Fig. 1.
Combination of tRNAs charged with noncognate/unnatural amino acids and quench-flow translation kinetics. (Upper) The 5 amino- and N-alkylamino acids used in this study, one of which is shown charged on tRNAPheB. This synthetic, unmodified tRNA is based on natural E. coli tRNAPhe (black with purple anticodon; posttranscriptional modifications are in green), with changes in blue (11). (Lower) Aminoacyl-tRNA prebound to elongation factor Tu–GTP is mixed with ribosomes preinitiated with fMet-tRNAinitiator and then quenched rapidly with formic acid. Reactants are in green; products measured are in red.