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Pallan PS, Lybrand TP, Rozners E, Abramov M, Schepers G, Eremeeva E, Herdewijn P, Egli M. Conformational Morphing by a DNA Analogue Featuring 7-Deazapurines and 5-Halogenpyrimidines and the Origins of Adenine-Tract Geometry. Biochemistry 2023; 62:2854-2867. [PMID: 37694722 PMCID: PMC11062489 DOI: 10.1021/acs.biochem.3c00327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Several efforts are currently directed at the creation and cellular implementation of alternative genetic systems composed of pairing components that are orthogonal to the natural dA/dT and dG/dC base pairs. In an alternative approach, Watson-Crick-type pairing is conserved, but one or all of the four letters of the A, C, G, and T alphabet are substituted by modified components. Thus, all four nucleobases were altered to create halogenated deazanucleic acid (DZA): dA was replaced by 7-deaza-2'-deoxyadenosine (dzA), dG by 7-deaza-2'-deoxyguanosine (dzG), dC by 5-fluoro-2'-deoxycytidine (FdC), and dT by 5-chloro-2'-deoxyuridine (CldU). This base-pairing system was previously shown to retain function in Escherichia coli. Here, we analyze the stability, hydration, structure, and dynamics of a DZA Dickerson-Drew Dodecamer (DDD) of sequence 5'-FdC-dzG-FdC-dzG-dzA-dzA-CldU-CldU-FdC-dzG-FdC-dzG-3'. Contrary to similar stabilities of DDD and DZA-DDD, osmotic stressing revealed a dramatic loss of hydration for the DZA-DDD relative to that for the DDD. The parent DDD 5'-d(CGCGAATTCGCG)-3' features an A-tract, a run of adenosines uninterrupted by a TpA step, and exhibits a hallmark narrow minor groove. Crystal structures─in the presence of RNase H─and MD simulations show increased conformational plasticity ("morphing") of DZA-DDD relative to that of the DDD. The narrow dzA-tract minor groove in one structure widens to resemble that in canonical B-DNA in a second structure. These changes reflect an indirect consequence of altered DZA major groove electrostatics (less negatively polarized compared to that in DNA) and hydration (reduced compared to that in DNA). Therefore, chemical modifications outside the minor groove that lead to collapse of major groove electrostatics and hydration can modulate A-tract geometry.
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Affiliation(s)
- Pradeep S Pallan
- School of Medicine, Department of Biochemistry, and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Terry P Lybrand
- Department of Chemistry and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Eriks Rozners
- Department of Chemistry, Binghamton University, Binghamton, New York 13902, United States
| | - Mikhail Abramov
- Laboratory of Medicinal Chemistry, KU Leuven, Rega Institute for Medical Research, Minderbroedersstraat 10, Leuven 3000, Belgium
| | - Guy Schepers
- Laboratory of Medicinal Chemistry, KU Leuven, Rega Institute for Medical Research, Minderbroedersstraat 10, Leuven 3000, Belgium
| | - Elena Eremeeva
- Laboratory of Medicinal Chemistry, KU Leuven, Rega Institute for Medical Research, Minderbroedersstraat 10, Leuven 3000, Belgium
| | - Piet Herdewijn
- Laboratory of Medicinal Chemistry, KU Leuven, Rega Institute for Medical Research, Minderbroedersstraat 10, Leuven 3000, Belgium
| | - Martin Egli
- School of Medicine, Department of Biochemistry, and Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
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Yang H, Eremeeva E, Abramov M, Jacquemyn M, Groaz E, Daelemans D, Herdewijn P. CRISPR-Cas9 recognition of enzymatically synthesized base-modified nucleic acids. Nucleic Acids Res 2023; 51:1501-1511. [PMID: 36611237 PMCID: PMC9976875 DOI: 10.1093/nar/gkac1147] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/09/2022] [Accepted: 11/17/2022] [Indexed: 01/09/2023] Open
Abstract
An enzymatic method has been successfully established enabling the generation of partially base-modified RNA (previously named RZA) constructs, in which all G residues were replaced by isomorphic fluorescent thienoguanosine (thG) analogs, as well as fully modified RZA featuring thG, 5-bromocytosine, 7-deazaadenine and 5-chlorouracil. The transcriptional efficiency of emissive fully modified RZA was found to benefit from the use of various T7 RNA polymerase variants. Moreover, dthG could be incorporated into PCR products by Taq DNA polymerase together with the other three base-modified nucleotides. Notably, the obtained RNA products containing thG as well as thG together with 5-bromocytosine could function as effectively as natural sgRNAs in an in vitro CRISPR-Cas9 cleavage assay. N1-Methylpseudouridine was also demonstrated to be a faithful non-canonical substitute of uridine to direct Cas9 nuclease cleavage when incorporated in sgRNA. The Cas9 inactivation by 7-deazapurines indicated the importance of the 7-nitrogen atom of purines in both sgRNA and PAM site for achieving efficient Cas9 cleavage. Additional aspects of this study are discussed in relation to the significance of sgRNA-protein and PAM--protein interactions that were not highlighted by the Cas9-sgRNA-DNA complex crystal structure. These findings could expand the impact and therapeutic value of CRISPR-Cas9 and other RNA-based technologies.
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Affiliation(s)
- Hui Yang
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49, Box 1041, 3000 Leuven, Belgium
| | - Elena Eremeeva
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49, Box 1041, 3000 Leuven, Belgium.,Queensland University of Technology, Centre for Agriculture and the Bioeconomy, Molecular Engineering Group, George Street 2, 4000 Brisbane, Queensland, Australia
| | - Mikhail Abramov
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49, Box 1041, 3000 Leuven, Belgium
| | - Maarten Jacquemyn
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, Box 1043, 3000 Leuven, Belgium
| | - Elisabetta Groaz
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49, Box 1041, 3000 Leuven, Belgium.,University of Padova, Department of Pharmaceutical and Pharmacological Sciences, Via Marzolo 5, 35131 Padova, Italy
| | - Dirk Daelemans
- KU Leuven, Department of Microbiology, Immunology and Transplantation, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, Herestraat 49, Box 1043, 3000 Leuven, Belgium
| | - Piet Herdewijn
- KU Leuven, Department of Pharmaceutical and Pharmacological Sciences, Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49, Box 1041, 3000 Leuven, Belgium
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Ondruš M, Sýkorová V, Hocek M. Traceless enzymatic synthesis of monodispersed hypermodified oligodeoxyribonucleotide polymers from RNA templates. Chem Commun (Camb) 2022; 58:11248-11251. [PMID: 36124894 DOI: 10.1039/d2cc03588j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have developed a new alternative for enzymatic synthesis of single-stranded hypermodified oligodeoxyribonucleotides displaying four different hydrophobic groups based on reverse transcription from RNA templates catalyzed by DNA polymerases using a set of base-modified dNTPs followed by digestion of RNA by RNases. Using mixed oligodeoxyribonucleotide primers containing a ribonucleotide at the 3'-end, RNase AT1 simultaneously digested the template and cleaved off the primer to release a fully modified oligonucleotide that can be further 3'-labelled with a fluorescent nucleotide using TdT. The resulting hypermodified oligonucleotides could find applications in selection of aptamers or other functional macromolecules.
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Affiliation(s)
- Marek Ondruš
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16000 Prague 6, Czech Republic. .,Dept. of Organic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, CZ-12843, Prague 2, Czech Republic
| | - Veronika Sýkorová
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16000 Prague 6, Czech Republic.
| | - Michal Hocek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nam. 2, 16000 Prague 6, Czech Republic. .,Dept. of Organic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 8, CZ-12843, Prague 2, Czech Republic
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Nguyen H, Abramov M, Rozenski J, Eremeeva E, Herdewijn P. In vivo assembly and expression of DNA containing non-canonical bases in the yeast Saccharomyces cerevisiae. Chembiochem 2022; 23:e202200060. [PMID: 35322918 DOI: 10.1002/cbic.202200060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/16/2022] [Indexed: 11/10/2022]
Abstract
Chemically modified nucleic acids are of utmost interest in synthetic biology to create a regulable and sophisticated synthetic system with tailor-made properties. Implanting chemically modified nucleic acids in microorganisms might serve biotechnological applications, while using them in human cells might lead to new advanced medicines. Previously, we reported that a fully modified DNA sequence (called DZA) composed of the four base-modified nucleotides - 7-deaza-adenine, 5-chlorouracil, 7-deaza-guanine and 5-fluorocytosine - could function as a genetic template in prokaryotic cells, Escherichia coli . Here, we report the synthesis of long, partially or fully modified DZA fragments that encode the yeast-enhanced red fluorescence protein (yEmRFP). The DZA sequences were directly introduced in the genome of the eukaryotic cells, Saccharomyces cerevisiae , via the yeast natural homologous recombination. The simple and straightforward DZA cloning strategy reported herein might be of interest to scientists working in the field of xenobiology in yeast.
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Affiliation(s)
- Hoai Nguyen
- KU Leuven Rega Institute for Medical Research.: Katholieke Universiteit Leuven Rega Institute for Medical Research, Medicinal Chemistry, BELGIUM
| | - Mikhail Abramov
- KU Leuven Rega Institute for Medical Research: Katholieke Universiteit Leuven Rega Institute for Medical Research, Medicinal Chemistry, BELGIUM
| | - Jef Rozenski
- KU Leuven Rega Institute for Medical Research.: Katholieke Universiteit Leuven Rega Institute for Medical Research, Medicinal Chemistry, BELGIUM
| | - Elena Eremeeva
- KU Leuven Rega Institute for Medical Research.: Katholieke Universiteit Leuven Rega Institute for Medical Research, Medicinal Chemistry, BELGIUM
| | - Piet Herdewijn
- Rega Institute for Medical Research, Medicinal Chemistry, Herestraat 49 - box 1030, 3000, Leuven, BELGIUM
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