Single-stranded RNAs adopt frequently folded hairpin structures, which contain apical loops often involved in biological processes through specific interactions with proteins or complementary RNA sequences. Several examples of interactions between two natural or synthetic RNA loops have been reported in literature. [1], [2], [3], [4], [5] and [6] These interactions forming very stable 'kissing-loop' complexes resulted from complementary base pairing of the residues of the ...