Fig. 1. (A) Chemical structures of modified deoxynucleotides for RNase A mimic: dAimTP 1, dUgaTP 2, dCaaTP 3. (B) Unimolecular construct for in vitro selection of all-RNA cleaving DNAzymes. The 17 nt all-RNA substrate is depicted in red and is taken from the HIV-LTR untranslated message; the potential cleavage was directed at either of the four unpaired RNA linkages (indicated by arrows) opposite the initial random region (N40); the two fixed sequence regions (P1 and P2) flanking the N40 random region ensuring PCR amplification are depicted in black, with the nucleosides in the substrate recognition arms (arm I and arm II) underlined.
