difluoroboron residue that generates aminotroponyl-BODIPY analog. These could be employed for the synthesis of at-dU/dfbat-dU containing DNA oligonucleotides for designing the 11 B/19 F-NMR/fluorescence-based DNA probes. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Synthesis of N-propargyl-2-aminotropone (2) and difluoroboronyl N-propargyl-2-aminotropone (3) molecules. Basic Protocol 2: Synthesis of N-propargyl-2-aminotroponyl deoxyuridinyl (at-dU) phosphoramidites (7). Basic Protocol 3: Synthesis of difluoroboronyl N-propargyl-2-aminotroponyl deoxyuridinyl (dfbat-dU) phosphoramidites (10).
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Affiliation(s)
- Bibhuti Bhusana Palai
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) Bhubaneswar, Jatani, Odisha, India.,Homi Bhabha National Institute (HBNI)-Mumbai, Mumbai, India
| | - Subhashree S Panda
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) Bhubaneswar, Jatani, Odisha, India.,Homi Bhabha National Institute (HBNI)-Mumbai, Mumbai, India
| | - Nagendra K Sharma
- School of Chemical Sciences, National Institute of Science Education and Research (NISER) Bhubaneswar, Jatani, Odisha, India.,Homi Bhabha National Institute (HBNI)-Mumbai, Mumbai, India
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9
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He Y, Liu M, Teng S, Wojtas L, Gu G, Shi X. Synthesis and Characterization of Fluorescence Active G 4-Quartet and Direct Evaluation of Self-Assembly Impact on Emission. CHINESE CHEM LETT 2022; 33:4203-4207. [PMID: 38107831 PMCID: PMC10723654 DOI: 10.1016/j.cclet.2022.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fluorescence (FL) active 8-aryl guanosine derivatives were prepared and applied for cation mediated self-assembly to form the H-bonded G8-quadruplexes. The p-cyano (p-CN) and 8-anthracene (8-An) substituted guanosines were identified to give the strongest fluorescence with the formation of G8-octamers (G8) both in solution (NMR) and solid state (X-ray). This well-defined G8-octamer system has provided the first direct evidence on the self-assembled G-quadruplex fluorescence emission with aggregation-induced emission (AIE), which could be applied as the foundation for FL molecular probe design toward G-quadruplex recognition.
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Affiliation(s)
- Ying He
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Mengjia Liu
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Shun Teng
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Lukasz Wojtas
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
| | - Guangxin Gu
- Department of Materials Science, Fudan University, 2005 Songhu Rd., Shanghai, 200438, PR China
| | - Xiaodong Shi
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, Tampa, Florida 33620, United States
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10
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Khatik SY, Srivatsan SG. Environment-Sensitive Nucleoside Probe Unravels the Complex Structural Dynamics of i-Motif DNAs. Bioconjug Chem 2022; 33:1515-1526. [PMID: 35819865 DOI: 10.1021/acs.bioconjchem.2c00237] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Although evidence for the existence and biological role of i-motif (iM) DNA structures in cells is emerging, probing their structural polymorphism and identifying physiologically active conformations using currently available tools remain a major challenge. Here, we describe the development of an innovative device to investigate the conformation equilibrium of different iMs formed by C-rich telomeric repeat and oncogenic B-raf promoter sequences using a new conformation-sensitive dual-purpose nucleoside probe. The nucleoside is composed of a trifluoromethyl-benzofuran-2-yl moiety at the C5 position of 2'-deoxyuridine, which functions as a responsive fluorescent and 19F NMR probe. While the fluorescent component is useful in monitoring and estimating the folding process, the 19F label provides spectral signatures for various iMs, thereby enabling a systematic analysis of their complex population equilibrium under different conditions (e.g., pH, temperature, metal ions, and cell lysate). Distinct 19F signals exhibited by the iMs formed by the human telomeric repeat helped in calculating their relative population. A battery of fluorescence and 19F NMR studies using native and mutated B-raf oligonucleotides gave valuable insights into the iM structure landscape and its dependence on environmental conditions and also helped in predicting the structure of the major iM conformation. Overall, our findings indicate that the probe is highly suitable for studying complex nucleic acid systems.
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Affiliation(s)
- Saddam Y Khatik
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
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11
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Ghosh P, Kropp HM, Betz K, Ludmann S, Diederichs K, Marx A, Srivatsan SG. Microenvironment-Sensitive Fluorescent Nucleotide Probes from Benzofuran, Benzothiophene, and Selenophene as Substrates for DNA Polymerases. J Am Chem Soc 2022; 144:10556-10569. [PMID: 35666775 DOI: 10.1021/jacs.2c03454] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
DNA polymerases can process a wide variety of structurally diverse nucleotide substrates, but the molecular basis by which the analogs are processed is not completely understood. Here, we demonstrate the utility of environment-sensitive heterocycle-modified fluorescent nucleotide substrates in probing the incorporation mechanism of DNA polymerases in real time and at the atomic level. The nucleotide analogs containing a selenophene, benzofuran, or benzothiophene moiety at the C5 position of 2'-deoxyuridine are incorporated into oligonucleotides (ONs) with varying efficiency, which depends on the size of the heterocycle modification and the DNA polymerase sequence family used. KlenTaq (A family DNA polymerase) is sensitive to the size of the modification as it incorporates only one heterobicycle-modified nucleotide into the growing polymer, whereas it efficiently incorporates the selenophene-modified nucleotide analog at multiple positions. Notably, in the single nucleotide incorporation assay, irrespective of the heterocycle size, it exclusively adds a single nucleotide at the 3'-end of a primer, which enabled devising a simple two-step site-specific ON labeling technique. KOD and Vent(exo-) DNA polymerases, belonging to the B family, tolerate all the three modified nucleotides and produce ONs with multiple labels. Importantly, the benzofuran-modified nucleotide (BFdUTP) serves as an excellent reporter by providing real-time fluorescence readouts to monitor enzyme activity and estimate the binding events in the catalytic cycle. Further, a direct comparison of the incorporation profiles, fluorescence data, and crystal structure of a ternary complex of KlenTaq DNA polymerase with BFdUTP poised for catalysis provides a detailed understanding of the mechanism of incorporation of heterocycle-modified nucleotides.
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Affiliation(s)
- Pulak Ghosh
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune 411008, India
| | - Heike M Kropp
- Department of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Karin Betz
- Department of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Samra Ludmann
- Department of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Kay Diederichs
- Department of Biology and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Andreas Marx
- Department of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune 411008, India
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12
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Manna S, Sontakke VA, Srivatsan SG. Incorporation and Utility of a Responsive Ribonucleoside Analogue in Probing the Conformation of a Viral RNA Motif by Fluorescence and 19 F NMR Spectroscopy. Chembiochem 2021; 23:e202100601. [PMID: 34821449 DOI: 10.1002/cbic.202100601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 11/24/2021] [Indexed: 11/09/2022]
Abstract
Development of versatile probes that can enable the study of different conformations and recognition properties of therapeutic nucleic acid motifs by complementing biophysical techniques can greatly aid nucleic acid analysis and therapy. Here, we report the design, synthesis and incorporation of an environment-sensitive ribonucleoside analogue, which serves as a two-channel biophysical platform to investigate RNA structure and recognition by fluorescence and 19 F NMR spectroscopy techniques. The nucleoside analogue is based on a 5-fluorobenzofuran-uracil core and its fluorescence and 19 F NMR chemical shifts are highly sensitive to changes in solvent polarity and viscosity. Notably, the modified ribonucleotide and phosphoramidite substrates can be efficiently incorporated into RNA oligonucleotides (ONs) by in vitro transcription and standard solid-phase ON synthesis protocol, respectively. Fluorescence and 19 F readouts of the nucleoside incorporated into model RNA ONs are sensitive to the neighbouring base environment. The responsiveness of the probe was aptly utilized in detecting and quantifying the metal ion-induced conformational change in an internal ribosome entry site RNA motif of hepatitis C virus, which is an important therapeutic target. Taken together, our probe is a good addition to the nucleic acid analysis toolbox with the advantage that it can be used to study nucleic acid conformation and recognition simultaneously by two biophysical techniques.
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Affiliation(s)
- Sudeshna Manna
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune, 411008, India
| | - Vyankat A Sontakke
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune, 411008, India
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune, 411008, India
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13
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Ramos CIV, Monteiro AR, Moura NMM, Faustino MAF, Trindade T, Neves MGPMS. The Interactions of H 2TMPyP, Analogues and Its Metal Complexes with DNA G-Quadruplexes-An Overview. Biomolecules 2021; 11:biom11101404. [PMID: 34680037 PMCID: PMC8533071 DOI: 10.3390/biom11101404] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/16/2021] [Accepted: 09/22/2021] [Indexed: 12/26/2022] Open
Abstract
The evidence that telomerase is overexpressed in almost 90% of human cancers justifies the proposal of this enzyme as a potential target for anticancer drug design. The inhibition of telomerase by quadruplex stabilizing ligands is being considered a useful approach in anticancer drug design proposals. Several aromatic ligands, including porphyrins, were exploited for telomerase inhibition by adduct formation with G-Quadruplex (GQ). 5,10,15,20-Tetrakis(N-methyl-4-pyridinium)porphyrin (H2TMPyP) is one of the most studied porphyrins in this field, and although reported as presenting high affinity to GQ, its poor selectivity for GQ over duplex structures is recognized. To increase the desired selectivity, porphyrin modifications either at the peripheral positions or at the inner core through the coordination with different metals have been handled. Herein, studies involving the interactions of TMPyP and analogs with different DNA sequences able to form GQ and duplex structures using different experimental conditions and approaches are reviewed. Some considerations concerning the structural diversity and recognition modes of G-quadruplexes will be presented first to facilitate the comprehension of the studies reviewed. Additionally, considering the diversity of experimental conditions reported, we decided to complement this review with a screening where the behavior of H2TMPyP and of some of the reviewed metal complexes were evaluated under the same experimental conditions and using the same DNA sequences. In this comparison under unified conditions, we also evaluated, for the first time, the behavior of the AgII complex of H2TMPyP. In general, all derivatives showed good affinity for GQ DNA structures with binding constants in the range of 106–107 M−1 and ligand-GQ stoichiometric ratios of 3:1 and 4:1. A promising pattern of selectivity was also identified for the new AgII derivative.
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Affiliation(s)
- Catarina I. V. Ramos
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (A.R.M.); (N.M.M.M.); (M.A.F.F.); (M.G.P.M.S.N.)
- Correspondence: ; Tel.: +351-234-370-692
| | - Ana R. Monteiro
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (A.R.M.); (N.M.M.M.); (M.A.F.F.); (M.G.P.M.S.N.)
- CICECO-Aveiro, Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal;
| | - Nuno M. M. Moura
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (A.R.M.); (N.M.M.M.); (M.A.F.F.); (M.G.P.M.S.N.)
| | - Maria Amparo F. Faustino
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (A.R.M.); (N.M.M.M.); (M.A.F.F.); (M.G.P.M.S.N.)
| | - Tito Trindade
- CICECO-Aveiro, Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal;
| | - Maria Graça P. M. S. Neves
- LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; (A.R.M.); (N.M.M.M.); (M.A.F.F.); (M.G.P.M.S.N.)
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14
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Tao Y, Zheng Y, Zhai Q, Wei D. Recent advances in the development of small molecules targeting RNA G-quadruplexes for drug discovery. Bioorg Chem 2021; 110:104804. [PMID: 33740677 DOI: 10.1016/j.bioorg.2021.104804] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 12/12/2022]
Abstract
Extensive evidence indicates that RNA G-quadruplexes have associated with some important cellular events. Investigation of RNA G-quadruplexes is thus vital to revealing their biofunctions. Several small molecules have been developed to target RNA G-quadruplexes to date. Some of the small molecules showed significantly light-up fluorescence signals upon binding to RNA G-quadruplexes, while some of them regulated the biofunctions of RNA G-quadruplexes. In this mini-review, the small molecules divided into four kinds are expounded which focused mainly on their structural features and biological activities. Moreover, we raised the current challenges and promising prospects. This mini-review might contribute to exploiting more sophisticated small molecules targeting RNA G-quadruplexes with high specificity based on the reported chemical structural features.
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Affiliation(s)
- Yanfei Tao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Yingge Zheng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Qianqian Zhai
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; Department of Chemistry, College of Science, Huazhong Agricultural University, Wuhan 430070, China.
| | - Dengguo Wei
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China; National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China.
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15
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McKenzie LK, El-Khoury R, Thorpe JD, Damha MJ, Hollenstein M. Recent progress in non-native nucleic acid modifications. Chem Soc Rev 2021; 50:5126-5164. [DOI: 10.1039/d0cs01430c] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
While Nature harnesses RNA and DNA to store, read and write genetic information, the inherent programmability, synthetic accessibility and wide functionality of these nucleic acids make them attractive tools for use in a vast array of applications.
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Affiliation(s)
- Luke K. McKenzie
- Institut Pasteur
- Department of Structural Biology and Chemistry
- Laboratory for Bioorganic Chemistry of Nucleic Acids
- CNRS UMR3523
- 75724 Paris Cedex 15
| | | | | | | | - Marcel Hollenstein
- Institut Pasteur
- Department of Structural Biology and Chemistry
- Laboratory for Bioorganic Chemistry of Nucleic Acids
- CNRS UMR3523
- 75724 Paris Cedex 15
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16
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Abstract
The structural and regulatory elements in therapeutically relevant RNAs offer many opportunities for targeting by small molecules, yet fundamental understanding of what drives selectivity in small molecule:RNA recognition has been a recurrent challenge. In particular, RNAs tend to be more dynamic and offer less chemical functionality than proteins, and biologically active ligands must compete with the highly abundant and highly structured RNA of the ribosome. Indeed, the only small molecule drug targeting RNA other than the ribosome was just approved in August 2020, and our recent survey of the literature revealed fewer than 150 reported chemical probes that target non-ribosomal RNA in biological systems. This Feature outlines our efforts to improve small molecule targeting strategies and gain fundamental insights into small molecule:RNA recognition by analyzing patterns in both RNA-biased small molecule chemical space and RNA topological space privileged for differentiation. First, we synthesized libraries based on RNA binding scaffolds that allowed us to reveal general principles in small molecule:recognition and to ask precise chemical questions about drivers of affinity and selectivity. Elaboration of these scaffolds has led to recognition of medicinally relevant RNA targets, including viral and long noncoding RNA structures. More globally, we identified physicochemical, structural, and spatial properties of biologically active RNA ligands that are distinct from those of protein-targeted ligands, and we have provided the dataset and associated analytical tools as part of a publicly available online platform to facilitate RNA ligand discovery. At the same time, we used pattern recognition protocols to identify RNA topologies that can be differentially recognized by small molecules and have elaborated this technique to visualize conformational changes in RNA secondary structure. These fundamental insights into the drivers of RNA recognition in vitro have led to functional targeting of RNA structures in biological systems. We hope that these initial guiding principles, as well as the approaches and assays developed in their pursuit, will enable rapid progress toward the development of RNA-targeted chemical probes and ultimately new therapeutic approaches to a wide range of deadly human diseases.
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Affiliation(s)
- Amanda E Hargrove
- Department of Chemistry, Duke University, 124 Science Drive, Box 90346, Durham, NC 27708, USA.
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17
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Walunj MB, Srivatsan SG. Nucleic Acid Conformation Influences Postsynthetic Suzuki-Miyaura Labeling of Oligonucleotides. Bioconjug Chem 2020; 31:2513-2521. [PMID: 33089687 PMCID: PMC7611128 DOI: 10.1021/acs.bioconjchem.0c00466] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chemoselective transformations that work under physiological conditions have emerged as powerful tools to label nucleic acids in cell-free and cellular environments. However, detailed studies investigating the influence of nucleic acid conformation on the performance of such chemoselective nucleic labeling methods are less explored. Given that nucleic acids adopt complex structures, it is highly important to study the scope of the chemical modification method in the context of nucleic acid conformations. Here we report a systematic study on the effect of local conformation on the postsynthetic Suzuki-Miyaura functionalization of human telomeric (H-Telo) DNA repeat oligonucleotide (ON) sequences, which form multiple G-quadruplex (GQ) structures. 5-Iodo-2'-deoxyuridine (IdU)-modified H-Telo ONs were synthesized by the solid-phase method, and when subjected to Suzuki-Miyaura cross-coupling reaction, its efficiency was found to depend on the type of conformation and the position of IdU label in different loops of the GQ structure. IdU-labeled GQs gave better yields as compared to single-stranded random coil structures. However, the IdU-labeled duplex under different ionic conditions did not undergo the coupling reaction. Further, using this method, we directly installed an environment-sensitive fluorescent probe, which photophysically reported the formation as well as distinguished different GQ topologies of telomeric repeat. Collectively, this systematic study underscores the influence of nucleic acid conformation, which has to be taken into account when establishing postsynthetic chemoselective functionalization strategies.
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Affiliation(s)
- Manisha B. Walunj
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India
| | - Seergazhi G. Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008, India
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18
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Gray MD, Deore PS, Chung AJ, Van Riesen AJ, Manderville RA, Prabhakar PS, Wetmore SD. Lighting Up the Thrombin-Binding Aptamer G-Quadruplex with an Internal Cyanine-Indole-Quinolinium Nucleobase Surrogate. Direct Fluorescent Intensity Readout for Thrombin Binding without Topology Switching. Bioconjug Chem 2020; 31:2596-2606. [PMID: 33156614 DOI: 10.1021/acs.bioconjchem.0c00530] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Fluorescent nucleobases represent an important class of molecular reporters of nucleic acid interactions. In this work, the advantages of utilizing a noncanonical fluorescent nucleobase surrogate for monitoring thrombin binding by the 15-mer thrombin binding aptamer (TBA) is presented. TBA folds into an antiparallel G-quadruplex (GQ) with loop thymidine (T) residues interacting directly with the protein in the thrombin-TBA complex. In the free GQ, T3 is solvent-exposed and does not form canonical base-pairs within the antiparallel GQ motif. Upon thrombin binding, T3 interacts directly with a hydrophobic protein binding pocket. Replacing T3 with a cyanine-indole-quinolinium (4QI) hemicyanine dye tethered to an acyclic 1,2-propanediol linker is shown to have minimal impact on GQ stability and structure with the internal 4QI displaying a 40-fold increase in emission intensity at 586 nm (excitation 508 nm) compared to the free dye in solution. Molecular dynamics (MD) simulations demonstrate that the 4QI label π-stacks with T4 and T13 within the antiparallel GQ fold, which is supported by strong energy transfer (ET) fluorescence from the GQ (donor) to the 4QI label (acceptor). Thrombin binding to 4QI-TBA diminishes π-stacking interactions between 4QI and the GQ structure to cause a turn-off emission intensity response with an apparent dissociation constant (Kd) of 650 nM and a limit of detection (LoD) of 150 nM. These features highlight the utility of internal noncanonical fluorescent surrogates for monitoring protein binding by GQ-folding aptamers in the absence of DNA topology switching.
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Affiliation(s)
- Micaela D Gray
- Department of Chemistry & Toxicology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Prashant S Deore
- Department of Chemistry & Toxicology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Andrew J Chung
- Department of Chemistry & Toxicology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Abigail J Van Riesen
- Department of Chemistry & Toxicology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Richard A Manderville
- Department of Chemistry & Toxicology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Preethi Seelam Prabhakar
- Department of Chemistry & Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
| | - Stacey D Wetmore
- Department of Chemistry & Biochemistry, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4
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19
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George JT, Srivatsan SG. Responsive fluorescent nucleotides serve as efficient substrates to probe terminal uridylyl transferase. Chem Commun (Camb) 2020; 56:12319-12322. [PMID: 32939524 PMCID: PMC7611084 DOI: 10.1039/d0cc05092j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We repurposed a terminal uridylyl transferase enzyme to site-specifically label RNA with microenvironment sensing fluorescent nucleotide mimics, which in turn provided direct read-outs to estimate the binding affinities of the enzyme to RNA and nucleotide substrates. This enzyme-probe system provides insights into the catalytic cycle, and can facilitate the development of discovery platforms to identify robust enzyme inhibitors.
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Affiliation(s)
- Jerrin Thomas George
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr Homi Bhabha Road, Pashan, Pune 411008, India.
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20
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Zuffo M, Gandolfini A, Heddi B, Granzhan A. Harnessing intrinsic fluorescence for typing of secondary structures of DNA. Nucleic Acids Res 2020; 48:e61. [PMID: 32313962 PMCID: PMC7293009 DOI: 10.1093/nar/gkaa257] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/28/2020] [Accepted: 04/03/2020] [Indexed: 12/15/2022] Open
Abstract
High-throughput investigation of structural diversity of nucleic acids is hampered by the lack of suitable label-free methods, combining fast and cheap experimental workflow with high information content. Here, we explore the use of intrinsic fluorescence emitted by nucleic acids for this scope. After a preliminary assessment of suitability of this phenomenon for tracking conformational changes of DNA, we examined steady-state emission spectra of an 89-membered set of oligonucleotides with reported conformation (G-quadruplexes (G4s), i-motifs, single- and double-strands) by means of multivariate analysis. Principal component analysis of emission spectra resulted in successful clustering of oligonucleotides into three corresponding conformational groups, without discrimination between single- and double-stranded structures. Linear discriminant analysis was exploited for the assessment of novel sequences, allowing the evaluation of their G4-forming propensity. Our method does not require any labeling agent or dye, avoiding the related bias, and can be utilized to screen novel sequences of interest in a high-throughput and cost-effective manner. In addition, we observed that left-handed (Z-) G4 structures were systematically more fluorescent than most other G4 structures, almost reaching the quantum yield of 5'-d[(G3T)3G3]-3' (G3T, the most fluorescent G4 structure reported to date).
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Affiliation(s)
- Michela Zuffo
- CNRS UMR9187, INSERM U1196, Institut Curie, PSL Research University, F-91405 Orsay, France.,CNRS UMR9187, INSERM U1196, Université Paris-Saclay, F-91405 Orsay, France
| | - Aurélie Gandolfini
- CNRS UMR9187, INSERM U1196, Institut Curie, PSL Research University, F-91405 Orsay, France.,CNRS UMR9187, INSERM U1196, Université Paris-Saclay, F-91405 Orsay, France
| | - Brahim Heddi
- Laboratoire de Biologie et de Pharmacologie Appliquée, CNRS UMR8113, École Normale Supérieure Paris-Saclay, F-94235 Cachan, France
| | - Anton Granzhan
- CNRS UMR9187, INSERM U1196, Institut Curie, PSL Research University, F-91405 Orsay, France.,CNRS UMR9187, INSERM U1196, Université Paris-Saclay, F-91405 Orsay, France
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21
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Sontakke VA, Srivatsan SG. A dual-app nucleoside probe reports G-quadruplex formation and ligand binding in the long terminal repeat of HIV-1 proviral genome. Bioorg Med Chem Lett 2020; 30:127345. [PMID: 32631544 DOI: 10.1016/j.bmcl.2020.127345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 06/07/2020] [Accepted: 06/09/2020] [Indexed: 12/12/2022]
Abstract
We have developed a dual-app nucleoside analog, 5-selenophene-modified 2'-deoxyuridine (SedU), to probe the structure and ligand-binding properties of a G-rich segment present in the long terminal repeat (LTR) of the HIV-1 proviral DNA promoter region. The nucleoside probe is made of an environment-responsive fluorophore and X-ray crystallography phasing label (Se atom). SedU incorporated into LTR-IV sequence, fluorescently reports the formation of G-quadruplex (GQ) structure without affecting the native fold. Further, using the environment sensitivity of the probe, a fluorescence assay was designed to estimate the binding affinity of small molecule ligands to the GQ motif. An added feature of this probe system is that it would enable direct correlation of structure and recognition properties in solution and atomic level by using a combination of fluorescence and X-ray crystallography techniques.
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Affiliation(s)
- Vyankat A Sontakke
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune 411008, India
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune 411008, India.
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22
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Nuthanakanti A, Ahmed I, Khatik SY, Saikrishnan K, Srivatsan SG. Probing G-quadruplex topologies and recognition concurrently in real time and 3D using a dual-app nucleoside probe. Nucleic Acids Res 2020; 47:6059-6072. [PMID: 31106340 PMCID: PMC6614846 DOI: 10.1093/nar/gkz419] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/30/2019] [Accepted: 05/06/2019] [Indexed: 12/30/2022] Open
Abstract
Comprehensive understanding of structure and recognition properties of regulatory nucleic acid elements in real time and atomic level is highly important to devise efficient therapeutic strategies. Here, we report the establishment of an innovative biophysical platform using a dual-app nucleoside analog, which serves as a common probe to detect and correlate different GQ structures and ligand binding under equilibrium conditions and in 3D by fluorescence and X-ray crystallography techniques. The probe (SedU) is composed of a microenvironment-sensitive fluorophore and an excellent anomalous X-ray scatterer (Se), which is assembled by attaching a selenophene ring at 5-position of 2'-deoxyuridine. SedU incorporated into the loop region of human telomeric DNA repeat fluorescently distinguished subtle differences in GQ topologies and enabled quantify ligand binding to different topologies. Importantly, anomalous X-ray dispersion signal from Se could be used to determine the structure of GQs. As the probe is minimally perturbing, a direct comparison of fluorescence data and crystal structures provided structural insights on how the probe senses different GQ conformations without affecting the native fold. Taken together, our dual-app probe represents a new class of tool that opens up new experimental strategies to concurrently investigate nucleic acid structure and recognition in real time and 3D.
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Affiliation(s)
- Ashok Nuthanakanti
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Ishtiyaq Ahmed
- Department of Biology, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Saddam Y Khatik
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Kayarat Saikrishnan
- Department of Biology, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
- Correspondence may also be addressed to Kayarat Saikrishnan.
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
- To whom correspondence should be addressed. Tel: +91 2025908086;
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23
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24
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Füchtbauer AF, Wranne MS, Bood M, Weis E, Pfeiffer P, Nilsson JR, Dahlén A, Grøtli M, Wilhelmsson LM. Interbase FRET in RNA: from A to Z. Nucleic Acids Res 2019; 47:9990-9997. [PMID: 31544922 PMCID: PMC6821158 DOI: 10.1093/nar/gkz812] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 09/02/2019] [Accepted: 09/11/2019] [Indexed: 01/22/2023] Open
Abstract
Interbase FRET can reveal highly detailed information about distance, orientation and dynamics in nucleic acids, complementing the existing structure and dynamics techniques. We here report the first RNA base analogue FRET pair, consisting of the donor tCO and the non-emissive acceptor tCnitro. The acceptor ribonucleoside is here synthesised and incorporated into RNA for the first time. This FRET pair accurately reports the average structure of A-form RNA, and its utility for probing RNA structural changes is demonstrated by monitoring the transition from A- to Z-form RNA. Finally, the measured FRET data were compared with theoretical FRET patterns obtained from two previously reported Z-RNA PDB structures, to shed new light on this elusive RNA conformation.
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Affiliation(s)
- Anders F Füchtbauer
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg SE-412 96, Sweden
| | - Moa S Wranne
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg SE-412 96, Sweden
| | - Mattias Bood
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg SE-412 96, Sweden.,Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Erik Weis
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg SE-412 96, Sweden.,Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Pauline Pfeiffer
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg SE-412 96, Sweden
| | - Jesper R Nilsson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg SE-412 96, Sweden
| | - Anders Dahlén
- Medicinal Chemistry, Research and Early Development Cardiovascular, Renal and Metabolism, BioPharmaceuticals R&D, AstraZeneca, Gothenburg, Sweden
| | - Morten Grøtli
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg SE-412 96, Sweden
| | - L Marcus Wilhelmsson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg SE-412 96, Sweden
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25
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Leonard P, Kondhare D, Jentgens X, Daniliuc C, Seela F. Nucleobase-Functionalized 5-Aza-7-deazaguanine Ribo- and 2′-Deoxyribonucleosides: Glycosylation, Pd-Assisted Cross-Coupling, and Photophysical Properties. J Org Chem 2019; 84:13313-13328. [DOI: 10.1021/acs.joc.9b01347] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Peter Leonard
- Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology, Heisenbergstrasse 11, 48149 Münster, Germany
| | - Dasharath Kondhare
- Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology, Heisenbergstrasse 11, 48149 Münster, Germany
| | - Xenia Jentgens
- Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology, Heisenbergstrasse 11, 48149 Münster, Germany
| | - Constantin Daniliuc
- Institut für Organische Chemie, Universität Münster, Corrensstrasse 40, 48149 Münster, Germany
| | - Frank Seela
- Laboratory of Bioorganic Chemistry and Chemical Biology, Center for Nanotechnology, Heisenbergstrasse 11, 48149 Münster, Germany
- Laboratorium für Organische und Bioorganische Chemie, Institut für Chemie neuer Materialien, Universität Osnabrück, Barbarastrasse 7, 49069 Osnabrück, Germany
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26
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Eubanks CS, Zhao B, Patwardhan NN, Thompson RD, Zhang Q, Hargrove AE. Visualizing RNA Conformational Changes via Pattern Recognition of RNA by Small Molecules. J Am Chem Soc 2019; 141:5692-5698. [DOI: 10.1021/jacs.8b09665] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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27
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Ramos CIV, Almeida SP, Lourenço LMO, Pereira PMR, Fernandes R, Faustino MAF, Tomé JPC, Carvalho J, Cruz C, Neves MGPMS. Multicharged Phthalocyanines as Selective Ligands for G-Quadruplex DNA Structures. Molecules 2019; 24:E733. [PMID: 30781675 PMCID: PMC6412362 DOI: 10.3390/molecules24040733] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 02/12/2019] [Accepted: 02/13/2019] [Indexed: 01/21/2023] Open
Abstract
The stabilization of G-Quadruplex DNA structures by ligands is a promising strategy for telomerase inhibition in cancer therapy since this enzyme is responsible for the unlimited proliferation of cancer cells. To assess the potential of a compound as a telomerase inhibitor, selectivity for quadruplex over duplex DNA is a fundamental attribute, as the drug must be able to recognize quadruplex DNA in the presence of a large amount of duplex DNA, in the cellular nucleus. By using different spectroscopic techniques, such as ultraviolet-visible, fluorescence and circular dichroism, this work evaluates the potential of a series of multicharged phthalocyanines, bearing four or eight positive charges, as G-Quadruplex stabilizing ligands. This work led us to conclude that the existence of a balance between the number and position of the positive charges in the phthalocyanine structure is a fundamental attribute for its selectivity for G-Quadruplex structures over duplex DNA structures. Two of the studied phthalocyanines, one with four peripheral positive charges (ZnPc1) and the other with less exposed eight positive charges (ZnPc4) showed high selectivity and affinity for G-Quadruplex over duplex DNA structures and were able to accumulate in the nucleus of UM-UC-3 bladder cancer cells.
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Affiliation(s)
- Catarina I V Ramos
- QOPNA & LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Susana P Almeida
- QOPNA & LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Leandro M O Lourenço
- QOPNA & LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - Patrícia M R Pereira
- QOPNA & LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal.
- CNC.IBILI Consortium, University of Coimbra, 3000-548 Coimbra, Portugal.
| | - Rosa Fernandes
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal.
- CNC.IBILI Consortium, University of Coimbra, 3000-548 Coimbra, Portugal.
| | - M Amparo F Faustino
- QOPNA & LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
| | - João P C Tomé
- CQE & Departamento de Engenharia Química, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, n1, 1049-001 Lisboa, Portugal.
| | - Josué Carvalho
- CICS-UBI-Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
| | - Carla Cruz
- CICS-UBI-Centro de Investigação em Ciências da Saúde, Universidade da Beira Interior, Av. Infante D. Henrique, 6200-506 Covilhã, Portugal.
| | - M Graça P M S Neves
- QOPNA & LAQV-REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
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28
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Sabale PM, Tanpure AA, Srivatsan SG. Probing the competition between duplex and G-quadruplex/i-motif structures using a conformation-sensitive fluorescent nucleoside probe. Org Biomol Chem 2019; 16:4141-4150. [PMID: 29781489 PMCID: PMC6086326 DOI: 10.1039/c8ob00646f] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Double-stranded segments of a genome that can potentially form G-quadruplex (GQ) and/or i-motif (iM) structures are considered to be important regulatory elements. Hence, the development of a common probe that can detect GQ and iM structures and also distinguish them from a duplex structure will be highly useful in understanding the propensity of such segments to adopt duplex or non-canonical four-stranded structures. Here, we describe the utility of a conformation-sensitive fluorescent nucleoside analog, which was originally developed as a GQ sensor, in detecting the iM structures of C-rich DNA oligonucleotides (ONs). The analog is based on a 5-(benzofuran-2-yl)uracil scaffold, which when incorporated into C-rich ONs (e.g., telomeric repeats) fluorescently distinguishes an iM from random coil and duplex structures. Steady-state and time-resolved fluorescence techniques enabled the determination of transition pH for the transformation of a random coil to an iM structure. Furthermore, a qualitative understanding on the relative population of duplex and GQ/iM forms under physiological conditions could be gained by correlating the fluorescence, CD and thermal melting data. Taken together, this sensor could provide a general platform to profile double-stranded promoter regions in terms of their ability to adopt four-stranded structures, and also could support approaches to discover functional GQ and iM binders.
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Affiliation(s)
- Pramod M Sabale
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India.
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29
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Synthesis, characterization and significant optoelectronic parameters of 1-(7-methoxy-1-benzofuran-2-yl) substituted chalcone derivatives. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2018.10.043] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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30
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Stendevad J, Hornum M, Wüstner D, Kongsted J. Photophysical investigation of two emissive nucleosides exhibiting gigantic stokes shifts. Photochem Photobiol Sci 2019; 18:1858-1865. [DOI: 10.1039/c9pp00172g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present discovery of two highly emissive nucleoside analogs with gigantic Stokes shifts and use in silico methods for rationalizing their striking fluorescent properties.
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Affiliation(s)
- Julie Stendevad
- Department of Physics
- Chemistry and Pharmacy
- University of Southern Denmark
- DK-5230 Odense M
- Denmark
| | - Mick Hornum
- Department of Physics
- Chemistry and Pharmacy
- University of Southern Denmark
- DK-5230 Odense M
- Denmark
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology
- University of Southern Denmark
- DK-5230 Odense M
- Denmark
| | - Jacob Kongsted
- Department of Physics
- Chemistry and Pharmacy
- University of Southern Denmark
- DK-5230 Odense M
- Denmark
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31
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Teppang KL, Lee RW, Burns DD, Turner MB, Lokensgard ME, Cooksy AL, Purse BW. Electronic Modifications of Fluorescent Cytidine Analogues Control Photophysics and Fluorescent Responses to Base Stacking and Pairing. Chemistry 2018; 25:1249-1259. [PMID: 30338571 DOI: 10.1002/chem.201803653] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Indexed: 11/07/2022]
Abstract
The rational design of fluorescent nucleoside analogues is greatly hampered by the lack of a general method to predict their photophysics, a problem that is especially acute when base pairing and stacking change fluorescence. To better understand these effects, a series of tricyclic cytidine (tC and tCO ) analogues ranging from electron-rich to electron-deficient was designed and synthesized. They were then incorporated into oligonucleotides, and photophysical responses to base pairing and stacking were studied. When inserted into double-stranded DNA oligonucleotides, electron-rich analogues exhibit a fluorescence turn-on effect, in contrast with the electron-deficient compounds, which show diminished fluorescence. The magnitude of these fluorescence changes is correlated with the oxidation potential of nearest neighbor nucleobases. Moreover, matched base pairing enhances fluorescence turn-on for the electron-rich compounds, and it causes a fluorescence decrease for the electron-deficient compounds. For the tCO compounds, the emergence of vibrational fine structure in the fluorescence spectra in response to base pairing and stacking was observed, offering a potential new tool for studying nucleic acid structure and dynamics. These results, supported by DFT calculations, help to rationalize fluorescence changes in the base stack and will be useful for selecting the best fluorescent nucleoside analogues for a desired application.
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Affiliation(s)
- Kristine L Teppang
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, 92182, USA
| | - Raymond W Lee
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, 92182, USA
| | - Dillon D Burns
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, 92182, USA
| | - M Benjamin Turner
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, 92182, USA
| | - Melissa E Lokensgard
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, 92182, USA
| | - Andrew L Cooksy
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, 92182, USA
| | - Byron W Purse
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, 92182, USA
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32
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Eubanks CS, Hargrove AE. RNA Structural Differentiation: Opportunities with Pattern Recognition. Biochemistry 2018; 58:199-213. [PMID: 30513196 DOI: 10.1021/acs.biochem.8b01090] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Our awareness and appreciation of the many regulatory roles of RNA have dramatically increased in the past decade. This understanding, in addition to the impact of RNA in many disease states, has renewed interest in developing selective RNA-targeted small molecule probes. However, the fundamental guiding principles in RNA molecular recognition that could accelerate these efforts remain elusive. While high-resolution structural characterization can provide invaluable insight, examples of well-characterized RNA structures, not to mention small molecule:RNA complexes, remain limited. This Perspective provides an overview of the current techniques used to understand RNA molecular recognition when high-resolution structural information is unavailable. We will place particular emphasis on a new method, pattern recognition of RNA with small molecules (PRRSM), that provides rapid insight into critical components of RNA recognition and differentiation by small molecules as well as into RNA structural features.
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Affiliation(s)
- Christopher S Eubanks
- Department of Chemistry , Duke University , Durham , North Carolina 27708-0354 , United States
| | - Amanda E Hargrove
- Department of Chemistry , Duke University , Durham , North Carolina 27708-0354 , United States
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33
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Ishizuka T, Zhao PY, Bao HL, Xu Y. A multi-functional guanine derivative for studying the DNA G-quadruplex structure. Analyst 2018; 142:4083-4088. [PMID: 28932835 DOI: 10.1039/c7an00941k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In the present study, we developed a multi-functional guanine derivative, 8FG, as a G-quadruplex stabilizer, a fluorescent probe for the detection of G-quadruplex formation, and a 19F sensor for the observation of the G-quadruplex. We demonstrate that the functional nucleoside bearing a 3,5-bis(trifluoromethyl)benzene group at the 8-position of guanine stabilizes the DNA G-quadruplex structure and fluoresces following the G-quadruplex formation. Furthermore, we show that the functional sensor can be used to directly observe DNA G-quadruplexes by 19F-NMR in living cells. To our knowledge, this is the first study showing that the nucleoside derivative simultaneously allows for three kinds of functions at a single G-quadruplex DNA. Our results suggest that the multi-functional nucleoside derivative can be broadly used for studying the G-quadruplex structure and serves as a powerful tool for examining the molecular basis of G-quadruplex formation in vitro and in living cells.
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Affiliation(s)
- Takumi Ishizuka
- Division of Chemistry, Department of Medical Sciences, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan.
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34
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Turner MB, Anderson BA, Samaan GN, Coste M, Burns DD, Purse BW. Synthesis of Fluorescence Turn-On DNA Hybridization Probe Using the DEA tC 2'-Deoxycytidine Analog. CURRENT PROTOCOLS IN NUCLEIC ACID CHEMISTRY 2018; 75:e59. [PMID: 30369083 PMCID: PMC6284819 DOI: 10.1002/cpnc.59] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
DEA tC is a tricyclic 2'-deoxycytidine analog that can be incorporated into oligonucleotides by solid-phase synthesis and that exhibits a large fluorescence enhancement when correctly base-paired with a guanine base in a DNA-DNA duplex. The synthesis of DEA tC begins with 5-amino-2-methylbenzothiazole and provides the DEA tC nucleobase analog over five synthetic steps. This nucleobase analog is then silylated using N,O-bis(trimethylsilyl)acetamide and conjugated to Hoffer's chlorosugar to provide the protected DEA tC nucleoside in good yield. Following protective-group removal and chromatographic isolation of the β-anomer, dimethoxytritylation and phosphoramidite synthesis offer the monomer for solid-phase DNA synthesis. Solid-phase DNA synthesis conditions using extended coupling of the DEA tC amidite and a short deprotection time are employed to maximize efficiency. By following the protocols described in this unit, the DEA tC fluorescent probe can be synthesized and can be incorporated into any desired synthetic DNA oligonucleotide. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- M Benjamin Turner
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California
| | - Brooke A Anderson
- Department of Chemistry, The Scripps Research Institute, La Jolla, California
| | - George N Samaan
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California
| | - Michael Coste
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California
| | - Dillon D Burns
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California
| | - Byron W Purse
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, California
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35
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Manna S, Sarkar D, Srivatsan SG. A Dual-App Nucleoside Probe Provides Structural Insights into the Human Telomeric Overhang in Live Cells. J Am Chem Soc 2018; 140:12622-12633. [PMID: 30192541 PMCID: PMC6348103 DOI: 10.1021/jacs.8b08436] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Understanding the topology adopted by individual G-quadruplex (GQ)-forming sequences in vivo and targeting a specific GQ motif among others in the genome will have a profound impact on GQ-directed therapeutic strategies. However, this remains a major challenge as most of the tools poorly distinguish different GQ conformations and are not suitable for both cell-free and in-cell analysis. Here, we describe an innovative probe design to investigate GQ conformations and recognition in both cell-free and native cellular environments by using a conformation-sensitive dual-app nucleoside analogue probe. The nucleoside probe, derived by conjugating fluorobenzofuran at the 5-position of 2'-deoxyuridine, is composed of a microenvironment-sensitive fluorophore and an in-cell NMR compatible 19F label. This noninvasive nucleoside, incorporated into the human telomeric DNA oligonucleotide repeat, serves as a common probe to distinguish different GQ topologies and quantify topology-specific binding of ligands by fluorescence and NMR techniques. Importantly, unique signatures displayed by the 19F-labeled nucleoside for different GQs enabled a systematic study in Xenopus laevis oocytes to provide new structural insights into the GQ topologies adopted by human telomeric overhang in cells, which so far has remained unclear. Studies using synthetic cell models, immunostaining on fixed cells, and crystallization conditions suggest that parallel GQ is the preferred conformation of telomeric DNA repeat. However, our findings using the dual-app probe clearly indicate that multiple structures including hybrid-type parallel-antiparallel and parallel GQs are formed in the cellular environment. Taken together, our findings open new experimental strategies to investigate topology, recognition, and therapeutic potential of individual GQ-forming motifs in a biologically relevant context.
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Affiliation(s)
- Sudeshna Manna
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Debayan Sarkar
- Department of Biology, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Seergazhi G. Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pune 411008, India
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36
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Whitfield CJ, Little RC, Khan K, Ijiro K, Connolly BA, Tuite EM, Pike AR. Self-Priming Enzymatic Fabrication of Multiply Modified DNA. Chemistry 2018; 24:15267-15274. [PMID: 29931815 DOI: 10.1002/chem.201801976] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/19/2018] [Indexed: 12/15/2022]
Abstract
The self-priming synthesis of multiply modified DNA by the extension of repeating unit duplex "oligoseeds" provides a source of versatile DNA. Sterically-demanding nucleotides 5-Br-dUTP, 7-deaza-7-I-dATP, 6-S-dGTP, 5-I-dCTP as well as 5-(octadiynyl)-dCTP were incorporated into two extending oligoseeds; [GATC]5 /[GATC]5 and [A4 G]4 /[CT4 ]4 . The products contained modifications on one or both strands of DNA, demonstrating their recognition by the polymerase as both template (reading) and substrate (writing). Nucleobase modifications that lie in the major groove were reliably read and written by the polymerase during the extension reaction, even when bulky or in contiguous sequences. Repeat sequence DNA over 500 bp long, bearing four different modified units was produced by this method. The number, position and type of modification, as well as the overall length of the DNA can be controlled to yield designer DNA that offers sequence-determined sites for further chemical adaptations, targeted small molecule binding studies, or sensing and sequencing applications.
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Affiliation(s)
- Colette J Whitfield
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Rachel C Little
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Kasid Khan
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Kuniharu Ijiro
- Research Institute for Electronic Science, Hokkaido University, Sapporo, 001-0021, Japan
| | - Bernard A Connolly
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Eimer M Tuite
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Andrew R Pike
- Chemistry-School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
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37
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Seio K, Kanamori T, Masaki Y. Synthesis of Fluorescent Nucleic Acids bearing Nucleobases Modified with Heteroaryl Group and Fluorophores. J SYN ORG CHEM JPN 2018. [DOI: 10.5059/yukigoseikyokaishi.76.792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Kohji Seio
- Department of Life Science and Technology, Tokyo Institute of Technology
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38
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Manna S, Srivatsan SG. Fluorescence-based tools to probe G-quadruplexes in cell-free and cellular environments. RSC Adv 2018; 8:25673-25694. [PMID: 30210793 PMCID: PMC6130854 DOI: 10.1039/c8ra03708f] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/08/2018] [Indexed: 12/26/2022] Open
Abstract
Biophysical and biochemical investigations provide compelling evidence connecting the four-stranded G-quadruplex (GQ) structure with its role in regulating multiple cellular processes. Hence, modulating the function of GQs by using small molecule binders is being actively pursued as a strategy to develop new chemotherapeutic agents. However, sequence diversity and structural polymorphism of GQs have posed immense challenges in terms of understanding what conformation a G-rich sequence adopts inside the cell and how to specifically target a GQ motif amidst several other GQ-forming sequences. In this context, here we review recent developments in the applications of biophysical tools that use fluorescence readout to probe the GQ structure and recognition in cell-free and cellular environments. First, we provide a detailed discussion on the utility of covalently labeled environment-sensitive fluorescent nucleoside analogs in assessing the subtle difference in GQ structures and their ligand binding abilities. Furthermore, a detailed discussion on structure-specific antibodies and small molecule probes used to visualize and confirm the existence of DNA and RNA GQs in cells is provided. We also highlight the open challenges in the study of tetraplexes (GQ and i-motif structures) and how addressing these challenges by developing new tools and techniques will have a profound impact on tetraplex-directed therapeutic strategies.
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Affiliation(s)
- Sudeshna Manna
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), PuneDr. Homi Bhabha RoadPune 411008India
| | - Seergazhi G. Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), PuneDr. Homi Bhabha RoadPune 411008India
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39
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Walunj MB, Tanpure AA, Srivatsan SG. Post-transcriptional labeling by using Suzuki-Miyaura cross-coupling generates functional RNA probes. Nucleic Acids Res 2018; 46:e65. [PMID: 29546376 PMCID: PMC6009664 DOI: 10.1093/nar/gky185] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 02/12/2018] [Accepted: 03/01/2018] [Indexed: 12/21/2022] Open
Abstract
Pd-catalyzed C-C bond formation, an important vertebra in the spine of synthetic chemistry, is emerging as a valuable chemoselective transformation for post-synthetic functionalization of biomacromolecules. While methods are available for labeling protein and DNA, development of an analogous procedure to label RNA by cross-coupling reactions remains a major challenge. Herein, we describe a new Pd-mediated RNA oligonucleotide (ON) labeling method that involves post-transcriptional functionalization of iodouridine-labeled RNA transcripts by using Suzuki-Miyaura cross-coupling reaction. 5-Iodouridine triphosphate (IUTP) is efficiently incorporated into RNA ONs at one or more sites by T7 RNA polymerase. Further, using a catalytic system made of Pd(OAc)2 and 2-aminopyrimidine-4,6-diol (ADHP) or dimethylamino-substituted ADHP (DMADHP), we established a modular method to functionalize iodouridine-labeled RNA ONs in the presence of various boronic acid and ester substrates under very mild conditions (37°C and pH 8.5). This method is highly chemoselective, and offers direct access to RNA ONs labeled with commonly used fluorescent and affinity tags and new fluorogenic environment-sensitive nucleoside probes in a ligand-controlled stereoselective fashion. Taken together, this simple approach of generating functional RNA ON probes by Suzuki-Miyaura coupling will be a very important addition to the resources and tools available for analyzing RNA motifs.
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Affiliation(s)
- Manisha B Walunj
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune 411008, India
| | - Arun A Tanpure
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune 411008, India
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune Dr. Homi Bhabha Road, Pune 411008, India
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40
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Seio K, Kanamori T, Masaki Y. Solvent- and environment-dependent fluorescence of modified nucleobases. Tetrahedron Lett 2018. [DOI: 10.1016/j.tetlet.2018.04.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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41
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Eubanks CS, Hargrove AE. Sensing the impact of environment on small molecule differentiation of RNA sequences. Chem Commun (Camb) 2018; 53:13363-13366. [PMID: 29199743 DOI: 10.1039/c7cc07157d] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Using pattern recognition of RNA with small molecules (PRRSM) with fluorescent RNA chemosensors and aminoglycosides, we reveal the impact of changing environmental conditions on the differentiation of a range of RNA structures as well as the ability to predict different sequence/size compositions of five canonical RNA motifs.
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42
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Sabale PM, Ambi UB, Srivatsan SG. A Lucifer-Based Environment-Sensitive Fluorescent PNA Probe for Imaging Poly(A) RNAs. Chembiochem 2018; 19:826-835. [PMID: 29396904 PMCID: PMC5972818 DOI: 10.1002/cbic.201700661] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Indexed: 12/14/2022]
Abstract
Fluorescence‐based oligonucleotide (ON) hybridization probes greatly aid the detection and profiling of RNA sequences in cells. However, certain limitations such as target accessibility and hybridization efficiency in cellular environments hamper their broad application because RNAs can form complex and stable structures. In this context, we have developed a robust hybridization probe suitable for imaging RNA in cells by combining the properties of 1) a new microenvironment‐sensitive fluorescent nucleobase analogue, obtained by attaching the Lucifer chromophore (1,8‐naphthalimide) at the 5‐position of uracil, and 2) a peptide nucleic acid (PNA) capable of forming stable hybrids with RNA. The fluorescence of the PNA base analogue labeled with the Lucifer chromophore, when incorporated into PNA oligomers and hybridized to complementary and mismatched ONs, is highly responsive to its neighboring base environment. Notably, the PNA base reports the presence of an adenine repeat in an RNA ON with reasonable enhancement in fluorescence. This feature of the emissive analogue enabled the construction of a poly(T) PNA probe for the efficient visualization of polyadenylated [poly(A)] RNAs in cells—poly(A) being an important motif that plays vital roles in the lifecycle of many types of RNA. Our results demonstrate that such responsive fluorescent nucleobase analogues, when judiciously placed in PNA oligomers, could generate useful hybridization probes to detect nucleic acid sequences in cells and also to image them.
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Affiliation(s)
- Pramod M Sabale
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pune, 411008, India
| | - Uddhav B Ambi
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pune, 411008, India
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pune, 411008, India
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43
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Satpathi S, Kulkarni M, Mukherjee A, Hazra P. Ionic liquid induced G-quadruplex formation and stabilization: spectroscopic and simulation studies. Phys Chem Chem Phys 2018; 18:29740-29746. [PMID: 27766324 DOI: 10.1039/c6cp05732b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Among different polymorphs of DNA, G-quadruplex (GQ) formation in guanine rich sequences has received special attention due to its direct relevance to cellular aging and abnormal cell growths. To date, smaller ions like Na+, K+, Li+, and NH4+ are the best possible selective GQ stabilizing materials. Herein, we report that an ionic liquid (IL), i.e. guanidinium tris(pentafluoroethyl)trifluorophosphate, can not only instigate the GQ formation in the absence of conventional GQ forming ions (like Na+, K+, NH4+, etc.), but also stabilizes the GQ structure. This conformational transition has been confirmed through different spectroscopic tools and molecular dynamics (MD) simulation studies. MD simulation shows that one of the guanidinium cations resides in the G-tetrad core, while bulky anions prefer to stay near the GQ surface resulting in GQ formation and stabilization. This study thus brings out a special type of ionic liquid that acts as a GQ stabilizer. The origin of GQ stabilization by IL presented here may also help in the future design of IL for GQ formation and stabilization.
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Affiliation(s)
- Sagar Satpathi
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India.
| | - Mandar Kulkarni
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India.
| | - Arnab Mukherjee
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India.
| | - Partha Hazra
- Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune, Dr. Homi Bhabha Road, Pashan, Pune, 411008, India.
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Sagi J. In What Ways Do Synthetic Nucleotides and Natural Base Lesions Alter the Structural Stability of G-Quadruplex Nucleic Acids? J Nucleic Acids 2017; 2017:1641845. [PMID: 29181193 PMCID: PMC5664352 DOI: 10.1155/2017/1641845] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 08/15/2017] [Indexed: 01/03/2023] Open
Abstract
Synthetic analogs of natural nucleotides have long been utilized for structural studies of canonical and noncanonical nucleic acids, including the extensively investigated polymorphic G-quadruplexes (GQs). Dependence on the sequence and nucleotide modifications of the folding landscape of GQs has been reviewed by several recent studies. Here, an overview is compiled on the thermodynamic stability of the modified GQ folds and on how the stereochemical preferences of more than 70 synthetic and natural derivatives of nucleotides substituting for natural ones determine the stability as well as the conformation. Groups of nucleotide analogs only stabilize or only destabilize the GQ, while the majority of analogs alter the GQ stability in both ways. This depends on the preferred syn or anti N-glycosidic linkage of the modified building blocks, the position of substitution, and the folding architecture of the native GQ. Natural base lesions and epigenetic modifications of GQs explored so far also stabilize or destabilize the GQ assemblies. Learning the effect of synthetic nucleotide analogs on the stability of GQs can assist in engineering a required stable GQ topology, and exploring the in vitro action of the single and clustered natural base damage on GQ architectures may provide indications for the cellular events.
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Affiliation(s)
- Janos Sagi
- Rimstone Laboratory, RLI, Carlsbad, CA 92010, USA
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45
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Bağda E, Bağda E, Durmuş M. G-quadruplex and calf thymus DNA interaction of quaternized tetra and octa pyridyloxy substituted indium (III) phthalocyanines. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2017; 175:9-19. [DOI: 10.1016/j.jphotobiol.2017.08.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/17/2017] [Accepted: 08/05/2017] [Indexed: 01/12/2023]
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46
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Manna S, Panse CH, Sontakke VA, Sangamesh S, Srivatsan SG. Probing Human Telomeric DNA and RNA Topology and Ligand Binding in a Cellular Model by Using Responsive Fluorescent Nucleoside Probes. Chembiochem 2017; 18:1604-1615. [PMID: 28569423 PMCID: PMC5724660 DOI: 10.1002/cbic.201700283] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Indexed: 01/03/2023]
Abstract
The development of biophysical systems that enable an understanding of the structure and ligand-binding properties of G-quadruplex (GQ)-forming nucleic acid sequences in cells or models that mimic the cellular environment would be highly beneficial in advancing GQ-directed therapeutic strategies. Herein, the establishment of a biophysical platform to investigate the structure and recognition properties of human telomeric (H-Telo) DNA and RNA repeats in a cell-like confined environment by using conformation-sensitive fluorescent nucleoside probes and a widely used cellular model, bis(2-ethylhexyl) sodium sulfosuccinate reverse micelles (RMs), is described. The 2'-deoxy and ribonucleoside probes, composed of a 5-benzofuran uracil base analogue, faithfully report the aqueous micellar core through changes in their fluorescence properties. The nucleoside probes incorporated into different loops of H-Telo DNA and RNA oligonucleotide repeats are minimally perturbing and photophysically signal the formation of respective GQ structures in both aqueous buffer and RMs. Furthermore, these sensors enable a direct comparison of the binding affinity of a ligand to H-Telo DNA and RNA GQ structures in the bulk and confined environment of RMs. These results demonstrate that this combination of a GQ nucleoside probe and easy-to-handle RMs could provide new opportunities to study and devise screening-compatible assays in a cell-like environment to discover GQ binders of clinical potential.
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Affiliation(s)
- Sudeshna Manna
- Department of ChemistryIndian Institute of Science Education and Research (IISER)Dr. Homi Bhabha RoadPune411008India
| | - Cornelia H. Panse
- Department of ChemistryIndian Institute of Science Education and Research (IISER)Dr. Homi Bhabha RoadPune411008India
| | - Vyankat A. Sontakke
- Department of ChemistryIndian Institute of Science Education and Research (IISER)Dr. Homi Bhabha RoadPune411008India
| | - Sarangamath Sangamesh
- Department of ChemistryIndian Institute of Science Education and Research (IISER)Dr. Homi Bhabha RoadPune411008India
| | - Seergazhi G. Srivatsan
- Department of ChemistryIndian Institute of Science Education and Research (IISER)Dr. Homi Bhabha RoadPune411008India
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47
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George JT, Srivatsan SG. Vinyluridine as a Versatile Chemoselective Handle for the Post-transcriptional Chemical Functionalization of RNA. Bioconjug Chem 2017; 28:1529-1536. [PMID: 28406614 DOI: 10.1021/acs.bioconjchem.7b00169] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The development of modular and efficient methods to functionalize RNA with biophysical probes is very important in advancing the understanding of the structural and functional relevance of RNA in various cellular events. Herein, we demonstrate a two-step bioorthogonal chemical functionalization approach for the conjugation of multiple probes onto RNA transcripts using a 5-vinyl-modified uridine nucleotide analog (VUTP). VUTP, containing a structurally noninvasive and versatile chemoselective handle, was efficiently incorporated into RNA transcripts by in vitro transcription reactions. Furthermore, we show for the first time the use of a palladium-mediated oxidative Heck reaction in functionalizing RNA with fluorogenic probes by reacting vinyl-labeled RNA transcripts with appropriate boronic acid substrates. The vinyl label also permitted the post-transcriptional functionalization of RNA by a reagent-free inverse electron demand Diels-Alder (IEDDA) reaction in the presence of tetrazine substrates. Collectively, our results demonstrate that the incorporation of VUTP provides newer possibilities for the modular functionalization of RNA with variety of reporters.
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Affiliation(s)
- Jerrin Thomas George
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune , Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Seergazhi G Srivatsan
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune , Dr. Homi Bhabha Road, Pashan, Pune 411008, India
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Dolinnaya NG, Ogloblina AM, Yakubovskaya MG. Structure, Properties, and Biological Relevance of the DNA and RNA G-Quadruplexes: Overview 50 Years after Their Discovery. BIOCHEMISTRY (MOSCOW) 2017; 81:1602-1649. [PMID: 28260487 PMCID: PMC7087716 DOI: 10.1134/s0006297916130034] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
G-quadruplexes (G4s), which are known to have important roles in regulation of key biological processes in both normal and pathological cells, are the most actively studied non-canonical structures of nucleic acids. In this review, we summarize the results of studies published in recent years that change significantly scientific views on various aspects of our understanding of quadruplexes. Modern notions on the polymorphism of DNA quadruplexes, on factors affecting thermodynamics and kinetics of G4 folding–unfolding, on structural organization of multiquadruplex systems, and on conformational features of RNA G4s and hybrid DNA–RNA G4s are discussed. Here we report the data on location of G4 sequence motifs in the genomes of eukaryotes, bacteria, and viruses, characterize G4-specific small-molecule ligands and proteins, as well as the mechanisms of their interactions with quadruplexes. New information on the structure and stability of G4s in telomeric DNA and oncogene promoters is discussed as well as proof being provided on the occurrence of G-quadruplexes in cells. Prominence is given to novel experimental techniques (single molecule manipulations, optical and magnetic tweezers, original chemical approaches, G4 detection in situ, in-cell NMR spectroscopy) that facilitate breakthroughs in the investigation of the structure and functions of G-quadruplexes.
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Affiliation(s)
- N G Dolinnaya
- Lomonosov Moscow State University, Department of Chemistry, Moscow, 119991, Russia.
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Burns DD, Teppang KL, Lee RW, Lokensgard ME, Purse BW. Fluorescence Turn-On Sensing of DNA Duplex Formation by a Tricyclic Cytidine Analogue. J Am Chem Soc 2017; 139:1372-1375. [PMID: 28080035 DOI: 10.1021/jacs.6b10410] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Most fluorescent nucleoside analogues are quenched when base stacked and some maintain their brightness, but there has been little progress toward developing nucleoside analogues that markedly increase their fluorescence upon duplex formation. Here, we report on the design and synthesis of a new tricyclic cytidine analogue, 8-diethylamino-tC (8-DEA-tC), that responds to DNA duplex formation with up to a 20-fold increase in fluorescent quantum yield as compared with the free nucleoside, depending on neighboring bases. This turn-on response to duplex formation is the greatest of any reported nucleoside analogue that can participate in Watson-Crick base pairing. Measurements of the quantum yield of 8-DEA-tC mispaired with adenosine and, separately, opposite an abasic site show that there is almost no fluorescence increase without the formation of correct Watson-Crick hydrogen bonds. Kinetic isotope effects from the use of deuterated buffer show that the duplex protects 8-DEA-tC against quenching by excited state proton transfer. These results, supported by DFT calculations, suggest a rationale for the observed photophysical properties that is dependent on duplex integrity and the electronic structure of the analogue.
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Affiliation(s)
- Dillon D Burns
- Department of Chemistry and Biochemistry, San Diego State University , San Diego, California 92182, United States
| | - Kristine L Teppang
- Department of Chemistry and Biochemistry, San Diego State University , San Diego, California 92182, United States
| | - Raymond W Lee
- Department of Chemistry and Biochemistry, San Diego State University , San Diego, California 92182, United States
| | - Melissa E Lokensgard
- Department of Chemistry and Biochemistry, San Diego State University , San Diego, California 92182, United States
| | - Byron W Purse
- Department of Chemistry and Biochemistry, San Diego State University , San Diego, California 92182, United States
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50
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Eubanks CS, Forte JE, Kapral GJ, Hargrove AE. Small Molecule-Based Pattern Recognition To Classify RNA Structure. J Am Chem Soc 2017; 139:409-416. [PMID: 28004925 PMCID: PMC5465965 DOI: 10.1021/jacs.6b11087] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Three-dimensional RNA structures are notoriously difficult to determine, and the link between secondary structure and RNA conformation is only beginning to be understood. These challenges have hindered the identification of guiding principles for small molecule:RNA recognition. We herein demonstrate that the strong and differential binding ability of aminoglycosides to RNA structures can be used to classify five canonical RNA secondary structure motifs through principal component analysis (PCA). In these analyses, the aminoglycosides act as receptors, while RNA structures labeled with a benzofuranyluridine fluorophore act as analytes. Complete (100%) predictive ability for this RNA training set was achieved by incorporating two exhaustively guanidinylated aminoglycosides into the receptor library. The PCA was then externally validated using biologically relevant RNA constructs. In bulge-stem-loop constructs of HIV-1 transactivation response element (TAR) RNA, we achieved nucleotide-specific classification of two independent secondary structure motifs. Furthermore, examination of cheminformatic parameters and PCA loading factors revealed trends in aminoglycoside:RNA recognition, including the importance of shape-based discrimination, and suggested the potential for size and sequence discrimination within RNA structural motifs. These studies present a new approach to classifying RNA structure and provide direct evidence that RNA topology, in addition to sequence, is critical for the molecular recognition of RNA.
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Affiliation(s)
- Christopher S Eubanks
- Department of Chemistry, Duke University , Durham, North Carolina 27708, United States
| | - Jordan E Forte
- Department of Chemistry, Duke University , Durham, North Carolina 27708, United States
| | - Gary J Kapral
- Department of Chemistry, Duke University , Durham, North Carolina 27708, United States
| | - Amanda E Hargrove
- Department of Chemistry, Duke University , Durham, North Carolina 27708, United States
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