Guanine quadruplex formation by RNA/DNA hybrid analogs of Oxytricha telomere G(4)T(4)G(4) fragment
Jazyk angličtina Země Spojené státy americké Médium print
Typ dokumentu časopisecké články, práce podpořená grantem
PubMed
18491413
DOI
10.1002/bip.21015
Knihovny.cz E-zdroje
- MeSH
- cirkulární dichroismus MeSH
- DNA chemie MeSH
- draslík chemie MeSH
- G-kvadruplexy * MeSH
- guanin chemie MeSH
- kationty chemie MeSH
- Oxytricha chemie genetika MeSH
- RNA chemie MeSH
- roztoky MeSH
- sodík chemie MeSH
- telomery chemie MeSH
- thymin chemie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- DNA MeSH
- draslík MeSH
- guanin MeSH
- kationty MeSH
- RNA MeSH
- roztoky MeSH
- sodík MeSH
- thymin MeSH
Using circular dichroism spectroscopy, gel electrophoresis, and ultraviolet absorption spectroscopy, we have studied quadruplex folding of RNA/DNA analogs of the Oxytricha telomere fragment, G(4)T(4)G(4), which forms the well-known basket-type, antiparallel quadruplex. We have substituted riboguanines (g) for deoxyriboguanines (G) in the positions G1, G9, G4, and G12; these positions form the terminal tetrads of the G(4)T(4)G(4) quadruplex and adopt syn, syn, anti, and anti glycosidic geometries, respectively. We show that substitution of a single sugar was able to change the quadruplex topology. With the exception of G(4)T(4)G(3)g, which adopted an antiparallel structure, all the RNA/DNA hybrid analogs formed parallel, bimolecular quadruplexes in concentrated solution at low salt. In dilute solutions ( approximately 0.1 mM nucleoside), the RNA/DNA hybrids substituted at positions 4 or 12 adopted antiparallel quadruplexes, which were especially stable in Na(+) solutions. The hybrids substituted at positions 1 and 9 preferably formed parallel quadruplexes, which were more stable than the nonmodified G(4)T(4)G(4) quadruplex in K(+) solutions. Substitutions near the 3'end of the molecule affected folding more than substitutions near the 5'end. The ability to control quadruplex folding will allow further studies of biophysical and biological properties of the various folding topologies.
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