Search results for "A-DNA"
showing 10 items of 30 documents
DNA-binding studies of AV-153, an antimutagenic and DNA repair-stimulating derivative of 1,4-dihydropiridine.
2014
Abstract The ability to intercalate between DNA strands determines the cytotoxic activity of numerous anticancer drugs. Strikingly, intercalating activity was also reported for some compounds considered to be antimutagenic. The aim of this study was to determine the mode of interaction of DNA with the antimutagenic and DNA repair-stimulating dihydropyridine (DHP) AV-153. DNA and AV-153 interactions were studied by means of UV/VIS spectroscopy, fluorimetry and infrared spectroscopy. Compound AV-153 is a 1,4 dihydropyridine with ethoxycarbonyl groups in positions 3 and 5. Computer modeling of AV-153 and DNA interactions suggested an ability of the compound to dock between DNA strands at a sin…
DNA-based biosensor on flexible nylon substrate by dip-pen lithography for topoisomerase detection
2019
Dip-pen lithography (DPL) technique has been employed to develop a new flexible biosensor realized on nylon with the aim to detect the activity of human topoisomerase. The sensor is constituted by an ordered array of a DNA substrate on flexible nylon supports that can be exploited as a drug screening platform for anticancer molecules. Here, we demonstrate a rapid protocol that permits to immobilize minute quantities of DNA oligonucleotides by DPL on nylon surfaces. Theoretical and experimental aspects have been investigated to successfully print DNA oligonucleotides by DPL on such a porous and irregular substrate.
Unraveling the Reaction Mechanism of Enzymatic C5-Cytosine Methylation of DNA. A Combined Molecular Dynamics and QM/MM Study of Wild Type and Gln119 …
2016
M.HhaI is a DNA methyltransferase from Haemophilus hemolyticus that catalyzes the transfer of a methyl group from S-adenosyl-l-methionine (SAM) to the C5 position of a cytosine. This enzyme is a paradigmatic model for C5 DNA methyltransferases due to its major homology to mammalian enzymes and to the availability of high-resolution structures of the DNA–enzyme complex. In spite of the number of experimental and theoretical analyses carried out for this system, many mechanistic details remain unraveled. We have used full atomistic classical molecular dynamics simulations to explore the protein–SAM–DNA ternary complex, where the target cytosine base is flipped out into the active site for bot…
Dramatic selectivity differences in the association of DNA and RNA models with new ethylene- and propylene diamine derivatives and their copper compl…
2006
The affinities of polyamines consisting of ethylenediamine units equipped with either one or two terminal naphthyl-, anthryl-, or acridyl units towards PolyA.PolyU as an RNA model, and Poly(dA).Poly(dT) as a DNA model are screened by measuring the melting point changes (DeltaT(m)) of the double strands, and also partially by a fluorimetric binding assay using ethidium bromide. The larger aromatic moieties with long spacers between them allow bisintercalation; this leads to an increased preference for DNA in comparison to RNA, where ion pairing of the ammonium centers with the major RNA groove phosphates dominates. Allosteric affinity control by metalation is achieved e.g. with Cu(2+) ions, …
Modelling Photoionisation in Isocytosine: Potential Formation of Longer‐Lived Excited State Cations in its Keto Form
2021
The front cover artwork is provided by Dr. Javier Segarra-Martí (University of Valencia, Spain) and Prof. Michael J. Bearpark (Imperial College London, UK). The image shows the ultrafast photoionisation of DNA canonical nucleobase cytosine and the slower ionization process in non-canonical base isocytosine embedded within a DNA backbone. Read the full text of the Article at 10.1002/cphc.202100402.
Monoclonal antibody to a DNA-binding domain of p53 mimics charge structure of DNA: anti-idiotypes to the anti-p53 antibody are anti-DNA
2004
Antibodies to DNA are important markers of various autoimmune diseases and can be pathogenic; however, their generation is not understood. We previously reported that anti-DNA antibodies could be induced in mice by idiotypic immunization to PAb-421, an antibody to a DNA-binding domain of p53. We now report that two monoclonal antibodies of moderate affinity (K(D) asymptotically equal to 10(-7)), raised from PAb-421-immunized mice, specifically recognized both PAb-421 and DNA. These antibodies feature multiple arginine residues in the antigen-binding site, a unique characteristic of disease-associated anti-DNA antibodies; nevertheless, these anti-DNA antibodies show specific complementarity …
Toward Single Electron Nanoelectronics Using Self-Assembled DNA Structure
2016
DNA based structures offer an adaptable and robust way to develop customized nanostructures for various purposes in bionanotechnology. One main aim in this field is to develop a DNA nanobreadboard for a controllable attachment of nanoparticles or biomolecules to form specific nanoelectronic devices. Here we conjugate three gold nanoparticles on a defined size TX-tile assembly into a linear pattern to form nanometer scale isolated islands that could be utilized in a room temperature single electron transistor. To demonstrate this, conjugated structures were trapped using dielectrophoresis for current-voltage characterization. After trapping only high resistance behavior was observed. However…
N -Diphenylmethyl-2-propenamide: theoretical study of the structure and interaction with a DNA model system
2001
Abstract N -diphenylmethyl-2-propenamide (NDP) was synthesised and characterised. Pharmacological in vitro tests pointed out that NDP had a cytotoxic activity on a human ovarian carcinoma comparable to that of doxorubicin. Hypothesising that this in vitro cytotoxic activity could be mainly due to intercalating interactions, between the drug and DNA fragments, ab initio calculations, at the Hartree–Fock (HF) level, were performed on the structure, and on the conformational properties of NDP, whereas its interaction with an (AC)(TG) dinucleotide triphosphate duplex (DD) was studied by the ONIOM method, at HF and PM3 level for NDP and DD, respectively. The supposed intercalation process with t…
Direct measurement of the melting temperature of supported DNA by electrochemical method
2003
The development of biosensors based on DNA hybridization requires a more precise knowledge of the thermodynamics of the hybridization at a solid interface. In particular, the selectivity of hybridization can be affected by a lot of parameters such as the single-strand (ss)DNA density, the pH, the ionic strength or the temperature. The melting temperature, T(m), is in part a function of the ionic strength and of the temperature and therefore provides a useful variable in the control of the selectivity and sensitivity of a DNA chip. The electrochemical technique has been used to determine the T(m) values when the probe is tethered by a DNA self-assembled monolayer (SAM). We have built a speci…
Compact-envelope bright solitary wave in a DNA double strand
2012
International audience; We study the nonlinear dynamics of a homogeneous DNA chain which is based on site-dependent finite stacking and pairing enthalpies. We introduce an extended nonlinear Schroedinger equation describing the dynamics of modulated waves in DNA model. We obtain envelope bright solitary waves with compact support as a solution. Analytical criteria of existence and stability of this solution are derived. The stability of bright compactons is confirmed by numerical simulations of the exact equations of the lattice. The impact of the fi nite stacking energy is investigated and we show that some of these compact bright solitary waves are very robust, while others decompose quic…