1
|
Tao S, Run Y, Monchaud D, Zhang W. i-Motif DNA: identification, formation, and cellular functions. Trends Genet 2024:S0168-9525(24)00133-1. [PMID: 38902139 DOI: 10.1016/j.tig.2024.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 05/29/2024] [Accepted: 05/29/2024] [Indexed: 06/22/2024]
Abstract
An i-motif (iM) is a four-stranded (quadruplex) DNA structure that folds from cytosine (C)-rich sequences. iMs can fold under many different conditions in vitro, which paves the way for their formation in living cells. iMs are thought to play key roles in various DNA transactions, notably in the regulation of genome stability, gene transcription, mRNA translation, DNA replication, telomere and centromere functions, and human diseases. We summarize the different techniques used to assess the folding of iMs in vitro and provide an overview of the internal and external factors that affect their formation and stability in vivo. We describe the possible biological relevance of iMs and propose directions towards their use as target in biology.
Collapse
Affiliation(s)
- Shentong Tao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production (CIC-MCP), Nanjing Agricultural University, 1 Weigang, Nanjing, Jiangsu 210095, China
| | - Yonghang Run
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production (CIC-MCP), Nanjing Agricultural University, 1 Weigang, Nanjing, Jiangsu 210095, China
| | - David Monchaud
- Institut de Chimie Moleculaire de l'Université de Bourgogne (ICMUB), Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 6302, Université Bourgogne Franche Comté (UBFC), Dijon, France
| | - Wenli Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement and Utilization, Collaborative Innovation Center for Modern Crop Production (CIC-MCP), Nanjing Agricultural University, 1 Weigang, Nanjing, Jiangsu 210095, China.
| |
Collapse
|
2
|
Bchara L, Eritja R, Gargallo R, Benavente F. Rapid and Highly Efficient Separation of i-Motif DNA Species by CE-UV and Multivariate Curve Resolution. Anal Chem 2023; 95:15189-15198. [PMID: 37782260 PMCID: PMC10585953 DOI: 10.1021/acs.analchem.3c01730] [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] [Received: 04/21/2023] [Accepted: 09/12/2023] [Indexed: 10/03/2023]
Abstract
The i-motif is a class of nonstandard DNA structure with potential biological implications. A novel capillary electrophoresis with an ultraviolet absorption spectrophotometric detection (CE-UV) method has been developed for the rapid analysis of the i-motif folding equilibrium as a function of pH and temperature. The electrophoretic analyses are performed in reverse polarity of the separation voltage with 32 cm long fused silica capillaries permanently coated with hydroxypropyl cellulose (HPC), after an appropriate conditioning procedure was used to achieve good repeatability. However, the electrophoretic separation between the folded and unfolded conformers of the studied cytosine-rich i-motif sequences (i.e., TT, Py39WT, and nmy01) is compromised, especially for Py39WT and nmy01, which result in completely overlapped peaks. Therefore, deconvolution with multivariate curve resolution-alternating least-squares (MCR-ALS) has been required for the efficient separation of the folded and unfolded species found at different concentration levels at pH 6.5 and between 12 and 40 °C, taking advantage of the small dissimilarities in the electrophoretic mobilities and UV spectra levels. MCR-ALS has also provided quantitative information that has been used to estimate melting temperatures (Tm), which are similar to those determined by UV and circular dichroism (CD) spectroscopies. The obtained results demonstrate that CE-UV assisted by MCR-ALS may become a very useful tool to get novel insight into the folding of i-motifs and other complex DNA structures.
Collapse
Affiliation(s)
- Laila Bchara
- Department
of Chemical Engineering and Analytical Chemistry, University of Barcelona, Marti i Franquès 1-11, E-08028 Barcelona, Spain
| | - Ramon Eritja
- Institute
for Advanced Chemistry of Catalonia (IQAC−CSIC), CIBER-BBN, Jordi Girona 18-26, E-08034 Barcelona, Spain
| | - Raimundo Gargallo
- Department
of Chemical Engineering and Analytical Chemistry, University of Barcelona, Marti i Franquès 1-11, E-08028 Barcelona, Spain
| | - Fernando Benavente
- Department
of Chemical Engineering and Analytical Chemistry, University of Barcelona, Marti i Franquès 1-11, E-08028 Barcelona, Spain
- Institute
for Research on Nutrition and Food Safety (INSA·UB), University of Barcelona, Av. Prat de la Riba 171, E-08921 Santa Coloma de Gramenet, Spain
| |
Collapse
|
3
|
Craig JS, Melidis L, Williams HD, Dettmer SJ, Heidecker AA, Altmann PJ, Guan S, Campbell C, Browning DF, Sigel RKO, Johannsen S, Egan RT, Aikman B, Casini A, Pöthig A, Hannon MJ. Organometallic Pillarplexes That Bind DNA 4-Way Holliday Junctions and Forks. J Am Chem Soc 2023. [PMID: 37318835 DOI: 10.1021/jacs.3c00118] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Holliday 4-way junctions are key to important biological DNA processes (insertion, recombination, and repair) and are dynamic structures that adopt either open or closed conformations, the open conformation being the biologically active form. Tetracationic metallo-supramolecular pillarplexes display aryl faces about a cylindrical core, an ideal structure to interact with open DNA junction cavities. Combining experimental studies and MD simulations, we show that an Au pillarplex can bind DNA 4-way (Holliday) junctions in their open form, a binding mode not accessed by synthetic agents before. Pillarplexes can bind 3-way junctions too, but their large size leads them to open up and expand that junction, disrupting the base pairing, which manifests in an increased hydrodynamic size and lower junction thermal stability. At high loading, they rearrange both 4-way and 3-way junctions into Y-shaped forks to increase the available junction-like binding sites. Isostructural Ag pillarplexes show similar DNA junction binding behavior but lower solution stability. This pillarplex binding contrasts with (but complements) that of metallo-supramolecular cylinders, which prefer 3-way junctions and can rearrange 4-way junctions into 3-way junction structures. The pillarplexes' ability to bind open 4-way junctions creates exciting possibilities to modulate and switch such structures in biology, as well as in synthetic nucleic acid nanostructures. In human cells, the pillarplexes do reach the nucleus, with antiproliferative activity at levels similar to those of cisplatin. The findings provide a new roadmap for targeting higher-order junction structures using a metallo-supramolecular approach, as well as expanding the toolbox available to design bioactive junction binders into organometallic chemistry.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Roland K O Sigel
- Department of Chemistry, University of Zürich, Winterthurerstr. 190, 8057 Zürich, Switzerland
| | - Silke Johannsen
- Department of Chemistry, University of Zürich, Winterthurerstr. 190, 8057 Zürich, Switzerland
| | | | | | | | | | | |
Collapse
|
4
|
Rodgers MT, Seidu YS, Israel E. Influence of 5-Halogenation on the Base-Pairing Energies of Protonated Cytidine Nucleoside Analogue Base Pairs: Implications for the Stabilities of Synthetic i-Motif Structures for DNA Nanotechnology Applications. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1697-1715. [PMID: 35921530 DOI: 10.1021/jasms.2c00137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
DNA nanotechnology has been employed to develop devices based on i-motif structures. The protonated cytosine-cytosine base pairs that stabilize i-motif conformations are favored under slightly acidic conditions. This unique property has enabled development of the first DNA molecular motor driven by pH changes. The ability to alter the stability and pH transition range of such DNA molecular motors is desirable. Understanding how i-motif structures are influenced by modifications, and which modifications enhance stability and/or affect the pH characteristics, are therefore of great interest. Here, the influence of 5-halogenation of the cytosine nucleobases on the base pairing of protonated cytidine nucleoside analogue base pairs is examined using complementary threshold collision-induced dissociation techniques and computational methods. The nucleoside analogues examined here include the 5-halogenated forms of the canonical DNA and RNA cytidine nucleosides. Comparisons among these systems and to the analogous canonical base pairs previously examined enable the influence of 5-halogenation and the 2'-hydroxy substituent on the base pairing to be elucidated. 5-Halogenation of the cytosine nucleobases is found to enhance the strength of base pairing of DNA base pairs and generally weakens the base pairing for RNA base pairs. Trends in the strength of base pairing indicate that both inductive and polarizability effects influence the strength of base pairing. Overall, the present results suggest that 5-halogenation, and in particular, 5-fluorination and 5-iodination, provide effective means of stabilizing DNA i-motif conformations for applications in nanotechnology, whereas only 5-iodination is effective for stabilizing RNA i-motif conformations but the enhancement in stability is less significant.
Collapse
Affiliation(s)
- M T Rodgers
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Yakubu S Seidu
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - E Israel
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| |
Collapse
|
5
|
Mustafa G, Gyawali P, Taylor JA, Maleki P, Nunez MV, Guntrum MC, Shiekh S, Balci H. A single molecule investigation of i-motif stability, folding intermediates, and potential as in-situ pH sensor. Front Mol Biosci 2022; 9:977113. [PMID: 36072435 PMCID: PMC9441956 DOI: 10.3389/fmolb.2022.977113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 07/26/2022] [Indexed: 11/13/2022] Open
Abstract
We present a collection of single molecule work on the i-motif structure formed by the human telomeric sequence. Even though it was largely ignored in earlier years of its discovery due to its modest stability and requirement for low pH levels (pH < 6.5), the i-motif has been attracting more attention recently as both a physiologically relevant structure and as a potent pH sensor. In this manuscript, we establish single molecule Förster resonance energy transfer (smFRET) as a tool to study the i-motif over a broad pH and ionic conditions. We demonstrate pH and salt dependence of i-motif formation under steady state conditions and illustrate the intermediate states visited during i-motif folding in real time at the single molecule level. We also show the prominence of intermediate folding states and reversible folding/unfolding transitions. We present an example of using the i-motif as an in-situ pH sensor and use this sensor to establish the time scale for the pH drop in a commonly used oxygen scavenging system.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Hamza Balci
- Department of Physics, Kent State University, Kent, OH, United States
| |
Collapse
|
6
|
Dubrovin EV, Barinov NA, Klinov DV. Visualization of G-Quadruplexes, i-Motifs and Their Associates. Acta Naturae 2022; 14:4-18. [PMID: 36348720 PMCID: PMC9611856 DOI: 10.32607/actanaturae.11705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 07/13/2022] [Indexed: 09/07/2024] Open
Abstract
The non-canonical structures formed by G- or C-rich DNA regions, such as quadruplexes and i-motifs, as well as their associates, have recently been attracting increasing attention both because of the arguments in favor of their existence in vivo and their potential application in nanobiotechnology. When studying the structure and properties of non-canonical forms of DNA, as well as when controlling the artificially created architectures based on them, visualization plays an important role. This review analyzes the methods used to visualize quadruplexes, i-motifs, and their associates with high spatial resolution: fluorescence microscopy, transmission electron microscopy (TEM), and atomic force microscopy (AFM). The key approaches to preparing specimens for the visualization of this type of structures are presented. Examples of visualization of non-canonical DNA structures having various morphologies, such as G-wires, G-loops, as well as individual quadruplexes, i-motifs and their associates, are considered. The potential for using AFM for visualizing non-canonical DNA structures is demonstrated.
Collapse
Affiliation(s)
- E. V. Dubrovin
- M.V. Lomonosov Moscow State University, Faculty of Physics, Moscow, 119991 Russia
| | - N. A. Barinov
- M.V. Lomonosov Moscow State University, Faculty of Physics, Moscow, 119991 Russia
| | - D. V. Klinov
- Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, 119435 Russia
- Peoples’ Friendship University of Russia (RUDN University), Moscow, 117198 Russia
| |
Collapse
|
7
|
Amato J, Iaccarino N, D'Aria F, D'Amico F, Randazzo A, Giancola C, Cesàro A, Di Fonzo S, Pagano B. Conformational plasticity of DNA secondary structures: probing the conversion between i-motif and hairpin species by circular dichroism and ultraviolet resonance Raman spectroscopies. Phys Chem Chem Phys 2022; 24:7028-7044. [PMID: 35258065 DOI: 10.1039/d2cp00058j] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The promoter regions of important oncogenes such as BCL2 and KRAS contain GC-rich sequences that can form distinctive noncanonical DNA structures involved in the regulation of transcription: G-quadruplexes on the G-rich strand and i-motifs on the C-rich strand. Interestingly, BCL2 and KRAS promoter i-motifs are highly dynamic in nature and exist in a pH-dependent equilibrium with hairpin and even with hybrid i-motif/hairpin species. Herein, the effects of pH and presence of cell-mimicking molecular crowding conditions on conformational equilibria of the BCL2 and KRAS i-motif-forming sequences were investigated by ultraviolet resonance Raman (UVRR) and circular dichroism (CD) spectroscopies. Multivariate analysis of CD data was essential to model the presence and identity of the species involved. Analysis of UVRR spectra measured as a function of pH, performed also by the two-dimensional correlation spectroscopy (2D-COS) technique, showed the role of several functional groups in the DNA conformational transitions, and provided structural and dynamic information. Thus, the UVRR investigation of intramolecular interactions and of local and environmental dynamics in promoting the different species induced by the solution conditions provided valuable insights into i-motif conformational transitions. The combined use of the two spectroscopic tools is emphasized by the relevant possibility of working in the same DNA concentration range and by the heterospectral UVRR/CD 2D-COS analysis. The results of this study shed light on the factors that can influence at the molecular level the equilibrium between the different conformational species putatively involved in the oncogene expression.
Collapse
Affiliation(s)
- Jussara Amato
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| | - Nunzia Iaccarino
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| | - Federica D'Aria
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| | - Francesco D'Amico
- Elettra-Sincrotrone Trieste S. C. p. A., Science Park, Trieste, I-34149, Italy.
| | - Antonio Randazzo
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| | - Concetta Giancola
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| | - Attilio Cesàro
- Elettra-Sincrotrone Trieste S. C. p. A., Science Park, Trieste, I-34149, Italy.
| | - Silvia Di Fonzo
- Elettra-Sincrotrone Trieste S. C. p. A., Science Park, Trieste, I-34149, Italy.
| | - Bruno Pagano
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| |
Collapse
|
8
|
Stability and context of intercalated motifs (i-motifs) for biological applications. Biochimie 2022; 198:33-47. [PMID: 35259471 DOI: 10.1016/j.biochi.2022.03.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 02/21/2022] [Accepted: 03/03/2022] [Indexed: 11/24/2022]
Abstract
DNA is naturally dynamic and can self-assemble into alternative secondary structures including the intercalated motif (i-motif), a four-stranded structure formed in cytosine-rich DNA sequences. Until recently, i-motifs were thought to be unstable in physiological cellular environments. Studies demonstrating their existence in the human genome and role in gene regulation are now shining light on their biological relevance. Herein, we review the effects of epigenetic modifications on i-motif structure and stability, and biological factors that affect i-motif formation within cells. Furthermore, we highlight recent progress in targeting i-motifs with structure-specific ligands for biotechnology and therapeutic purposes.
Collapse
|
9
|
Luteran EM, Paukstelis PJ. The parallel-stranded d(CGA) duplex is a highly predictable structural motif with two conformationally distinct strands. Acta Crystallogr D Struct Biol 2022; 78:299-309. [PMID: 35234144 PMCID: PMC8900823 DOI: 10.1107/s2059798322000304] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 01/10/2022] [Indexed: 11/10/2022] Open
Abstract
DNA can adopt noncanonical structures that have important biological functions while also providing structural diversity for applications in nanotechnology. Here, the crystal structures of two oligonucleotides composed of d(CGA) triplet repeats in the parallel-stranded duplex form are described. The structure determination of four unique d(CGA)-based parallel-stranded duplexes across two crystal structures has allowed the structural parameters of d(CGA) triplets in the parallel-stranded duplex form to be characterized and established. These results show that d(CGA) units are highly uniform, but that each strand in the duplex is structurally unique and has a distinct role in accommodating structural asymmetries induced by the C-CH+ base pair.
Collapse
Affiliation(s)
- Emily M. Luteran
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
| | - Paul J. Paukstelis
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
| |
Collapse
|
10
|
Zhao Z, Li X, Cui Z, Tong T, Zhang Y, Zhang Y, Yang X, Keerthiga R, Fu C, Fu A. Synthesis of Hemiprotonic Phenanthroline-Phenanthroline + Compounds with both Antitumor and Antimicrobial Activity. J Med Chem 2022; 65:2532-2547. [PMID: 35073076 DOI: 10.1021/acs.jmedchem.1c01982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Currently, cancer patients with microbial infection are a severe challenge in clinical treatment. To address the problem, we synthesized hemiprotonic compounds based on the unique structure of hemiprotonic nucleotide base pairs in a DNA i-motif. These compounds were produced from phenanthroline (ph) dimerization with phenanthroline as a proton receptor and ammonium as a donor. The biological activity shows that the compounds have a selective antitumor effect through inducing cell apoptosis. The molecular mechanism could be related to specific inhibition of transcription factor PLAGL2 of tumor cells, assessed by transcriptomic analysis. Moreover, results show that the hemiprotonic ph-ph+ has broad-spectrum antibacterial and antifungal activities, and drug-resistant bacteria, including methicillin-resistant Staphylococcus aureus, are sensitive to the compound. In animal models of liver cancer with fungal infection, the ph-ph+ retards proliferation of hepatoma cells in tumor-bearing mice and remedies pneumonia and encephalitis caused by Cryptococcus neoformans. The study provides a novel therapeutic candidate for cancer patients accompanied by infection.
Collapse
Affiliation(s)
- Zizhen Zhao
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China
| | - Xiaorong Li
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China
| | - Zhihong Cui
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China
| | - Tingting Tong
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China
| | - Yingying Zhang
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China
| | - Yuping Zhang
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China
| | - Xiaoxi Yang
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China
| | - Rajendiran Keerthiga
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China
| | - Chen Fu
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China
| | - Ailing Fu
- College of Pharmaceutical Sciences, Southwest University, Chongqing 400716, China
| |
Collapse
|
11
|
Yu G, Niu K, Peng Y, Liu Z, Song Q, Feng Q. Large-scale screening of i-motif binding compounds in the silkworm, Bombyx mori. Biochem Biophys Res Commun 2021; 589:9-15. [PMID: 34883288 DOI: 10.1016/j.bbrc.2021.11.092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 11/25/2021] [Indexed: 11/02/2022]
Abstract
DNA secondary structure i-motif involves in gene transcription and considered as a novel target for cancer gene therapy. I-motif-binding compounds can either stabilize or destroy the structure, resulting in change in target gene transcription. In this study, a large-scale screening of binding compounds was conducted using the i-motif structure of BmPOUM2, a transcription factor in silkworm, Bombyx mori. Surface plasmon resonance imaging (SPRi) high-throughput binding screening of 3642 compounds found 60 compounds with an binding affinity Kd of 10-7-10-6 M. SPRi and circular dichroism (CD) double screening demonstrated that the BmPOUM2 i-motif structure bound the compounds IF1, IF3, IF4, IF6 and IF7 with Kd of 10-7 M, and the compounds IF2 and tetrakis (4-N-methylpyridyl) porphine (TMPyP4) with a Kd of 10-8 M. Interestingly, IF2, IF3, IF4, IF6 and IF7 promoted the binding of the i-motif-binding protein BmILF with the i-motif structure, whereas TMPyP4 inhibited the binding. This study provided a list of compounds that have potential applications in functional analysis of i-motif structure and in pesticide and drug development through gene transcription regulation by i-motif structure.
Collapse
Affiliation(s)
- Guoxing Yu
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Kangkang Niu
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Yuling Peng
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Zhenming Liu
- School of Pharmacy, Peking University, Beijing, 100191, China
| | - Qisheng Song
- Division of Plant Sciences, University of Missouri, Columbia, MO, 65211, USA.
| | - Qili Feng
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology, School of Life Sciences, South China Normal University, Guangzhou, 510631, China.
| |
Collapse
|
12
|
Amato J, D'Aria F, Marzano S, Iaccarino N, Randazzo A, Giancola C, Pagano B. On the thermodynamics of folding of an i-motif DNA in solution under favorable conditions. Phys Chem Chem Phys 2021; 23:15030-15037. [PMID: 34151914 DOI: 10.1039/d1cp01779a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Under slightly acidic conditions, cytosine-rich DNA sequences can form non-canonical secondary structures called i-motifs, which occur as four stretches of cytosine repeats form hemi-protonated C·C+ base pairs. The growing interest in the i-motif structures as important components in functional DNA-based nanotechnology or as potential targets of anticancer drugs, increases the need for a deep understanding of the energetics of their structural transitions. Here, a combination of spectroscopic and calorimetric techniques is used to unravel the thermodynamics of folding of an i-motif DNA under favorable conditions. The results give new insights into the energetic aspects of i-motifs and show that thermodynamic and thermal stability are related but not identical properties of such DNA structures.
Collapse
Affiliation(s)
- Jussara Amato
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| | - Federica D'Aria
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| | - Simona Marzano
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| | - Nunzia Iaccarino
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| | - Antonio Randazzo
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| | - Concetta Giancola
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| | - Bruno Pagano
- Department of Pharmacy, University of Naples Federico II, Naples, I-80131, Italy.
| |
Collapse
|
13
|
Seidu YS, Roy HA, Rodgers MT. Influence of 5-Methylation and the 2'- and 3'-Hydroxy Substituents on the Base Pairing Energies of Protonated Cytidine Nucleoside Analogue Base Pairs: Implications for the Stabilities of i-Motif Structures. J Phys Chem A 2021; 125:5939-5955. [PMID: 34228469 DOI: 10.1021/acs.jpca.1c04303] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Repetitive nucleic acid sequences, which occur in abundance throughout the mammalian genome, are of enormous research interest due to their potential to adopt fascinating and unusual molecular structures such as the i-motif. In remarkable contrast to the DNA double helix, i-motif conformations are stabilized by protonated cytosine base pairs, (Cyt)H+(Cyt), that are centrally located in the core of the i-motif and intercalated vertically in an antiparallel fashion. An in-depth understanding of how modifications influence the stability of i-motif conformations is a prerequisite to understanding their biological functions and the development of effective means of tuning their stability for specific medical and technological applications. Here, the influence of the 2'- and 3'-hydroxy substituents of the sugar moieties and 5-methylation of the cytosine nucleobases on the base-pairing interactions of protonated cytidine nucleoside analogue base pairs, (xCyd)H+(xCyd), are examined by complementary threshold collision-induced dissociation techniques and computational methods. The xCyd nucleosides examined include the canonical DNA and RNA cytidine nucleosides, 2'-deoxycytidine (dCyd) and cytidine (Cyd), as well as several modified cytidine nucleoside analogues, 2',3'-dideoxycytidine (ddCyd), 5-methyl-2'-deoxycytidine (m5dCyd), and 5-methylcytidine (m5Cyd). Comparisons among these model base pairs indicate that the 2'- and 3'-hydroxy substituents of the sugar moieties have very little influence on the strength of the base-pairing interactions, whereas 5-methylation of the cytosine nucleobases is found to enhance the strength of the base-pairing interactions. The increase in stability resulting from 5-methylation is only modest but is more than twice as large for the DNA than RNA protonated cytidine base pair. Overall, present results suggest that canonical DNA i-motif conformations should be more stable than analogous RNA i-motif conformations and that 5-methylation of cytosine residues, a significant epigenetic marker, provides greater stabilization to DNA than RNA i-motif conformations.
Collapse
Affiliation(s)
- Yakubu S Seidu
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - H A Roy
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - M T Rodgers
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| |
Collapse
|
14
|
Brown SL, Kendrick S. The i-Motif as a Molecular Target: More Than a Complementary DNA Secondary Structure. Pharmaceuticals (Basel) 2021; 14:ph14020096. [PMID: 33513764 PMCID: PMC7911047 DOI: 10.3390/ph14020096] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 01/20/2021] [Accepted: 01/22/2021] [Indexed: 12/25/2022] Open
Abstract
Stretches of cytosine-rich DNA are capable of adopting a dynamic secondary structure, the i-motif. When within promoter regions, the i-motif has the potential to act as a molecular switch for controlling gene expression. However, i-motif structures in genomic areas of repetitive nucleotide sequences may play a role in facilitating or hindering expansion of these DNA elements. Despite research on the i-motif trailing behind the complementary G-quadruplex structure, recent discoveries including the identification of a specific i-motif antibody are pushing this field forward. This perspective reviews initial and current work characterizing the i-motif and providing insight into the biological function of this DNA structure, with a focus on how the i-motif can serve as a molecular target for developing new therapeutic approaches to modulate gene expression and extension of repetitive DNA.
Collapse
|
15
|
Chaudhary S, Kaushik M, Ahmed S, Kukreti S. Exploring potential of i-motif DNA formed in the promoter region of GRIN1 gene for nanotechnological applications. RESULTS IN CHEMISTRY 2020. [DOI: 10.1016/j.rechem.2020.100086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
|