A5091346274- DNA and Nucleic Acid Chemistry
- Advanced biosensing and bioanalysis techniques
- RNA Interference and Gene Delivery
- RNA and protein synthesis mechanisms
- Photoreceptor and optogenetics research
- Electrochemical sensors and biosensors
- Mosquito-borne diseases and control
- European and International Law Studies
- Helminth infection and control
- DNA Repair Mechanisms
- Plant Virus Research Studies
- Plant Toxicity and Pharmacological Properties
- Genomics and Chromatin Dynamics
- Parasites and Host Interactions
- Synthesis and Properties of Aromatic Compounds
- Bacteriophages and microbial interactions
- Toxoplasma gondii Research Studies
- Post-Soviet Geopolitical Dynamics
- Mass Spectrometry Techniques and Applications
- Telomeres, Telomerase, and Senescence
- Polar Research and Ecology
- European Politics and Security
- Chromosomal and Genetic Variations
- Vector-borne infectious diseases
Czech Academy of Sciences, Institute of Biophysics
2014-2023
Charles University
2022
Czech Academy of Sciences
2006-2017
Central European Institute of Technology – Masaryk University
2014-2015
Central European Institute of Technology
2014-2015
The arrangement of the human telomeric quadruplex in physiologically relevant conditions has not yet been unambiguously determined. Our spectroscopic results suggest that core sequence G 3 (TTAG ) forms an antiparallel same basket type solution containing either K + or Na ions. Analogous sequences extended by flanking nucleotides form a mixture and hybrid (3 1) quadruplexes -containing solutions. We, however, show long DNA behaves way as basic motif. Both are also able to adopt structure:...
The formation of intercalated motifs (iMs) - secondary DNA structures based on hemiprotonated C.C+ pairs in suitable cytosine-rich sequences, is reflected by typical changes CD and UV absorption spectra. By means spectroscopic methods, electrophoresis, chemical modifications other procedures, we characterized iM stability sequences with different cytosine block lengths interrupted various numbers types nucleotides. Particular attention was paid to the iMs at pH conditions close neutral. We...
8‐Oxoguanine is a ubiquitous oxidative base lesion. We report here on the effect of this lesion structure and stability quadruplexes formed by human telomeric DNA sequence 5′‐dG 3 (TTAG ) in NaCl KCl. CD, PAGE absorption‐based thermodynamic data showed that replacement any tetrad‐forming guanines 8‐oxoguanine did not hinder formation monomolecular, antiparallel NaCl. The modified were, however, destabilized both salts, extent depending position These results previous studies...
We have identified seven putative guanine quadruplexes (G4) in the RNA genome of tick-borne encephalitis virus (TBEV), a flavivirus causing thousands human infections and numerous deaths every year. The formation G4s was confirmed by biophysical methods on synthetic oligonucleotides derived from predicted TBEV sequences. TBEV-5, located at NS4b/NS5 boundary conserved among all known flaviviruses, tested along with its mutated variants for interactions panel G4 ligands, ability to affect...
Abstract DNA guanine quadruplexes are all based on stacks of tetrads, but they can be many types differing by mutual strand orientation, topology, position and structure loops, the number molecules constituting their structure. Here we have studied a series nine fragments (G 3 Xn) G , where X = A, C or T, n 1, 2 3, to find how particular bases numbers enable folding molecule into quadruplex what type is formed. We show that any single base between blocks gives rise only four‐molecular...
Abasic (AP) lesions are the most frequent type of damages occurring in cellular DNA. Here we describe conformational effects AP sites substituted for 2'-deoxyadenosine first (ap7), second (ap13) or third (ap19) loop quadruplex formed K(+) by human telomere DNA 5'-d[AG3(TTAG3)3]. CD spectra and electrophoresis reveal that presence does not hinder formation intramolecular quadruplexes. NMR show structural heterogeneity is substantially reduced ap7 ap19 as compared to wild-type. These two (ap7...
i-Motif (iM) is a four stranded DNA structure formed by cytosine-rich sequences, which are often present in functionally important parts of the genome such as promoters genes and telomeres. Using electronic circular dichroism UV absorption spectroscopies electrophoretic methods, we examined effect naturally occurring base lesions on folding stability iM human telomere sequence (C3TAA)3C3T. The results demonstrate that TAA loop lesions, apurinic site 8-oxoadenine substituting for adenine,...
Abstract Guanine tetraplexes are a biologically relevant alternative of the Watson and Crick duplex DNA. It is thought that potassium or other cations present in cavity between consecutive guanine tetrads an integral part tetraplexes. Here we show using CD spectroscopy ethanol induces like even better than cations. We examples stabilizing cases when fail to do so. Hence, besides A‐form Z‐form, stabilizes another conformation DNA, i.e., discuss mechanism stabilization. Use will permit studies...
Ionizing radiation produces clustered damage to DNA which is difficult repair and thus more harmful than single lesions. Clustered lesions have only been investigated in dsDNA models. Introducing the term 'clustered G-quadruplexes' we report here on structural effects of multiple tetrahydrofuranyl abasic sites replacing loop adenines (A/AP) tetrad guanines (G/AP) quadruplexes formed by human telomere d[AG3(TTAG3)3] (htel-22) d[TAG3(TTAG3)3TT] (htel-25) K+ solutions. Single triple A/APs...
There are two basic mechanisms that associated with the maintenance of telomere length, which endows cancer cells unlimited proliferative potential. One mechanism, referred to as alternative lengthening telomeres (ALT), accounts for approximately 10–15% all human cancers. Tumours engaged in ALT pathway characterised by presence single stranded 5′-C-rich telomeric overhang (C-overhang). This recently identified hallmark cancers distinguishes them from healthy tissues and renders C-overhang a...
Abstract Guanine quadruplexes (G4s) are noncanonical forms of nucleic acids that frequently found in genomes. The stability G4s depends, among other factors, on the number G‐tetrads. Three‐ or four‐tetrad and antiparallel two‐tetrad have been characterized experimentally; however, existence an intramolecular (i. e., not dimeric multimeric) parallel‐stranded DNA G4 has never experimentally observed. Many sequences compatible with can be important genomic regions, such as promoters, for which...
The transfer of protons or proton donor/acceptor abilities is an important phenomenon in many biomolecular systems.
Guanine quadruplexes, recently reported to form in vivo, represent a broad spectrum of non-canonical conformations nucleic acids. The actual conformation might differ between water solutions and crowding or dehydrating that better reflect the conditions cell. Here we show, using spectroscopic techniques, most guanine substitutions prevent conformational switch from antiparallel hybrid forms parallel ones when induced by agents. inhibitory effect does not depend on position substitution, but,...
As a widely distributed parasitic nematode of ruminants, Haemonchus contortus has become resistant to most anthelmintic classes, there been major demand for new compounds against H. and related nematodes. Recent phenotypic screening revealed two compounds, designated as BLK127 HBK4, that are active larvae. The present study was designed assess the activity these eggs adults, hepatotoxicity in rats sheep, well biotransformation adults ovine liver. Both exhibited no inhibitory effect on...
Recently, we reported an inhibitory effect of guanine substitutions on the conformational switch from antiparallel to parallel quadruplexes (G4) induced by dehydrating agents. As a possible cause, proposed difference in sensitivity and resulting thermodynamic stability. Reports influence biophysical properties intramolecular are rare. Moreover, such reports often complicated multimerisation tendencies quadruplexes. To address this incomplete knowledge, employed circular dichroism...