SITE-SPECIFIC CLEAVAGE OF TRANSFER-RNA BY IMIDAZOLE AND OR PRIMARY AMINE GROUPS BOUND AT THE 5'-END OF OLIGODEOXYRIBONUCLEOTIDES/

Sequence specific RNA cleaving molecules were synthesized by attaching novel polyamine derivatives bearing imidazole and/or primary amine gr oups to the 5'-end of DNA oligonucleotides as the sequence-recognizing moieties. The actions of the molecules on a half-tRNA(Asp) were inves tigated. The oligonucleotides directed the nuclease activity (the imid azole and the primary amine are the catalytic groups) of the enzyme to the nucleotides directly adjacent to the complementary target sequenc e on the substrate RNA. The cleavage reaction shows a bell-shaped pH d ependence with a maximum at pH 7.0, indicating the participation of pr otonated and non-protonated imidazoles residues in the process. The sp ecificity of these hybrid enzymes can be easily altered, and they shou ld prove to be useful tools for probing RNA structures in solution and as potential reactive groups in antisense oligonucleotide derivatives . We also describe the site-specific cleavage of tRNA(Asp) by the clea ving reagents bearing imidazole and/or primary amine groups at the 5'- end of oligodeoxyribonucleotides. (C) 1998 Elsevier Science B.V.