Sequence effects of single base loops in intramolecular quadruplex DNA.
We have examined the properties of intramolecular G-quadruplexes in which the G3 tracts are separated by single base loops. The most stable complex contained 1',2'-dideoxyribose in all three loops, while loops containing T and C were slightly less stable (by about 2 degrees C). Quadruplexes containing loops with single A residues were less stable by 8 degrees C for each T to A substitution. These folded sequences display similar CD spectra, which are consistent with the formation of parallel stranded complexes with double-chain reversal loops. These results demonstrate that loop sequence, and not just length, affects quadruplex stability.
Rachwal
Phillip A
PA
School of Biological Sciences, University of Southampton, Bassett Crescent East, Southampton SO16 7PX, UK.
Brown
Tom
T
Fox
Keith R
KR
D001483:Base Sequence; D004247:DNA / Q000737:chemistry* / Q000235:genetics*; D003855:Deoxyribose / Q000032:analysis; D054856:G-Quadruplexes; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry / Q000235:genetics; D013816:Thermodynamics
D009841:Oligonucleotides; D003855:Deoxyribose; D004247:DNA