G Quadruplex Structure
Mostrando 13-24 de 38 artigos, teses e dissertações.
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13. NMR solution structure of a parallel LNA quadruplex
The solution structure of a locked nucleic acid (LNA) quadruplex, formed by the oligomer d(TGGGT), containing only conformationally restricted LNA residues is reported. NMR and CD spectroscopy, as well as molecular dynamics and mechanic calculations, has been used to characterize the complex. The molecule adopts a parallel stranded conformation with a 4-fold
Oxford University Press.
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14. Unfolding of quadruplex structure in the G-rich strand of the minisatellite repeat by the binding protein UP1
The mouse hypervariable minisatellite (MN) Pc-1 consists of tandem repeats of d(GGCAG) and flanked sequences. We have previously demonstrated that single-stranded d(GGCAG)n folds into the intramolecular folded-back quadruplex structure under physiological conditions. Because DNA polymerase progression in vitro is blocked at the repeat, the characteristic int
The National Academy of Sciences.
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15. In vitro generated antibodies specific for telomeric guanine-quadruplex DNA react with Stylonychia lemnae macronuclei
Most eukaryotic telomeres contain a repeating motif with stretches of guanine residues that form a 3′-terminal overhang extending beyond the telomeric duplex region. The telomeric repeat of hypotrichous ciliates, d(T4G4), forms a 16-nucleotide 3′-overhang. Such sequences can adopt parallel-stranded as well as antiparallel-stranded quadruplex conformation
The National Academy of Sciences.
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16. The effect of chemical modifications on the thermal stability of different G-quadruplex-forming oligonucleotides
A systematic study of the thermal and conformational properties of chemically modified G-quadruplexes of different molecularities is reported. The effect of backbone charge and atom size, thymine/uracyl substitution as well as the effect of modification at the ribose 2′-position was analyzed by UV spectroscopy. Additional calorimetric studies were performe
Oxford University Press.
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17. Structure-based design of selective and potent G quadruplex-mediated telomerase inhibitors
The telomerase enzyme is a potential therapeutic target in many human cancers. A series of potent inhibitors has been designed by computer modeling, which exploit the unique structural features of quadruplex DNA. These 3,6,9-trisubstituted acridine inhibitors are predicted to interact selectively with the human DNA quadruplex structure, as a means of sp
The National Academy of Sciences.
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18. The contribution of thymine-thymine interactions to the stability of folded dimeric quadruplexes.
The loop of four thymines in the sodium form of the dimeric folded quadruplex [d(G3T4G3)]2 assumes a well-defined structure in which hydrogen bonding between the thymine bases appears to contribute to the stability and final conformation of the quadruplex. We have investigated the importance of the loop interactions by systematically replacing each thymine i
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19. Cell senescence and telomere shortening induced by a new series of specific G-quadruplex DNA ligands
Telomeres of human chromosomes contain a G-rich 3′-overhang that adopts an intramolecular G-quadruplex structure in vitro which blocks the catalytic reaction of telomerase. Agents that stabilize G-quadruplexes have the potential to interfere with telomere replication by blocking the elongation step catalyzed by telomerase and can therefore act as antitumor
The National Academy of Sciences.
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20. NMR observation of T-tetrads in a parallel stranded DNA quadruplex formed by Saccharomyces cerevisiae telomere repeats.
We report here the NMR structure of the DNA sequence d-TGGTGGC containing two repeats of Saccharomyces cerevisiae telomere DNA which is unique in that it has a single thymine in the repeat sequence and the number of Gs can vary from one to three. The structure is a novel quadruplex incor-porating T-tetrads formed by symmetrical pairing of four Ts via O4-H3 H
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21. Synthesis of unimolecularly circular G-quadruplexes as prospective molecular probes
Synthesis of unimolecularly circular G-quadruplex has been accomplished for the first time during our investigation on the template basis of G-quadruplex through chemical ligations of guanine-rich linear sequences of oligodeoxyribonucleotides. The uniqueness of this newly designed circularization course is its self-recognition and self-templating on the scal
Oxford University Press.
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22. Specific interactions of distamycin with G-quadruplex DNA
Distamycin binds the minor groove of duplex DNA at AT-rich regions and has been a valuable probe of protein interactions with double-stranded DNA. We find that distamycin can also inhibit protein interactions with G-quadruplex (G4) DNA, a stable four-stranded structure in which the repeating unit is a G-quartet. Using NMR, we show that distamycin binds speci
Oxford University Press.
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23. Thrombin-binding DNA aptamer forms a unimolecular quadruplex structure in solution.
We have used two-dimensional 1H NMR spectroscopy to study the conformation of the thrombin-binding aptamer d(GGTTGGTGTGGTTGG) in solution. This is one of a series of thrombin-binding DNA aptamers with a consensus 15-base sequence that was recently isolated and shown to inhibit thrombin-catalyzed fibrin clot formation in vitro [Bock, L. C., Griffin, L. C., La
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24. The bi-loop, a new general four-stranded DNA motif
The crystal structure of the cyclic octanucleotide d
contains two independent molecules that form a novel quadruplex by means of intermolecular Watson–Crick A⋅T pairs and base stacking. A virtually identical quadruplex composed of G⋅C pairs was found by earlier x-ray analysis of the linear heptamer d(GCATGCT), when the DNA was looped in the The National Academy of Sciences of the USA.