Figure 2.

Secondary structure and base sequence of the hairpin constituting the building core for library generation. The structure consists of a loop (U₅U₆C₇G₈), and a stem region (defined by G₁–C₄ and G₉–C₁₂ residues) that includes the ‘loop-closing base pair’ C·G. During diversity-oriented nucleic acid synthesis (DONAS) of the library, the stem can be either DNA:DNA ‘DD’, RNA:RNA ‘RR’, 2′,5′-RNA:2′,5′-RNA ‘RR’, DNA:RNA ‘DR’, DNA:2′,5′-RNA ‘DR’, or RNA:2′,5′-RNA ‘RR’, while the loop was modified with DNA ‘D’, RNA ‘R’ and 2′,5′-RNA ‘R’ residues.