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Petropoulos V, Uboldi L, Maiuri M, Cerullo G, Martinez-Fernandez L, Balanikas E, Markovitsi D. Effect of the DNA Polarity on the Relaxation of Its Electronic Excited States. J Phys Chem Lett 2023; 14:10219-10224. [PMID: 37931204 DOI: 10.1021/acs.jpclett.3c02580] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023]
Abstract
The DNA polarity, i.e., the order in which nucleobases are connected together via the phosphodiester backbone, is crucial for several biological processes. But, so far, there has not been experimental evidence regarding its effect on the relaxation of DNA electronic excited states. Here we examine this aspect for two dinucleotides containing adenine and guanine: 5'-dApdG-3' and 5'-dGpdA-3' in water. We used two different femtosecond transient absorption setups: one providing high temporal resolution and broad spectral coverage (330-650 nm) between 30 fs and 50 ps, and the other recording decays at selected wavelengths until 1.2 ns. The transient absorption spectra corresponding to the minima in the potential energy surface of the first excited state were computed by quantum chemistry methods. Our results show that the excited charge transfer state in 5'-dGpdA-3' is formed with a ∼75% higher quantum yield and exhibits slower decay (170 ± 10 ps vs 112 ± 12 ps) compared to 5'-dApdG-3'.
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Affiliation(s)
- Vasilis Petropoulos
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Lorenzo Uboldi
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Margherita Maiuri
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Giulio Cerullo
- IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
| | - Lara Martinez-Fernandez
- Departamento de Química, Facultad de Ciencias and Institute for Advanced Research in Chemical Sciences (IADCHEM), Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco, 28049 Madrid, Spain
| | - Evangelos Balanikas
- Department of Physical Chemistry, University of Geneva, CH-1211 Geneva-4, Switzerland
| | - Dimitra Markovitsi
- Université Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000, 91405 Orsay, France
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Luo Y, Granzhan A, Marquevielle J, Cucchiarini A, Lacroix L, Amrane S, Verga D, Mergny JL. Guidelines for G-quadruplexes: I. In vitro characterization. Biochimie 2023; 214:5-23. [PMID: 36596406 DOI: 10.1016/j.biochi.2022.12.019] [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: 10/29/2022] [Revised: 12/19/2022] [Accepted: 12/28/2022] [Indexed: 01/02/2023]
Abstract
Besides the well-known DNA double-helix, non-canonical nucleic acid structures regulate crucial biological activities. Among these oddities, guanine-rich DNA sequences can form unusual four-stranded secondary structures called G-quadruplexes (G4s). G4-prone sequences have been found in the genomes of most species, and G4s play important roles in essential processes such as transcription, replication, genome integrity and epigenetic regulation. Here, we present a short overview of G-quadruplexes followed by a detailed description of the biophysical and biochemical methods used to characterize G4s in vitro. The principles, experimental details and possible shortcomings of each method are discussed to provide a comprehensive view of the techniques used to study these structures. We aim to provide a set of guidelines for standardizing research on G-quadruplexes; these guidelines are not meant to be a dogmatic set of rules, but should rather provide useful information on the methods currently used to study these fascinating motifs.
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Affiliation(s)
- Yu Luo
- Laboratoire D'Optique et Biosciences, Ecole Polytechnique, CNRS, Inserm, Institut Polytechnique de Paris, 91120, Palaiseau, France; CNRS UMR9187, INSERM U1196, Université Paris-Saclay, F-91405, Orsay, France
| | - Anton Granzhan
- CNRS UMR9187, INSERM U1196, Université Paris-Saclay, F-91405, Orsay, France; CNRS UMR9187, INSERM U1196, Institut Curie, PSL Research University, F-91405, Orsay, France
| | - Julien Marquevielle
- Université de Bordeaux, ARNA Laboratory, INSERM U1212, CNRS UMR 5320, IECB, 33076, Bordeaux, France
| | - Anne Cucchiarini
- Laboratoire D'Optique et Biosciences, Ecole Polytechnique, CNRS, Inserm, Institut Polytechnique de Paris, 91120, Palaiseau, France
| | - Laurent Lacroix
- Institut de Biologie de L'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Samir Amrane
- Université de Bordeaux, ARNA Laboratory, INSERM U1212, CNRS UMR 5320, IECB, 33076, Bordeaux, France
| | - Daniela Verga
- CNRS UMR9187, INSERM U1196, Université Paris-Saclay, F-91405, Orsay, France; CNRS UMR9187, INSERM U1196, Institut Curie, PSL Research University, F-91405, Orsay, France.
| | - Jean-Louis Mergny
- Laboratoire D'Optique et Biosciences, Ecole Polytechnique, CNRS, Inserm, Institut Polytechnique de Paris, 91120, Palaiseau, France; Institute of Biophysics of the Czech Academy of Sciences, Brno, Czech Republic.
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Khan S, Singh A, Nain N, Kukreti S. Alkali cation-mediated topology displayed by an exonic G-rich sequence of TRPA1 gene. J Biomol Struct Dyn 2023; 41:9997-10008. [PMID: 36458452 DOI: 10.1080/07391102.2022.2150686] [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: 09/14/2022] [Accepted: 11/17/2022] [Indexed: 12/04/2022]
Abstract
G-rich sequences are intrinsic parts of the genome, widespread in promoters, telomeres, or other regulatory regions. The in vivo existence and biological significance have established the functional aspect of G-quadruplex structures and thus have developed immense interest in exploring their therapeutic aspects. Herein, using biophysical methods, we examined the structural status and comprehensive cation-dependence of a 17-bp G-rich genomic sequence (SKGT17) located in the coding region of the human TRPA1 gene, known to be associated with various neurovascular, cardiovascular, and respiratory conditions. TRPA1 is primarily seen as a therapeutic target for the development of novel analgesics. Bioinformatics analysis has suggested that 17-bp quadruplex motif is a binding site for transcription factor 'Sp1'. The formation and recognition of SKGT17 G-quadruplex might impact its regulatory functioning. Biophysical studies confirmed that the presence of alkali metal ions facilitated the formation of G-quadruplex in parallel topology. Native gel further substantiated the formation of a biomolecular species. Circular dichroism (CD), UV-thermal melting (Tm), and CD melting confirmed the formation of parallel G-quadruplex with metal ion-dependent stability. The stability of the G-quadruplex formed is found to be significantly high in the presence of K+ ions than that of other ions. Intriguingly, we have also established that this segment of the TRAP1 gene favors G-quadruplex formation over its participation in the corresponding duplex formation under K+ ions conditions. This study attempts to explain the rationale for the stabilization of G-quadruplex in the presence of alkali metal ions and may add to a better understanding and insights into DNA-metal ions interactions.
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Affiliation(s)
- Shoaib Khan
- Nucleic Acid Research Laboratory, Department of Chemistry, University of Delhi, Delhi, India
| | - Anju Singh
- Department of Chemistry, Ramjas College, University of Delhi, Delhi, India
| | - Nishu Nain
- Nucleic Acid Research Laboratory, Department of Chemistry, University of Delhi, Delhi, India
| | - Shrikant Kukreti
- Nucleic Acid Research Laboratory, Department of Chemistry, University of Delhi, Delhi, India
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Cao Y, Gao S, Yan Y, Bruist MF, Wang B, Guo X. Assembly of supramolecular DNA complexes containing both G-quadruplexes and i-motifs by enhancing the G-repeat-bearing capacity of i-motifs. Nucleic Acids Res 2016; 45:26-38. [PMID: 27899568 PMCID: PMC5224476 DOI: 10.1093/nar/gkw1049] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/17/2016] [Accepted: 10/20/2016] [Indexed: 12/13/2022] Open
Abstract
The single-step assembly of supramolecular complexes containing both i-motifs and G-quadruplexes (G4s) is demonstrated. This can be achieved because the formation of four-stranded i-motifs appears to be little affected by certain terminal residues: a five-cytosine tetrameric i-motif can bear ten-base flanking residues. However, things become complex when different lengths of guanine-repeats are added at the 3′ or 5′ ends of the cytosine-repeats. Here, a series of oligomers d(XGiXC5X) and d(XC5XGiX) (X = A, T or none; i < 5) are designed to study the impact of G-repeats on the formation of tetrameric i-motifs. Our data demonstrate that tetramolecular i-motif structure can tolerate specific flanking G-repeats. Assemblies of these oligonucleotides are polymorphic, but may be controlled by solution pH and counter ion species. Importantly, we find that the sequences d(TGiAC5) can form the tetrameric i-motif in large quantities. This leads to the design of two oligonucleotides d(TG4AC7) and d(TGBrGGBrGAC7) that self-assemble to form quadruplex supramolecules under certain conditions. d(TG4AC7) forms supramolecules under acidic conditions in the presence of K+ that are mainly V-shaped or ring-like containing parallel G4s and antiparallel i-motifs. d(TGBrGGBrGAC7) forms long linear quadruplex wires under acidic conditions in the presence of Na+ that consist of both antiparallel G4s and i-motifs.
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Affiliation(s)
- Yanwei Cao
- College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China
| | - Shang Gao
- College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China
| | - Yuting Yan
- College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China
| | - Michael F Bruist
- Department of Chemistry & Biochemistry, University of the Sciences, 600 South 43rd Street, Philadelphia, PA 19104, USA
| | - Bing Wang
- College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China
| | - Xinhua Guo
- College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China
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