Expanding the catalytic repertoire of nucleic acid catalysts: Simultaneousincorporation of two modified deoxyribonucleoside triphosphates bearing ammonium and imidazolyl functionalities.

Two nucleoside triphosphates, a pyrimidine modified with an ammonium functi onality and a purine modified with an imidazolyl functionality are compatib le with all conditions for a combinatorial selection of nucleic-acid cataly sts. We believe that this work is the first to demonstrate the potential fo r using not one but two modified nucleotides in tandem. The potential for a n enriched catalytic repertoire is envisioned.