Mirror-image RNA that binds D-adenosine

A 58-mer L -RNA ligand that binds to naturally occurring D -adenosine with a dissociation constant of 1.7 μM in solution was identified from a combinatorial library employing mirror-design. The corresponding D -RNA ligand shows identical binding affinity to L -adenosine. Reciprocal chiral specificity was also evident from ligand discrimination; the binding affinity of the L -RNA ligand for D -adenosine was 9000-fold greater than its affinity for L -adenosine and vice versa. While the D -RNA ligand was rapidly degraded in human serum, the L -RNA ligand displayed an extraordinary stability. This indicates the potential application of specifically designed L -RNA ligands as stable monoclonal antibody analogues and the development of highly stable L -ribozymes.