Comparison of ttRRF-binding positions before and after EF-G binding. (A, B) Cryo-EM densities and (C) flexibly fitted atomic coordinates corresponding to ttRRF in complex 1 (pink) and complex 2 (red) are superimposed. The overall direction and magnitude of ttRRF movement is depicted by straight arrows. The direction of rotational shift in domain II of ttRRF, upon EF-G binding, is indicated with curved arrows (see also Supplementary Figure S6). Thumbnails to the lower left in (A, C) depict the orientation of the 70S ribosome: In (A), the ribosome is in top view, whereas in (B, C) it is shown from the L7/L12 stalk side of the 50S subunit to reveal the shift in the elbow region of RRF.