1. Volume 7, Issue 5, Pages 1037-1045 (May 2001)
Localization of the Ribosomal Protection Protein Tet(O) on the Ribosome and the Mechanism of Tetracycline Resistance 
Christian M.T. Spahn, Gregor Blaha, Rajendra K. Agrawal, Pawel Penczek, Robert A. Grassucci, Catharine A. Trieber, Sean R. Connell, Diane E. Taylor, Knud H. Nierhaus, Joachim Frank 
Molecular Cell 
Volume 7, Issue 5, Pages (May 2001)
DOI: /S (01)

2. Figure 1 Cryo-EM Reconstructions of the 70S Ribosome from E. coli
Reconstructions of the 70S ribosome from E. coli in complex with (a) Tet(O)·GTPγS and fMet-tRNA in the P site and (b) in complex with EF-G·GMPPCP (adapted from Agrawal et al., 1999a). Tet(O) and EF-G are shown in red, and the tRNA is shown in green. The view is from the L7/L12 site. The small inset on the left is in the corresponding orientation, with the 30S and 50S subunits colored in yellow and blue, respectively, and has been added as an interpretation aid. Landmarks, small subunit: h, head; b, body; sh, shoulder; and sp, spur. Large subunit: CP, central protuberance; SB, stalk base; and h38, helix 38 of 23S rRNA
Molecular Cell 2001 7, DOI: ( /S (01) )

3. Figure 2 Relative Arrangement of tRNAs and Protein Factors
(a) Masses corresponding to Tet(O)·GTPγS are shown in red, the P-site bound fMet-tRNA is shown in green, together with a model of the tRNA in pink in a position equivalent to the observed position of A-site bound tRNA in the pretranslocational ribosome (Agrawal et al., 2000).
(b) The mass corresponding to EF-G in the GTP form (Agrawal et al., 1999b) is in red, together with the A-site (pink) and P-site bound tRNAs (green) as in (a). Roman numerals II–V and the letter G mark the domains of EF-G and the homologous domains in Tet(O)
Molecular Cell 2001 7, DOI: ( /S (01) )

4. Figure 3
50S Subunit Part of the E. coli 70S Cryo-EM Density Maps from Two Experiments, Showing the Binding Locations of the Two Protein Factors
(a) Tet(O) bound to fMet-tRNA·70S.
(b) EF-G bound to 70S in the presence of noncleavable GTP analog GMPPCP (Agrawal et al., 1999a).
Tet(O) and EF-G are shown in red, and the mass corresponding to the P-site bound fMet-tRNA is shown in green. The view is from the 30S side. The position of L9 is indicated (Matadeen et al., 1999; Spahn et al., 2000). Note that the C-terminal domain of L9 has different positions in the Tet(O) (a) and the EF-G map (b). Landmarks: CP, central protuberance; L1, L1 protuberance; SB, stalk base; St, extended stalk; h34, helix 34 of 23S rRNA; h38, helix 38 of 23S rRNA; and h69, helix 69 of 23S rRNA (bridge B2a)
Molecular Cell 2001 7, DOI: ( /S (01) )

5. Figure 4 Location of Protein Factors on the 30S Subunit
The 30S parts of the fMet-tRNA·70S·Tet(O) map (a) and the 70S·EF-G·GMPPCP map (b) (Agrawal et al., 1999a). The density corresponding to Tet(O) or EF-G is shown in red (a and b), and the density of fMet-tRNA is shown in green (a). The 30S part of the fMet-tRNA·70S map. Landmarks: h, head; b, body; h44, helix 44 of 16S rRNA; pt, platform; sh, shoulder; and sp, spur
Molecular Cell 2001 7, DOI: ( /S (01) )

6. Figure 5
Comparison of the Tet(O) Binding Site with the Tc Binding Site (Stereo View)
The atomic model of the 30S ribosomal subunit in complex with Tc (Brodersen et al., 2000) (Protein Data Bank ID code 1HNW) was docked into the cryo-EM map of the fMet-tRNA·70S·Tet(O). The EM density corresponding to Tet(O) is shown together with part of the atomic model corresponding to the Tc binding site. Roman numerals II–V and the letter G mark the domains in Tet(O). The atomic model is color coded as follows: yellow, helix 18; cyan, helix31; pink, helix 34; and blue, protein S12. Tc is shown in green. The figure was done using Ribbons (Carson, 1991)
Molecular Cell 2001 7, DOI: ( /S (01) )

7. Figure 6
Model of the Elongation Cycle in the Presence of Tc and Tet(O)
Various experimentally inferred tRNA and elongation factor positions are overlaid on the map of the 70S ribosome at 11.5 Å resolution (Gabashvili et al., 2000) to sketch the various functional states of the ribosome. The 70S ribosome is shown as a transparent map seen from the top, with the 30S subunit (yellow) below the 50S subunit (blue). The normal elongation cycle (states [a]–[e]) (Agrawal et al., 2000) starts with the ribosome in the posttranslocational state (a). The P-site bound peptidyl-tRNA is shown in green, and the E-site bound tRNA is shown in yellow. Ternary complex binding leads to an intermediate (b), where the E-site bound tRNA moves into the E2 site (brown) and subsequently dissociates from the ribosome. After GTP cleavage and dissociation of EF-Tu·GDP, the ribosome is in the pretranslocational state (c) with aminoacyl-tRNA (pink) in the A site and peptidyl-tRNA (green) in the P site. After spontaneous peptide bond formation, the pretranslocational ribosome (d) is occupied with a peptidyl-tRNA in the A site (purple) and deacylated tRNA in the P site. This state of the ribosome is the substrate for EF-G, which binds in the GTP conformation and translocates the tRNAs from A and P sites into P (green) and E sites (yellow), respectively (e). The elongation cycle finishes with the dissociation of EF-G·GDP, which brings the ribosome again into the posttranslocational state (a).
The events that might occur in the presence of Tc and Tet(O) are sketched out in (f)–(h). The presence of Tc leads to a posttranslocational ribosome with Tc (orange) bound to the decoding region ([f]; see Brodersen et al., 2000). As an indication that the status of the E-site bound tRNA is unclear and that its position is speculative in (f)–(h), it is shown in gray. Tc still allows the binding of ternary complex (g) but prevents stable A-site binding after dissociation of EF-Tu·GDP. Therefore, the ribosome is trapped, oscillating between states (f) and (g), which rapidly depletes the GTP pool of the cell (Brodersen et al., 2000). To rescue the ribosome, Tet(O)·GTP (red) binds to the ribosome and chases Tc (h). After GTP cleavage on Tet(O), Tet(O)·GDP leaves the ribosome, bringing it back into the normal posttranslocational state (a). (Adapted from Agrawal et al., 2000, with permission by The Rockefeller Press.)
Molecular Cell 2001 7, DOI: ( /S (01) )

8. Molecular Cell 2001 7, 1037-1045DOI: (10.1016/S1097-2765(01)00238-6)