Intramolecular Stacking Association of Three Dinucleoside Monophosphates Containing Naturally-occurring 1-Methyladenosine Residue(s): m1ApA. Apm1A, m1Apm1A

Article abstract of DOI:10.1246/bcsj.55.3598

Three modified dinucleoside monophosphates containing naturally-occurring 1-methyladenosine residue, m¹ApA, Apm¹A, and m¹Apm¹A, were prepared.Intramolecular stacking association properties of these dimers were studied quantitatively using two independent methods.Thermal denaturation and acid-base titration experiments reached to the same conclusion that both m¹<*>pA and Apm¹<*> were less stacked than ApA.Acid-base titration experiment also showed that the three modified dimers, in their neutral forms, were stacked to almost the same extent as ApA.These results indicate the N-1 methylation of an adenine base does not enhance stacking interaction of dimers, in sharp contrast to the N⁶ methylation of the same base.UV hypochromicity and CD measurements were also made for the three dimers, and the results were found to be consistent with those of th estacking quotient determination.