Probing the Function of Nucleotides in the Catalytic Cores of the 8−17 and 10−23 DNAzymes by Abasic Nucleotide and C3 Spacer Substitutions

8-17 and 10-23 are the two most comprehensively studied RNA-cleaving DNAzymes to date and have the ability to carry out sequence-specific cleavage of both all-RNA or chimeric RNA/DNA substrates. Mutagenesis studies of 8-17 and 10-23 DNAzymes using alternative natural nucleotides to substitute a given nucleotide in the DNAzyme sequence have found that both DNAzymes are able to tolerate a variety of alterations at many sequence locations. …