Cleavage of short oligoribonucleotides by a Zn2+ binding multi-nucleating azacrown conjugate.

A multi-nucleating azacrown conjugate ( 5a ) consisting of two 3,5-bis(1,5,9-triazacyclododecan-3-yloxymethyl)benzyl groups attached to 1 and 7 sites of cyclen was prepared and tested as an artificial ribonuclease. The conjugate in the presence of five equivalents of zinc nitrate expectedly showed uridine selectivity comparable to that 1,3,5-tris(1,5,9-triazacyclododecan-3-yl)benzene ( 2 ), a compound known to bind to two adjacent uridine residues and cleave the intervening phosphodiester bond. 5a was, however, unable to discriminate between two and three adjacent uridine residues, but cleaved oligonucleotides containing a UpU and UpUpU site at a comparable rate, even when present at sub-saturating concentrations. [ABSTRACT FROM AUTHOR]