Fig. 3.

EF4 effects on rate and accuracy of in vitro protein synthesis. (A, Left) Kinetics at 30 °C of poly(Phe) synthesis under optimal (4.5 mM) and high Mg²⁺ concentrations (14 mM) using S100 enzymes, which already contain EF4. (A, Right) Leu misincorporation per 1,000 incorporated Phe under the same conditions. (B, Left) Kinetics of oligo(Phe) in a pure system containing precharged 10 Phe-tRNAs per ribosome and the factors EF-Tu, EF-Ts, EF-G, and ± EF4. (B, Right) Oligo(Phe) incorporation in the pure system after 20 min at optimal and unfavorable Mg²⁺ concentrations (4.5 and 30 mM Mg²⁺, respectively). (C) Oligo(Phe) synthesis in the pure system incubated 30 °C for 60 min at various K(acetate) concentrations. (D) Oligo(Phe) synthesis in the pure system at various ionic concentrations either at 30 or 20 °C for 20 min as indicated.