Iterative selection rounds result in the enrichment of sense suppression by orthogonal tRNAs. (A) The binding of [35S]Met-labeled mRNA–peptide fusions to streptavidin-agarose for rounds 0–4 were measured by scintillation counting. Negative controls indicate the percent of mRNA–peptide fusions bound to immobilized streptavidin without any exogenous tRNAs added for each round during translation. The addition of 4.0 μg of the biocytin–tRNANNC pool to the translation reaction for each round is also shown. For a higher stringency selection in round 3, only 1.0 μg of the biocytin–tRNANNC pool was added. (B) Dose-response curve of the biocytin–tRNANNC pool on the translation of round 3 clones. Values for A and B are expressed as the percent of [35S]Met-labeled mRNA–peptide fusions bound to immobilized streptavidin.
