Abstract:

The concept of base stacking of nucleotides in solutions has been well accepted. However, direct evidence has not been found. Here we report for the first time the intermolecular NOE cross peaks between ATP (adenosine 5’-triphosphate) and GTP (guanosine 5’-triphosphate), which unambiguously indicates the base stacking of nucleotides in solutions. In 400 mmol•L -1 ATPGTP solutions, the base protons of ATP, AH2 and AH8, show NOE cross peaks with the sugar protons of GTP, GH1′,GH2′ and GH3′.Also there are NOE cross peaks between the base proton of GTP (GH8) and the sugar protons of ATP. Possible conformations of base stacking in solutions have been discussed, and the distance between the stacked bases is estimated.

Key words: Nucleotide, Base stacking, NOESY