1
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Kinetics of DNA strand transfer between polymerase and proofreading exonuclease active sites regulates error correction during high-fidelity replication. J Biol Chem 2022; 299:102744. [PMID: 36436560 PMCID: PMC9800556 DOI: 10.1016/j.jbc.2022.102744] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/18/2022] [Accepted: 11/20/2022] [Indexed: 11/25/2022] Open
Abstract
We show that T7 DNA polymerase (pol) and exonuclease (exo) domains contribute to selective error correction during DNA replication by regulating bidirectional strand transfer between the two active sites. To explore the kinetic basis for selective removal of mismatches, we used a fluorescent cytosine analog (1,3-diaza-2-oxophenoxazine) to monitor the kinetics of DNA transfer between the exo and pol sites. We globally fit stopped-flow fluorescence and base excision kinetic data and compared results obtained with ssDNA versus duplex DNA to resolve how DNA transfer governs exo specificity. We performed parallel studies using hydrolysis-resistant phosphorothioate oligonucleotides to monitor DNA transfer to the exo site without hydrolysis. ssDNA binds to the exo site at the diffusion limit (109 M-1 s-1, Kd = 40 nM) followed by fast hydrolysis of the 3'-terminal nucleotide (>5000 s-1). Analysis using duplex DNA with a 3'-terminal mismatch or a buried mismatch exposed a unique intermediate state between pol and exo active sites and revealed that transfer via the intermediate to the exo site is stimulated by free nucleoside triphosphates. Transfer from the exo site back to the pol site after cleavage is fast and efficient. We propose a model to explain why buried mismatches are removed faster than single 3'-terminal mismatches and thereby provide an additional opportunity for error correction. Our data provide the first comprehensive model to explain how DNA transfer from pol to exo active sites and back again after base excision allow efficient selective mismatch removal during DNA replication to improve fidelity by more than 1000-fold.
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2
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Yamaji R, Nakagawa O, Kishimoto Y, Fujii A, Matsumura T, Nakayama T, Kamada H, Osawa T, Yamaguchi T, Obika S. Synthesis and physical and biological properties of 1,3-diaza-2-oxophenoxazine-conjugated oligonucleotides. Bioorg Med Chem 2022; 72:116972. [DOI: 10.1016/j.bmc.2022.116972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 11/26/2022]
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3
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Chan SH, Whipple JM, Dai N, Kelley TM, Withers K, Tzertzinis G, Corrêa IR, Robb GB. RNase H-based analysis of synthetic mRNA 5' cap incorporation. RNA (NEW YORK, N.Y.) 2022; 28:1144-1155. [PMID: 35680168 PMCID: PMC9297845 DOI: 10.1261/rna.079173.122] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
Advances in mRNA synthesis and lipid nanoparticles technologies have helped make mRNA therapeutics and vaccines a reality. The 5' cap structure is a crucial modification required to functionalize synthetic mRNA for efficient protein translation in vivo and evasion of cellular innate immune responses. The extent of 5' cap incorporation is one of the critical quality attributes in mRNA manufacturing. RNA cap analysis involves multiple steps: generation of predefined short fragments from the 5' end of the kilobase-long synthetic mRNA molecules using RNase H, a ribozyme or a DNAzyme, enrichment of the 5' cleavage products, and LC-MS intact mass analysis. In this paper, we describe (1) a framework to design site-specific RNA cleavage using RNase H; (2) a method to fluorescently label the RNase H cleavage fragments for more accessible readout methods such as gel electrophoresis or high-throughput capillary electrophoresis; (3) a simplified method for post-RNase H purification using desthiobiotinylated oligonucleotides and streptavidin magnetic beads followed by elution using water. By providing a design framework for RNase H-based RNA 5' cap analysis using less resource-intensive analytical methods, we hope to make RNA cap analysis more accessible to the scientific community.
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Affiliation(s)
- S Hong Chan
- New England Biolabs, Ipswich, Massachusetts 01938, USA
| | | | - Nan Dai
- New England Biolabs, Ipswich, Massachusetts 01938, USA
| | | | | | | | - Ivan R Corrêa
- New England Biolabs, Ipswich, Massachusetts 01938, USA
| | - G Brett Robb
- New England Biolabs, Ipswich, Massachusetts 01938, USA
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4
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Structural and Molecular Kinetic Features of Activities of DNA Polymerases. Int J Mol Sci 2022; 23:ijms23126373. [PMID: 35742812 PMCID: PMC9224347 DOI: 10.3390/ijms23126373] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/01/2022] [Accepted: 06/06/2022] [Indexed: 02/01/2023] Open
Abstract
DNA polymerases catalyze DNA synthesis during the replication, repair, and recombination of DNA. Based on phylogenetic analysis and primary protein sequences, DNA polymerases have been categorized into seven families: A, B, C, D, X, Y, and RT. This review presents generalized data on the catalytic mechanism of action of DNA polymerases. The structural features of different DNA polymerase families are described in detail. The discussion highlights the kinetics and conformational dynamics of DNA polymerases from all known polymerase families during DNA synthesis.
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5
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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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6
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Lapa SA, Volkova OS, Kuznetsova VE, Zasedatelev AS, Chudinov AV. Study of Multiple Enzymatic Incorporation of Modified Nucleotides of Purine and Pyrimidine Nature in the Growing DNA Chain. Mol Biol 2022. [DOI: 10.1134/s0026893322010046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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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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8
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Espinasse A, Lembke HK, Cao AA, Carlson EE. Modified nucleoside triphosphates in bacterial research for in vitro and live-cell applications. RSC Chem Biol 2020; 1:333-351. [PMID: 33928252 PMCID: PMC8081287 DOI: 10.1039/d0cb00078g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/21/2020] [Indexed: 12/12/2022] Open
Abstract
Modified nucleoside triphosphates (NTPs) are invaluable tools to probe bacterial enzymatic mechanisms, develop novel genetic material, and engineer drugs and proteins with new functionalities. Although the impact of nucleobase alterations has predominantly been studied due to their importance for protein recognition, sugar and phosphate modifications have also been investigated. However, NTPs are cell impermeable due to their negatively charged phosphate tail, a major hurdle to achieving live bacterial studies. Herein, we review the recent advances made to investigate and evolve bacteria and their processes with the use of modified NTPs by exploring alterations in one of the three moieties: the nucleobase, the sugar and the phosphate tail. We also present the innovative methods that have been devised to internalize NTPs into bacteria for in vivo applications.
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Affiliation(s)
- Adeline Espinasse
- Department of Chemistry, University of Minnesota207 Pleasant Street SEMinneapolisMinnesota 55455USA
| | - Hannah K. Lembke
- Department of Chemistry, University of Minnesota207 Pleasant Street SEMinneapolisMinnesota 55455USA
| | - Angela A. Cao
- Department of Chemistry, University of Minnesota207 Pleasant Street SEMinneapolisMinnesota 55455USA
| | - Erin E. Carlson
- Department of Chemistry, University of Minnesota207 Pleasant Street SEMinneapolisMinnesota 55455USA
- Department of Medicinal Chemistry, University of Minnesota208 Harvard Street SEMinneapolisMinnesota 55454USA
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota321 Church St SEMinneapolisMinnesota 55454USA
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9
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Lapa SA, Guseinov TO, Pavlov AS, Shershov VE, Kuznetsova VE, Zasedatelev AS, Chudinov AV. A Simultaneous Use of Cy5-Modified Derivatives of Deoxyuridine and Deoxycytidine in PCR. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2020. [DOI: 10.1134/s1068162020040111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Turner MB, Purse BW. Fluorescent Tricyclic Cytidine Analogues as Substrates for Retroviral Reverse Transcriptases. Chempluschem 2020; 85:855-865. [PMID: 32378814 DOI: 10.1002/cplu.202000140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/21/2020] [Indexed: 11/05/2022]
Abstract
We report on the ability of the reverse transcriptases (RTs) from avian myeloblastosis virus (AMV), Moloney murine leukemia virus (M-MLV), and human immunodeficiency virus 1 (HIV-1) to generate labeled DNA using the fluorescent tricyclic cytidine analogues d(tC)TP and d(DEA tC)TP as substrates. Michaelis-Menten kinetics for the insertion of these analogues show Vmax /KM from 0.0-5 times that of natural dCTP across from G, depending on the polymerase and whether the template is RNA or DNA. The analogues are prone to misinsertion across from adenosine with both RNA and DNA templates. Elongation after analogue insertion is efficient with RNA templates, but the analogues cause stalling after insertion with DNA templates. A model reverse transcription assay using HIV-1-RT, including RNA-dependent DNA synthesis, degradation of the RNA template by the RT's RNase H activity, and synthesis of a second DNA strand to form fluorescently labeled dsDNA, shows that d(tC)TP and d(DEA tC)TP are compatible with a complete reverse transcription cycle in vitro.
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Affiliation(s)
- M Benjamin Turner
- Department of Chemistry and Biochemistry and the Viral Information Institute, San Diego State University, San Diego, CA, 92182, USA
| | - Byron W Purse
- Department of Chemistry and Biochemistry and the Viral Information Institute, San Diego State University, San Diego, CA, 92182, USA
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11
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Michel BY, Dziuba D, Benhida R, Demchenko AP, Burger A. Probing of Nucleic Acid Structures, Dynamics, and Interactions With Environment-Sensitive Fluorescent Labels. Front Chem 2020; 8:112. [PMID: 32181238 PMCID: PMC7059644 DOI: 10.3389/fchem.2020.00112] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 02/06/2020] [Indexed: 12/13/2022] Open
Abstract
Fluorescence labeling and probing are fundamental techniques for nucleic acid analysis and quantification. However, new fluorescent probes and approaches are urgently needed in order to accurately determine structural and conformational dynamics of DNA and RNA at the level of single nucleobases/base pairs, and to probe the interactions between nucleic acids with proteins. This review describes the means by which to achieve these goals using nucleobase replacement or modification with advanced fluorescent dyes that respond by the changing of their fluorescence parameters to their local environment (altered polarity, hydration, flipping dynamics, and formation/breaking of hydrogen bonds).
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Affiliation(s)
- Benoît Y. Michel
- Université Côte d'Azur, CNRS, Institut de Chimie de Nice, UMR 7272 – Parc Valrose, Nice, France
| | - Dmytro Dziuba
- Université Côte d'Azur, CNRS, Institut de Chimie de Nice, UMR 7272 – Parc Valrose, Nice, France
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
| | - Rachid Benhida
- Université Côte d'Azur, CNRS, Institut de Chimie de Nice, UMR 7272 – Parc Valrose, Nice, France
- Mohamed VI Polytechnic University, UM6P, Ben Guerir, Morocco
| | - Alexander P. Demchenko
- Laboratory of Nanobiotechnologies, Palladin Institute of Biochemistry, Kyiv, Ukraine
- Institute of Physical, Technical and Computer Science, Yuriy Fedkovych National University, Chernivtsi, Ukraine
| | - Alain Burger
- Université Côte d'Azur, CNRS, Institut de Chimie de Nice, UMR 7272 – Parc Valrose, Nice, France
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12
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Juliusson HY, Sigurdsson ST. Reduction Resistant and Rigid Nitroxide Spin-Labels for DNA and RNA. J Org Chem 2020; 85:4036-4046. [PMID: 32103670 DOI: 10.1021/acs.joc.9b02988] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy, coupled with site-directed spin labeling (SDSL), is a useful method for studying conformational changes of biomolecules in cells. To employ in-cell EPR using nitroxide-based spin labels, the structure of the nitroxides must confer reduction resistance to withstand the reductive environment within cells. Here, we report the synthesis of two new spin labels, EÇ and EÇm, both of which possess the rigidity and the reduction resistance needed for extracting detailed structural information by EPR spectroscopy. EÇ and EÇm were incorporated into DNA and RNA, respectively, by oligonucleotide synthesis. Both labels were shown to be nonperturbing of the duplex structure. The partial reduction of EÇm during RNA synthesis was circumvented by the protection of the nitroxide as a benzoylated hydroxylamine.
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Affiliation(s)
- Haraldur Y Juliusson
- Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavik, Iceland
| | - Snorri Th Sigurdsson
- Department of Chemistry, Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavik, Iceland
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13
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Kuznetsova AA, Kladova OA, Barthes NPF, Michel BY, Burger A, Fedorova OS, Kuznetsov NA. Comparative Analysis of Nucleotide Fluorescent Analogs for Registration of DNA Conformational Changes Induced by Interaction with Formamidopyrimidine-DNA Glycosylase Fpg. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2020. [DOI: 10.1134/s1068162019060256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Kuznetsov NA, Fedorova OS. Kinetic Milestones of Damage Recognition by DNA Glycosylases of the Helix-Hairpin-Helix Structural Superfamily. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1241:1-18. [DOI: 10.1007/978-3-030-41283-8_1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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15
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Sun SC, Lee CC, Chuang MC. Polymerase-assisted fluorescence resonance energy transfer (FRET) assay for simultaneous detection of binary viral sequences. Anal Chim Acta 2018; 1030:148-155. [DOI: 10.1016/j.aca.2018.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 05/01/2018] [Indexed: 12/20/2022]
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16
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Han JH, Park S, Hashiya F, Sugiyama H. Approach to the Investigation of Nucleosome Structure by Using the Highly Emissive Nucleobase
th
dG–tC FRET Pair. Chemistry 2018; 24:17091-17095. [DOI: 10.1002/chem.201803382] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/07/2018] [Indexed: 01/27/2023]
Affiliation(s)
- Ji Hoon Han
- Department of ChemistryGraduate School of ScienceKyoto University Kitashirakawa-Oiwakecho Sakyo-ku Kyoto 606–8502 Japan
| | - Soyoung Park
- Department of ChemistryGraduate School of ScienceKyoto University Kitashirakawa-Oiwakecho Sakyo-ku Kyoto 606–8502 Japan
| | - Fumitaka Hashiya
- Department of ChemistryGraduate School of ScienceKyoto University Kitashirakawa-Oiwakecho Sakyo-ku Kyoto 606–8502 Japan
| | - Hiroshi Sugiyama
- Department of ChemistryGraduate School of ScienceKyoto University Kitashirakawa-Oiwakecho Sakyo-ku Kyoto 606–8502 Japan
- Institute for Integrated Cell-Material Sciences (iCeMS)Kyoto University Yoshida-ushinomiyacho Sakyo-ku Kyoto 606–8501 Japan
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17
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Fluorescent nucleobases as tools for studying DNA and RNA. Nat Chem 2017; 9:1043-1055. [PMID: 29064490 DOI: 10.1038/nchem.2859] [Citation(s) in RCA: 214] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 07/11/2017] [Indexed: 02/07/2023]
Abstract
Understanding the diversity of dynamic structures and functions of DNA and RNA in biology requires tools that can selectively and intimately probe these biomolecules. Synthetic fluorescent nucleobases that can be incorporated into nucleic acids alongside their natural counterparts have emerged as a powerful class of molecular reporters of location and environment. They are enabling new basic insights into DNA and RNA, and are facilitating a broad range of new technologies with chemical, biological and biomedical applications. In this Review, we will present a brief history of the development of fluorescent nucleobases and explore their utility as tools for addressing questions in biophysics, biochemistry and biology of nucleic acids. We provide chemical insights into the two main classes of these compounds: canonical and non-canonical nucleobases. A point-by-point discussion of the advantages and disadvantages of both types of fluorescent nucleobases is made, along with a perspective into the future challenges and outlook for this burgeoning field.
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18
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Mei H, Shi C, Jimenez RM, Wang Y, Kardouh M, Chaput JC. Synthesis and polymerase activity of a fluorescent cytidine TNA triphosphate analogue. Nucleic Acids Res 2017; 45:5629-5638. [PMID: 28472363 PMCID: PMC5449585 DOI: 10.1093/nar/gkx368] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 04/21/2017] [Indexed: 02/04/2023] Open
Abstract
Threose nucleic acid (TNA) is an artificial genetic polymer capable of undergoing Darwinian evolution to produce aptamers with affinity to specific targets. This property, coupled with a backbone structure that is refractory to nuclease digestion, makes TNA an attractive biopolymer system for diagnostic and therapeutic applications. Expanding the chemical diversity of TNA beyond the natural bases would enable the development of functional TNA molecules with enhanced physiochemical properties. Here, we describe the synthesis and polymerase activity of a fluorescent cytidine TNA triphosphate analogue (1,3-diaza-2-oxo-phenothiazine, tCfTP) that maintains Watson-Crick base pairing with guanine. Polymerase-mediated primer-extension assays reveal that tCfTP is efficiently added to the growing end of a TNA primer. Detailed kinetic assays indicate that tCfTP and tCTP have comparable rates for the first nucleotide incorporation step (kobs1). However, addition of the second nucleotide (kobs2) is 700-fold faster for tCfTP than tCTP due the increased effects of base stacking. Last, we found that TNA replication using tCfTP in place of tCTP exhibits 98.4% overall fidelity for the combined process of TNA transcription and reverse transcription. Together, these results expand the chemical diversity of enzymatically generated TNA molecules to include a hydrophobic base analogue with strong fluorescent properties that is compatible with in vitro selection.
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Affiliation(s)
- Hui Mei
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, USA
| | - Changhua Shi
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, USA
| | - Randi M Jimenez
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, USA
| | - Yajun Wang
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, USA
| | - Miramar Kardouh
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, USA
| | - John C Chaput
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697-3958, USA
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19
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Polymerase/DNA interactions and enzymatic activity: multi-parameter analysis with electro-switchable biosurfaces. Sci Rep 2015; 5:12066. [PMID: 26174478 PMCID: PMC4502528 DOI: 10.1038/srep12066] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 06/17/2015] [Indexed: 11/29/2022] Open
Abstract
The engineering of high-performance enzymes for future sequencing and PCR technologies as well as the development of many anticancer drugs requires a detailed analysis of DNA/RNA synthesis processes. However, due to the complex molecular interplay involved, real-time methodologies have not been available to obtain comprehensive information on both binding parameters and enzymatic activities. Here we introduce a chip-based method to investigate polymerases and their interactions with nucleic acids, which employs an electrical actuation of DNA templates on microelectrodes. Two measurement modes track both the dynamics of the induced switching process and the DNA extension simultaneously to quantitate binding kinetics, dissociation constants and thermodynamic energies. The high sensitivity of the method reveals previously unidentified tight binding states for Taq and Pol I (KF) DNA polymerases. Furthermore, the incorporation of label-free nucleotides can be followed in real-time and changes in the DNA polymerase conformation (finger closing) during enzymatic activity are observable.
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20
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Kuznetsov NA, Kladova OA, Kuznetsova AA, Ishchenko AA, Saparbaev MK, Zharkov DO, Fedorova OS. Conformational Dynamics of DNA Repair by Escherichia coli Endonuclease III. J Biol Chem 2015; 290:14338-49. [PMID: 25869130 DOI: 10.1074/jbc.m114.621128] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Indexed: 11/06/2022] Open
Abstract
Escherichia coli endonuclease III (Endo III or Nth) is a DNA glycosylase with a broad substrate specificity for oxidized or reduced pyrimidine bases. Endo III possesses two types of activities: N-glycosylase (hydrolysis of the N-glycosidic bond) and AP lyase (elimination of the 3'-phosphate of the AP-site). We report a pre-steady-state kinetic analysis of structural rearrangements of the DNA substrates and uncleavable ligands during their interaction with Endo III. Oligonucleotide duplexes containing 5,6-dihydrouracil, a natural abasic site, its tetrahydrofuran analog, and undamaged duplexes carried fluorescent DNA base analogs 2-aminopurine and 1,3-diaza-2-oxophenoxazine as environment-sensitive reporter groups. The results suggest that Endo III induces several fast sequential conformational changes in DNA during binding, lesion recognition, and adjustment to a catalytically competent conformation. A comparison of two fluorophores allowed us to distinguish between the events occurring in the damaged and undamaged DNA strand. Combining our data with the available structures of Endo III, we conclude that this glycosylase uses a multistep mechanism of damage recognition, which likely involves Gln(41) and Leu(81) as DNA lesion sensors.
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Affiliation(s)
- Nikita A Kuznetsov
- From the Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentyev Ave., Novosibirsk 630090, Russia, the Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia, and
| | - Olga A Kladova
- From the Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentyev Ave., Novosibirsk 630090, Russia, the Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia, and
| | - Alexandra A Kuznetsova
- From the Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentyev Ave., Novosibirsk 630090, Russia, the Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia, and
| | - Alexander A Ishchenko
- the Groupe "Réparation de l'ADN," Université Paris-Sud XI, UMR8200 CNRS, Institute Gustave Roussy, Villejuif Cedex F-94805, France
| | - Murat K Saparbaev
- the Groupe "Réparation de l'ADN," Université Paris-Sud XI, UMR8200 CNRS, Institute Gustave Roussy, Villejuif Cedex F-94805, France
| | - Dmitry O Zharkov
- From the Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentyev Ave., Novosibirsk 630090, Russia, the Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia, and
| | - Olga S Fedorova
- From the Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentyev Ave., Novosibirsk 630090, Russia, the Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia, and
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21
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Kanamori T, Ohzeki H, Masaki Y, Ohkubo A, Takahashi M, Tsuda K, Ito T, Shirouzu M, Kuwasako K, Muto Y, Sekine M, Seio K. Controlling the fluorescence of benzofuran-modified uracil residues in oligonucleotides by triple-helix formation. Chembiochem 2014; 16:167-76. [PMID: 25469677 DOI: 10.1002/cbic.201402346] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Indexed: 12/16/2022]
Abstract
We developed fluorescent turn-on probes containing a fluorescent nucleoside, 5-(benzofuran-2-yl)deoxyuridine (dU(BF)) or 5-(3-methylbenzofuran-2-yl)deoxyuridine (dU(MBF)), for the detection of single-stranded DNA or RNA by utilizing DNA triplex formation. Fluorescence measurements revealed that the probe containing dU(MBF) achieved superior fluorescence enhancement than that containing dU(BF). NMR and fluorescence analyses indicated that the fluorescence intensity increased upon triplex formation partly as a consequence of a conformational change at the bond between the 3-methylbenzofuran and uracil rings. In addition, it is suggested that the microenvironment around the 3-methylbenzofuran ring contributed to the fluorescence enhancement. Further, we developed a method for detecting RNA by rolling circular amplification in combination with triplex-induced fluorescence enhancement of the oligonucleotide probe containing dU(MBF).
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Affiliation(s)
- Takashi Kanamori
- Education Academy of Computational Life Sciences, Tokyo Institute of Technology, 4259 Nagatsuta, Midoriku, Yokohama 226-8501 (Japan)
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22
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New environment-sensitive multichannel DNA fluorescent label for investigation of the protein-DNA interactions. PLoS One 2014; 9:e100007. [PMID: 24925085 PMCID: PMC4055743 DOI: 10.1371/journal.pone.0100007] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 05/20/2014] [Indexed: 12/24/2022] Open
Abstract
Here, we report the study of a new multichannel DNA fluorescent base analogue 3-hydroxychromone (3HC) to evaluate its suitability as a fluorescent reporter probe of structural transitions during protein-DNA interactions and its comparison with the current commercially available 2-aminopurine (aPu), pyrrolocytosine (Cpy) and 1,3-diaza-2-oxophenoxazine (tCO). For this purpose, fluorescent base analogues were incorporated into DNA helix on the opposite or on the 5'-side of the damaged nucleoside 5,6-dihydrouridine (DHU), which is specifically recognized and removed by Endonuclease VIII. These fluorophores demonstrated different sensitivities to the DNA helix conformational changes. The highest sensitivity and the most detailed information about the conformational changes of DNA induced by protein binding and processing were obtained using the 3HC probe. The application of this new artificial fluorescent DNA base is a very useful tool for the studies of complex mechanisms of protein-DNA interactions. Using 3HC biosensor, the kinetic mechanism of Endonuclease VIII action was specified.
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23
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Antibody mediated fluorescence enhancement of nucleoside analogue 1,3-diaza-2-oxophenoxazine (tC°). Talanta 2014; 124:67-70. [PMID: 24767447 DOI: 10.1016/j.talanta.2014.02.046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 02/14/2014] [Accepted: 02/20/2014] [Indexed: 11/20/2022]
Abstract
We report on the generation and analytical application of the monoclonal antibody G93-ED2 raised against the tricyclic fluorescent nucleoside analogue 1,3-diaza-2-oxophenoxazine (tC°). G93-ED2 is specifically binding this deoxycytidine analogue and was found to raise its fluorescence intensity by a factor of 5. This unique feature makes it a valuable tool in fluorescence dependent immunoassays. G93-ED2 was successfully applied in a homogeneous fluorescence quenching immunoassay (DNA-Q) for the sequence specific determination of DNA.
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24
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Segal M, Yavin E, Kafri P, Shav-Tal Y, Fischer B. Detection of mRNA of the cyclin D1 breast cancer marker by a novel duplex-DNA probe. J Med Chem 2013; 56:4860-9. [PMID: 23688195 DOI: 10.1021/jm301838y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Previously, we have described 5-((4-methoxy-phenyl)-trans-vinyl)-2'-deoxy-uridine, 6, as a fluorescent uridine analogue exhibiting a 3000-fold higher quantum yield (Φ 0.12) and maximum emission (478 nm) which is 170 nm red-shifted as compared to uridine. Here, we utilized 6 for preparation of labeled oligodeoxynucleotide (ODN) probes based on MS2 and cyclin D1 (a known breast cancer mRNA marker) sequences. Cyclin D1-derived labeled-ssODN showed a 9.5-fold decrease of quantum yield upon duplex formation. On the basis of this finding, we developed the ds-NIF (nucleoside with intrinsic fluorescence)-probe methodology for detection of cyclin D1 mRNA, by which the fluorescent probe is released upon recognition of target mRNA by the relatively dark NIF-duplex-probe. Indeed, we successfully detected, a ss-deoxynucleic acid (DNA) variant of cyclin D1 mRNA using a dark NIF-labeled duplex-probe, and monitoring the recognition process by fluorescence spectroscopy and gel electrophoresis. Furthermore, we successfully detected cyclin D1 mRNA in RNA extracted from cancerous human cells, using ds-NIF methodology.
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Affiliation(s)
- Meirav Segal
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
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25
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Wenge U, Ehrenschwender T, Wagenknecht HA. Synthesis of 2'-O-propargyl nucleoside triphosphates for enzymatic oligonucleotide preparation and "click" modification of DNA with Nile red as fluorescent probe. Bioconjug Chem 2013; 24:301-4. [PMID: 23425139 DOI: 10.1021/bc300624m] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Uridine, adenosine, guanosine, and cytidine that carry a propargyl group attached to the 2'-oxygen were converted efficiently to the corresponding nucleoside triphosphates (pNTPs). Primer extension experiments revealed that pUTP, pATP, and pGTP can be successfully incorporated in oligonucleotides in the so-called 9°N and Therminator DNA polymerases. Most importantly, the ethynyl group as single 2'-modification of the enzymatically prepared oligonucleotides can be applied for postsynthetic labeling. This was representatively shown by PAGE analysis after the "click"-type cycloaddition with the fluorescent nile red azide. These results show that the 2'-position as one of the most important modification sites in oligonucleotides is now accessible not only for synthetic, but also for enzymatic oligonucleotide preparation.
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Affiliation(s)
- Ulrike Wenge
- Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), D-76131, Karlsruhe, Germany
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26
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Weinberger M, Berndt F, Mahrwald R, Ernsting NP, Wagenknecht HA. Synthesis of 4-Aminophthalimide and 2,4-Diaminopyrimidine C-Nucleosides as Isosteric Fluorescent DNA Base Substitutes. J Org Chem 2013; 78:2589-99. [DOI: 10.1021/jo302768f] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michael Weinberger
- Department of Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg
6, Campus Süd, Geb. 30.42, 76131 Karlsruhe, Germany
| | - Falko Berndt
- Institute of Chemistry, Humboldt University Berlin, Brook-Taylor-Strasse 2,
12489 Berlin, Germany
| | - Rainer Mahrwald
- Institute of Chemistry, Humboldt University Berlin, Brook-Taylor-Strasse 2,
12489 Berlin, Germany
| | - Nikolaus P. Ernsting
- Institute of Chemistry, Humboldt University Berlin, Brook-Taylor-Strasse 2,
12489 Berlin, Germany
| | - Hans-Achim Wagenknecht
- Department of Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg
6, Campus Süd, Geb. 30.42, 76131 Karlsruhe, Germany
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27
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Walsh JM, Beuning PJ. Synthetic nucleotides as probes of DNA polymerase specificity. J Nucleic Acids 2012; 2012:530963. [PMID: 22720133 PMCID: PMC3377560 DOI: 10.1155/2012/530963] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 03/21/2012] [Indexed: 12/17/2022] Open
Abstract
The genetic code is continuously expanding with new nucleobases designed to suit specific research needs. These synthetic nucleotides are used to study DNA polymerase dynamics and specificity and may even inhibit DNA polymerase activity. The availability of an increasing chemical diversity of nucleotides allows questions of utilization by different DNA polymerases to be addressed. Much of the work in this area deals with the A family DNA polymerases, for example, Escherichia coli DNA polymerase I, which are DNA polymerases involved in replication and whose fidelity is relatively high, but more recent work includes other families of polymerases, including the Y family, whose members are known to be error prone. This paper focuses on the ability of DNA polymerases to utilize nonnatural nucleotides in DNA templates or as the incoming nucleoside triphosphates. Beyond the utility of nonnatural nucleotides as probes of DNA polymerase specificity, such entities can also provide insight into the functions of DNA polymerases when encountering DNA that is damaged by natural agents. Thus, synthetic nucleotides provide insight into how polymerases deal with nonnatural nucleotides as well as into the mutagenic potential of nonnatural nucleotides.
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Affiliation(s)
- Jason M. Walsh
- Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, 102 Hurtig Hall, Boston, MA 02115, USA
| | - Penny J. Beuning
- Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, 102 Hurtig Hall, Boston, MA 02115, USA
- Center for Interdisciplinary Research on Complex Systems, Northeastern University, Boston, MA 02115, USA
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28
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Abstract
Fluorescent sensors that make use of DNA structures have become widely useful in monitoring enzymatic activities. Early studies focused primarily on enzymes that naturally use DNA or RNA as the substrate. However, recent advances in molecular design have enabled the development of nucleic acid sensors for a wider range of functions, including enzymes that do not normally bind DNA or RNA. Nucleic acid sensors present some potential advantages over classical small-molecule sensors, including water solubility and ease of synthesis. An overview of the multiple strategies under recent development is presented in this critical review, and expected future developments in microarrays, single molecule analysis, and in vivo sensing are discussed (160 references).
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Affiliation(s)
- Nan Dai
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Eric T. Kool
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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29
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Sato K, Sasaki A, Matsuda A. Highly fluorescent 5-(5,6-dimethoxybenzothiazol-2-yl)-2'-deoxyuridine 5'-triphosphate as an efficient substrate for DNA polymerases. Chembiochem 2011; 12:2341-6. [PMID: 21887841 DOI: 10.1002/cbic.201100452] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Indexed: 11/08/2022]
Abstract
We herein describe the synthesis of fluorescent 5-(5,6-dimethoxybenzothiazol-2-yl)-2'-deoxyuridine 5'-triphosphate (d(bt)UTP) and primer extension reactions using d(bt)UTP. We also carried out primer extension reactions using the (bt)U template. B family DNA polymerases, such as KOD, Deep Vent (exo-), and 9°N(m) DNA polymerases, were effective for elongation with d(bt)UTP. Deep Vent (exo-) and KOD DNA polymerases have excellent fidelity for incorporating d(bt)UTP only at the site opposite the adenine template and only dATP when using the (bt)U template. Therefore, d(bt)UTP is an excellent fluorescent nucleotide that can be incorporated into DNA by DNA polymerases.
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Affiliation(s)
- Kousuke Sato
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Sapporo 060-0812, Japan
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30
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Discrimination against the Cytosine Analog tC by Escherichia coli DNA Polymerase IV DinB. J Mol Biol 2011; 409:89-100. [DOI: 10.1016/j.jmb.2011.03.069] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2011] [Revised: 03/27/2011] [Accepted: 03/30/2011] [Indexed: 01/30/2023]
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31
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Dierckx A, Dinér P, El-Sagheer AH, Kumar JD, Brown T, Grøtli M, Wilhelmsson LM. Characterization of photophysical and base-mimicking properties of a novel fluorescent adenine analogue in DNA. Nucleic Acids Res 2011; 39:4513-24. [PMID: 21278417 PMCID: PMC3105426 DOI: 10.1093/nar/gkr010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
To increase the diversity of fluorescent base analogues with improved properties, we here present the straightforward click-chemistry-based synthesis of a novel fluorescent adenine-analogue triazole adenine (AT) and its photophysical characterization inside DNA. AT shows promising properties compared to the widely used adenine analogue 2-aminopurine. Quantum yields reach >20% and >5% in single- and double-stranded DNA, respectively, and show dependence on neighbouring bases. Moreover, AT shows only a minor destabilization of DNA duplexes, comparable to 2-aminopurine, and circular dichroism investigations suggest that AT only causes minimal structural perturbations to normal B-DNA. Furthermore, we find that AT shows favourable base-pairing properties with thymine and more surprisingly also with normal adenine. In conclusion, AT shows strong potential as a new fluorescent adenine analogue for monitoring changes within its microenvironment in DNA.
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Affiliation(s)
- Anke Dierckx
- Department of Chemical and Biological Engineering/Physical Chemistry, Chalmers University of Technology, University of Gothenburg, S-41296 Gothenburg, Sweden
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32
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Jarchow-Choy SK, Krueger AT, Liu H, Gao J, Kool ET. Fluorescent xDNA nucleotides as efficient substrates for a template-independent polymerase. Nucleic Acids Res 2010; 39:1586-94. [PMID: 20947563 PMCID: PMC3045586 DOI: 10.1093/nar/gkq853] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Template independent polymerases, and terminal deoxynucleotidyl transferase (TdT) in particular, have been widely used in enzymatic labeling of DNA 3′-ends, yielding fluorescently-labeled polymers. The majority of fluorescent nucleotides used as TdT substrates contain tethered fluorophores attached to a natural nucleotide, and can be hindered by undesired fluorescence characteristics such as self-quenching. We previously documented the inherent fluorescence of a set of four benzo-expanded deoxynucleoside analogs (xDNA) that maintain Watson–Crick base pairing and base stacking ability; however, their substrate abilities for standard template-dependent polymerases were hampered by their large size. However, it seemed possible that a template-independent enzyme, due to lowered geometric constraints, might be less restrictive of nucleobase size. Here, we report the synthesis and study of xDNA nucleoside triphosphates, and studies of their substrate abilities with TdT. We find that this polymerase can incorporate each of the four xDNA monomers with kinetic efficiencies that are nearly the same as those of natural nucleotides, as measured by steady-state methods. As many as 30 consecutive monomers could be incorporated. Fluorescence changes over time could be observed in solution during the enzymatic incorporation of expanded adenine (dxATP) and cytosine (dxCTP) analogs, and after incorporation, when attached to a glass solid support. For (dxA)n polymers, monomer emission quenching and long-wavelength excimer emission was observed. For (dxC)n, fluorescence enhancement was observed in the polymer. TdT-mediated synthesis may be a useful approach for creating xDNA labels or tags on DNA, making use of the fluorescence and strong hybridization properties of the xDNA.
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33
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Site-specific fluorescent probing of RNA molecules by unnatural base-pair transcription for local structural conformation analysis. Nat Protoc 2010; 5:1312-23. [DOI: 10.1038/nprot.2010.77] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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34
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Preus S, Kilså K, Wilhelmsson LM, Albinsson B. Photophysical and structural properties of the fluorescent nucleobase analogues of the tricyclic cytosine (tC) family. Phys Chem Chem Phys 2010; 12:8881-92. [PMID: 20532361 DOI: 10.1039/c000625d] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Fundamental insight into the unique fluorescence and nucleobase-mimicking properties of the fluorescent nucleobase analogues of the tC family is not only vital in explaining the behaviour of these probes in nucleic acid environments, but will also be profitable in the development of new and improved fluorescent base analogues. Here, temperature-dependent fluorescence quantum yield measurements are used to successfully separate and quantify the temperature-dependent and temperature-independent non-radiative excited-state decay processes of the three nucleobase analogues tC, tC(O) and tC(nitro); all of which are derivatives of a phenothiazine or phenoxazine tricyclic framework. These results strongly suggest that the non-radiative decay process dominating the fast deactivation of tC(nitro) is an internal conversion of a different origin than the decay pathways of tC and tC(O). tC(nitro) is reported to be fluorescent only in less dipolar solvents at room temperature, which is explained by an increase in excited-state dipole moment along the main non-radiative decay pathway, a suggestion that applies in the photophysical discussion of large polycyclic nitroaromatics in general. New insight into the ground and excited-state potential energy surfaces of the isolated tC bases is obtained by means of high level DFT and TDDFT calculations. The S(0) potential energy surfaces of tC and tC(nitro) possess two global minima corresponding to geometries folded along the middle sulfur-nitrogen axis separated by an energy barrier of 0.05 eV as calculated at the B3LYP/6-311+G(2d,p) level. The ground-state potential energy surface of tC(O) is also predicted to be shallow along the bending coordinate but with an equilibrium geometry corresponding to the planar conformation of the tricyclic framework, which may explain some of the dissimilar properties of tC and tC(O) in various confined (biological) environments. The S(1) equilibrium geometries of all three base analogues are predicted to be planar. These results are discussed in the context of the tC bases positioned in double-stranded DNA scenarios.
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Affiliation(s)
- Søren Preus
- Department of Chemistry, University of Copenhagen, DK-2100 Copenhagen, Denmark.
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35
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Abstract
The use of fluorescent nucleic acid base analogues is becoming increasingly important in the fields of biology, biochemistry and biophysical chemistry as well as in the field of DNA nanotechnology. The advantage of being able to incorporate a fluorescent probe molecule close to the site of examination in the nucleic acid-containing system of interest with merely a minimal perturbation to the natural structure makes fluorescent base analogues highly attractive. In recent years, there has been a growing interest in developing novel candidates in this group of fluorophores for utilization in various investigations. This review describes the different classes of fluorophores that can be used for studying nucleic acid-containing systems, with an emphasis on choosing the right kind of probe for the system under investigation. It describes the characteristics of the large group of base analogues that has an emission that is sensitive to the surrounding microenvironment and gives examples of investigations in which this group of molecules has been used so far. Furthermore, the characterization and use of fluorescent base analogues that are virtually insensitive to changes in their microenvironment are described in detail. This group of base analogues can be used in several fluorescence investigations of nucleic acids, especially in fluorescence anisotropy and fluorescence resonance energy transfer (FRET) measurements. Finally, the development and characterization of the first nucleic base analogue FRET pair, tC(O)-tC(nitro), and its possible future uses are discussed.
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36
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Stengel G, Urban M, Purse BW, Kuchta RD. Incorporation of the fluorescent ribonucleotide analogue tCTP by T7 RNA polymerase. Anal Chem 2010; 82:1082-9. [PMID: 20067253 DOI: 10.1021/ac902456n] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fluorescent RNA is an important analytical tool in medical diagnostics, RNA cytochemistry, and RNA aptamer development. We have synthesized the fluorescent ribonucleotide analogue 1,3-diaza-2-oxophenothiazine-ribose-5'-triphosphate (tCTP) and tested it as substrate for T7 RNA polymerase in transcription reactions, a convenient route for generating RNA in vitro. When transcribing a guanine, T7 RNA polymerase incorporates tCTP with 2-fold higher catalytic efficiency than CTP and efficiently polymerizes additional NTPs onto the tC. Remarkably, T7 RNA polymerase does not incorporate tCTP with the same ambivalence opposite guanine and adenine with which DNA polymerases incorporate the analogous dtCTP. While several DNA polymerases discriminated against a d(tC-A) base pair only by factors <10, T7 RNA polymerase discriminates against tC-A base pair formation by factors of 40 and 300 when operating in the elongation and initiation mode, respectively. These catalytic properties make T7 RNA polymerase an ideal tool for synthesizing large fluorescent RNA, as we demonstrated by generating a approximately 800 nucleotide RNA in which every cytosine was replaced with tC.
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Affiliation(s)
- Gudrun Stengel
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 30309-0215, USA
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37
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Sinkeldam RW, Greco NJ, Tor Y. Fluorescent analogs of biomolecular building blocks: design, properties, and applications. Chem Rev 2010; 110:2579-619. [PMID: 20205430 PMCID: PMC2868948 DOI: 10.1021/cr900301e] [Citation(s) in RCA: 665] [Impact Index Per Article: 47.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Renatus W. Sinkeldam
- Department of Chemistry and Biochemistry, University of California, San Diego 9500 Gilman Drive, La Jolla, California 92093-0358
| | | | - Yitzhak Tor
- Department of Chemistry and Biochemistry, University of California, San Diego 9500 Gilman Drive, La Jolla, California 92093-0358
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38
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Stengel G, Urban M, Purse BW, Kuchta RD. High density labeling of polymerase chain reaction products with the fluorescent base analogue tCo. Anal Chem 2010; 81:9079-85. [PMID: 19810708 DOI: 10.1021/ac9017555] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Fluorescent DNA of high molecular weight is an important tool for studying the physical properties of DNA and DNA-protein interactions, and it plays a key role in modern biotechnology for DNA sequencing and detection. While several DNA polymerases can incorporate large numbers of dye-linked nucleotides into primed DNA templates, the amplification of the resulting densely labeled DNA strands by polymerase chain reaction (PCR) is problematic. Here, we report a method for high density labeling of DNA in PCR reactions employing the 5'-triphosphate of 1,3-diaza-2-oxo-phenoxazine (tCo) and Deep Vent DNA polymerase. tCo is a fluorescent cytosine analogue that absorbs and emits light at 365 and 460 nm, respectively. We obtained PCR products that were fluorescent enough to directly visualize them in a gel by excitation with long UV light, thus eliminating the need for staining with ethidium bromide. Reactions with Taq polymerase failed to produce PCR products in the presence of only small amounts of dtCoTP. A comparative kinetic study of Taq and Deep Vent polymerase revealed that Taq polymerase, although it inserts dtCoTP with high efficiency opposite G, is prone to forming mutagenic tCo-A base pairs and does not efficiently extend base pairs containing tCo. These kinetics features explain the poor outcome of the PCR reactions with Taq polymerase. Since tCo substitutes structurally for cytosine, the presented labeling method is believed to be less invasive than labeling with dye-linked nucleotides and, therefore, produces DNA that is ideally suited for biophysical studies.
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Affiliation(s)
- Gudrun Stengel
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 30309-0215, USA
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39
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Wahba AS, Esmaeili A, Damha MJ, Hudson RHE. A single-label phenylpyrrolocytidine provides a molecular beacon-like response reporting HIV-1 RT RNase H activity. Nucleic Acids Res 2010; 38:1048-56. [PMID: 19933258 PMCID: PMC2817455 DOI: 10.1093/nar/gkp1022] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2009] [Revised: 10/19/2009] [Accepted: 10/19/2009] [Indexed: 12/12/2022] Open
Abstract
6-Phenylpyrrolocytidine (PhpC), a structurally conservative and highly fluorescent cytidine analog, was incorporated into oligoribonucleotides. The PhpC-containing RNA formed native-like duplex structures with complementary DNA or RNA. The PhpC-modification was found to act as a sensitive reporter group being non-disruptive to structure and the enzymatic activity of RNase H. A RNA/DNA hybrid possessing a single PhpC insert was an excellent substrate for HIV-1 RT Ribonuclease H and rapidly reported cleavage of the RNA strand with a 14-fold increase in fluorescence intensity. The PhpC-based assay for RNase H was superior to the traditional molecular beacon approach in terms of responsiveness, rapidity and ease (single label versus dual). Furthermore, the PhpC-based assay is amenable to high-throughput microplate assay format and may form the basis for a new screen for inhibitors of HIV-RT RNase H.
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Affiliation(s)
- Alexander S. Wahba
- Department of Chemistry, McGill University, Montreal, QC, H3A 2K6 Canada, Department of Chemistry, University of Birjand, Birjand, Iran and Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7 Canada
| | - Abbasali Esmaeili
- Department of Chemistry, McGill University, Montreal, QC, H3A 2K6 Canada, Department of Chemistry, University of Birjand, Birjand, Iran and Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7 Canada
| | - Masad J. Damha
- Department of Chemistry, McGill University, Montreal, QC, H3A 2K6 Canada, Department of Chemistry, University of Birjand, Birjand, Iran and Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7 Canada
| | - Robert H. E. Hudson
- Department of Chemistry, McGill University, Montreal, QC, H3A 2K6 Canada, Department of Chemistry, University of Birjand, Birjand, Iran and Department of Chemistry, University of Western Ontario, London, ON, N6A 5B7 Canada
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