1
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Babar V, Sharma S, Shaikh AR, Oliva R, Chawla M, Cavallo L. Detecting Hachimoji DNA: An Eight-Building-Block Genetic System with MoS 2 and Janus MoSSe Monolayers. ACS APPLIED MATERIALS & INTERFACES 2024; 16:21427-21437. [PMID: 38634539 PMCID: PMC11071042 DOI: 10.1021/acsami.3c18400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 04/03/2024] [Accepted: 04/09/2024] [Indexed: 04/19/2024]
Abstract
In the pursuit of personalized medicine, the development of efficient, cost-effective, and reliable DNA sequencing technology is crucial. Nanotechnology, particularly the exploration of two-dimensional materials, has opened different avenues for DNA nucleobase detection, owing to their impressive surface-to-volume ratio. This study employs density functional theory with van der Waals corrections to methodically scrutinize the adsorption behavior and electronic band structure properties of a DNA system composed of eight hachimoji nucleotide letters adsorbed on both MoS2 and MoSSe monolayers. Through a comprehensive conformational search, we pinpoint the most favorable adsorption sites, quantifying their adsorption energies and charge transfer properties. The analysis of electronic band structure unveils the emergence of flat bands in close proximity to the Fermi level post-adsorption, a departure from the pristine MoS2 and MoSSe monolayers. Furthermore, leveraging the nonequilibrium Green's function approach, we compute the current-voltage characteristics, providing valuable insights into the electronic transport properties of the system. All hachimoji bases exhibit physisorption with a horizontal orientation on both monolayers. Notably, base G demonstrates high sensitivity on both substrates. The obtained current-voltage (I-V) characteristics, both without and with base adsorption on MoS2 and the Se side of MoSSe, affirm excellent sensing performance. This research significantly advances our understanding of potential DNA sensing platforms and their electronic characteristics, thereby propelling the endeavor for personalized medicine through enhanced DNA sequencing technologies.
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Affiliation(s)
- Vasudeo Babar
- Physical
Sciences and Engineering Division, KAUST Catalysis Center, King Abdullah University of Science and Technology
(KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Sitansh Sharma
- Department
of Research and Innovation, STEMskills Research
and Education Lab Private Limited, Faridabad, Haryana 121002, India
| | - Abdul Rajjak Shaikh
- Department
of Research and Innovation, STEMskills Research
and Education Lab Private Limited, Faridabad, Haryana 121002, India
| | - Romina Oliva
- Department
of Sciences and Technologies, University
Parthenope of Naples, Centro Direzionale Isola C4, 80143 Naples, Italy
| | - Mohit Chawla
- Physical
Sciences and Engineering Division, KAUST Catalysis Center, King Abdullah University of Science and Technology
(KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Luigi Cavallo
- Physical
Sciences and Engineering Division, KAUST Catalysis Center, King Abdullah University of Science and Technology
(KAUST), Thuwal 23955-6900, Saudi Arabia
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2
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Liu F, He L, Dong S, Xuan J, Cui Q, Feng Y. Artificial Small Molecules as Cofactors and Biomacromolecular Building Blocks in Synthetic Biology: Design, Synthesis, Applications, and Challenges. Molecules 2023; 28:5850. [PMID: 37570818 PMCID: PMC10421094 DOI: 10.3390/molecules28155850] [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: 06/29/2023] [Revised: 07/25/2023] [Accepted: 07/28/2023] [Indexed: 08/13/2023] Open
Abstract
Enzymes are essential catalysts for various chemical reactions in biological systems and often rely on metal ions or cofactors to stabilize their structure or perform functions. Improving enzyme performance has always been an important direction of protein engineering. In recent years, various artificial small molecules have been successfully used in enzyme engineering. The types of enzymatic reactions and metabolic pathways in cells can be expanded by the incorporation of these artificial small molecules either as cofactors or as building blocks of proteins and nucleic acids, which greatly promotes the development and application of biotechnology. In this review, we summarized research on artificial small molecules including biological metal cluster mimics, coenzyme analogs (mNADs), designer cofactors, non-natural nucleotides (XNAs), and non-natural amino acids (nnAAs), focusing on their design, synthesis, and applications as well as the current challenges in synthetic biology.
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Affiliation(s)
- Fenghua Liu
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101, China
- Shandong Energy Institute, 189 Songling Road, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, 189 Songling Road, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lingling He
- Department of Bioscience and Bioengineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Beijing 100083, China
| | - Sheng Dong
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101, China
- Shandong Energy Institute, 189 Songling Road, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, 189 Songling Road, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinsong Xuan
- Department of Bioscience and Bioengineering, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Beijing 100083, China
| | - Qiu Cui
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101, China
- Shandong Energy Institute, 189 Songling Road, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, 189 Songling Road, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingang Feng
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao 266101, China
- Shandong Energy Institute, 189 Songling Road, Qingdao 266101, China
- Qingdao New Energy Shandong Laboratory, 189 Songling Road, Qingdao 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Oh J, Kimoto M, Xu H, Chong J, Hirao I, Wang D. Structural basis of transcription recognition of a hydrophobic unnatural base pair by T7 RNA polymerase. Nat Commun 2023; 14:195. [PMID: 36635281 PMCID: PMC9836923 DOI: 10.1038/s41467-022-35755-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 12/23/2022] [Indexed: 01/14/2023] Open
Abstract
Bacteriophage T7 RNA polymerase (T7 RNAP) is widely used for synthesizing RNA molecules with synthetic modifications and unnatural base pairs (UBPs) for a variety of biotechnical and therapeutic applications. However, the molecular basis of transcription recognition of UBPs by T7 RNAP remains poorly understood. Here we focused on a representative UBP, 7-(2-thienyl)-imidazo[4,5-b]pyridine (Ds) and pyrrole 2-carbaldehyde (Pa), and investigated how the hydrophobic Ds-Pa pair is recognized by T7 RNAP. Our kinetic assays revealed that T7 RNAP selectively recognizes the Ds or Pa base in the templates and preferentially incorporates their cognate unnatural base nucleotide substrate (PaTP or DsTP) over natural NTPs. Our structural studies reveal that T7 RNAP recognizes the unnatural substrates at the pre-insertion state in a distinct manner compared to natural substrates. These results provide mechanistic insights into transcription recognition of UBP by T7 RNAP and provide valuable information for designing the next generation of UBPs.
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Affiliation(s)
- Juntaek Oh
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Michiko Kimoto
- Institute of Bioengineering and Bioimaging (IBB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Xenolis Pte. Ltd., Singapore, Singapore
| | - Haoqing Xu
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Jenny Chong
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Ichiro Hirao
- Institute of Bioengineering and Bioimaging (IBB), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
- Xenolis Pte. Ltd., Singapore, Singapore.
| | - Dong Wang
- Division of Pharmaceutical Sciences, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA.
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA.
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA.
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4
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Sun L, Ma X, Zhang B, Qin Y, Ma J, Du Y, Chen T. From polymerase engineering to semi-synthetic life: artificial expansion of the central dogma. RSC Chem Biol 2022; 3:1173-1197. [PMID: 36320892 PMCID: PMC9533422 DOI: 10.1039/d2cb00116k] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 08/08/2022] [Indexed: 11/21/2022] Open
Abstract
Nucleic acids have been extensively modified in different moieties to expand the scope of genetic materials in the past few decades. While the development of unnatural base pairs (UBPs) has expanded the genetic information capacity of nucleic acids, the production of synthetic alternatives of DNA and RNA has increased the types of genetic information carriers and introduced novel properties and functionalities into nucleic acids. Moreover, the efforts of tailoring DNA polymerases (DNAPs) and RNA polymerases (RNAPs) to be efficient unnatural nucleic acid polymerases have enabled broad application of these unnatural nucleic acids, ranging from production of stable aptamers to evolution of novel catalysts. The introduction of unnatural nucleic acids into living organisms has also started expanding the central dogma in vivo. In this article, we first summarize the development of unnatural nucleic acids with modifications or alterations in different moieties. The strategies for engineering DNAPs and RNAPs are then extensively reviewed, followed by summarization of predominant polymerase mutants with good activities for synthesizing, reverse transcribing, or even amplifying unnatural nucleic acids. Some recent application examples of unnatural nucleic acids with their polymerases are then introduced. At the end, the approaches of introducing UBPs and synthetic genetic polymers into living organisms for the creation of semi-synthetic organisms are reviewed and discussed.
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Affiliation(s)
- Leping Sun
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology 510006 Guangzhou China
| | - Xingyun Ma
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology 510006 Guangzhou China
| | - Binliang Zhang
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology 510006 Guangzhou China
| | - Yanjia Qin
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology 510006 Guangzhou China
| | - Jiezhao Ma
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology 510006 Guangzhou China
| | - Yuhui Du
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology 510006 Guangzhou China
| | - Tingjian Chen
- MOE International Joint Research Laboratory on Synthetic Biology and Medicines, School of Biology and Biological Engineering, South China University of Technology 510006 Guangzhou China
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5
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Hyun Lee K, Kimoto M, Kawai G, Okamoto I, Fin A, Hirao I. Dye‐Conjugated Spinach RNA by Genetic Alphabet Expansion. Chemistry 2022; 28:e202104396. [DOI: 10.1002/chem.202104396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Indexed: 11/09/2022]
Affiliation(s)
- Kyung Hyun Lee
- Institute of Bioengineering and Bioimaging A*STAR 31 Biopolis Way, The Nanos #07-01 Singapore 138669 Singapore
| | - Michiko Kimoto
- Institute of Bioengineering and Bioimaging A*STAR 31 Biopolis Way, The Nanos #07-01 Singapore 138669 Singapore
| | - Gota Kawai
- Chiba Institute of Technology (CIT) Tsudanuma 2-17-1 Narashino Chiba 275-0016 Japan
| | - Itaru Okamoto
- Institute of Bioengineering and Bioimaging A*STAR 31 Biopolis Way, The Nanos #07-01 Singapore 138669 Singapore
| | - Andrea Fin
- Institute of Bioengineering and Bioimaging A*STAR 31 Biopolis Way, The Nanos #07-01 Singapore 138669 Singapore
| | - Ichiro Hirao
- Institute of Bioengineering and Bioimaging A*STAR 31 Biopolis Way, The Nanos #07-01 Singapore 138669 Singapore
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6
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Wang H, Wang L, Ma N, Zhu W, Huo B, Zhu A, Li L. Access to Photostability-Enhanced Unnatural Base Pairs via Local Structural Modifications. ACS Synth Biol 2022; 11:334-342. [PMID: 34889587 DOI: 10.1021/acssynbio.1c00451] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Completing the storage and retrieval of increased genetic information in vivo and producing therapeutic proteins have been achieved by the unnatural base pair dNaM-dTPT3. Up to now, some biological and chemical approaches are implemented to improve the semi-synthetic organism (SSO). However, the photosensitivity of this pair, suggested as a potential threat to the healthy growth of cells, is still a problem to solve. Hence, we designed and synthesized a panel of TPT3 analogues with the basic structural skeletons of TPT3 but modified thiophene rings at variant sites to improve the photostability of unnatural base pairs. A comprehensive screening strategy, including photosensitivity tests, kinetic experiments, and replication in vitro by PCR and in vivo by amplification, was implemented. A new pair, dNaM-dTAT1, which had almost equally high efficiency and fidelity with the dNaM-dTPT3 pair itself both in vivo and in vitro, was proven to be more photostable and thermostable and less toxic to E. coli cells. The discovery of dNaM-dTAT1 represents our first progress for the optimization of this type of bases toward more photostable properties; our data also suggest that less photosensitive unnatural base pairs will be beneficial to build a healthier cellular replication system.
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Affiliation(s)
- Honglei Wang
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
| | - Luying Wang
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
| | - Nana Ma
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
| | - Wuyuan Zhu
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
| | - Bianbian Huo
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
| | - Anlian Zhu
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
| | - Lingjun Li
- Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Henan Normal University, Xinxiang, Henan 453007, China
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7
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Kimoto M, Hirao I. Genetic alphabet expansion technology by creating unnatural base pairs. Chem Soc Rev 2020; 49:7602-7626. [PMID: 33015699 DOI: 10.1039/d0cs00457j] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recent advancements in the creation of artificial extra base pairs (unnatural base pairs, UBPs) are opening the door to a new research area, xenobiology, and genetic alphabet expansion technologies. UBPs that function as third base pairs in replication, transcription, and/or translation enable the site-specific incorporation of novel components into DNA, RNA, and proteins. Here, we describe the UBPs developed by three research teams and their application in PCR-based diagnostics, high-affinity DNA aptamer generation, site-specific labeling of RNAs, semi-synthetic organism creation, and unnatural-amino-acid-containing protein synthesis.
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Affiliation(s)
- Michiko Kimoto
- Institute of Bioengineering and Nanotechnology, A*STAR, Singapore.
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8
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Kimoto M, Hirao I. New Research Area, Xenobiology, by Integrating Chemistry and Biology. J SYN ORG CHEM JPN 2020. [DOI: 10.5059/yukigoseikyokaishi.78.465] [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)
| | - Ichiro Hirao
- Institute of Bioengineering and Nanotechnology, A*STAR
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9
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Yamashige R, Kimoto M, Okumura R, Hirao I. Visual Detection of Amplified DNA by Polymerase Chain Reaction Using a Genetic Alphabet Expansion System. J Am Chem Soc 2018; 140:14038-14041. [PMID: 30336010 DOI: 10.1021/jacs.8b08121] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Visual DNA amplification using a simple polymerase chain reaction (PCR) device is useful for field tests to detect target DNA and RNA. We hereby describe a detection system involving PCR amplification visualized with the naked eye, by genetic alphabet expansion. The system employs fluorescence resonance energy transfer (FRET) between unnatural base combinations: self-quenched dinucleotides of 2-amino-6-(2-thienyl)purine (s) as a donor and Cy3-conjugated 2-nitro-4-propynylpyrrole (Cy3-hx-Px) as an acceptor. During PCR, the triphosphate substrate of Cy3-hx-Px (Cy3-hx-dPxTP) is incorporated into DNA opposite its pairing partner, 7-(2-thienyl)-imidazo[4,5- b]pyridine (Ds), in the primer, which also contains the dinucleotides of s. Thus, the amplified DNA can be visualized by the Cy3 fluorescence resulting from the FRET between the s-dinucleotides and the incorporated Cy3-hx-Px upon 365 nm irradiation. Using this system, we demonstrated the visual single nucleotide polymorphism detection of a series of quinolone-resistant bacteria genes.
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Affiliation(s)
- Rie Yamashige
- RIKEN Center for Life Science Technologies , 1-7-22 Suehiro-cho , Tsurumi-ku, Yokohama , Kanagawa 230-0045 , Japan
| | - Michiko Kimoto
- RIKEN Center for Life Science Technologies , 1-7-22 Suehiro-cho , Tsurumi-ku, Yokohama , Kanagawa 230-0045 , Japan.,Institute of Bioengineering and Nanotechnology , 31 Biopolis Way, The Nanos, #07-01 , Singapore 138669 , Singapore
| | - Ryo Okumura
- Rare Disease Laboratories, Group I, R&D Division , Daiichi Sankyo Co. Ltd. , 1-2-58 Hiromachi , Shinagawa-ku , Tokyo 140-8710 Japan
| | - Ichiro Hirao
- RIKEN Center for Life Science Technologies , 1-7-22 Suehiro-cho , Tsurumi-ku, Yokohama , Kanagawa 230-0045 , Japan.,Institute of Bioengineering and Nanotechnology , 31 Biopolis Way, The Nanos, #07-01 , Singapore 138669 , Singapore
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10
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Hamashima K, Kimoto M, Hirao I. Creation of unnatural base pairs for genetic alphabet expansion toward synthetic xenobiology. Curr Opin Chem Biol 2018; 46:108-114. [PMID: 30059833 DOI: 10.1016/j.cbpa.2018.07.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/02/2018] [Accepted: 07/13/2018] [Indexed: 01/10/2023]
Abstract
Artificial extra base pairs (unnatural base pairs, UBPs) expand the genetic alphabet of DNA, thus broadening entire biological systems in the central dogma. UBPs function as third base pairs in replication, transcription, and/or translation, and have created a new research area, synthetic xenobiology, providing genetic engineering tools to generate novel DNAs, RNAs, and proteins with increased functionalities. Several UBPs have been developed and applied to PCR technology, DNA aptamer generation, and semi-synthetic organism creation. Among them, we developed a series of UBPs and demonstrated unique quantitative PCR and high-affinity DNA aptamer generation methods.
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Affiliation(s)
- Kiyofumi Hamashima
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #07-01, Singapore 138669, Singapore
| | - Michiko Kimoto
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #07-01, Singapore 138669, Singapore
| | - Ichiro Hirao
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #07-01, Singapore 138669, Singapore.
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11
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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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12
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Design of a fused triazolyl 2-quinolinone unnatural nucleoside via tandem CuAAC-Ullmann coupling reaction and study of photophysical property. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.03.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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14
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Okamoto I, Miyatake Y, Kimoto M, Hirao I. High Fidelity, Efficiency and Functionalization of Ds-Px Unnatural Base Pairs in PCR Amplification for a Genetic Alphabet Expansion System. ACS Synth Biol 2016; 5:1220-1230. [PMID: 26814421 DOI: 10.1021/acssynbio.5b00253] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Genetic alphabet expansion of DNA using an artificial extra base pair (unnatural base pair) could augment nucleic acid and protein functionalities by increasing their components. We previously developed an unnatural base pair between 7-(2-thienyl)-imidazo[4,5-b]pyridine (Ds) and 2-nitro-4-propynylpyrrole (Px), which exhibits high fidelity as a third base pair in PCR amplification. Here, the fidelity and efficiency of Ds-Px pairing using modified Px bases with functional groups, such as diol, azide, ethynyl and biotin, were evaluated by an improved method with optimized PCR conditions. The results revealed that all of the base pairs between Ds and either one of the modified Px bases functioned with high amplification efficiency (0.76-0.81), high selectivity (≥99.96% per doubling), and less sequence dependency, in PCR using 3'-exonuclease-proficient Deep Vent DNA polymerase. We also demonstrated that the azide-Px in PCR-amplified DNA was efficiently modified with any functional groups by copper-free click reaction. This genetic alphabet expansion system could endow nucleic acids with a wide variety of increased functionalities by the site-specific incorporation of modified Px bases at desired positions in DNA.
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Affiliation(s)
- Itaru Okamoto
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #04-01, Singapore 138669,
- RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Yuya Miyatake
- RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- Department
of Life Science, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, Kanagawa 226-8501, Japan
| | - Michiko Kimoto
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #04-01, Singapore 138669,
- RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- PRESTO, JST, Honcho, Kawaguchi-shi, Saitama 332-0012, Japan
| | - Ichiro Hirao
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #04-01, Singapore 138669,
- RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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15
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Chawla M, Credendino R, Chermak E, Oliva R, Cavallo L. Theoretical Characterization of the H-Bonding and Stacking Potential of Two Nonstandard Nucleobases Expanding the Genetic Alphabet. J Phys Chem B 2016; 120:2216-24. [DOI: 10.1021/acs.jpcb.6b00125] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Mohit Chawla
- Physical
Sciences and Engineering Division (PSE), Kaust Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Raffaele Credendino
- Physical
Sciences and Engineering Division (PSE), Kaust Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Edrisse Chermak
- Physical
Sciences and Engineering Division (PSE), Kaust Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Romina Oliva
- Department
of Sciences and Technologies, University Parthenope of Naples, Centro Direzionale Isola C4, I-80143 Naples, Italy
| | - Luigi Cavallo
- Physical
Sciences and Engineering Division (PSE), Kaust Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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16
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Someya T, Ando A, Kimoto M, Hirao I. Site-specific labeling of RNA by combining genetic alphabet expansion transcription and copper-free click chemistry. Nucleic Acids Res 2015; 43:6665-76. [PMID: 26130718 PMCID: PMC4538826 DOI: 10.1093/nar/gkv638] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 06/10/2015] [Indexed: 12/16/2022] Open
Abstract
Site-specific labeling of long-chain RNAs with desired molecular probes is an imperative technique to facilitate studies of functional RNA molecules. By genetic alphabet expansion using an artificial third base pair, called an unnatural base pair, we present a post-transcriptional modification method for RNA transcripts containing an incorporated azide-linked unnatural base at specific positions, using a copper-free click reaction. The unnatural base pair between 7-(2-thienyl)imidazo[4,5-b]pyridine (Ds) and pyrrole-2-carbaldehyde (Pa) functions in transcription. Thus, we chemically synthesized a triphosphate substrate of 4-(4-azidopentyl)-pyrrole-2-carbaldehyde (N3-PaTP), which can be site-specifically introduced into RNA, opposite Ds in templates by T7 transcription. The N3-Pa incorporated in the transcripts was modified with dibenzocyclooctyne (DIBO) derivatives. We demonstrated the transcription of 17-, 76- and 260-mer RNA molecules and their site-specific labeling with Alexa 488, Alexa 594 and biotin. This method will be useful for preparing RNA molecules labeled with any functional groups of interest, toward in vivo experiments.
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Affiliation(s)
- Tatsuhiko Someya
- RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Ami Ando
- RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Michiko Kimoto
- RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan TagCyx Biotechnologies, 1-6-126 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan PRESTO, JST, Honcho, Kawaguchi-shi, Saitama 332-0012, Japan
| | - Ichiro Hirao
- RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan TagCyx Biotechnologies, 1-6-126 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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17
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18
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Pawar MG, Nuthanakanti A, Srivatsan SG. Heavy atom containing fluorescent ribonucleoside analog probe for the fluorescence detection of RNA-ligand binding. Bioconjug Chem 2014; 24:1367-77. [PMID: 23841942 DOI: 10.1021/bc400194g] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Although numerous biophysical tools have provided effective systems to study nucleic acids, our current knowledge on how RNA structure complements its function is limited. Therefore, development of robust tools to study the structure–function relationship of RNA is highly desired. Toward this endeavor, we have developed a new ribonucleoside analog, based on a (selenophen-2-yl)pyrimidine core, which could serve as a fluorescence probe to study the function of RNA in real time and as an anomalous scattering label (selenium atom) for the phase determination in X-ray crystallography. The fluorescent selenophene-modified uridine analog is minimally perturbing and exhibits probe-like properties such as sensitivity to microenvironment and conformation changes. Utilizing these properties and amicability of the corresponding ribonucleotide analog to enzymatic incorporation, we have synthesized a fluorescent bacterial ribosomal decoding site (A-site) RNA construct and have developed a fluorescence binding assay to effectively monitor the binding of aminoglycoside antibiotics to the A-site. Our results demonstrate that this simple approach of building a dual probe could provide new avenues to study the structure–function relationship of not only nucleic acids, but also other biomacromolecules.
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19
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Halder A, Datta A, Bhattacharyya D, Mitra A. Why does substitution of thymine by 6-ethynylpyridone increase the thermostability of DNA double helices? J Phys Chem B 2014; 118:6586-96. [PMID: 24857638 DOI: 10.1021/jp412416p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Efficiency of 6-ethynylpyridone (E), a potential thymine (T) analogue, which forms high-fidelity base pairs with adenine (A) and gives rise to stabler DNA duplexes, with stability comparable to those containing canonical cytosine(C):guanine(G) base pairs, has been reported recently. Estimates of the interaction energies, involving geometry optimization at the DFT level (including middle range dispersion interactions) followed by single point energy calculation at MP2 level, in excellent correlation with the experimentally observed trends, show that E binds more strongly and more discriminately with A than T does. Detailed analysis reveals that the increase in base-base interaction arises out of conjugation of acetylenic π electrons with the ring π system of E, which results in not only an extra stabilizing C-H···π interaction in the EA pair, but also a strengthening of the conventional hydrogen bonds. However, the computed base-base interaction energy for the EA pair was found to be much less than that of the canonical CG pair, implying that the difference in the TA versus EA base pairing interaction alone cannot explain the large experimentally observed increase in the thermostability of DNA duplexes, where a TA pair is replaced with an EA pair. Our computations show that the conjugation of acetylenic π electrons with the ring π system also possibly plays a role in increasing the stacking potential of the EA pair, which in turn can explain its marked influence in the enhancement of duplex stability.
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Affiliation(s)
- Antarip Halder
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology Hyderabad , Gachibowli, Hyderabad, 500032, AP, India
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20
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Tanpure AA, Srivatsan SG. Synthesis, photophysical properties and incorporation of a highly emissive and environment-sensitive uridine analogue based on the Lucifer chromophore. Chembiochem 2014; 15:1309-16. [PMID: 24861713 DOI: 10.1002/cbic.201402052] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Indexed: 11/10/2022]
Abstract
The majority of fluorescent nucleoside analogues used in nucleic acid studies have excitation maxima in the UV region and show very low fluorescence within oligonucleotides (ONs); hence, they cannot be utilised with certain fluorescence methods and for cell-based analysis. Here, we describe the synthesis, photophysical properties and incorporation of a highly emissive and environment-sensitive uridine analogue, derived by attaching a Lucifer chromophore (1,8-naphthalimide core) at the 5-position of uracil. The emissive nucleoside displays excitation and emission maxima in the visible region and exhibits high quantum yield. Importantly, when incorporated into ON duplexes it retains appreciable fluorescence efficiency and is sensitive to the neighbouring base environment. Notably, the nucleoside signals the presence of purine repeats in ON duplexes with an enhancement in fluorescence intensity, a property rarely displayed by other nucleoside analogues.
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Affiliation(s)
- Arun A Tanpure
- Department of Chemistry, Indian Institute of Science Education and Research, Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008 (India)
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21
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Rodgers BJ, Elsharif NA, Vashisht N, Mingus MM, Mulvahill MA, Stengel G, Kuchta RD, Purse BW. Functionalized tricyclic cytosine analogues provide nucleoside fluorophores with improved photophysical properties and a range of solvent sensitivities. Chemistry 2013; 20:2010-5. [PMID: 24311229 DOI: 10.1002/chem.201303410] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Indexed: 12/11/2022]
Abstract
Tricyclic cytosines (tC and tC(O) frameworks) have emerged as a unique class of fluorescent nucleobase analogues that minimally perturb the structure of B-form DNA and that are not quenched in duplex nucleic acids. Systematic derivatization of these frameworks is a likely approach to improve on and diversify photophysical properties, but has not so far been examined. Synthetic methods were refined to improve on tolerance for electron-donating and electron-withdrawing groups, resulting in a series of eight new, fluorescent cytidine analogues. Photophysical studies show that substitution of the framework results in a pattern of effects largely consistent across tC and tC(O) and provides nucleoside fluorophores that are brighter than either parent. Moreover, a range of solvent sensitivities is observed, offering promise that this family of probes can be extended to new applications that require reporting on the local environment.
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Affiliation(s)
- Brittney J Rodgers
- Department of Chemistry and Biochemistry, University of Denver, 2199 S. University Blvd., Denver, CO 80208 (USA)
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22
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Noé MS, Sinkeldam RW, Tor Y. Oligodeoxynucleotides containing multiple thiophene-modified isomorphic fluorescent nucleosides. J Org Chem 2013; 78:8123-8. [PMID: 23859712 DOI: 10.1021/jo4008964] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
5-(Thien-2-yl)-2'-deoxyuridine, an isomorphic fluorescent nucleoside analogue, was incorporated into multiple positions within single stranded oligodeoxynucleotides. With minimal impact on duplex stability and overall structure, oligonucleotides containing three identical isomorphic fluorescent nucleosides in alternating or neighboring positions display enhanced, sequence-dependent on-signals for either duplex formation or dissociation.
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Affiliation(s)
- Mary S Noé
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, USA
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23
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Mallemula VR, Sanghai NN, Himabindu V, Chakravarthy AK. Synthesis and characterization of antibacterial 2-(pyridin-3-yl)-1H-benzo[d]imidazoles and 2-(pyridin-3-yl)-3H-imidazo[4,5-b]pyridine derivatives. RESEARCH ON CHEMICAL INTERMEDIATES 2013. [DOI: 10.1007/s11164-013-1335-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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24
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Kimoto M, Hikida Y, Hirao I. Site-Specific Functional Labeling of Nucleic Acids by In Vitro Replication and Transcription using Unnatural Base Pair Systems. Isr J Chem 2013. [DOI: 10.1002/ijch.201300013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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25
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Tanpure AA, Pawar MG, Srivatsan SG. Fluorescent Nucleoside Analogs: Probes for Investigating Nucleic Acid Structure and Function. Isr J Chem 2013. [DOI: 10.1002/ijch.201300010] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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26
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Hirao I, Kimoto M, Yamashige R. Natural versus artificial creation of base pairs in DNA: origin of nucleobases from the perspectives of unnatural base pair studies. Acc Chem Res 2012; 45:2055-65. [PMID: 22263525 DOI: 10.1021/ar200257x] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Since life began on Earth, the four types of bases (A, G, C, and T(U)) that form two sets of base pairs have remained unchanged as the components of nucleic acids that replicate and transfer genetic information. Throughout evolution, except for the U to T modification, the four base structures have not changed. This constancy within the genetic code raises the question of how these complicated nucleotides were generated from the molecules in a primordial soup on the early Earth. At some prebiotic stage, the complementarity of base pairs might have accelerated the generation and accumulation of nucleotides or oligonucleotides. We have no clues whether one pair of nucleobases initially appeared on the early Earth during this process or a set of two base pairs appeared simultaneously. Recently, researchers have developed new artificial pairs of nucleobases (unnatural base pairs) that function alongside the natural base pairs. Some unnatural base pairs in duplex DNA can be efficiently and faithfully amplified in a polymerase chain reaction (PCR) using thermostable DNA polymerases. The addition of unnatural base pair systems could expand the genetic alphabet of DNA, thus providing a new mechanism for the generation novel biopolymers by the site-specific incorporation of functional components into nucleic acids and proteins. Furthermore, the process of unnatural base pair development might provide clues to the origin of the natural base pairs in a primordial soup on the early Earth. In this Account, we describe the development of three representative types of unnatural base pairs that function as a third pair of nucleobases in PCR and reconsider the origin of the natural nucleic acids. As researchers developing unnatural base pairs, they use repeated "proof of concept" experiments. As researchers design new base pairs, they improve the structures that function in PCR and eliminate those that do not. We expect that this process is similar to the one functioning in the chemical evolution and selection of the natural nucleobases. Interestingly, the initial structures designed by each research group were quite similar to those of the latest successful unnatural base pairs. In this regard, it is tempting to form a hypothesis that the base pairs on the primordial Earth, in which the natural purine bases, A and G, and pyrimidine bases, C and T(U), originated from structurally similar compounds, such as hypoxanthine for a purine base predecessor. Subsequently, the initial base pair evolved to the present two sets of base pairs via a keto-enol tautomerization of the initial compounds.
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Affiliation(s)
- Ichiro Hirao
- RIKEN Systems and Structural Biology Center (SSBC), 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- TagCyx Biotechnologies, 1-6-126 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Michiko Kimoto
- RIKEN Systems and Structural Biology Center (SSBC), 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
- TagCyx Biotechnologies, 1-6-126 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Rie Yamashige
- RIKEN Systems and Structural Biology Center (SSBC), 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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27
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Nakano SI, Oka H, Yamaguchi D, Fujii M, Sugimoto N. Base-pairing selectivity of a ureido-linked phenyl-2'-deoxycytidine derivative. Org Biomol Chem 2012; 10:9664-70. [PMID: 23147647 DOI: 10.1039/c2ob26897c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Incorporation of modified nucleotides into nucleic acid strands often produces conformational constraints and steric hindrances that may change the property of base pairing. In this study, we investigated a 2'-deoxycytidine derivative that tethers a phenyl moiety to the exocyclic amino group of cytosine linked through a ureido group. This derivative compound is structurally similar to the carbamoylated DNA base lesions produced in cells. The thermodynamic and structural studies showed that the modified dC formed the base pair with dG in the complementary strand, but the base-pairing selectivity toward dG was decreased under poly(ethylene glycol)-mediated osmotic stress. The phenyl group and the ureido linker attached to dC provided selectivity for the formation of base pairing exclusively with dG in a wide range of pH conditions, whereas unmodified dC stabilized the pairings with dA or dC in acidic solutions. Moreover, this modified base could not form self-pairing through intermolecular hydrogen bonds. We suggest that formation of weak pairing and protonation of the cytosine base are hindered due to the base modification. These data provide insights into the pairing selectivity of carbamoylated cytosine lesions produced in cells, and suggest applications of the 2'-deoxycytidine derivatives in medical technologies, molecular biology experiments, and synthesis of a supramolecular network of DNA strands.
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Affiliation(s)
- Shu-ichi Nakano
- Faculty of Frontiers of Innovative Research in Science and Technology (FIRST), Konan University, 7-1-20, Minatojima-minamimachi, Kobe 650-0047, Japan.
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28
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PCR amplification and transcription for site-specific labeling of large RNA molecules by a two-unnatural-base-pair system. J Nucleic Acids 2012; 2012:230943. [PMID: 22792445 PMCID: PMC3390107 DOI: 10.1155/2012/230943] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 04/16/2012] [Indexed: 01/04/2023] Open
Abstract
For the site-specific labeling and modification of RNA by genetic alphabet expansion, we developed a PCR and transcription system using two hydrophobic unnatural base pairs: 7-(2-thienyl)-imidazo[4,5-b]pyridine (Ds) and 2-nitro-4-propynylpyrrole (Px) as a third pair for PCR amplification and Ds and pyrrole-2-carbaldehyde (Pa) for the incorporation of functional components as modified Pa bases into RNA by T7 transcription. To prepare Ds-containing DNA templates with long chains, the Ds-Px pair was utilized in a fusion PCR method, by which we demonstrated the synthesis of 282-bp DNA templates containing Ds at specific positions. Using these Ds-containing DNA templates and a biotin-linked Pa substrate (Biotin-PaTP) as a modified Pa base, 260-mer RNA transcripts containing Biotin-Pa at a specific position were generated by T7 RNA polymerase. This two-unnatural-base-pair system, combining the Ds-Px and Ds-Pa pairs with modified Pa substrates, provides a powerful tool for the site-specific labeling and modification of desired positions in large RNA molecules.
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29
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Rao H, Tanpure AA, Sawant AA, Srivatsan SG. Enzymatic incorporation of an azide-modified UTP analog into oligoribonucleotides for post-transcriptional chemical functionalization. Nat Protoc 2012; 7:1097-112. [PMID: 22576108 DOI: 10.1038/nprot.2012.046] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This protocol describes the detailed experimental procedure for the synthesis of an azide-modified uridine triphosphate analog and its effective incorporation into an oligoribonucleotide by in vitro transcription reactions. Furthermore, procedures for labeling azide-modified oligoribonucleotides post-transcriptionally with biophysical probes by copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) and Staudinger reactions are also provided. This post-transcriptional chemical modification protocol is simple and modular, and it affords labeled oligonucleotides in reasonable amounts for biophysical assays. The procedure for enzymatic incorporation of the monophosphate of azide-modified UTP into an oligoribonucleotide transcript takes ∼2 d, and subsequent post-transcriptional chemical functionalization of the transcript takes about 2 d.
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Affiliation(s)
- Harita Rao
- Department of Chemistry, Indian Institute of Science Education and Research, Pune, India
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30
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Ishizuka T, Kimoto M, Sato A, Hirao I. Site-specific functionalization of RNA molecules by an unnatural base pair transcription system via click chemistry. Chem Commun (Camb) 2012; 48:10835-7. [DOI: 10.1039/c2cc36293g] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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31
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Hirao I, Kimoto M. Unnatural base pair systems toward the expansion of the genetic alphabet in the central dogma. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2012; 88:345-67. [PMID: 22850726 PMCID: PMC3422687 DOI: 10.2183/pjab.88.345] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 06/01/2012] [Indexed: 05/30/2023]
Abstract
Toward the expansion of the genetic alphabet of DNA, several artificial third base pairs (unnatural base pairs) have been created. Synthetic DNAs containing the unnatural base pairs can be amplified faithfully by PCR, along with the natural A-T and G-C pairs, and transcribed into RNA. The unnatural base pair systems now have high potential to open the door to next generation biotechnology. The creation of unnatural base pairs is a consequence of repeating "proof of concept" experiments. In the process, initially designed base pairs were modified to address their weak points. Some of them were artificially evolved to ones with higher efficiency and selectivity in polymerase reactions, while others were eliminated from the analysis. Here, we describe the process of unnatural base pair development, as well as the tests of their applications.
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Affiliation(s)
- Ichiro Hirao
- RIKEN Systems and Structural Biology Center (SSBC), Yokohama, Japan.
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32
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Yamashige R, Kimoto M, Takezawa Y, Sato A, Mitsui T, Yokoyama S, Hirao I. Highly specific unnatural base pair systems as a third base pair for PCR amplification. Nucleic Acids Res 2011; 40:2793-806. [PMID: 22121213 PMCID: PMC3315302 DOI: 10.1093/nar/gkr1068] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Toward the expansion of the genetic alphabet of DNA, we present highly efficient unnatural base pair systems as an artificial third base pair for PCR. Hydrophobic unnatural base pair systems between 7-(2-thienyl)imidazo[4,5-b]pyridine (Ds) and 2-nitro-4-propynylpyrrole (Px) were fine-tuned for efficient PCR, by assessing the amplification efficiency and fidelity using different polymerases and template sequence contexts and modified Px bases. Then, we found that some modifications of the Px base reduced the misincorporation rate of the unnatural base substrates opposite the natural bases in templates without reducing the Ds–Px pairing selectivity. Under optimized conditions using Deep Vent DNA polymerase, the misincorporation rate was extremely low (0.005%/bp/replication), which is close to that of the natural base mispairings by the polymerase. DNA fragments with different sequence contexts were amplified ∼1010-fold by 40 cycles of PCR, and the selectivity of the Ds–Px pairing was >99.9%/replication, except for 99.77%/replication for unfavorable purine-Ds-purine motifs. Furthermore, >97% of the Ds–Px pair in DNA survived in the 1028-fold amplified products after 100-cycle PCR (10 cycles repeated 10 times). This highly specific Ds–Px pair system provides a framework for new biotechnology.
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Affiliation(s)
- Rie Yamashige
- RIKEN Systems and Structural Biology Center (SSBC), 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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33
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Tanpure AA, Srivatsan SG. A microenvironment-sensitive fluorescent pyrimidine ribonucleoside analogue: synthesis, enzymatic incorporation, and fluorescence detection of a DNA abasic site. Chemistry 2011; 17:12820-7. [PMID: 21956450 DOI: 10.1002/chem.201101194] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 07/18/2011] [Indexed: 11/10/2022]
Abstract
Base-modified fluorescent ribonucleoside-analogue probes are valuable tools in monitoring RNA structure and function because they closely resemble the structure of natural nucleobases. Especially, 2-aminopurine, a highly environment-sensitive adenosine analogue, is the most extensively utilized fluorescent nucleoside analogue. However, only a few isosteric pyrimidine ribonucleoside analogues that are suitable for probing the structure and recognition properties of RNA molecules are available. Herein, we describe the synthesis and photophysical characterization of a small series of base-modified pyrimidine ribonucleoside analogues derived from tagging indole, N-methylindole, and benzofuran onto the 5-position of uracil. One of the analogues, based on a 5-(benzofuran-2-yl)pyrimidine core, shows emission in the visible region with a reasonable quantum yield and, importantly, displays excellent solvatochromism. The corresponding triphosphate substrate is effectively incorporated into oligoribonucleotides by T7 RNA polymerase to produce fluorescent oligoribonucleotide constructs. Steady-state and time-resolved spectroscopic studies with fluorescent oligoribonucleotide constructs demonstrate that the fluorescent ribonucleoside photophysically responds to subtle changes in its environment brought about by the interaction of the chromophore with neighboring bases. In particular, the emissive ribonucleoside, if incorporated into an oligoribonucleotide, positively reports the presence of a DNA abasic site with an appreciable enhancement in fluorescence intensity. The straightforward synthesis, amicability to enzymatic incorporation, and sensitivity to changes in the microenvironment highlight the potential of the benzofuran-conjugated pyrimidine ribonucleoside as an efficient fluorescent probe to investigate nucleic acid structure, dynamics, and recognition events.
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Affiliation(s)
- Arun A Tanpure
- Department of Chemistry, Indian Institute of Science Education and Research, Pashan, Pune, India
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34
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Nakano SI, Fujii M, Sugimoto N. Use of nucleic Acid analogs for the study of nucleic Acid interactions. J Nucleic Acids 2011; 2011:967098. [PMID: 21822475 PMCID: PMC3142669 DOI: 10.4061/2011/967098] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 05/02/2011] [Indexed: 12/27/2022] Open
Abstract
Unnatural nucleosides have been explored to expand the properties and the applications of oligonucleotides. This paper briefly summarizes nucleic acid analogs in which the base is modified or replaced by an unnatural stacking group for the study of nucleic acid interactions. We also describe the nucleoside analogs of a base pair-mimic structure that we have examined. Although the base pair-mimic nucleosides possess a simplified stacking moiety of a phenyl or naphthyl group, they can be used as a structural analog of Watson-Crick base pairs. Remarkably, they can adopt two different conformations responding to their interaction energies, and one of them is the stacking conformation of the nonpolar aromatic group causing the site-selective flipping of the opposite base in a DNA double helix. The base pair-mimic nucleosides can be used to study the mechanism responsible for the base stacking and the flipping of bases out of a nucleic acid duplex.
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Affiliation(s)
- Shu-Ichi Nakano
- Faculty of Frontiers of Innovative Research in Science and Technology, Konan University, 7-1-20 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan
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35
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Hernández AR, Kool ET. The components of xRNA: synthesis and fluorescence of a full genetic set of size-expanded ribonucleosides. Org Lett 2011; 13:676-9. [PMID: 21214222 PMCID: PMC3039074 DOI: 10.1021/ol102915f] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The synthesis and properties of a full set of four benzo-expanded ribonucleosides (xRNA), analogous to A, G, C, and U RNA monomers, are described. The nucleosides are efficient fluorophores with emission maxima of 369-411 nm. The compounds are expected to be useful as RNA pathway probes and as components of an unnatural ribopolymer.
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Affiliation(s)
| | - Eric T. Kool
- Department of Chemistry, Stanford University, Stanford, California 94305-5080
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36
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Kimoto M, Mitsui T, Yamashige R, Sato A, Yokoyama S, Hirao I. A new unnatural base pair system between fluorophore and quencher base analogues for nucleic acid-based imaging technology. J Am Chem Soc 2011; 132:15418-26. [PMID: 20939572 DOI: 10.1021/ja1072383] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the development of orthogonal extra base pairs for expanding the genetic alphabet, we created novel, unnatural base pairs between fluorophore and quencher nucleobase analogues. We found that the nucleobase analogue, 2-nitropyrrole (denoted by Pn), and its 4-substitutions, such as 2-nitro-4-propynylpyrrole (Px) and 4-[3-(6-aminohexanamido)-1-propynyl]-2-nitropyrrole (NH(2)-hx-Px), act as fluorescence quenchers. The Pn and Px bases specifically pair with their pairing partner, 7-(2,2'-bithien-5-yl)imidazo[4,5-b]pyridine (Dss), which is strongly fluorescent. Thus, these unnatural Dss-Pn and Dss-Px base pairs function as reporter-quencher base pairs, and are complementarily incorporated into DNA by polymerase reactions as a third base pair in combination with the natural A-T and G-C pairs. Due to the static contact quenching, the Pn and Px quencher bases significantly decreased the fluorescence intensity of Dss by the unnatural base pairings in DNA duplexes. In addition, the Dss-Px pair exhibited high efficiency and selectivity in PCR amplification. Thus, this new unnatural base pair system would be suitable for detection methods of target nucleic acid sequences, and here we demonstrated the applications of the Dss-Pn and Dss-Px pairs as molecular beacons and in real-time PCR. The genetic alphabet expansion system with the replicable, unnatural fluorophore-quencher base pair will be a useful tool for sensing and diagnostic applications, as well as an imaging tool for basic research.
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Affiliation(s)
- Michiko Kimoto
- RIKEN Systems and Structural Biology Center and TagCyx Biotechnologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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37
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Pawar MG, Srivatsan SG. Synthesis, photophysical characterization, and enzymatic incorporation of a microenvironment-sensitive fluorescent uridine analog. Org Lett 2011; 13:1114-7. [PMID: 21275418 DOI: 10.1021/ol103147t] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The synthesis of a microenvironment-sensitive base-modified fluorescent ribonucleoside analog based on a 5-(benzo[b]thiophen-2-yl)pyrimidine core, enzymatic incorporation of its corresponding triphosphate into RNA oligonucleotides, and photophysical characterization of fluorescently modified oligoribonucleotides are described.
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Affiliation(s)
- Maroti G Pawar
- Indian Institute of Science Education and Research, Pashan, Pune, India
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38
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Yamashige R, Kimoto M, Mitsui T, Yokoyama S, Hirao I. Monitoring the site-specific incorporation of dual fluorophore-quencher base analogues for target DNA detection by an unnatural base pair system. Org Biomol Chem 2011; 9:7504-9. [DOI: 10.1039/c1ob06118f] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Site-specific incorporation of extra components into RNA by transcription using unnatural base pair systems. Methods Mol Biol 2010; 634:355-69. [PMID: 20676996 DOI: 10.1007/978-1-60761-652-8_25] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The expansion of the genetic alphabet, by an unnatural base pair system, provides a powerful tool for the site-specific incorporation of extra, functional components into nucleic acids by replication and transcription. We developed several unnatural base pairs that function in PCR and in vitro transcription. Among them, a hydrophobic, unnatural base pair between 7-(2-thienyl)-imidazo[4,5-b]pyridine (denoted by Ds) and pyrrole-2-carbaldehyde (denoted by Pa) exhibits high fidelity in PCR and T7 transcription. Modified Pa bases linked with functional groups of interest can also be site-specifically incorporated into RNA opposite Ds in DNA templates, by T7 RNA polymerase. Here, we describe the methods for the site-specific biotinylation of RNA molecules by transcription using the Ds-Pa pair with biotinylated PaTP (Biotin-PaTP).
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40
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Kimoto M, Mitsui T, Yokoyama S, Hirao I. A unique fluorescent base analogue for the expansion of the genetic alphabet. J Am Chem Soc 2010; 132:4988-9. [PMID: 20334374 DOI: 10.1021/ja100806c] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fluorescent nucleobase analogues are useful in a wide variety of biology and biotechnology tools as molecular probes and reporters for nucleic acids. Here we present a novel fluorescent purine analogue, 7-(2,2'-bithien-5-yl)-imidazo[4,5-b]pyridine (denoted as Dss). The nucleoside triphosphates of Dss can be site-specifically incorporated into DNA and RNA by polymerases, opposite its pairing partner, pyrrole-2-carbaldehyde (Pa), in DNA templates. Despite its high specificity in replication and transcription, Dss in oligonucleotides functions as a universal base that pairs with all four natural bases with nearly equal thermal stabilities. Thus, Dss would be a powerful tool for fluorescent base replacements at specific positions in functional DNA and RNA molecules.
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Affiliation(s)
- Michiko Kimoto
- RIKEN Systems and Structural Biology Center (SSBC) and TagCyx Biotechnologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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41
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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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42
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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: 36] [Impact Index Per Article: 2.6] [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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43
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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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44
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Onizuka K, Taniguchi Y, Sasaki S. A new usage of functionalized oligodeoxynucleotide probe for site-specific modification of a guanine base within RNA. Nucleic Acids Res 2010; 38:1760-6. [PMID: 20123727 PMCID: PMC2836579 DOI: 10.1093/nar/gkp930] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Site-specific modification of RNA is of great significance to investigate RNA structure, function and dynamics. Recently, we reported a new method for sequence- and cytosine-selective chemical modification of RNA based on the functional group transfer reaction of the 1-phenyl-2-methylydene-1,3-diketone unit of the 6-thioguanosine base incorporated in the oligodeoxynucleotide probe. In this study, we describe that the functionality transfer rate is greatly enhanced and the selectivity is shifted to the guanine base when the reaction is performed under alkaline conditions. Detailed investigation indicated that the 2-amino group of the enolate form of rG is the reactant of the functionality transfer reaction. As a potential application of this efficient functionality transfer reaction, a pyrene group as a relatively large fluorescent group was successfully transferred to the target guanine base of RNA with a high guanine and site selectivity. This functionality transfer reaction with high efficiency and high site-selectivity would provide a new opportunity as a unique tool for the study of RNA.
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Affiliation(s)
- Kazumitsu Onizuka
- Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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45
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Abstract
An unnatural base pair that is replicated and transcribed with good efficiency would lay the foundation for the long term goal of creating a semisynthetic organism, but also would have immediate in vitro applications, such as the enzymatic synthesis of site-specifically modified DNA and/or RNA. One of the most promising of the unnatural base pairs that we have identified is formed between d5SICS and dMMO2. The ortho substituents of these nucleotides are included to facilitate unnatural base pair extension, presumably by forming a hydrogen-bond with the polymerase, but the synthesis of the unnatural base pair still requires optimization. Recently, we have shown that meta and/or para substituents within the dMMO2 scaffold can facilitate unnatural base pair synthesis, although the mechanism remains unclear. To explore this issue, we synthesized and evaluated several dMMO2 derivatives with meta-chlorine, -bromine, -iodine, -methyl, or -propinyl substituents. Complete characterization of unnatural base pair and mispair synthesis and extension reveal that the modifications have large effects only on the efficiency of unnatural base pair synthesis and that the effects likely result from a combination of changes in steric interactions, polarity, and polarizability. The results also suggest that functionalized versions of the propinyl moiety of d5PrM should serve as suitable linkers to site-specifically incorporate other chemical functionalities into DNA. Similar modifications of d5SICS should allow labeling of DNA with two different functionalities, and the previously demonstrated efficient transcription of the unnatural base pair suggests that derivatives might similarly enable site-specific labeling of RNA.
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Affiliation(s)
- Young Jun Seo
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
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46
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Loakes D, Gallego J, Pinheiro VB, Kool ET, Holliger P. Evolving a polymerase for hydrophobic base analogues. J Am Chem Soc 2009; 131:14827-37. [PMID: 19778048 PMCID: PMC2762193 DOI: 10.1021/ja9039696] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hydrophobic base analogues (HBAs) have shown great promise for the expansion of the chemical and coding potential of nucleic acids but are generally poor polymerase substrates. While extensive synthetic efforts have yielded examples of HBAs with favorable substrate properties, their discovery has remained challenging. Here we describe a complementary strategy for improving HBA substrate properties by directed evolution of a dedicated polymerase using compartmentalized self-replication (CSR) with the archetypal HBA 5-nitroindole (d5NI) and its derivative 5-nitroindole-3-carboxamide (d5NIC) as selection substrates. Starting from a repertoire of chimeric polymerases generated by molecular breeding of DNA polymerase genes from the genus Thermus, we isolated a polymerase (5D4) with a generically enhanced ability to utilize HBAs. The selected polymerase. 5D4 was able to form and extend d5NI and d5NIC (d5NI(C)) self-pairs as well as d5NI(C) heteropairs with all four bases with efficiencies approaching, or exceeding, those of the cognate Watson-Crick pairs, despite significant distortions caused by the intercalation of the d5NI(C) heterocycles into the opposing strand base stack, as shown by nuclear magnetic resonance spectroscopy (NMR). Unlike Taq polymerase, 5D4 was also able to extend HBA pairs such as Pyrene: varphi (abasic site), d5NI: varphi, and isocarbostyril (ICS): 7-azaindole (7AI), allowed bypass of a chemically diverse spectrum of HBAs, and enabled PCR amplification with primers comprising multiple d5NI(C)-substitutions, while maintaining high levels of catalytic activity and fidelity. The selected polymerase 5D4 promises to expand the range of nucleobase analogues amenable to replication and should find numerous applications, including the synthesis and replication of nucleic acid polymers with expanded chemical and functional diversity.
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Affiliation(s)
- David Loakes
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - José Gallego
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - Vitor B. Pinheiro
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
| | - Eric T. Kool
- Stanford University, Department of Chemistry, Stanford, CA 94305, USA
| | - Philipp Holliger
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK
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47
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Loakes D, Holliger P. Polymerase engineering: towards the encoded synthesis of unnatural biopolymers. Chem Commun (Camb) 2009:4619-31. [PMID: 19641798 DOI: 10.1039/b903307f] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
DNA is not only a repository of genetic information for life, it is also a unique polymer with remarkable properties: it associates according to well-defined rules, it can be assembled into diverse nanostructures of defined geometry, it can be evolved to bind ligands and catalyse chemical reactions and it can serve as a supramolecular scaffold to arrange chemical groups in space. However, its chemical makeup is rather uniform and the physicochemical properties of the four canonical bases only span a narrow range. Much wider chemical diversity is accessible through solid-phase synthesis but oligomers are limited to <100 nucleotides and variations in chemistry can usually not be replicated and thus are not amenable to evolution. Recent advances in nucleic acid chemistry and polymerase engineering promise to bring the synthesis, replication and ultimately evolution of nucleic acid polymers with greatly expanded chemical diversity within our reach.
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Affiliation(s)
- David Loakes
- Medical Research Council, Laboratory of Molecular Biology, Hills Road, Cambridge, Cambridgeshire, UKCB2 0QH
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48
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Krueger AT, Kool ET. Redesigning the architecture of the base pair: toward biochemical and biological function of new genetic sets. ACTA ACUST UNITED AC 2009; 16:242-8. [PMID: 19318205 DOI: 10.1016/j.chembiol.2008.12.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 12/04/2008] [Accepted: 12/04/2008] [Indexed: 11/16/2022]
Abstract
Recognition of the nucleic acid bases within the DNA scaffold comprises the basis for transmission of genetic information, dictating protein and cell assembly, organismal development, and evolution. Driven in part by the need to test our current understanding of this information transfer, chemists have begun to design and synthesize nonnatural bases and base pair structures to mimic the function of DNA without relying on Nature's purine-pyrimidine base pair scaffold. Multiple examples have been recently described that self-assemble stably and sequence specifically in vitro, and some isolated unnatural base pairs can be replicated in vitro as well. Moreover, recent experiments with unnatural bases in bacterial cells have demonstrated surprisingly efficient reading of the chemical information. This suggests the future possibility of redesigning and replacing the chemical information of an evolving cell while retaining biological function.
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Affiliation(s)
- Andrew T Krueger
- Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA
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49
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Abstract
The enzymatic incorporation of a series of emissive pyrimidine analogues into RNA oligonucleotides is explored. T7 RNA polymerase is challenged with accepting three non-natural, yet related, triphosphates as substrates and incorporating them into diverse RNA transcripts. The three ribonucleoside triphosphates differ only in the modification of their uracil nucleus and include a thieno[3,2-d]pyrimidine nucleoside, a thieno[3,4-d]pyrimidine derivative, and a uridine containing a thiophene ring conjugated at its 5-position. All thiophene-containing uridine triphosphates (UTPs) get incorporated into RNA oligonucleotides at positions that are remote to the promoter, although the yields of the transcripts vary compared with the transcript obtained with only native triphosphates. Among the three derivatives, the 5-modified UTP is found to be the most "polymerase-friendly" and is well accommodated by T7 RNA polymerase. Although the fused thiophene analogues cannot be incorporated next to the promoter region, the 5-modified non-natural UTP gets incorporated near the promoter (albeit in relatively low yields) and even in multiple copies. Labeling experiments shed light on the mediocre incorporation of the fused analogues, suggesting the enzyme frequently pauses at the incorporation position. When incorporation does take place, the enzyme fails to elongate the modified oligonucleotide and yields aborted transcripts. Taken together, these results highlight the versatility and robustness, as well as the scope and limitation, of T7 RNA polymerase in accepting and incorporating reporter nucleotides into modified RNA transcripts.
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Affiliation(s)
- Seergazhi G Srivatsan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
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50
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Grigorenko N, Leumann C. 2-Phenanthrenyl-DNA: Synthesis, Pairing, and Fluorescence Properties. Chemistry 2009; 15:639-45. [DOI: 10.1002/chem.200801135] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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