Proton Magnetic Resonance Studies of Dinucleotide Conformation in Aqueous Solution. 2′-Deoxythymidylyl-(3′,5′)-2′-deoxy-3′-thymidylate, d(TpTp)

Proton magnetic resonance studies of 2′-deoxythymidine, its 3′-and 5′-monophosphate, its 3′,5′-diphosphate, and the dimer molecules d(TpT) and d(TpTp) in aqueous solution are de scribed. Spectral analysis yields 1H–1H and 1H–31P coupling constants and 1H chemical shifts which can be discussed in terms of the conformational properties of the nucleoside fragments. An important observation is the apparent phosphate–phosphate interaction in a 3′,5′-diphosphate fragment which stabilizes the gauche-gauche conformation about the C4′—C5′ bond.