Figure 7: The ability of P. aeruginosa EF-Tu to deliver Phe- to the ribosome in poly(U)-dependent reactions. (a) Requirement of components for binding [3H]Phe- to the ribosome as described under Section 2. Reactions contained 1 μM (50 pmol) ribosome, 0.75 μM [3H]Phe- (37.5 pmol, 25 cpm/pmol), and 3.2 μM EF-Tu. (b) Reactions were as in “A” except that P. aeruginosa EF-Tu was varied from 0.32 to 1.6 μM in the reactions. The “tRNA bound” refers to the amount of [3H] Phe- bound to the ribosome. Background activity (minus EF-Tu) was subtracted to show only EF-Tu promoted A-site binding.