Figure 1.

The assignment of tRNA configurations for the FRET states of 0.2, 0.47, and 0.68. The six boxes stand for tRNA binding sites in the 50S (top three) and the 30S (the bottom three), which are labeled with “A,” “P,” and “E,” respectively. The triangle and circle stand for formyl methionine and phenylalanine, respectively. In the Hy1 state, the tRNAs are in the A/A-P/E configuration; in the C state, the tRNAs are in the A/A/-P/P configuration; and in the Hy2 state, the tRNAs are in the A/P-P/E configuration. The FRET values are corresponding to the signals between L27 (residue C53 is labeled with Cy5, the red star) and the A-site labeled tRNA (position D16/17 is labeled with Cy3, the blue star). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]