Molecular Recognition through H-Bonding in Micelles Formed by Dioctylphosphatidyl Nucleosides

Abstract

Short-chain phospholiponucleosides, namely diC 8 P-adenosine and diC 8 P-uridine have been, for the first time, synthesized through an enzymatic pathway that allows transphosphatidylation of phosphatidylcholines. Phospholiponucleosides, which have a number of potential applications in several areas such as anticancer therapy, are able to give in water self-organized aggregates. diC 8 P-adenosine and diC 8 P-uridine phosphatidylnucleosides form micelles in water solution with critical micellar concentrations around 10 -3 M. Mixed micelles, formed from equimolar mixture of phosphatidylnucleosides, show nonideal mixing, suggesting specific interactions between the polar heads of the nucleolipids. We show through NMR, UV−vis, and CD spectroscopies that in mixed micelles formed from diC 8 P-adenosine and diC 8 P-uridine phosphatidylnucleosides, both stacking and hydrogen-bonding interactions are present between the bases at the micellar surface. NMR indicates that a H-bonded Watson−Crick adduct is formed despite the exposure of the bases to the highly competitive aqueous environment. This suggests a specific molecular recognition pattern between the complementary bases adenosine and uridine that resembles polynucleotides' behavior.