FIGURE 5. Rearrangements and packing of the switch loop of RF1.
From the following article:
Structural basis for translation termination on the 70S ribosome
Martin Laurberg, Haruichi Asahara, Andrei Korostelev, Jianyu Zhu, Sergei Trakhanov & Harry F. Noller
Nature 454, 852-857(14 August 2008)
doi:10.1038/nature07115
a, Superposition of domain 2 of free RF2 (ref. 37; pink) on that of ribosome-bound RF1 (yellow). Rearrangement of the switch loop (red in free RF2 and orange in bound RF1) results in reorientation of 
7 and extension of its length by two helical turns. Free RF2 is shown because of local disorder in the structure of the otherwise similar free RF1 (ref. 37). b, Stereo view of packing of the switch loop (orange) in a pocket formed by elements of protein S12 (dark blue), the 
-sheet of domain 2 of RF1 (yellow), the 530 loop of 16S rRNA (cyan) and nucleotides A1492 of 16S rRNA (cyan) and A1913 of 23S rRNA (grey), which form the floor of the pocket.
