Nonenzymatic Oligomerization of Ribonucleotides: Towards in vitro Selection Experiments

Inspired by the polymerase chain reaction, orthogonal primer–template pairs have been applied in template‐controlled oligomerization experiments with Orgel's imidazole‐activated ribonucleotide‐5′‐phosphates. Variation of the linker length allowed us to monitor the extension of both primers simultaneously on a DNA sequencer. Sets of hexapyrimidine primers were found that are capable of inducing the reciprocal synthesis of each other's binding site. Considerable cross‐inhibition by different monomers was observed. However, this effect is a function of primer sequence and can disappear in favorable cases. With random sequences introduced into the templates, selection experiments are within reach. First results are reported below.