Figure 4.

Structures of ribosomes from different species. The small subunit is on the left. (a) X-ray structure of the T. thermophilus 70S ribosome [12]. (b) Cryo-EM map of the E. coli 70S ribosome [46]. (c) Cryo-EM map of the yeast 80S ribosome [14]. Expansion regions are darker. The dashed line indicates a flat surface that suggests eukaryotic specialization of 60S subunit for association with a planar membrane. (d) Cryo-EM map of the mammalian mitochondrial ribosome [37]. Reproduced with permission from (a) [12], (b) [46], (c) [14] and (d) [37].