RNA-cleaving 10-23 deoxyribozyme with a single amino acid-like functionality operates without metal ion cofactors

摘要

A series of 10-23 deoxyribozymes (D2-D9) containing single amino-acid-bearing nucleosides (thr~6dA, hisam~6dA, hisam~5dU and ncmnm~5dU) at positions 4, 5, 8 or 15 of the catalytic core was obtained by chemical synthesis. The deoxyribozymes were screened for their catalytic efficiency, and in the presence of 1 mM Mg~(2+) two of them, containing at position 8 either hisam~5dU (D8) or ncmnm~5dU (D9), were found to be RNA nucleases several times more active than their non-modified precursor. Moreover, in the magnesium-free TRIS or PIPES buffers, these enzymes were able to catalyze the cleavage of the phosphodiester bond located between the 5'-GpU-3' sequence of the complementary RNA substrate. The cleavage reaction proceeded with the highest efficiency at pH > 7.