RNase T1 mimicking artificial ribonuclease

Recently, artificial ribonucleases (aRNases)--conjugates of oligodeoxyribonucleotides and peptide (LR)(4)-G-amide--were designed and assessed in terms of the activity and specificity of RNA cleavage. The conjugates were shown to cleave RNA at Pyr-A and G-X sequences. Variations of oligonucleotide length and sequence, peptide and linker structure led to the development of conjugates exhibiting G-X cleavage specificity only. The most efficient catalyst is built of nonadeoxyribonucleotide of unique sequence and peptide (LR)(4)-G-NH(2) connected by the linker of three abasic deoxyribonucleotides (conjugate pep-9). Investigation of the cleavage specificity of conjugate pep-9 showed that the compound is the first single-stranded guanine-specific aRNase, which mimics RNase T1. Rate enhancement of RNA cleavage at G-X linkages catalysed by pep-9 is 10(8) compared to non-catalysed reaction, pep-9 cleaves these linkages only 10(5)-fold less efficiently than RNase T1 (k(cat_RNase T1)/k(cat)_(pep)(-9) = 10(5)).