In an attempt to get a better insight in specific base pairing by self-organization of DNA or RNA, the synthesis of a complete set of monoalkyl ribonucleotides is described. The thermodynamic phase and mixing properties of these self-organizing RNA amphiphiles were analyzed within two dimensions using film balance technique. The pure compounds form stable monolayers at the air−water interface on a physiological buffer. In analogy to base-paired RNA or DNA in solution, the monolayers were mostly stabilized by complexing the phosphate groups by calcium or magnesium ions. By use of mixtures of RNA amphiphiles, specific recognition and base-pair formation of monoalkyl phospho adenosine/uridine were demonstrated.

We describe the properties of aqueous micelles obtained from n-alkyl phosphoryl nucleosides, in particular n-hexadecylphosphoryladenosine (C16-AMP), uridine (C16-UMP), and -cytidine (C16-CMP). These compounds were obtained enzymatically. It is shown that each of these compounds form micelles spontaneously in water with a critical micelle concentration in the range of 20−35 μM and an aggregation number of 69, which indicates that the chemical structure of the bases has no significant influence on the aggregation behavior. UV-absorption and circular dichroic measurements suggest that the nucleoside is in an aqueous environment, as expected from the amphiphilic character of the compounds. UV absorption suggests a moderate self-stacking among the bases for each type of micelle. When we mixed micelles bearing complementary bases with each other (e.g., C16-AMP with C16-CMP), a weak hypochromic effect was observed, which can be taken as an indication of complementary base interaction. However, such electronic perturbation was observed also in noncomplementary bases, e.g., when C16-CMP micelles were mixed with C16-UMP micelles. These micelle data are compared with the corresponding data obtained with liposomes obtained from phosphatidyl nucleosides. All together, these data illustrate a novel type of polymeric nucleoside interaction with which no covalent bonds form among the monomers, and in which the nucleobases are distributed as a supramolecular spherical aggregate.