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Search results for: G-QUADRUPLEXES
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Why Are Left-Handed G-Quadruplexes Scarce?
PublicationG-quadruplexes (G4s) are nucleic acid structures crucial for the regulation of gene expression and genome maintenance. While they hold promise as nanodevice components, achieving desired G4 folds requires understanding the interplay between stability and structural properties, like helicity. Although right-handed G4 structures dominate the experimental data, the molecular basis for this preference over left-handed helicity is unclear....
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Mechanism of recognition of parallel G-quadruplexes by DEAH/RHAU helicase DHX36 explored by molecular dynamics simulations
PublicationBecause of high stability and slow unfolding rates of G-quadruplexes (G4), cells have evolved specialized helicases that disrupt these non-canonical DNA and RNA structures in an ATP-dependent manner. One example is DHX36, a DEAH-box helicase, which participates in gene expression and replication by recognizing and unwinding parallel G4s. Here, we studied the molecular basis for the high affinity and specificity of DHX36 for parallel-type...
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Mechanism of recognition of parallel G-quadruplexes by DEAH/RHAU helicase DHX36 explored by molecular dynamics simulations
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Why do G-quadruplexes dimerize through the 5’-ends? Driving forces for G4 DNA dimerization examined in atomic detail
PublicationG-quadruplexes (G4) are secondary structures formed by guanine-rich nucleic acid sequences and shown to exist in living cells where they participate in regulation of gene expression and chromosome maintenance. G-quadruplexes with solvent-exposed guanine tetrads show the tendency to associate together through cofacial stacking, which may be important for packaging of G4-forming sequences and allows for the design of higher-order...
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Design, synthesis and high antitumor potential of new unsymmetrical bisacridine derivatives towards human solid tumors, specifically pancreatic cancers and their unique ability to stabilize DNA G-quadruplexes
PublicationNew promising unsymmetrical bisacridine derivatives (UAs), have been developed. Three groupsincluding 36 compounds were synthesized by the condensation of 4-nitro or 4-methylacridinone, imi-dazoacridinone and triazoloacridinone derivatives with 1-nitroacridine compounds linked with anaminoalkyl chain. Cytotoxicity screening revealed the high potency of these compounds against severaltumor cell lines. Particularly, imidazoacridinone-1-nitroacridine...
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Initial geometries and MD trajectories of right- and left-handed G-quadruplexes
Open Research DataDataset contains initial geometries of 12 monomeric, 2-tetrad G-quadruplexes featuring three different loop lengths (T1, T2 and T3), adapted by the sequence GGTnGGTnGGTnGG where n=(1-3). For each loop length variant two directions of strand progression (clockwise (+) and anti-clockwise (-)) and two helicities (left-handed (LH) and right-handed (RH))...
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NMR-Based Structural Insight into DNA G-Quadruplex
PublicationEmerging as a promising area in anticancer research, noncanonical DNA structures such as G-quadruplexes are studied using NMR spectroscopy. NOESY spectra reveals crucial interactions between ligands and G-quadruplexes, helping to understand non-covalent binding mechanisms. This knowledge is essential for rational drug design targeting these structures.
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Molecular dynamics simulations reveal the balance of forces governing the formation of a guanine tetrad—a common structural unit of G-quadruplex DNA
PublicationG-quadruplexes (G4) are nucleic acid conformations of guanine-rich sequences, in which guanines are arranged in the square-planar G-tetrads, stacked on one another. G4 motifs form in vivo and are implicated in regulation of such processes as gene expression and chromosome maintenance. The structure and stability of various G4 topologies were determined experimentally; however, the driving forces for their formation are not fully...
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Unraveling the Interplay between DNA and Proteins: A Computational Exploration of Sequence and Structure-Specific Recognition Mechanisms
PublicationMy PhD dissertation focused on DNA-protein interactions and the recognition of specific DNA sequences and structures. I discovered that acidic amino acid residues (Asp/Glu) play a crucial role by exhibiting a preference for cytosine. Their contribution to binding affinity depends on nearby cytosines, balancing electrostatic repulsion with specific interactions. Acidic residues act as negative selectors, discouraging non-cytosine...
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c-Myc Protein Level Affected by Unsymmetrical Bisacridines Influences Apoptosis and Senescence Induced in HCT116 Colorectal and H460 Lung Cancer Cells
PublicationUnsymmetrical bisacridines (UAs) are highly active antitumor compounds. They contain in their structure the drugs previously synthesized in our Department: C-1311 and C-1748. UAs exhibit different properties than their monomer components. They do not intercalate to dsDNA but stabilize the G-quadruplex structures, particularly those of the MYC and KRAS genes. Since MYC and KRAS are often mutated and constitutively expressed in cancer...
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Thermodynamic, Anticoagulant, and Antiproliferative Properties of Thrombin Binding Aptamer Containing Novel UNA Derivative
PublicationThrombin is a serine protease that plays a crucial role in hemostasis, fibrinolysis, cell proliferation, and migration. Thrombin binding aptamer (TBA) is able to inhibit the activity of thrombin molecule via binding to its exosite I. This 15-nt DNA oligonucleotide forms an intramolecular, antiparallel G-quadruplex structure with a chair-like conformation. In this paper, we report on our investigations on the influence of certain...
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Michał Jurkowski
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