Fig. 2.

Kinetics of dipeptide synthesis with aminoacyl- and N-alkylaminoacyl-tRNA_S^Phe. Kinetics of dipeptide synthesis (▴) from fMet-tRNA_i^fMet and from Phe-tRNA^Phe (A), Phe-tRNA^PheB (B), Ala-tRNA^PheB (C), N-methyl-Phe-tRNA^PheB (D), N-butyl-Phe-tRNA^PheB (E), and Pro-tRNA^PheB (F) are shown. Kinetics of the prerequisite, faster GTP hydrolysis (▵) by EF-Tu in the same reactions are shown. The ribosome had the Phe codon UUC at the A site. All kinetics were measured at 37 °C in high-accuracy polyamine containing LS3 buffer (see Materials and Methods). Representative plots are shown for each assay.