Influence of uracil defect on DNA structure: 1H NMR investigation at 500 MHz.
The local structure of two self complementary oligonucleotides d(GTAC-GTAC) and d(GTACGUAC) which differ only by the presence of uracil, not a normal component of DNA, have been investigated by 1H NMR at 500 MHz. The two octamers exhibit the same thermodynamical constants (t 1/2, delta H), their exchangeable protons broaden and disappear at the same temperature. The T-U substitution did not induce any significant changes on non exchangeable protons resonances from 2-D COSY and 2-D NOESY experiments. So the two octamers exhibit the same global structure. The only variation was detected by 1D NOE measurements: the base orientations around the N glycosidic bonds (chi angles) are different.
D004247:DNA; D009682:Magnetic Resonance Spectroscopy; D008433:Mathematics; D008722:Methods; D009690:Nucleic Acid Conformation; D013696:Temperature; D014498:Uracil
D014498:Uracil; D004247:DNA