Specific RNA Dinucleotide Cleavage by a Synthetic Calix[4]arene-Based Trinuclear Metallo(II)-phosphodiesterase

Large rate enhancements and considerable nucleobase specificity in the catalytic transesterification of RNA dinucleotides are observed with the calix[4]arene enzyme mimic 1-Zn(3) (the computer-generated model of the complex with GpG is shown). The higher activity toward GpG over ApA (factor of 160) originates from favorable substrate binding and cooperative catalytic action of all three Zn(II) ions. The heterotrinuclear metallo-phosphoesterase mimic 1-Zn(2)Cu is even more active.