1
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Debnath T, Cisneros GA. Investigation of the stability of D5SIC-DNAM-incorporated DNA duplex in Taq polymerase binary system: a systematic classical MD approach. Phys Chem Chem Phys 2024; 26:7287-7295. [PMID: 38353000 DOI: 10.1039/d3cp05571j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
DNA polymerases are fundamental enzymes that play a crucial role in processing DNA with high fidelity and accuracy ensuring the faithful transmission of genetic information. The recognition of unnatural base pairs (UBPs) by polymerases, enabling their replication, represents a significant and groundbreaking discovery with profound implications for genetic expansion. Romesberg et al. examined the impact of DNA containing 2,6-dimethyl-2H-isoquiniline-1-thione: D5SIC (DS) and 2-methoxy-3-methylnaphthalene: DNAM (DN) UBPs bound to T. aquaticus DNA polymerase (Taq) through crystal structure analysis. Here, we have used polarizable and nonpolarizable classical molecular dynamics (MD) simulations to investigate the structural aspects and stability of Taq in complex with a DNA duplex including a DS-DN pair in the terminal 3' and 5' positions. Our results suggest that the flexibility of UBP-incorporated DNA in the terminal position is arrested by the polymerase, thus preventing fraying and mispairing. Our investigation also reveals that the UBP remains in an intercalated conformation inside the active site, exhibiting two distinct orientations in agreement with experimental findings. Our analysis pinpoints particular residues responsible for favorable interactions with the UBP, with some relying on van der Waals interactions while other on Coulombic forces.
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Affiliation(s)
- Tanay Debnath
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, Dallas, USA.
| | - G Andrés Cisneros
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, Dallas, USA.
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080, Dallas, USA
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2
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Debnath T, Cisneros GA. Investigation of dynamical flexibility of D5SIC-DNAM inside DNA duplex in aqueous solution: a systematic classical MD approach. Phys Chem Chem Phys 2024; 26:7435-7445. [PMID: 38353005 PMCID: PMC11080001 DOI: 10.1039/d3cp05572h] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Incorporation of artificial 3rd base pairs (unnatural base pairs, UBPs) has emerged as a fundamental technique in pursuit of expanding the genetic alphabet. 2,6-Dimethyl-2H-isoquiniline-1-thione: D5SIC (DS) and 2-methoxy-3-methylnaphthalene: DNAM (DN), a potential unnatural base pair (UBP) developed by Romesberg and colleagues, has been shown to have remarkable capability for replication within DNA. Crystal structures of a Taq polymerase/double-stranded DNA (ds-DNA) complex containing a DS-DN pair in the 3' terminus showed a parallelly stacked geometry for the pre-insertion, and an intercalated geometry for the post-insertion structure. Unconventional orientations of DS-DN inside a DNA duplex have inspired scientists to investigate the conformational orientations and structural properties of UBP-incorporated DNA. In recent years, computational simulations have been used to investigate the geometry of DS-DN within the DNA duplex; nevertheless, unresolved questions persist owing to inconclusive findings. In this work, we investigate the structural and dynamical properties of DS and DN inside a ds-DNA strand in aqueous solution considering both short and long DNA templates using polarizable, and non-polarizable classical MD simulations. Flexible conformational change of UBP with major populations of Watson-Crick-Franklin (WCF) and three distinct non-Watson-Crick-Franklin (nWCFP1, nWCFP2, nWCFO) conformations through intra and inter-strand flipping have been observed. Our results suggest that a dynamical conformational change leads to the production of diffierent conformational distribution for the systems. Simulations with a short ds-DNA duplex suggest nWCF (P1 and O) as the predominant structures, whereas long ds-DNA duplex simulations indicate almost equal populations of WCF, nWCFP1, nWCFO. DS-DN in the terminal position is found to be more flexible with occasional mispairing and fraying. Overall, these results suggest flexibility and dynamical conformational change of the UBP as well as indicate varied conformational distribution irrespective of starting orientation of the UBP and length og DNA strand.
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Affiliation(s)
- Tanay Debnath
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, Dallas, USA.
| | - G Andrés Cisneros
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, Dallas, USA.
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas 75080, Dallas, USA
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3
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Huo B, Wang C, Hu X, Wang H, Zhu G, Zhu A, Li L. Peripheral substitution effects on unnatural base pairs: A case of brominated TPT3 to enhance replication fidelity. Bioorg Chem 2023; 140:106827. [PMID: 37683537 DOI: 10.1016/j.bioorg.2023.106827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 08/11/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023]
Abstract
The high fidelity poses a central role in developing unnatural base pairs (UBPs), which means the high pairing capacity of unnatural bases with their partners, and low mispairing with all the natural bases. Different strategies have been used to develop higher-fidelity UBPs, including optimizing hydrophobic interaction forces between UBPs. Variant substituent groups are allowed to fine tune the hydrophobic forces of different UBPs' candidates. However, the modifications on the skeleton of TPT3 base are rare and the replication fidelity of TPT3-NaM remains hardly to improve so far. In this paper, we reasoned that modifying and/or expanding the aromatic surface by Bromo-substituents to slightly increase hydrophobicity of TPT3 might offer a way to increase the fidelity of this pair. Based on the hypothesis, we synthesized the bromine substituted TPT3, 2-bromo-TPT3 and 2, 4-dibromo-TPT3 as the new TPT3 analogs. While the enzyme reaction kinetic experiments showed that d2-bromo-TPT3-dNaM pair and d2, 4-dibromo-TPT3TP-dNaM pair had slightly less efficient incorporation and extension rates than that of dTPT3-dNaM pair, the assays did reveal that the mispairing of 2-bromo-TPT3 and 2, 4-dibromo-TPT3 with all the natural bases could dramatically decrease in contrast to TPT3. Their lower mispairing capacity promoted us to run polymerase chain amplification reactions, and a higher fidelity of d2-bromo-TPT3-dNaM pair could be obtained with 99.72 ± 0.01% of the in vitro replication fidelity than that of dTPT3-dNaM pair, 99.52 ± 0.09%. In addition, d2-bromo-TPT3-dNaM can also be effectively copied in E. coli cells, which showed the same replication fidelity as that of dTPT3-dNaM in the specific sequence, but a higher fidelity in the random sequence context.
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Affiliation(s)
- Bianbian Huo
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, China Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Henan Normal University, Xinxiang, Henan 453007, China
| | - Chao Wang
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, China Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Henan Normal University, Xinxiang, Henan 453007, China
| | - Xiaoqi Hu
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, China Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Henan Normal University, Xinxiang, Henan 453007, China
| | - Honglei Wang
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, China Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Henan Normal University, Xinxiang, Henan 453007, China
| | - Gongming Zhu
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, China Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Henan Normal University, Xinxiang, Henan 453007, China
| | - Anlian Zhu
- 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
- NMPA Key Laboratory for Research and Evaluation of Innovative Drug, China Henan Key Laboratory of Organic Functional Molecule and Drug Innovation, Henan Normal University, Xinxiang, Henan 453007, China; 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; Pingyuan Laboratory, Henan Normal University, Xinxiang 453007, China.
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4
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Dörrenhaus R, Wagner PK, Kath-Schorr S. Two are not enough: synthetic strategies and applications of unnatural base pairs. Biol Chem 2023; 404:883-896. [PMID: 37354104 DOI: 10.1515/hsz-2023-0169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 06/05/2023] [Indexed: 06/26/2023]
Abstract
Nucleic acid chemistry is a rapidly evolving field, and the need for novel nucleotide modifications and artificial nucleotide building blocks for diagnostic and therapeutic use, material science or for studying cellular processes continues unabated. This review focusses on the development and application of unnatural base pairs as part of an expanded genetic alphabet. Not only recent developments in "nature-like" artificial base pairs are presented, but also current synthetic methods to get access to C-glycosidic nucleotides. Wide-ranging viability in synthesis is a prerequisite for the successful use of unnatural base pairs in a broader spectrum and will be discussed.
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5
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Romesberg FE. Discovery, implications and initial use of semi-synthetic organisms with an expanded genetic alphabet/code. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220030. [PMID: 36633274 PMCID: PMC9835597 DOI: 10.1098/rstb.2022.0030] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 08/25/2022] [Indexed: 01/13/2023] Open
Abstract
Much recent interest has focused on developing proteins for human use, such as in medicine. However, natural proteins are made up of only a limited number of canonical amino acids with limited functionalities, and this makes the discovery of variants with some functions difficult. The ability to recombinantly express proteins containing non-canonical amino acids (ncAAs) with properties selected to impart the protein with desired properties is expected to dramatically improve the discovery of proteins with different functions. Perhaps the most straightforward approach to such an expansion of the genetic code is through expansion of the genetic alphabet, so that new codon/anticodon pairs can be created to assign to ncAAs. In this review, I briefly summarize more than 20 years of effort leading ultimately to the discovery of synthetic nucleotides that pair to form an unnatural base pair, which when incorporated into DNA, is stably maintained, transcribed and used to translate proteins in Escherichia coli. In addition to discussing wide ranging conceptual implications, I also describe ongoing efforts at the pharmaceutical company Sanofi to employ the resulting 'semi-synthetic organisms' or SSOs, for the production of next-generation protein therapeutics. This article is part of the theme issue 'Reactivity and mechanism in chemical and synthetic biology'.
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Affiliation(s)
- Floyd E. Romesberg
- Platform Innovation, Synthorx, a Sanofi Company, 11099 N. Torrey Pines Road, Suite 190, La Jolla, CA 92037, USA
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6
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Jena NR, Das P. Hybrid nucleobases as new and efficient unnatural genetic letters. J Biomol Struct Dyn 2023; 41:366-376. [PMID: 34796792 DOI: 10.1080/07391102.2021.2003863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
To expand the existing genetic letters beyond the natural four nucleotides, such as G, C, A, and T, it is necessary to design robust nucleotides that can not only produce stable and unperturbed DNA but also function naturally in living cells. Although hydrophobic bases, such as d5SICS (2,6-dimethyl-2H-isoquiniline-1-thione) and dNaM (2-methoxy-3-methylnaphthalene) were shown to be replicated in bacterial cells, the d5SICS:dNaM base-pair was found to perturb the structure of the duplex DNA. Therefore, it is necessary to design nucleobases that can form base pairs like the natural G:C and A:T pairs. Here, a reliable dispersion-corrected density functional theory has been used to design several nucleobases that can produce three-hydrogen-bonded base pairs like the G:C pair. In doing so, the Watson-Crick faces of d5SICS and dNaM were modified by replacing the hydrophobic groups with hydrogen bond donors and acceptors. As dNaM contains an unnatural C-glycosidic bond (C-dNaM), it was also modified to contain the natural N-glycosidic bond (N-dNaM). This technique produced 91 new bases (N-d5SICS-X (X = 1-33), C-dNaM-X (X = 1-35), and N-dNaM-X (X = 1-23), where X is the different types of modifications applied to d5SICS and dNaM) and 259 base-pairs. Among these base pairs, 76 base pairs are found to be more stable than the G:C pair. Interestingly, the N-d5SICS-32:C-dNaM-32 and N-d5SICS-32:N-dNaM-20 pairs are found to be the most stable with binding energies of about -28.0 kcal/mol. The base-pair patterns of these pairs are also analogous to that of the G:C pair. Hence, it is proposed that N-d5SICS-32, C-dNaM-32, and N-dNaM-20 would act as efficient new genetic letters to produce stable and unperturbed artificial DNA.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- N R Jena
- Discipline of Natural Sciences, Indian Institute of Information Technology, Design, and Manufacturing, Khamaria, Jabalpur, India
| | - P Das
- Discipline of Natural Sciences, Indian Institute of Information Technology, Design, and Manufacturing, Khamaria, Jabalpur, India
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7
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Kimoto M, Hirao I. Genetic Code Engineering by Natural and Unnatural Base Pair Systems for the Site-Specific Incorporation of Non-Standard Amino Acids Into Proteins. Front Mol Biosci 2022; 9:851646. [PMID: 35685243 PMCID: PMC9171071 DOI: 10.3389/fmolb.2022.851646] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 04/25/2022] [Indexed: 12/21/2022] Open
Abstract
Amino acid sequences of proteins are encoded in nucleic acids composed of four letters, A, G, C, and T(U). However, this four-letter alphabet coding system limits further functionalities of proteins by the twenty letters of amino acids. If we expand the genetic code or develop alternative codes, we could create novel biological systems and biotechnologies by the site-specific incorporation of non-standard amino acids (or unnatural amino acids, unAAs) into proteins. To this end, new codons and their complementary anticodons are required for unAAs. In this review, we introduce the current status of methods to incorporate new amino acids into proteins by in vitro and in vivo translation systems, by focusing on the creation of new codon-anticodon interactions, including unnatural base pair systems for genetic alphabet expansion.
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Affiliation(s)
| | - Ichiro Hirao
- *Correspondence: Michiko Kimoto, ; Ichiro Hirao,
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8
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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: 0] [Impact Index Per Article: 0] [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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9
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Zhang J, Huang Y, Sun M, Wan S, Yang C, Song Y. Recent Advances in Aptamer-Based Liquid Biopsy. ACS APPLIED BIO MATERIALS 2022; 5:1954-1979. [PMID: 35014838 DOI: 10.1021/acsabm.1c01202] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Liquid biopsy capable of noninvasive and real-time molecular profiling is considered as a breakthrough technology, endowing an opportunity for precise diagnosis of individual patients. Extracellular vesicles (EVs) and circulating tumor cells (CTCs) consisting of substantial disease-related molecular information play an important role in liquid biopsy. Therefore, it is critically significant to exploit high-performance recognition ligands for efficient isolation and analysis of EVs and CTCs from complex body fluids. Aptamers exhibit extraordinary merits of high specificity and affinity, which are considered as superior recognition ligands for liquid biopsy. In this review, we first summarize recent advanced strategies for the evolution of high-performance aptamers and the construction of various aptamer-based recognition elements. Subsequently, we mainly discuss the isolation and analysis of EVs and CTCs based on the aptamer functioned biomaterials/biointerface. Ultimately, we envision major challenges and future direction of aptamer-based liquid biopsy for clinical utilities.
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Affiliation(s)
- Jialu Zhang
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yihao Huang
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Miao Sun
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Shuang Wan
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Chaoyong Yang
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.,Institute of Molecular Medicine, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China
| | - Yanling Song
- The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, State Key Laboratory of Physical Chemistry of Solid Surfaces, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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10
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Romesberg FE. Creation, Optimization, and Use of Semi-Synthetic Organisms that Store and Retrieve Increased Genetic Information. J Mol Biol 2021; 434:167331. [PMID: 34710400 DOI: 10.1016/j.jmb.2021.167331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 12/18/2022]
Abstract
With few exceptions, natural proteins are built from only 20 canonical (proteogenic) amino acids which limits the functionality and accordingly the properties they can possess. Genetic code expansion, i.e. the creation of codons and the machinery needed to assign them to non-canonical amino acids (ncAAs), promises to enable the discovery of proteins with novel properties that are otherwise difficult or impossible to obtain. One approach to expanding the genetic code is to expand the genetic alphabet via the development of unnatural nucleotides that pair to form an unnatural base pair (UBP). Semi-synthetic organisms (SSOs), i.e. organisms that stably maintain the UBP, transcribe its component nucleotides into RNA, and use it to translate proteins, would have available to them new codons and the anticodons needed to assign them to ncAAs. This review summarizes the development of a family of UBPs, their use to create SSOs, and the optimization and application of the SSOs to produce candidate therapeutic proteins with improved properties that are now undergoing evaluation in clinical trials.
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Transcriptional processing of an unnatural base pair by eukaryotic RNA polymerase II. Nat Chem Biol 2021; 17:906-914. [PMID: 34140682 PMCID: PMC8319059 DOI: 10.1038/s41589-021-00817-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 05/10/2021] [Indexed: 02/05/2023]
Abstract
The development of unnatural base pairs (UBPs) has greatly increased the information storage capacity of DNA, allowing for transcription of unnatural RNA by the heterologously expressed T7 RNA polymerase (RNAP) in Escherichia coli. However, little is known about how UBPs are transcribed by cellular RNA polymerases. Here, we investigated how synthetic unnatural nucleotides, NaM and TPT3, are recognized by eukaryotic RNA polymerase II (Pol II) and found that Pol II is able to selectively recognize UBPs with high fidelity when dTPT3 is in the template strand and rNaMTP acts as the nucleotide substrate. Our structural analysis and molecular dynamics simulation provide structural insights into transcriptional processing of UBPs in a stepwise manner. Intriguingly, we identified a novel 3'-RNA binding site after rNaM addition, termed the swing state. These results may pave the way for future studies in the design of transcription and translation strategies in higher organisms with expanded genetic codes.
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12
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Ouaray Z, Benner SA, Georgiadis MM, Richards NGJ. Building better polymerases: Engineering the replication of expanded genetic alphabets. J Biol Chem 2020; 295:17046-17059. [PMID: 33004440 PMCID: PMC7863901 DOI: 10.1074/jbc.rev120.013745] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 09/30/2020] [Indexed: 11/30/2022] Open
Abstract
DNA polymerases are today used throughout scientific research, biotechnology, and medicine, in part for their ability to interact with unnatural forms of DNA created by synthetic biologists. Here especially, natural DNA polymerases often do not have the "performance specifications" needed for transformative technologies. This creates a need for science-guided rational (or semi-rational) engineering to identify variants that replicate unnatural base pairs (UBPs), unnatural backbones, tags, or other evolutionarily novel features of unnatural DNA. In this review, we provide a brief overview of the chemistry and properties of replicative DNA polymerases and their evolved variants, focusing on the Klenow fragment of Taq DNA polymerase (Klentaq). We describe comparative structural, enzymatic, and molecular dynamics studies of WT and Klentaq variants, complexed with natural or noncanonical substrates. Combining these methods provides insight into how specific amino acid substitutions distant from the active site in a Klentaq DNA polymerase variant (ZP Klentaq) contribute to its ability to replicate UBPs with improved efficiency compared with Klentaq. This approach can therefore serve to guide any future rational engineering of replicative DNA polymerases.
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Affiliation(s)
- Zahra Ouaray
- School of Chemistry, Cardiff University, Park Place, Cardiff, United Kingdom
| | - Steven A Benner
- Foundation for Applied Molecular Evolution, Alachua, Florida, USA
| | - Millie M Georgiadis
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
| | - Nigel G J Richards
- School of Chemistry, Cardiff University, Park Place, Cardiff, United Kingdom; Foundation for Applied Molecular Evolution, Alachua, Florida, USA.
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13
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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: 60] [Impact Index Per Article: 15.0] [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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14
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Abstract
DNA polymerases play a central role in biology by transferring genetic information from one generation to the next during cell division. Harnessing the power of these enzymes in the laboratory has fueled an increase in biomedical applications that involve the synthesis, amplification, and sequencing of DNA. However, the high substrate specificity exhibited by most naturally occurring DNA polymerases often precludes their use in practical applications that require modified substrates. Moving beyond natural genetic polymers requires sophisticated enzyme-engineering technologies that can be used to direct the evolution of engineered polymerases that function with tailor-made activities. Such efforts are expected to uniquely drive emerging applications in synthetic biology by enabling the synthesis, replication, and evolution of synthetic genetic polymers with new physicochemical properties.
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15
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New codons for efficient production of unnatural proteins in a semisynthetic organism. Nat Chem Biol 2020; 16:570-576. [PMID: 32251411 PMCID: PMC7263176 DOI: 10.1038/s41589-020-0507-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 01/20/2020] [Accepted: 02/25/2020] [Indexed: 12/02/2022]
Abstract
Natural organisms use a four-letter genetic alphabet that makes available
64 triplet codons, of which 61 are sense codons used to encode proteins with the
20 canonical amino acids. We have shown that the unnatural nucleotides dNaM and
dTPT3 pair to form an unnatural base pair (UBP) and allow for the creation of
semi-synthetic organisms (SSOs) with additional sense codons. Here we report a
systematic analysis of the unnatural codons. We identify nine unnatural codons
that can produce unnatural protein with nearly complete incorporation of an
encoded non-canonical amino acid (ncAA). We also show that at least three of the
codons are orthogonal and can be simultaneously decoded in the SSO, affording
the first 67-codon organism. The ability to site-specifically incorporate
multiple, different ncAAs into a protein should now allow for the development of
proteins with novel activities and possibly even SSOs with new forms and
functions.
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16
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Eberlein L, Beierlein FR, van Eikema Hommes NJR, Radadiya A, Heil J, Benner SA, Clark T, Kast SM, Richards NGJ. Tautomeric Equilibria of Nucleobases in the Hachimoji Expanded Genetic Alphabet. J Chem Theory Comput 2020; 16:2766-2777. [PMID: 32125859 DOI: 10.1021/acs.jctc.9b01079] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Evolution has yielded biopolymers that are constructed from exactly four building blocks and are able to support Darwinian evolution. Synthetic biology aims to extend this alphabet, and we recently showed that 8-letter (hachimoji) DNA can support rule-based information encoding. One source of replicative error in non-natural DNA-like systems, however, is the occurrence of alternative tautomeric forms, which pair differently. Unfortunately, little is known about how structural modifications impact free-energy differences between tautomers of the non-natural nucleobases used in the hachimoji expanded genetic alphabet. Determining experimental tautomer ratios is technically difficult, and so, strategies for improving hachimoji DNA replication efficiency will benefit from accurate computational predictions of equilibrium tautomeric ratios. We now report that high-level quantum-chemical calculations in aqueous solution by the embedded cluster reference interaction site model, benchmarked against free-energy molecular simulations for solvation thermodynamics, provide useful quantitative information on the tautomer ratios of both Watson-Crick and hachimoji nucleobases. In agreement with previous computational studies, all four Watson-Crick nucleobases adopt essentially only one tautomer in water. This is not the case, however, for non-natural nucleobases and their analogues. For example, although the enols of isoguanine and a series of related purines are not populated in water, these heterocycles possess N1-H and N3-H keto tautomers that are similar in energy, thereby adversely impacting accurate nucleobase pairing. These robust computational strategies offer a firm basis for improving experimental measurements of tautomeric ratios, which are currently limited to studying molecules that exist only as two tautomers in solution.
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Affiliation(s)
- Lukas Eberlein
- Physikalische Chemie III, Technische Universität Dortmund, Dortmund 44227, Germany
| | - Frank R Beierlein
- Computer-Chemistry-Centre and Interdisciplinary Centre for Molecular Materials, Department of Chemistry & Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91054, Germany
| | - Nico J R van Eikema Hommes
- Computer-Chemistry-Centre and Interdisciplinary Centre for Molecular Materials, Department of Chemistry & Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91054, Germany
| | - Ashish Radadiya
- School of Chemistry, Cardiff University, Cardiff CF10 3AT, U.K
| | - Jochen Heil
- Physikalische Chemie III, Technische Universität Dortmund, Dortmund 44227, Germany
| | - Steven A Benner
- Foundation for Applied Molecular Evolution, Alachua, Florida 32615, United States
| | - Timothy Clark
- Computer-Chemistry-Centre and Interdisciplinary Centre for Molecular Materials, Department of Chemistry & Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen 91054, Germany
| | - Stefan M Kast
- Physikalische Chemie III, Technische Universität Dortmund, Dortmund 44227, Germany
| | - Nigel G J Richards
- School of Chemistry, Cardiff University, Cardiff CF10 3AT, U.K.,Foundation for Applied Molecular Evolution, Alachua, Florida 32615, United States
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17
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Marx A, Betz K. The Structural Basis for Processing of Unnatural Base Pairs by DNA Polymerases. Chemistry 2020; 26:3446-3463. [PMID: 31544987 PMCID: PMC7155079 DOI: 10.1002/chem.201903525] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 09/17/2019] [Indexed: 12/16/2022]
Abstract
Unnatural base pairs (UBPs) greatly increase the diversity of DNA and RNA, furthering their broad range of molecular biological and biotechnological approaches. Different candidates have been developed whereby alternative hydrogen-bonding patterns and hydrophobic and packing interactions have turned out to be the most promising base-pairing concepts to date. The key in many applications is the highly efficient and selective acceptance of artificial base pairs by DNA polymerases, which enables amplification of the modified DNA. In this Review, computational as well as experimental studies that were performed to characterize the pairing behavior of UBPs in free duplex DNA or bound to the active site of KlenTaq DNA polymerase are highlighted. The structural studies, on the one hand, elucidate how base pairs lacking hydrogen bonds are accepted by these enzymes and, on the other hand, highlight the influence of one or several consecutive UBPs on the structure of a DNA double helix. Understanding these concepts facilitates optimization of future UBPs for the manifold fields of applications.
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Affiliation(s)
- Andreas Marx
- Department of ChemistryKonstanz Research School Chemical BiologyUniversity of KonstanzUniversitätsstrasse 1078464KonstanzGermany
| | - Karin Betz
- Department of ChemistryKonstanz Research School Chemical BiologyUniversity of KonstanzUniversitätsstrasse 1078464KonstanzGermany
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18
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Galindo-Murillo R, Barroso-Flores J. Hydrophobic unnatural base pairs show a Watson-Crick pairing in micro-second molecular dynamics simulations. J Biomol Struct Dyn 2019; 38:4098-4106. [PMID: 31542995 DOI: 10.1080/07391102.2019.1671898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Two unnatural hydrophobic nucleotides, d5SICS (2,6-dimethyl-2H-isoquiniline-1-thione) and dNaM (2-methoxy-3-methylnaphthalene), were previously replicated in vivo by a modified E. coli strand, however, a consistent structure for their pairing in terms of specific and selective directional interactions remains elusive, as data from spectroscopy experiments and simulations are inconsistent. The proposed d5SICS-dNaM pairing has been suggested to be a stacked configuration as suggested by NMR data; simulations have failed to reproduce this configuration and a Watson-Crick like pairing is observed. Previously, we focused on reproducing the d5SICS-dNaM Unnatural Base Pair (UBP) paring using an older (bsc0) AMBER force field, which was not able to correctly reproduce the experimental data. We present our efforts to reproduce the experimental pairing using the current version of the AMBER DNA force fields (OL15 and bsc1), two water models (OPC and TIP3P) and external electrostatic stabilization by Mg2+ ions. Opposite to previously reported simulations, a Watson-Crick-like pairing with no hydrogen bonds persists throughout all our results. Despite our efforts to replicate the reported stacked conformation, we cannot confirm its plausibility nor obtain a consistent structure that is independent of the neighboring nucleotides. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Rodrigo Galindo-Murillo
- Department of Medicinal Chemistry, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Joaquín Barroso-Flores
- Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Estado de México, C.P., México.,Instituto de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, México
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19
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Zhou H, Rauch S, Dai Q, Cui X, Zhang Z, Nachtergaele S, Sepich C, He C, Dickinson BC. Evolution of a reverse transcriptase to map N 1-methyladenosine in human messenger RNA. Nat Methods 2019; 16:1281-1288. [PMID: 31548705 PMCID: PMC6884687 DOI: 10.1038/s41592-019-0550-4] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 08/05/2019] [Indexed: 11/09/2022]
Abstract
Chemical modifications to messenger RNA are increasingly recognized as a critical regulatory layer in the flow of genetic information, but quantitative tools to monitor RNA modifications in a whole-transcriptome and site-specific manner are lacking. Here we describe a versatile platform for directed evolution that rapidly selects for reverse transcriptases that install mutations at sites of a given type of RNA modification during reverse transcription, allowing for site-specific identification of the modification. To develop and validate the platform, we evolved the HIV-1 reverse transcriptase against N1-methyladenosine (m1A). Iterative rounds of selection yielded reverse transcriptases with both robust read-through and high mutation rates at m1A sites. The optimal evolved reverse transcriptase enabled detection of well-characterized m1A sites and revealed hundreds of m1A sites in human mRNA. This work develops and validates the reverse transcriptase evolution platform, and provides new tools, analysis methods and datasets to study m1A biology.
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Affiliation(s)
- Huiqing Zhou
- Department of Chemistry, University of Chicago, Chicago, IL, USA.,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA
| | - Simone Rauch
- Department of Chemistry, University of Chicago, Chicago, IL, USA.,Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA
| | - Qing Dai
- Department of Chemistry, University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, University of Chicago, Chicago, IL, USA
| | - Xiaolong Cui
- Department of Chemistry, University of Chicago, Chicago, IL, USA.,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA
| | - Zijie Zhang
- Department of Chemistry, University of Chicago, Chicago, IL, USA.,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA.,Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, University of Chicago, Chicago, IL, USA
| | - Sigrid Nachtergaele
- Department of Chemistry, University of Chicago, Chicago, IL, USA.,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA.,Howard Hughes Medical Institute, University of Chicago, Chicago, IL, USA
| | - Caraline Sepich
- Department of Chemistry, University of Chicago, Chicago, IL, USA.,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA.,Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA.,University of Chicago Medical Scientist Training Program, Chicago, USA
| | - Chuan He
- Department of Chemistry, University of Chicago, Chicago, IL, USA. .,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA. .,Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA. .,Howard Hughes Medical Institute, University of Chicago, Chicago, IL, USA.
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20
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Singh I, Laos R, Hoshika S, Benner SA, Georgiadis MM. Snapshots of an evolved DNA polymerase pre- and post-incorporation of an unnatural nucleotide. Nucleic Acids Res 2019; 46:7977-7988. [PMID: 29986111 PMCID: PMC6125688 DOI: 10.1093/nar/gky552] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 06/15/2018] [Indexed: 01/20/2023] Open
Abstract
The next challenge in synthetic biology is to be able to replicate synthetic nucleic acid sequences efficiently. The synthetic pair, 2-amino-8-(1-beta-d-2′- deoxyribofuranosyl) imidazo [1,2-a]-1,3,5-triazin-[8H]-4-one (trivially designated P) with 6-amino-3-(2′-deoxyribofuranosyl)-5-nitro-1H-pyridin-2-one (trivially designated Z), is replicated by certain Family A polymerases, albeit with lower efficiency. Through directed evolution, we identified a variant KlenTaq polymerase (M444V, P527A, D551E, E832V) that incorporates dZTP opposite P more efficiently than the wild-type enzyme. Here, we report two crystal structures of this variant KlenTaq, a post-incorporation complex that includes a template-primer with P:Z trapped in the active site (binary complex) and a pre-incorporation complex with dZTP paired to template P in the active site (ternary complex). In forming the ternary complex, the fingers domain exhibits a larger closure angle than in natural complexes but engages the template-primer and incoming dNTP through similar interactions. In the binary complex, although many of the interactions found in the natural complexes are retained, there is increased relative motion of the thumb domain. Collectively, our analyses suggest that it is the post-incorporation complex for unnatural substrates that presents a challenge to the natural enzyme and that more efficient replication of P:Z pairs requires a more flexible polymerase.
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Affiliation(s)
- Isha Singh
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Roberto Laos
- Foundation for Applied Molecular Evolution and the Westheimer Institute of Science & Technology, Alachua, FL 32615, USA
| | - Shuichi Hoshika
- Foundation for Applied Molecular Evolution and the Westheimer Institute of Science & Technology, Alachua, FL 32615, USA
| | - Steven A Benner
- Foundation for Applied Molecular Evolution and the Westheimer Institute of Science & Technology, Alachua, FL 32615, USA.,Firebird Biomolecular Sciences LLC, Alachua, FL 32615, USA
| | - Millie M Georgiadis
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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21
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Guo WW, Zhang TS, Fang WH, Cui G. QM/MM studies on the excited-state relaxation mechanism of a semisynthetic dTPT3 base. Phys Chem Chem Phys 2018; 20:5067-5073. [PMID: 29388994 DOI: 10.1039/c7cp08696b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Semisynthetic alphabets can potentially increase the genetic information stored in DNA through the formation of unusual base pairs. Recent experiments have shown that near-visible-light irradiation of the dTPT3 chromophore could lead to the formation of a reactive triplet state and of singlet oxygen in high quantum yields. However, the detailed excited-state relaxation paths that populate the lowest triplet state are unclear. Herein, we have for the first time employed the QM(MS-CASPT2//CASSCF)/MM method to explore the spectroscopic properties and excited-state relaxation mechanism of the aqueous dTPT3 chromophore. On the basis of the results, we have found that (1) the S2(1ππ*) state of dTPT3 is the initially populated excited singlet state upon near-visible light irradiation; and (2) there are two efficient relaxation pathways to populate the lowest triplet state, i.e. T1(3ππ*). In the first one, the S2(1ππ*) system first decays to the S1(1nπ*) state near the S2/S1 conical intersection, which is followed by an efficient S1 → T1 intersystem crossing process at the S1/T1 crossing point; in the second one, an efficient S2 → T2 intersystem crossing takes place first, and then, the T2(3nπ*) system hops to the T1(3ππ*) state through an internal conversion process at the T2/T1 conical intersection. Moreover, an S2/S1/T2 intersection region is found to play a vital role in the excited-state relaxation. These new mechanistic insights help in understanding the photophysics and photochemistry of unusual base pairs.
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Affiliation(s)
- Wei-Wei Guo
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China.
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22
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Dien VT, Holcomb M, Feldman AW, Fischer EC, Dwyer TJ, Romesberg FE. Progress Toward a Semi-Synthetic Organism with an Unrestricted Expanded Genetic Alphabet. J Am Chem Soc 2018; 140:16115-16123. [PMID: 30418780 DOI: 10.1021/jacs.8b08416] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We have developed a family of unnatural base pairs (UBPs), exemplified by the pair formed between dNaM and dTPT3, for which pairing is mediated not by complementary hydrogen bonding but by hydrophobic and packing forces. These UBPs enabled the creation of the first semisynthetic organisms (SSOs) that store increased genetic information and use it to produce proteins containing noncanonical amino acids. However, retention of the UBPs was poor in some sequence contexts. Here, to optimize the SSO, we synthesize two novel benzothiophene-based dNaM analogs, dPTMO and dMTMO, and characterize the corresponding UBPs, dPTMO-dTPT3 and dMTMO-dTPT3. We demonstrate that these UBPs perform similarly to, or slightly worse than, dNaM-dTPT3 in vitro. However, in the in vivo environment of an SSO, retention of dMTMO-dTPT3, and especially dPTMO-dTPT3, is significantly higher than that of dNaM-dTPT3. This more optimal in vivo retention results from better replication, as opposed to more efficient import of the requisite unnatural nucleoside triphosphates. Modeling studies suggest that the more optimal replication results from specific internucleobase interactions mediated by the thiophene sulfur atoms. Finally, we show that dMTMO and dPTMO efficiently template the transcription of RNA containing TPT3 and that their improved retention in DNA results in more efficient production of proteins with noncanonical amino acids. This is the first instance of using performance within the SSO as part of the UBP evaluation and optimization process. From a general perspective, the results demonstrate the importance of evaluating synthetic biology "parts" in their in vivo context and further demonstrate the ability of hydrophobic and packing interactions to replace the complementary hydrogen bonding that underlies the replication of natural base pairs. From a more practical perspective, the identification of dMTMO-dTPT3 and especially dPTMO-dTPT3 represents significant progress toward the development of SSOs with an unrestricted ability to store and retrieve increased information.
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Affiliation(s)
- Vivian T Dien
- Department of Chemistry , The Scripps Research Institute , La Jolla , California 92037 United States
| | - Matthew Holcomb
- Department of Chemistry , The Scripps Research Institute , La Jolla , California 92037 United States
| | - Aaron W Feldman
- Department of Chemistry , The Scripps Research Institute , La Jolla , California 92037 United States
| | - Emil C Fischer
- Department of Chemistry , The Scripps Research Institute , La Jolla , California 92037 United States
| | - Tammy J Dwyer
- Department of Chemistry and Biochemistry , University of San Diego , San Diego , California 92110 , United States
| | - Floyd E Romesberg
- Department of Chemistry , The Scripps Research Institute , La Jolla , California 92037 United States
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23
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Snapshots of a modified nucleotide moving through the confines of a DNA polymerase. Proc Natl Acad Sci U S A 2018; 115:9992-9997. [PMID: 30224478 PMCID: PMC6176618 DOI: 10.1073/pnas.1811518115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Despite being evolved to process the four canonical nucleotides, DNA polymerases are known to incorporate and extend from modified nucleotides, which is the key to numerous core biotechnology applications. The structural basis for postincorporation elongation remained elusive. We successfully crystallized KlenTaq DNA polymerase in six complexes, providing high-resolution snapshots of the modification “moving” from the 3′ terminus upstream to the sixth nucleotide in the primer strand. Combining these data with quantum mechanics/molecular mechanics calculations and biochemical studies elucidates how the enzyme and the modified substrate mutually modulate their conformations without compromising the enzyme’s activity. This highlights the unexpected plasticity of the system as origin of the broad substrate properties of the DNA polymerase and guide for the design of improved systems. DNA polymerases have evolved to process the four canonical nucleotides accurately. Nevertheless, these enzymes are also known to process modified nucleotides, which is the key to numerous core biotechnology applications. Processing of modified nucleotides includes incorporation of the modified nucleotide and postincorporation elongation to proceed with the synthesis of the nascent DNA strand. The structural basis for postincorporation elongation is currently unknown. We addressed this issue and successfully crystallized KlenTaq DNA polymerase in six closed ternary complexes containing the enzyme, the modified DNA substrate, and the incoming nucleotide. Each structure shows a high-resolution snapshot of the elongation of a modified primer, where the modification “moves” from the 3′-primer terminus upstream to the sixth nucleotide in the primer strand. Combining these data with quantum mechanics/molecular mechanics calculations and biochemical studies elucidates how the enzyme and the modified substrate mutually modulate their conformations without compromising the enzyme’s activity significantly. The study highlights the plasticity of the system as origin of the broad substrate properties of DNA polymerases and facilitates the design of improved systems.
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24
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Dien VT, Morris SE, Karadeema RJ, Romesberg FE. Expansion of the genetic code via expansion of the genetic alphabet. Curr Opin Chem Biol 2018; 46:196-202. [PMID: 30205312 DOI: 10.1016/j.cbpa.2018.08.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 08/14/2018] [Accepted: 08/20/2018] [Indexed: 12/14/2022]
Abstract
Current methods to expand the genetic code enable site-specific incorporation of non-canonical amino acids (ncAAs) into proteins in eukaryotic and prokaryotic cells. However, current methods are limited by the number of codons possible, their orthogonality, and possibly their effects on protein synthesis and folding. An alternative approach relies on unnatural base pairs to create a virtually unlimited number of genuinely new codons that are efficiently translated and highly orthogonal because they direct ncAA incorporation using forces other than the complementary hydrogen bonds employed by their natural counterparts. This review outlines progress and achievements made towards developing a functional unnatural base pair and its use to generate semi-synthetic organisms with an expanded genetic alphabet that serves as the basis of an expanded genetic code.
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Affiliation(s)
- Vivian T Dien
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Sydney E Morris
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Rebekah J Karadeema
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Floyd E Romesberg
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA.
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25
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Abstract
The emergence of functional cooperation between the three main classes of biomolecules - nucleic acids, peptides and lipids - defines life at the molecular level. However, how such mutually interdependent molecular systems emerged from prebiotic chemistry remains a mystery. A key hypothesis, formulated by Crick, Orgel and Woese over 40 year ago, posits that early life must have been simpler. Specifically, it proposed that an early primordial biology lacked proteins and DNA but instead relied on RNA as the key biopolymer responsible not just for genetic information storage and propagation, but also for catalysis, i.e. metabolism. Indeed, there is compelling evidence for such an 'RNA world', notably in the structure of the ribosome as a likely molecular fossil from that time. Nevertheless, one might justifiably ask whether RNA alone would be up to the task. From a purely chemical perspective, RNA is a molecule of rather uniform composition with all four bases comprising organic heterocycles of similar size and comparable polarity and pK a values. Thus, RNA molecules cover a much narrower range of steric, electronic and physicochemical properties than, e.g. the 20 amino acid side-chains of proteins. Herein we will examine the functional potential of RNA (and other nucleic acids) with respect to self-replication, catalysis and assembly into simple protocellular entities.
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26
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Negi I, Kathuria P, Sharma P, Wetmore SD. How do hydrophobic nucleobases differ from natural DNA nucleobases? Comparison of structural features and duplex properties from QM calculations and MD simulations. Phys Chem Chem Phys 2018; 19:16365-16374. [PMID: 28657627 DOI: 10.1039/c7cp02576a] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Computational (DFT and MD simulation) methods are employed to systematically characterize the structural and energetic properties of five hydrophobic nucleobases (FEMO, MMO2, NaM, 5SICS and TPT3) that constitute four unnatural base pairs (FEMO:5SICS, MMO2:5SICS, NaM:5SICS and TPT3:NaM). These hydrophobic bases have been recently shown to be replicated when present between natural bases in DNA duplexes, with the highest replication fidelity and efficiency occuring for the TPT3:NaM pair. Our QM calculations suggest that the preferred (anti) glycosidic orientations of nucleosides containing hydrophobic bases are similar to the natural DNA nucleosides despite differences in their chemical structures. However, due to the inability to form interbase hydrogen bonds, hydrophobic base pairs intrinsically prefer nonplanar, distorted geometries, many of which are stabilized through π-π stacking interactions. Furthermore, the intrinsic stacking potential between a hydrophobic and a natural base is similar to that between two natural bases, indicating that the strength of stacking interactions in DNA duplexes containing hydrophobic bases is likely comparable to natural DNA. However, in contrast to the isolated base-pair geometries, our MD simulations suggest that the hydrophobic base pairs adopt variable geometries within DNA, which range from stacked (5SICS:FEMO) to nearly planar (5SICS:NaM and SICS:MMO2) to planar (TPT3:NaM). As a result, the duplex structural features at the site of modification depend on the identity of the hydrophobic base pair, where the TPT3:NaM pair causes the least structural changes compared to natural DNA. Overall, the structural insight obtained from our calculations on DNA containing hydrophobic base pairs explains the experimentally-observed higher fidelity and efficiency during replication of TPT3:NaM compared to other hydrophobic nucleobase pairs. By providing valuable structural information that explains the intrinsic and duplex properties of this class of unnatural nucleobases, the present work may aid the future design of improved hydrophobic analogues.
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Affiliation(s)
- Indu Negi
- Computational Biochemistry Laboratory, Department of Chemistry and Centre for Advanced Studies in Chemistry, Panjab University, Chandigarh, 160014, India.
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27
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Abstract
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The information available to any organism is encoded in a four
nucleotide, two base pair genetic code. Since its earliest days, the
field of synthetic biology has endeavored to impart organisms with
novel attributes and functions, and perhaps the most fundamental approach
to this goal is the creation of a fifth and sixth nucleotide that
pair to form a third, unnatural base pair (UBP) and thus allow for
the storage and retrieval of increased information. Achieving this
goal, by definition, requires synthetic chemistry to create unnatural
nucleotides and a medicinal chemistry-like approach to guide their
optimization. With this perspective, almost 20 years ago we began
designing unnatural nucleotides with the ultimate goal of developing
UBPs that function in vivo, and thus serve as the
foundation of semi-synthetic organisms (SSOs) capable of storing and
retrieving increased information. From the beginning, our efforts
focused on the development of nucleotides that bear predominantly
hydrophobic nucleobases and thus that pair not based on the complementary
hydrogen bonds that are so prominent among the natural base pairs
but rather via hydrophobic and packing interactions. It was envisioned
that such a pairing mechanism would provide a basal level of selectivity
against pairing with natural nucleotides, which we expected would
be the greatest challenge; however, this choice mandated starting
with analogs that have little or no homology to their natural counterparts
and that, perhaps not surprisingly, performed poorly. Progress toward
their optimization was driven by the construction of structure–activity
relationships, initially from in vitro steady-state
kinetic analysis, then later from pre-steady-state and PCR-based assays,
and ultimately from performance in vivo, with the
results augmented three times with screens that explored combinations
of the unnatural nucleotides that were too numerous to fully characterize
individually. The structure–activity relationship data identified
multiple features required by the UBP, and perhaps most prominent
among them was a substituent ortho to the glycosidic linkage that
is capable of both hydrophobic packing and hydrogen bonding, and nucleobases
that stably stack with flanking natural nucleobases in lieu of the potentially more stabilizing stacking interactions afforded
by cross strand intercalation. Most importantly, after the examination
of hundreds of unnatural nucleotides and thousands of candidate UBPs,
the efforts ultimately resulted in the identification of a family
of UBPs that are well recognized by DNA polymerases when incorporated
into DNA and that have been used to create SSOs that store and retrieve
increased information. In addition to achieving a longstanding goal
of synthetic biology, the results have important implications for
our understanding of both the molecules and forces that can underlie
biological processes, so long considered the purview of molecules
benefiting from eons of evolution, and highlight the promise of applying
the approaches and methodologies of synthetic and medical chemistry
in the pursuit of synthetic biology.
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Affiliation(s)
- Aaron W. Feldman
- Department of Chemistry, The Scripps Research Institute, La
Jolla, California 92037, United States
| | - Floyd E. Romesberg
- Department of Chemistry, The Scripps Research Institute, La
Jolla, California 92037, United States
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28
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Galindo-Murillo R, Barroso-Flores J. Structural and dynamical instability of DNA caused by high occurrence of d5SICS and dNaM unnatural nucleotides. Phys Chem Chem Phys 2018; 19:10571-10580. [PMID: 28394373 DOI: 10.1039/c7cp01477e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In vivo inclusion of unnatural base pairs (UBPs) into functional DNA was recently reported for compounds 2,6-dimethyl-2H-isoquiniline-1-thione (d5SICS, X) and 2-methoxy-3-methylnaphthalene (dNaM, Y) in a modified E. coli strand, for which high-fidelity replication was observed. Yet, little is known about possible genetic consequences they have in largely substituted DNA. Using a converged microsecond long molecular dynamics (MD) simulation of the sequences 5'-GCGCAAXTTGCGC-3' and 5'-GCGCXAXTXGCGC-3', where X represents the UBP, we show that in the system with only a single XY UBP pair present, the global RMS deviation from canonical B-DNA in our control simulations is ∼3 Å and a fully converged ensemble is achieved within 2 µs. With three UBPs, deviation increases to ∼5 Å and convergence is not achieved within 10 µs of sampling time. With five UBPs, no convergence is observed and the double helix collapses into a globular structure. A fully optimized structure of the trimer d(GXC) was obtained using the density functional theory method B97D/cc-pVTZ and resulted in an RMSD value of ∼2 Å when compared to the most populated structure obtained from the MD simulations. Their calculated interaction energy is -3.7 kcal mol-1. It is thus unlikely that d5SICS and dNaM could be useful as tools in DNA manipulation. This theoretical methodology can be used in the de novo design of UBPs.
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Affiliation(s)
- Rodrigo Galindo-Murillo
- Department of Medicinal Chemistry, College of Pharmacy, University of Utah, 2000 East 30 South Skaggs 201, Salt Lake City, Utah 84112, USA
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Wang W, Sheng X, Zhang S, Huang F, Sun C, Liu J, Chen D. Theoretical characterization of the conformational features of unnatural oligonucleotides containing a six nucleotide genetic alphabet. Phys Chem Chem Phys 2018; 18:28492-28501. [PMID: 27711557 DOI: 10.1039/c6cp05594j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The addition of the unnatural P:Z base pair to the four naturally occurring DNA bases expands the genetic alphabet and yields an artificially expanded genetic information system (AEGIS). Herein, the structural feature of oligonucleotides containing a novel unnatural P:Z base pair is characterized using both molecular dynamics and quantum chemistry. The results show that the incorporation of the novel artificial base pair (P:Z) preserves the global conformational feature of duplex DNA except for some local structures. The Z-nitro group imparts new properties to the groove width, which widens the major groove. The unnatural oligonucleotides containing mismatched base pairs exhibit low stability. This ensures efficient and high-fidelity replication. In general, the incorporation of the P:Z pair strengthens the stability of the corresponding DNA duplex. The calculated results also show that the thermostability originates from both hydrogen interaction and stacking interaction. The Z-nitro group plays an important role in enhancing the stability of the H-bonds and stacking strength of the P:Z pair. Overall, the present results provide theoretical insights in the exploration of artificially expanded genetic information systems.
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Affiliation(s)
- Wenjuan Wang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan 250014, P. R. China.
| | - Xiehuang Sheng
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan 250014, P. R. China.
| | - Shaolong Zhang
- College of Physics and Electronics, Shandong Normal University, Jinan 250014, P. R. China
| | - Fang Huang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan 250014, P. R. China.
| | - Chuanzhi Sun
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan 250014, P. R. China.
| | - Jianbiao Liu
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan 250014, P. R. China.
| | - Dezhan Chen
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Provincial Key Laboratory of Clean Production of Fine Chemicals, Shandong Normal University, Jinan 250014, P. R. China.
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Ledbetter MP, Karadeema RJ, Romesberg FE. Reprograming the Replisome of a Semisynthetic Organism for the Expansion of the Genetic Alphabet. J Am Chem Soc 2018; 140:758-765. [PMID: 29309130 DOI: 10.1021/jacs.7b11488] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Semisynthetic organisms (SSOs) created from Escherichia coli can replicate a plasmid containing an unnatural base pair (UBP) formed between the synthetic nucleosides dNaM and dTPT3 (dNaM-dTPT3) when the corresponding unnatural triphosphates are imported via expression of a nucleoside triphosphate transporter. The UBP can also be transcribed and used to translate proteins containing unnatural amino acids. However, UBPs are not well retained in all sequences, limiting the information that can be encoded, and are invariably lost upon extended growth. Here we explore the contributions of the E. coli DNA replication and repair machinery to the propagation of DNA containing dNaM-dTPT3 and show that replication by DNA polymerase III, supplemented with the activity of polymerase II and methyl-directed mismatch repair contribute to retention of the UBP and that recombinational repair of stalled forks is responsible for the majority of its loss. This work elucidates fundamental aspects of how bacteria replicate DNA and we use this information to reprogram the replisome of the SSO for increased UBP retention, which then allowed for the first time the construction of SSOs harboring a UBP in their chromosome.
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Affiliation(s)
- Michael P Ledbetter
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Rebekah J Karadeema
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Floyd E Romesberg
- Department of Chemistry, The Scripps Research Institute , La Jolla, California 92037, United States
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31
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Synthetic biological approaches for RNA labelling and imaging: design principles and future opportunities. Curr Opin Biotechnol 2017; 48:153-158. [DOI: 10.1016/j.copbio.2017.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 04/07/2017] [Accepted: 04/17/2017] [Indexed: 12/15/2022]
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32
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Wang Q, Xie XY, Han J, Cui G. QM and QM/MM Studies on Excited-State Relaxation Mechanisms of Unnatural Bases in Vacuo and Base Pairs in DNA. J Phys Chem B 2017; 121:10467-10478. [DOI: 10.1021/acs.jpcb.7b09046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Qian Wang
- Key Laboratory of Theoretical
and Computational Photochemistry, Ministry of Education, College of
Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xiao-Ying Xie
- Key Laboratory of Theoretical
and Computational Photochemistry, Ministry of Education, College of
Chemistry, Beijing Normal University, Beijing 100875, China
| | - Juan Han
- Key Laboratory of Theoretical
and Computational Photochemistry, Ministry of Education, College of
Chemistry, Beijing Normal University, Beijing 100875, China
| | - Ganglong Cui
- Key Laboratory of Theoretical
and Computational Photochemistry, Ministry of Education, College of
Chemistry, Beijing Normal University, Beijing 100875, China
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33
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Recent progress in dissecting molecular recognition by DNA polymerases with non-native substrates. Curr Opin Chem Biol 2017; 41:43-49. [PMID: 29096323 DOI: 10.1016/j.cbpa.2017.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/05/2017] [Indexed: 11/22/2022]
Abstract
DNA polymerases must discriminate the correct Watson-Crick base pair-forming deoxynucleoside triphosphate (dNTP) substrate from three other dNTPs and additional triphosphates found in the cell. The rarity of misincorporations in vivo, then, belies the high tolerance for dNTP analogs observed in vitro. Advances over the last 10 years in single-molecule fluorescence and electronic detection of dNTP analog incorporation enable exploration of the mechanism and limits to base discrimination by DNA polymerases. Such studies reveal transient motions of DNA polymerase during substrate recognition and mutagenesis in the context of erroneous dNTP incorporation that can lead to evolution and genetic disease. Further improvements in time resolution and noise reduction of single-molecule studies will uncover deeper mechanistic understanding of this critical, first step in evolution.
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Morris SE, Feldman AW, Romesberg FE. Synthetic Biology Parts for the Storage of Increased Genetic Information in Cells. ACS Synth Biol 2017; 6:1834-1840. [PMID: 28654252 DOI: 10.1021/acssynbio.7b00115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To bestow cells with novel forms and functions, the goal of synthetic biology, we have developed the unnatural nucleoside triphosphates dNaMTP and dTPT3TP, which form an unnatural base pair (UBP) and expand the genetic alphabet. While the UBP may be retained in the DNA of a living cell, its retention is sequence-dependent. We now report a steady-state kinetic characterization of the rate with which the Klenow fragment of E. coli DNA polymerase I synthesizes the UBP and its mispairs in a variety of sequence contexts. Correct UBP synthesis is as efficient as for a natural base pair, except in one sequence context, and in vitro performance is correlated with in vivo performance. The data elucidate the determinants of efficient UBP synthesis, show that the dNaM-dTPT3 UBP is the first generally recognized natural-like base pair, and importantly, demonstrate that dNaMTP and dTPT3TP are well optimized and standardized parts for the expansion of the genetic alphabet.
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Affiliation(s)
- Sydney E. Morris
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Aaron W. Feldman
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Floyd E. Romesberg
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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35
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Kimoto M, Hirao I. Unique Thermal Stability of Unnatural Hydrophobic Ds Bases in Double-Stranded DNAs. ACS Synth Biol 2017; 6:1944-1951. [PMID: 28704034 DOI: 10.1021/acssynbio.7b00165] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Genetic alphabet expansion technology, the introduction of unnatural bases or base pairs into replicable DNA, has rapidly advanced as a new synthetic biology area. A hydrophobic unnatural base pair between 7-(2-thienyl)imidazo[4,5-b]pyridine (Ds) and 2-nitro-4-propynylpyrrole (Px) exhibited high fidelity as a third base pair in PCR. SELEX methods using the Ds-Px pair enabled high-affinity DNA aptamer generation, and introducing a few Ds bases into DNA aptamers extremely augmented their affinities and selectivities to target proteins. Here, to further scrutinize the functions of this highly hydrophobic Ds base, the thermal stabilities of double-stranded DNAs (dsDNA) containing a noncognate Ds-Ds or G-Ds pair were examined. The thermal stability of the Ds-Ds self-pair was as high as that of the natural G-C pair, and apart from the generally higher stability of the G-C pair than that of the A-T pair, most of the 5'-pyrimidine-Ds-purine-3' sequences, such as CDsA and TDsA, exhibited higher stability than the 5'-purine-Ds-pyrimidine-3' sequences, such as GDsC and ADsC, in dsDNAs. This trait enabled the GC-content-independent control of the thermal stability of the designed dsDNA fragments. The melting temperatures of dsDNA fragments containing the Ds-Ds pair can be predicted from the nearest-neighbor parameters including the Ds base. In addition, the noncognate G-Ds pair can efficiently distinguish its neighboring cognate natural base pairs from noncognate pairs. We demonstrated that real-time PCR using primers containing Ds accurately detected a single-nucleotide mismatch in target DNAs. These unique properties of the Ds base that affect the stabilities of the neighboring base pairs could impart new functions to DNA molecules and technologies.
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Affiliation(s)
- Michiko Kimoto
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #09-01, Singapore 138669
- RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
| | - Ichiro Hirao
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #09-01, Singapore 138669
- RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan
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36
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Lee KH, Hamashima K, Kimoto M, Hirao I. Genetic alphabet expansion biotechnology by creating unnatural base pairs. Curr Opin Biotechnol 2017; 51:8-15. [PMID: 29049900 DOI: 10.1016/j.copbio.2017.09.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 09/19/2017] [Indexed: 12/17/2022]
Abstract
Recent studies have made it possible to expand the genetic alphabet of DNA, which is originally composed of the four-letter alphabet with A-T and G-C pairs, by introducing an unnatural base pair (UBP). Several types of UBPs function as a third base pair in replication, transcription, and/or translation. Through the UBP formation, new components with different physicochemical properties from those of the natural ones can be introduced into nucleic acids and proteins site-specifically, providing their increased functionalities. Here, we describe the genetic alphabet expansion technology by focusing on three types of UBPs, which were recently applied to the creations of DNA aptamers that bind to proteins and cells and semi-synthetic organisms containing DNAs with a six-letter alphabet.
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Affiliation(s)
- Kyung Hyun Lee
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #09-01, Singapore 138669, Singapore
| | - Kiyofumi Hamashima
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #09-01, Singapore 138669, Singapore
| | - Michiko Kimoto
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #09-01, Singapore 138669, Singapore
| | - Ichiro Hirao
- Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, #09-01, Singapore 138669, Singapore.
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37
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Feldman AW, Romesberg FE. In Vivo Structure-Activity Relationships and Optimization of an Unnatural Base Pair for Replication in a Semi-Synthetic Organism. J Am Chem Soc 2017; 139:11427-11433. [PMID: 28796508 DOI: 10.1021/jacs.7b03540] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In an effort to expand the genetic alphabet and create semi-synthetic organisms (SSOs) that store and retrieve increased information, we have developed the unnatural base pairs (UBPs) dNaM and d5SICS or dTPT3 (dNaM-d5SICS and dNaM-dTPT3). The UBPs form based on hydrophobic and packing forces, as opposed to complementary hydrogen bonding, and while they are both retained within the in vivo environment of an Escherichia coli SSO, their development was based on structure-activity relationship (SAR) data generated in vitro. To address the likely possibility of different requirements of the in vivo environment, we screened 135 candidate UBPs for optimal performance in the SSO. Interestingly, we find that in vivo SARs differ from those collected in vitro, and most importantly, we identify four UBPs whose retention in the DNA of the SSO is higher than that of dNaM-dTPT3, which was previously the most promising UBP identified. The identification of these four UBPs further demonstrates that when optimized, hydrophobic and packing forces may be used to replace the complementary hydrogen bonding used by natural pairs and represents a significant advance in our continuing efforts to develop SSOs that store and retrieve more information than natural organisms.
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Affiliation(s)
- Aaron W Feldman
- Department of Chemistry, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Floyd E Romesberg
- Department of Chemistry, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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38
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Betz K, Kimoto M, Diederichs K, Hirao I, Marx A. Strukturelle Studie zur Erweiterung des genetischen Codes durch ein artifizielles Nucleobasenpaar. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704190] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Karin Betz
- Fachbereiche Chemie und Biologie und Konstanz Research School Chemical Biology Universität Konstanz Universitätsstraße 10 78464 Konstanz Deutschland
| | - Michiko Kimoto
- Institute of Bioengineering and Nanotechnology 31 Biopolis Way, The Nanos, #09-01 138669 Singapore Singapur
- RIKEN Center for Life Science Technologies 1–7 22 Suehiro-cho, Tsurumi-ku, Yokohama Kanagawa 230-0045 Japan
| | - Kay Diederichs
- Fachbereiche Chemie und Biologie und Konstanz Research School Chemical Biology Universität Konstanz Universitätsstraße 10 78464 Konstanz Deutschland
| | - Ichiro Hirao
- Institute of Bioengineering and Nanotechnology 31 Biopolis Way, The Nanos, #09-01 138669 Singapore Singapur
- RIKEN Center for Life Science Technologies 1–7 22 Suehiro-cho, Tsurumi-ku, Yokohama Kanagawa 230-0045 Japan
| | - Andreas Marx
- Fachbereiche Chemie und Biologie und Konstanz Research School Chemical Biology Universität Konstanz Universitätsstraße 10 78464 Konstanz Deutschland
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39
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Betz K, Kimoto M, Diederichs K, Hirao I, Marx A. Structural Basis for Expansion of the Genetic Alphabet with an Artificial Nucleobase Pair. Angew Chem Int Ed Engl 2017; 56:12000-12003. [DOI: 10.1002/anie.201704190] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Indexed: 01/09/2023]
Affiliation(s)
- Karin Betz
- Departments of Chemistry and Biology and Konstanz Research School Chemical Biology Universität Konstanz Universitätsstrasse 10 78464 Konstanz Germany
| | - Michiko Kimoto
- Institute of Bioengineering and Nanotechnology 31 Biopolis Way, The Nanos, #09-01 138669 Singapore Singapore
- RIKEN Center for Life Science Technologies 1–7 22 Suehiro-cho, Tsurumi-ku, Yokohama Kanagawa 230-0045 Japan
| | - Kay Diederichs
- Departments of Chemistry and Biology and Konstanz Research School Chemical Biology Universität Konstanz Universitätsstrasse 10 78464 Konstanz Germany
| | - Ichiro Hirao
- Institute of Bioengineering and Nanotechnology 31 Biopolis Way, The Nanos, #09-01 138669 Singapore Singapore
- RIKEN Center for Life Science Technologies 1–7 22 Suehiro-cho, Tsurumi-ku, Yokohama Kanagawa 230-0045 Japan
| | - Andreas Marx
- Departments of Chemistry and Biology and Konstanz Research School Chemical Biology Universität Konstanz Universitätsstrasse 10 78464 Konstanz Germany
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40
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Rekik N, Alshammari MF. Electrical anharmonicity and dampings contributions to Cl- H→ stretching band in gaseous (CH 3 ) 2 O…HCl complex: Quantum dynamic study and prediction of the temperature effects. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.04.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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41
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Zhang F, Liang Y, Li J, Gao F, Liu H, Zhao Y. A Concise Synthesis of Novel Aryl Pyrimidine C
-Nucleoside Analogs from Sugar Alkynes. ASIAN J ORG CHEM 2017. [DOI: 10.1002/ajoc.201600583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Fuyi Zhang
- The College of Chemistry and Molecular Engineering; The Key Laboratory of Chemical Biology and Organic Chemistry; Zhengzhou University; Zhengzhou 450001 China
| | - Yan Liang
- The College of Chemistry and Molecular Engineering; The Key Laboratory of Chemical Biology and Organic Chemistry; Zhengzhou University; Zhengzhou 450001 China
| | - Jing Li
- The College of Chemistry and Molecular Engineering; The Key Laboratory of Chemical Biology and Organic Chemistry; Zhengzhou University; Zhengzhou 450001 China
| | - Fei Gao
- The College of Chemistry and Molecular Engineering; The Key Laboratory of Chemical Biology and Organic Chemistry; Zhengzhou University; Zhengzhou 450001 China
| | - Hong Liu
- The College of Chemistry and Molecular Engineering; The Key Laboratory of Chemical Biology and Organic Chemistry; Zhengzhou University; Zhengzhou 450001 China
| | - Yufen Zhao
- The College of Chemistry and Molecular Engineering; The Key Laboratory of Chemical Biology and Organic Chemistry; Zhengzhou University; Zhengzhou 450001 China
- College of Chemistry and Chemical Engineering; Xiamen University; Xiamen 361005 China
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42
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Molt RW, Georgiadis MM, Richards NG. Consecutive non-natural PZ nucleobase pairs in DNA impact helical structure as seen in 50 μs molecular dynamics simulations. Nucleic Acids Res 2017; 45:3643-3653. [PMID: 28334863 PMCID: PMC5397145 DOI: 10.1093/nar/gkx144] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 02/12/2017] [Accepted: 02/24/2017] [Indexed: 12/25/2022] Open
Abstract
Z Little is known about the influence of multiple consecutive 'non-standard' ( , 6-amino-5-nitro-2(1H)-pyridone, and , 2-amino-imidazo[1,2-a]-1,3,5-triazin-4(8H)-one) nucleobase pairs on the structural parameters of duplex DNA. nucleobase pairs follow standard rules for Watson-Crick base pairing but have rearranged hydrogen bonding donor and acceptor groups. Using the X-ray crystal structure as a starting point, we have modeled the motions of a DNA duplex built from a self-complementary oligonucleotide (5΄-CTTATPPPZZZATAAG-3΄) in water over a period of 50 μs and calculated DNA local parameters, step parameters, helix parameters, and major/minor groove widths to examine how the presence of multiple, consecutive nucleobase pairs might impact helical structure. In these simulations, the -containing DNA duplex exhibits a significantly wider major groove and greater average values of stagger, slide, rise, twist and h-rise than observed for a 'control' oligonucleotide in which nucleobase pairs are replaced by . The molecular origins of these structural changes are likely associated with at least two differences between and . First, the electrostatic properties of differ from in terms of density distribution and dipole moment. Second, differences are seen in the base stacking of pairs in dinucleotide steps, arising from energetically favorable stacking of the nitro group in with π-electrons of the adjacent base.
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Affiliation(s)
- Robert W. Molt
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- School of Chemistry, Cardiff University, Cardiff, CF10 3AT, UK
- Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA
- ENSCO, Inc., 4849 North Wickham Road, Melbourne, FL 32940, USA
| | - Millie M. Georgiadis
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Department of Chemistry and Chemical Biology, Indiana University Purdue University Indianapolis, Indianapolis, IN 46202, USA
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43
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Feldman AW, Dien VT, Romesberg FE. Chemical Stabilization of Unnatural Nucleotide Triphosphates for the in Vivo Expansion of the Genetic Alphabet. J Am Chem Soc 2017; 139:2464-2467. [PMID: 28170246 DOI: 10.1021/jacs.6b12731] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We have developed an unnatural base pair (UBP) and a semisynthetic organism (SSO) that imports the constituent unnatural nucleoside triphosphates and uses them to replicate DNA containing the UBP. However, propagation of the UBP is at least in part limited by the stability of the unnatural triphosphates, which are degraded by cellular and secreted phosphatases. To circumvent this problem, we now report the synthesis and evaluation of unnatural triphosphates with their β,γ-bridging oxygen replaced with a difluoromethylene moiety, yielding dNaMTPCF2 and dTPT3TPCF2. We find that although dNaMTPCF2 cannot support in vivo replication, likely due to poor polymerase recognition, dTPT3TPCF2 can, and moreover, its increased stability can contribute to increased UBP retention. The data demonstrate the promise of this chemical approach to SSO optimization, and suggest that other modifications should be sought that confer phosphatase resistance without interfering with polymerase recognition.
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Affiliation(s)
- Aaron W Feldman
- Department of Chemistry, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Vivian T Dien
- Department of Chemistry, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Floyd E Romesberg
- Department of Chemistry, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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44
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A semisynthetic organism engineered for the stable expansion of the genetic alphabet. Proc Natl Acad Sci U S A 2017; 114:1317-1322. [PMID: 28115716 DOI: 10.1073/pnas.1616443114] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
All natural organisms store genetic information in a four-letter, two-base-pair genetic alphabet. The expansion of the genetic alphabet with two synthetic unnatural nucleotides that selectively pair to form an unnatural base pair (UBP) would increase the information storage potential of DNA, and semisynthetic organisms (SSOs) that stably harbor this expanded alphabet would thereby have the potential to store and retrieve increased information. Toward this goal, we previously reported that Escherichia coli grown in the presence of the unnatural nucleoside triphosphates dNaMTP and d5SICSTP, and provided with the means to import them via expression of a plasmid-borne nucleoside triphosphate transporter, replicates DNA containing a single dNaM-d5SICS UBP. Although this represented an important proof-of-concept, the nascent SSO grew poorly and, more problematically, required growth under controlled conditions and even then was unable to indefinitely store the unnatural information, which is clearly a prerequisite for true semisynthetic life. Here, to fortify and vivify the nascent SSO, we engineered the transporter, used a more chemically optimized UBP, and harnessed the power of the bacterial immune response by using Cas9 to eliminate DNA that had lost the UBP. The optimized SSO grows robustly, constitutively imports the unnatural triphosphates, and is able to indefinitely retain multiple UBPs in virtually any sequence context. This SSO is thus a form of life that can stably store genetic information using a six-letter, three-base-pair alphabet.
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45
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Hottin A, Betz K, Diederichs K, Marx A. Structural Basis for the KlenTaq DNA Polymerase Catalysed Incorporation of Alkene- versus Alkyne-Modified Nucleotides. Chemistry 2017; 23:2109-2118. [PMID: 27901305 DOI: 10.1002/chem.201604515] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Indexed: 01/12/2023]
Abstract
Efficient incorporation of modified nucleotides by DNA polymerases is essential for many cutting-edge biomolecular technologies. The present study compares the acceptance of either alkene- or alkyne-modified nucleotides by KlenTaq DNA polymerase and provides structural insights into how 7-deaza-adenosine and deoxyuridine with attached alkene-modifications are incorporated into the growing DNA strand. Thereby, we identified modified nucleotides that prove to be superior substrates for KlenTaq DNA polymerase compared with their natural analogues. The knowledge can be used to guide future design of functionalized nucleotide building blocks.
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Affiliation(s)
- Audrey Hottin
- Department of Chemistry and Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
| | - Karin Betz
- Department of Chemistry and Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
| | - Kay Diederichs
- Department of Chemistry and Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
| | - Andreas Marx
- Department of Chemistry and Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany
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Ashwood B, Pollum M, Crespo-Hernández CE. Can a Six-Letter Alphabet Increase the Likelihood of Photochemical Assault to the Genetic Code? Chemistry 2016; 22:16648-16656. [PMID: 27723147 DOI: 10.1002/chem.201602160] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Indexed: 12/21/2022]
Abstract
In 2014, two unnatural nucleosides, d5SICS and dNaM, were shown to selectively base pair and replicate with high fidelity in a modified strain of E. coli, thus effectively expanding its genetic alphabet from four to six letters. More recently, a significant reduction in cell proliferation was reported in cells cultured with d5SICS, and putatively with dNaM, upon exposure to brief periods of near-visible radiation. The photosensitizing properties of the lowest-energy excited triplet state of both d5SICS and dNaM were implicated in their cytotoxicity. Importantly, however, the excited-state mechanisms by which near-visible excitation populates the triplet states of d5SICS and dNaM are currently unknown. In this study, steady-state and time-resolved spectroscopies are combined with quantum-chemical calculations in order to reveal the excited-state relaxation mechanisms leading to efficient population of the triplet states in these unnatural nucleosides in solution. It is shown that excitation of d5SICS or dNaM with near-visible light leads overwhelmingly to ultrafast population of their triplet states on the femtosecond time scale. The results presented in this work lend strong support to the proposal that photoexcitation of these unnatural nucleosides can accelerate oxidatively generated damage to DNA and other biomolecules within the cellular environment.
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Affiliation(s)
- Brennan Ashwood
- Department of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, Cleveland, Ohio, 44106, USA
| | - Marvin Pollum
- Department of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, Cleveland, Ohio, 44106, USA
| | - Carlos E Crespo-Hernández
- Department of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, Cleveland, Ohio, 44106, USA.
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47
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Probst M, Aeschimann W, Chau TTH, Langenegger SM, Stocker A, Häner R. Structural insight into DNA-assembled oligochromophores: crystallographic analysis of pyrene- and phenanthrene-modified DNA in complex with BpuJI endonuclease. Nucleic Acids Res 2016; 44:7079-89. [PMID: 27422870 PMCID: PMC5009758 DOI: 10.1093/nar/gkw644] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 07/07/2016] [Accepted: 07/08/2016] [Indexed: 01/13/2023] Open
Abstract
The use of the DNA duplex as a supramolecular scaffold is an established approach for the assembly of chromophore aggregates. In the absence of detailed structural insight, the characterization of thus assembled oligochromophores is, today, largely based on solution-phase spectroscopy. Here, we describe the crystal structures of three DNA-organized chromophore aggregates. DNA hybrids containing non-nucleosidic pyrene and phenanthrene building blocks were co-crystallized with the recently described binding domain of the restriction enzyme BpuJI. Crystal structures of these complexes were determined at 2.7, 1.9 and 1.6 Å resolutions. The structures reveal aromatic stacking interactions between pyrene and/or phenanthrene units within the framework of the B-DNA duplex. In hybrids containing a single modification in each DNA strand near the end of the duplex, the two polyaromatic hydrocarbons are engaged in a face-to-face stacking orientation. Due to crystal packing and steric effects, the terminal GC base pair is disrupted in all three crystal structures, which results in a non-perfect stacking arrangement of the aromatic chromophores in two of the structures. In a hybrid containing a total of three pyrenes, crystal lattice induced end-to-end stacking of individual DNA duplexes leads to the formation of an extended aromatic π-stack containing four co-axially arranged pyrenes. The aromatic planes of the stacked pyrenes are oriented in a parallel way. The study demonstrates the value of co-crystallization of chemically modified DNA with the recombinant binding domain of the restriction enzyme BpuJI for obtaining detailed structural insight into DNA-assembled oligochromophores.
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Affiliation(s)
- Markus Probst
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Walter Aeschimann
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Thi T H Chau
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Simon M Langenegger
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Achim Stocker
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
| | - Robert Häner
- Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
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48
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Bosmans RPG, Briels JM, Milroy LG, de Greef TFA, Merkx M, Brunsveld L. Supramolecular Control over Split-Luciferase Complementation. Angew Chem Int Ed Engl 2016; 55:8899-903. [PMID: 27356091 PMCID: PMC5113697 DOI: 10.1002/anie.201602807] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/17/2016] [Indexed: 01/18/2023]
Abstract
Supramolecular split-enzyme complementation restores enzymatic activity and allows for on-off switching. Split-luciferase fragment pairs were provided with an N-terminal FGG sequence and screened for complementation through host-guest binding to cucurbit[8]uril (Q8). Split-luciferase heterocomplex formation was induced in a Q8 concentration dependent manner, resulting in a 20-fold upregulation of luciferase activity. Supramolecular split-luciferase complementation was fully reversible, as revealed by using two types of Q8 inhibitors. Competition studies with the weak-binding FGG peptide revealed a 300-fold enhanced stability for the formation of the ternary heterocomplex compared to binding of two of the same fragments to Q8. Stochiometric binding by the potent inhibitor memantine could be used for repeated cycling of luciferase activation and deactivation in conjunction with Q8, providing a versatile module for in vitro supramolecular signaling networks.
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Affiliation(s)
- Ralph P G Bosmans
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612, AZ, Eindhoven, The Netherlands
| | - Jeroen M Briels
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612, AZ, Eindhoven, The Netherlands
| | - Lech-Gustav Milroy
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612, AZ, Eindhoven, The Netherlands
| | - Tom F A de Greef
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612, AZ, Eindhoven, The Netherlands
| | - Maarten Merkx
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612, AZ, Eindhoven, The Netherlands
| | - Luc Brunsveld
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612, AZ, Eindhoven, The Netherlands.
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49
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Bosmans RPG, Briels JM, Milroy LG, de Greef TFA, Merkx M, Brunsveld L. Supramolecular Control over Split-Luciferase Complementation. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201602807] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Ralph P. G. Bosmans
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering; Eindhoven University of Technology; Den Dolech 2 5612 AZ Eindhoven The Netherlands
| | - Jeroen M. Briels
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering; Eindhoven University of Technology; Den Dolech 2 5612 AZ Eindhoven The Netherlands
| | - Lech-Gustav Milroy
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering; Eindhoven University of Technology; Den Dolech 2 5612 AZ Eindhoven The Netherlands
| | - Tom F. A. de Greef
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering; Eindhoven University of Technology; Den Dolech 2 5612 AZ Eindhoven The Netherlands
| | - Maarten Merkx
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering; Eindhoven University of Technology; Den Dolech 2 5612 AZ Eindhoven The Netherlands
| | - Luc Brunsveld
- Laboratory of Chemical Biology and Institute of Complex Molecular Systems, Department of Biomedical Engineering; Eindhoven University of Technology; Den Dolech 2 5612 AZ Eindhoven The Netherlands
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50
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Domnick C, Eggert F, Kath-Schorr S. Site-specific enzymatic introduction of a norbornene modified unnatural base into RNA and application in post-transcriptional labeling. Chem Commun (Camb) 2016; 51:8253-6. [PMID: 25874847 DOI: 10.1039/c5cc01765c] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Inverse electron demand Diels-Alder cycloadditions have proven to be extremely useful for mild and additive-free orthogonal labeling of biomolecules, amongst others, for RNA labeling in vitro and in a cellular context. Here we present a method for site-specific introduction of an alkene modification into RNA via T7 in vitro transcription. For this, an unnatural, hydrophobic base pairing system developed by Romesberg and coworkers was modified introducing one or two norbornene moieties at predefined positions into RNA oligonucleotides in an in vitro transcription reaction. This allows post-transcriptional functionalization of these RNA molecules with tetrazine derivatives containing for instance fluorophores or biotin.
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Affiliation(s)
- Christof Domnick
- Life and Medical Sciences Institute, University of Bonn, Bonn, Germany.
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