Abstract: | The interaction of adenylyl (3′ → 5′) adenosine (ApA) with polyuridylic acid in D2O solution at neutral pD has been studied by high resolution proton magnetic, resonance spectroscopy. At temperatures above ~32°C, no evidence was obtained for the interaction of ApA with poly U. Below this temperature, a rigid triple-stranded complex involving a stoichiometry of 1 adenine to 2 uracil bases is formed, presumably via specific adenine–uracil base-pairing and cooperative base stacking of the adenine bases in a manner similar to that previously reported for the adenosine–poly U complex. |