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Sundar Rajan V, Viader-Godoy X, Lin YL, Dutta U, Ritort F, Westerlund F, Wilhelmsson LM. Mechanical characterization of base analogue modified nucleic acids by force spectroscopy. Phys Chem Chem Phys 2021; 23:14151-14155. [PMID: 34180930 PMCID: PMC8261857 DOI: 10.1039/d1cp01985f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We use mechanical unfolding of single DNA hairpins with modified bases to accurately assess intra- and intermolecular forces in nucleic acids. As expected, the modification stabilizes the hybridized hairpin, but we also observe intriguing stacking interactions in the unfolded hairpin. Our study highlights the benefit of using base-modified nucleic acids in force-spectroscopy.
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Affiliation(s)
- Vinoth Sundar Rajan
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Sweden. and Department of Biology and Biological Engineering, Chalmers University of Technology, Sweden.
| | - Xavier Viader-Godoy
- Small Biosystems Lab, Condensed Matter Physics Department, Universitat de Barcelona, C/Marti i Franques 1, Barcelona 08028, Spain
| | - Yii-Lih Lin
- Department of Biology and Biological Engineering, Chalmers University of Technology, Sweden.
| | - Uttama Dutta
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Sweden. and Department of Biology and Biological Engineering, Chalmers University of Technology, Sweden.
| | - Felix Ritort
- Small Biosystems Lab, Condensed Matter Physics Department, Universitat de Barcelona, C/Marti i Franques 1, Barcelona 08028, Spain
| | - Fredrik Westerlund
- Department of Biology and Biological Engineering, Chalmers University of Technology, Sweden.
| | - L Marcus Wilhelmsson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Sweden.
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2
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Gupta MK, Madhanagopal BR, Ganesh KN. Peptide Nucleic Acid with Double Face: Homothymine–Homocytosine Bimodal Cα-PNA (bm-Cα-PNA) Forms a Double Duplex of the bm-PNA2:DNA Triplex. J Org Chem 2020; 86:414-428. [DOI: 10.1021/acs.joc.0c02158] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Manoj Kumar Gupta
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Karkambadi Road, Tirupati 517507, India
| | - Bharath Raj Madhanagopal
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Karkambadi Road, Tirupati 517507, India
| | - Krishna N. Ganesh
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr Homi Bhabha Road, Pune 411008, India
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Karkambadi Road, Tirupati 517507, India
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Cristofalo M, Kovari D, Corti R, Salerno D, Cassina V, Dunlap D, Mantegazza F. Nanomechanics of Diaminopurine-Substituted DNA. Biophys J 2019; 116:760-771. [PMID: 30795872 DOI: 10.1016/j.bpj.2019.01.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 10/27/2022] Open
Abstract
2,6-diaminopurine (DAP) is a nucleobase analog of adenine. When incorporated into double-stranded DNA (dsDNA), it forms three hydrogen bonds with thymine. Rare in nature, DAP substitution alters the physical characteristics of a DNA molecule without sacrificing sequence specificity. Here, we show that in addition to stabilizing double-strand hybridization, DAP substitution also changes the mechanical and conformational properties of dsDNA. Thermal melting experiments reveal that DAP substitution raises melting temperatures without diminishing sequence-dependent effects. Using a combination of atomic force microscopy (AFM), magnetic tweezer (MT) nanomechanical assays, and circular dichroism spectroscopy, we demonstrate that DAP substitution increases the flexural rigidity of dsDNA yet also facilitates conformational shifts, which manifest as changes in molecule length. DAP substitution increases both the static and dynamic persistence length of DNA (measured by AFM and MT, respectively). In the static case (AFM), in which tension is not applied to the molecule, the contour length of DAP-DNA appears shorter than wild-type (WT)-DNA; under tension (MT), they have similar dynamic contour lengths. At tensions above 60 pN, WT-DNA undergoes characteristic overstretching because of strand separation (tension-induced melting) and spontaneous adoption of a conformation termed S-DNA. Cyclic overstretching and relaxation of WT-DNA at near-zero loading rates typically yields hysteresis, indicative of tension-induced melting; conversely, cyclic stretching of DAP-DNA showed little or no hysteresis, consistent with the adoption of the S-form, similar to what has been reported for GC-rich sequences. However, DAP-DNA overstretching is distinct from GC-rich overstretching in that it happens at a significantly lower tension. In physiological salt conditions, evenly mixed AT/GC DNA typically overstretches around 60 pN. GC-rich sequences overstretch at similar if not slightly higher tensions. Here, we show that DAP-DNA overstretches at 52 pN. In summary, DAP substitution decreases the overall stability of the B-form double helix, biasing toward non-B-form DNA helix conformations at zero tension and facilitating the B-to-S transition at high tension.
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Affiliation(s)
- Matteo Cristofalo
- School of Medicine and Surgery, Università di Milano-Bicocca, Monza (MB), Italy
| | - Daniel Kovari
- Department of Physics, Emory University, Atlanta, Georgia
| | - Roberta Corti
- School of Medicine and Surgery, Università di Milano-Bicocca, Monza (MB), Italy
| | - Domenico Salerno
- School of Medicine and Surgery, Università di Milano-Bicocca, Monza (MB), Italy.
| | - Valeria Cassina
- School of Medicine and Surgery, Università di Milano-Bicocca, Monza (MB), Italy
| | - David Dunlap
- Department of Physics, Emory University, Atlanta, Georgia.
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Electronic properties of DNA: Description of weak interactions in TATA-box-like chains. Biophys Chem 2017; 233:26-35. [PMID: 29287183 DOI: 10.1016/j.bpc.2017.11.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/28/2017] [Accepted: 11/28/2017] [Indexed: 11/23/2022]
Abstract
DNA is one of the most important biomolecules since it contains all the genetic information about an organism. The tridimensional structure of DNA is a determinant factor that influences the physiological and biochemical mechanisms by which this molecule carries out its biological functions. It is believed that hydrogen bonds and π-π stacking are the most relevant non-covalent interactions regarding DNA stability. Due to its importance, several theoretical works have been made to describe these interactions, however, most of them often consider only the presence of two nitrogenous bases, having a limited overview of the participation of these in B-DNA stabilization. Furthermore, due to the complexity of the system, there are discrepancies between which involved interaction is more important in duplex stability. Therefore, in this project we describe these interactions considering the effect of chain length on the energy related to both hydrogen bonds and π-π stacking, using as model TATA-box-like chains with n base pairs (n=1 to 14) and taking into consideration two different models: ideal and optimized B-DNA. We have found that there is a cooperative effect on hydrogen bond and π-π stacking mean energies when the presence of other base pairs is considered. In addition, it was found that hydrogen bonds contribute more importantly than π-π stacking to B-DNA stability; nevertheless, the participation of π-π stacking is not negligible: when B-DNA looks for a conformation of lower energy, π-π stacking interaction are the first to be optimized. All work was realized under the framework of DFT using the DMol3 code (M06-L/DNP).
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Verona MD, Verdolino V, Palazzesi F, Corradini R. Focus on PNA Flexibility and RNA Binding using Molecular Dynamics and Metadynamics. Sci Rep 2017; 7:42799. [PMID: 28211525 PMCID: PMC5314342 DOI: 10.1038/srep42799] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 01/13/2017] [Indexed: 12/20/2022] Open
Abstract
Peptide Nucleic Acids (PNAs) can efficiently target DNA or RNA acting as chemical tools for gene regulation. Their backbone modification and functionalization is often used to increase the affinity for a particular sequence improving selectivity. The understanding of the trading forces that lead the single strand PNA to bind the DNA or RNA sequence is preparatory for any further rational design, but a clear and unique description of this process is still not complete. In this paper we report further insights into this subject, by a computational investigation aiming at the characterization of the conformations of a single strand PNA and how these can be correlated to its capability in binding DNA/RNA. Employing Metadynamics we were able to better define conformational pre-organizations of the single strand PNA and γ-modified PNA otherwise unrevealed through classical molecular dynamics. Our simulations driven on backbone modified PNAs lead to the conclusion that this γ-functionalization affects the single strand preorganization and targeting properties to the DNA/RNA, in agreement with circular dichroism (CD) spectra obtained for this class of compounds. MD simulations on PNA:RNA dissociation and association mechanisms allowed to reveal the critical role of central bases and preorganization in the binding process.
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Affiliation(s)
| | - Vincenzo Verdolino
- Department of Chemistry and Applied Biosciences, ETH Zurich, c/o Università della Svizzera Italiana Campus, 6900 Lugano, Switzerland
- Facoltà di Informatica, Instituto di Scienze Computazionali, Università della Svizzera Italiana, 6900 Lugano, Switzerland
| | - Ferruccio Palazzesi
- Department of Chemistry and Applied Biosciences, ETH Zurich, c/o Università della Svizzera Italiana Campus, 6900 Lugano, Switzerland
- Facoltà di Informatica, Instituto di Scienze Computazionali, Università della Svizzera Italiana, 6900 Lugano, Switzerland
| | - Roberto Corradini
- Dipartimento di Chimica, University of Parma, Italy, 43124, Italy
- National Institute for Biostructures and Biosystems (INBB)-Viale delle Medaglie d’Oro, 305, 00136 Roma, Italy
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Zhao XJ, Gao ZF, Jiang ZY. A Study of HCl Gas Adsorption/Desorption Properties of PNIPAM Brushes. MACROMOL THEOR SIMUL 2015. [DOI: 10.1002/mats.201500027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Xin Jun Zhao
- National Laboratory of Solid State Microstructures; Department of Physics; Nanjing University; Nanjing 210093 China
- Xinjiang Laboratory of Phase Transitions and Microstructures of Condensed Matter Physics; Yi Li Normal University; Yining 835000 China
| | - Zhi Fu Gao
- Xinjiang Astronomical Observatory; Chinese Academy of Sciences; Urumqi Xinjiang 830011 China
| | - Zhong Ying Jiang
- National Laboratory of Solid State Microstructures; Department of Physics; Nanjing University; Nanjing 210093 China
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Cao M, Cao C, Zhang L, Xia D, Xu H. Tuning of peptide assembly through force balance adjustment. J Colloid Interface Sci 2013; 407:287-95. [DOI: 10.1016/j.jcis.2013.06.051] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 06/18/2013] [Accepted: 06/20/2013] [Indexed: 11/15/2022]
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Gupta SK, Sur S, Prasad Ojha R, Tandon V. Influence of PNA containing 8-aza-7-deazaadenine on structure stability and binding affinity of PNA·DNA duplex: insights from thermodynamics, counter ion, hydration and molecular dynamics analysis. MOLECULAR BIOSYSTEMS 2013; 9:1958-71. [PMID: 23636232 DOI: 10.1039/c3mb25561a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This paper describes the synthesis of a novel 8-aza-7-deazapurin-2,6-diamine (DPP)-containing peptide nucleic acid (PNA) monomer and Boc protecting group-based oligomerization of PNA, replacing adenine (A) with DPP monomers in the PNA strand. The PNA oligomers were synthesized against the biologically relevant SV40 promoter region (2494-AATTTTTTTTATTTA-2508) of pEGFP-N3 plasmid. The DPP-PNA·DNA duplex showed enhanced stability as compared to normal duplex (A-PNA·DNA). The electronic distribution of DPP monomer suggested that DPP had better electron donor properties over 2,6-diamino purine. UV melting and thermodynamic analysis revealed that the PNA oligomer containing a diaminopyrazolo(3,4-d)pyrimidine moiety (DPP) stabilized the PNA·DNA hybrids compared to A-PNA·DNA. DPP-PNA·DNA duplex showed higher water activity (Δnw = 38.5) in comparison to A-PNA·DNA duplex (Δnw = 14.5). The 50 ns molecular dynamics simulations of PNA·DNA duplex containing DPP or unmodified nucleobase-A showed average H-bond distances in the DPP-dT base pair of 2.90 Å (OH-N bond) and 2.91 Å (NH-N bond), which were comparably shorter than in the A-dT base pair, in which the average distances were 3.18 Å (OH-N bond) and 2.97 Å (NH-N bond), and there was one additional H-bond in the DPP-dT base pair of around 2.98 Å (O2H-N2 bond), supporting the higher stability of DPP-PNA·DNA. The analysis of molecular dynamics simulation data showed that the system binding free energy increased at a rate of approximately -4.5 kcal mol(-1) per DPP base of the PNA·DNA duplex. In summary, increased thermal stability, stronger hydrogen bonding and more stable conformation in the DPP-PNA·DNA duplex make it a better candidate as antisense/antigene therapeutic agents.
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Affiliation(s)
- Sharad K Gupta
- Dr B. R. Ambedkar Center for Biomedical Research, Delhi, India.
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Bowler FR, Diaz-Mochon JJ, Swift MD, Bradley M. DNA analysis by dynamic chemistry. Angew Chem Int Ed Engl 2010; 49:1809-12. [PMID: 20155766 DOI: 10.1002/anie.200905699] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Frank R Bowler
- School of Chemistry, University of Edinburgh, EH9 3JJ, Edinburgh, UK
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10
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Bowler F, Diaz-Mochon J, Swift M, Bradley M. DNA Analysis by Dynamic Chemistry. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.200905699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Brown KL, Voehler MW, Magee SM, Harris CM, Harris TM, Stone MP. Structural perturbations induced by the alpha-anomer of the aflatoxin B(1) formamidopyrimidine adduct in duplex and single-strand DNA. J Am Chem Soc 2010; 131:16096-107. [PMID: 19831353 PMCID: PMC2773149 DOI: 10.1021/ja902052v] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
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The guanine N7 adduct of aflatoxin B1exo-8,9-epoxide hydrolyzes to form the formamidopyrimidine (AFB-FAPY) adduct, which interconverts between α and β anomers. The β anomer is highly mutagenic in Escherichia coli, producing G → T transversions; it thermally stabilizes the DNA duplex. The AFB-α-FAPY adduct blocks replication; it destabilizes the DNA duplex. Herein, the structure of the AFB-α-FAPY adduct has been elucidated in 5′-d(C1T2A3T4X5A6T7T8C9A10)-3′·5′-d(T11G12A13A14T15C16A17T18A19G20)-3′ (X = AFB-α-FAPY) using molecular dynamics calculations restrained by NMR-derived distances and torsion angles. The AFB moiety intercalates on the 5′ face of the pyrimidine moiety at the damaged nucleotide between base pairs T4·A17 and X5·C16, placing the FAPY C5−N5 bond in the Ra axial conformation. Large perturbations of the ε and ζ backbone torsion angles are observed, and the base stacking register of the duplex is perturbed. The deoxyribose orientation shifts to become parallel to the FAPY base and displaced toward the minor groove. Intrastrand stacking between the AFB moiety and the 5′ neighbor thymine remains, but strong interstrand stacking is not observed. A hydrogen bond between the formyl group and the exocyclic amine of the 3′-neighbor adenine stabilizes the E conformation of the formamide moiety. NMR studies reveal a similar 5′-intercalation of the AFB moiety for the AFB-α-FAPY adduct in the tetramer 5′-d(C1T2X3A4)-3′, involving the Ra axial conformation of the FAPY C5−N5 bond and the E conformation of the formamide moiety. Since in duplex DNA the AFB moiety of the AFB-β-FAPY adduct also intercalates on the 5′ side of the pyrimidine moiety at the damaged nucleotide, we conclude that favorable 5′-stacking leads to the Ra conformational preference about the C5−N5 bond; the same conformational preference about this bond is also observed at the nucleoside and base levels. The structural distortions and the less favorable stacking interactions induced by the AFB-α-FAPY adduct explain its lower stability as compared to the AFB-β-FAPY adduct in duplex DNA. In this DNA sequence, hydrogen bonding between the formyl oxygen and the exocyclic amine of the 3′-neighboring adenine stabilizing the E configuration of the formamide moiety is also observed for the AFB-β-FAPY adduct, and suggests that the identity of the 3′-neighbor nucleotide modulates the stability and biological processing of AFB adducts.
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Affiliation(s)
- Kyle L Brown
- Department of Chemistry, Center in Molecular Toxicology, and the Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, USA
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Feng B, Frykholm K, Nordén B, Westerlund F. DNA strand exchange catalyzed by molecular crowding in PEG solutions. Chem Commun (Camb) 2010; 46:8231-3. [DOI: 10.1039/c0cc03117h] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Heshmati E, Abdolmaleki P, Mozdarani H, Sarvestani AS. Effects of halogen substitution on Watson–Crick base pairing: A possible mechanism for radiosensitivity. Bioorg Med Chem Lett 2009; 19:5256-60. [DOI: 10.1016/j.bmcl.2009.06.105] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Revised: 05/21/2009] [Accepted: 06/18/2009] [Indexed: 11/15/2022]
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