Binding of initiator tRNA stabilizes the 30S PIC formed with structured mRNA. (A–C) EFRET histograms of F+11hp in the states of mRNA alone (A), 30S PIC (B), and 30S IC (C). Gray bars and orange lines represent histograms before and after buffer washing, respectively. A representative FRET time trace is shown for the 30S PIC. (D–F) Corresponding to A–C, except that F+14 was measured. (G–I) Corresponding to A–C, except that F+11 was measured. (J–L) Corresponding to A–C, except that F+8 was measured.