Views of the structure of the T. thermophilus 70S ribosome. (A) to (D) are successive 90° rotations about the vertical axis; (E) is a 90° rotation around the horizontal axis of the view shown in (A). (A) View from the back of the 30S subunit. H, head; P, platform; N, neck; B, body. (B) View from the right-hand side, showing the subunit interface cavity, with the 30S subunit on the left and the 50S on the right. The anticodon arm of the A-tRNA (gold) is visible in the interface cavity. (C) View from the back of the 50S subunit. EC, the end of the polypeptide exit channel. (D) View from the left-hand side, with the 50S subunit on the left and the 30S on the right. The anticodon arm of the E-tRNA (red) is partly visible. (E) View from the top, with the 50S subunit above and the 30S below. The E-, P-, and A-tRNAs are visible in the interface cavity with their anticodon arms pointed downward into the 30S subunit. (G) Interface view of the 30S subunit [rotated 180° from (A)], showing the positions of the three tRNAs. (F) Interface view of the 50S subunit. ASF, A-site finger; SRL, sarcin-ricin loop. The different molecular components are colored for identification: cyan, 16S rRNA; gray, 23S rRNA; light blue, 5S rRNA (5S); dark blue, 30S proteins; magenta, 50S proteins. Proteins fitted to the electron density are numbered in orange; 50S proteins whose electron density has been identified but not fitted are numbered in magenta. A, P, and E are the A-, P-, and E-site tRNAs (gold, orange, and red, respectively).
From: M. M. Yusupov,.G. Zh. Yusupova, A. Baucom, K. Lieberman, T. N. Earnest, J. H. D. Cate, H. F. Noller (2001) Crystal Structure of the Ribosome at 5.5 Å Resolution, Science 292, 883-896.