G Quadruplex Structure
Mostrando 1-12 de 38 artigos, teses e dissertações.
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1. Identificação de estruturas biológicas por microscopia de força atômica / Identification of biological structures by atomic force microscopy
Este trabalho tem como finalidade mostrar a importância dos diferentes modos da Microscopia de Varredura por Ponta de Prova (SPM) numa abordagem complementar para o estudo de dois diferentes sistemas biológicos. O processo de formação de biofilmes da bactéria fitopatogênica Xylella fastidiosa (Xf) foi o primeiro sistema abordado neste trabalho. Neste c
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 18/11/2011
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2. Direct evidence for a G-quadruplex in a promoter region and its targeting with a small molecule to repress c-MYC transcription
The nuclease hypersensitivity element III1 upstream of the P1 promoter of c-MYC controls 85–90% of the transcriptional activation of this gene. We have demonstrated that the purine-rich strand of the DNA in this region can form two different intramolecular G-quadruplex structures, only one of which seems to be biologically relevant. This biologically relev
The National Academy of Sciences.
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3. Divalent transition metal cations counteract potassium-induced quadruplex assembly of oligo(dG) sequences.
Nucleic acids containing tracts of contiguous guanines tend to self-associate into four-stranded (quadruplex) structures, based on reciprocal non-Watson-Crick (G*G*G*G) hydrogen bonds. The quadruplex structure is induced/stabilized by monovalent cations, particularly potassium. Using circular dichroism, we have determined that the induction/stabilization of
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4. A DNA polymerase stop assay for G-quadruplex-interactive compounds.
We have developed and characterized an assay for G-quadruplex-interactive compounds that makes use of the fact that G-rich DNA templates present obstacles to DNA synthesis by DNA polymerases. Using Taq DNA polymerase and the G-quadruplex binding 2, 6-diamidoanthraquinone BSU-1051, we find that BSU-1051 leads to enhanced arrest of DNA synthesis in the presenc
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5. Identification and Characterization of Nucleolin as a c-myc G-quadruplex-binding Protein*
myc is a proto-oncogene that plays an important role in the promotion of cellular growth and proliferation. Understanding the regulation of c-myc is important in cancer biology, as it is overexpressed in a wide variety of human cancers, including most gynecological, breast, and colon cancers. We previously demonstrated that a guanine-rich region upstream of
American Society for Biochemistry and Molecular Biology.
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6. Small-Molecule Selectively Recognizes Human Telomeric G-Quadruplex DNA and Regulates Its Conformational Switch
Structural complexity is an inherent feature of the human telomeric sequence, and it presents a major challenge for developing ligands of pharmaceutical interest. Recent studies have pointed out that the induction of a quadruplex or change of a quadruplex conformation on binding may be the most powerful method to exert the desired biological effect. In this
The Biophysical Society.
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7. Quadruplex structure of d(G3T4G3) stabilized by K+ or Na+ is an asymmetric hairpin dimer.
The ends of chromosomes contain repeats of guanine-rich sequences that can assume highly compact conformations and are presumed necessary for their biological role in chromosomal stabilization and association. We have investigated the conformational behavior of d(G3T4G3) as a function of the addition of either KCl or NaCl, in the concentration range of 50-20
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8. Telomerase inhibitors based on quadruplex ligands selected by a fluorescence assay
The reactivation of telomerase activity in most cancer cells supports the concept that telomerase is a relevant target in oncology, and telomerase inhibitors have been proposed as new potential anticancer agents. The telomeric G-rich single-stranded DNA can adopt in vitro an intramolecular quadruplex structure, which has been shown to inhibit telomerase
The National Academy of Sciences.
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9. Structural transition from antiparallel to parallel G-quadruplex of d(G4T4G4) induced by Ca2+
Guanine quadruplex (G-quadruplex) structures are formed by guanine-rich oligonucleotides. Because of their in vivo and in vitro importance, numerous studies have been demonstrated that the structure and stability of the G-quadruplex are dependent on the sequence of oligonucleotide and environmental conditions such as existing cations. Previously, we quantita
Oxford University Press.
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10. Ethidium derivatives bind to G-quartets, inhibit telomerase and act as fluorescent probes for quadruplexes
The telomeric G-rich single-stranded DNA can adopt in vitro an intramolecular quadruplex structure, which has been shown to directly inhibit telomerase activity. The reactivation of this enzyme in immortalized and most cancer cells suggests that telomerase is a relevant target in oncology, and telomerase inhibitors have been proposed as new potential an
Oxford University Press.
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11. Mutations in the G-quadruplex silencer element and their relationship to c-MYC overexpression, NM23 repression, and therapeutic rescue
We have demonstrated that a parallel G-quadruplex structure in the c-MYC promoter functions as a transcriptional repressor element. Furthermore, a specific G-to-A mutation in this element results in destabilization of the G-quadruplex repressor element and an increase in basal transcriptional activity. To validate this model in an in vivo context, we have ex
National Academy of Sciences.
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12. Structural properties of the [d(G3T4G3)]2 quadruplex: evidence for sequential syn-syn deoxyguanosines.
Two-dimensional 1H NMR studies on the dimeric hairpin quadruplex formed by d(G3T4G3) in the presence of either NaCl or KCl are presented. In the presence of either salt, the quadruplex structure is characterized by half the guanine nucleosides in the syn conformation about the glycosidic bond, the other half in the anti conformation, as reported for other si