Artificial ribonucleases. 1. Synthesis and properties of conjugates containing an RNA-binding fragment with Lys residues and an RNA-hydrolyzing fragment with imidazole residue

A series of RNA-hydrolyzing constructions was synthesized on the basis of p eptide-like molecules containing residues of L-lysine, histamine and histid ine methylester. These were shown to hydrolyze RNA effectively at neutral p H values. The in vitro transcript of tRNA(Lys) from human mitochondria and a tRNA-like fragment of RNA of Turnip Yellow Mosaic Virus were used in the experiments. Our chemical RNases quantitatively depolymerize some definite sequences (CA greater than or equal to UA > CG much greater than UC, CC, or CU) in both RNA molecules under optimum conditions. Moreover, no other sit es were affected and no statistical hydrolysis was observed even after prol onged RNA incubation with the compounds of this series. The depolymerizatio n rate of the RNA substrates exhibits a complex dependence on the concentra tion of ions of monovalent metals and on the concentration of the artificia l ribonucleases.