(A) Structure of the 70S•RelA complex lacking deacyl-tRNA in the A site (Structure I) reveals the C-terminal superdomain comprising the RIS and ACT domains (red). This superdomain binds near the A …
Structure I-IV map resolution and refinement statistics.
All particles were initially aligned to a single model, resulting in a 3.5 Å resolution averaged map. 3D classification into 15 classes yielded 7 high-resolution classes of which 4 were found to …
For panels (A–D), the maps were B-factor sharpened by applying a B-factor of 42 Å2 (Structure II) or -65 Å2 (Structure I, III and IV). (A) Cryo-EM map of Structure I, 70S•RelA complex in the absence …
The N-terminal portion of L11 contacts the elbow of A/R tRNA. Structure IV is shown colored as in Figure 1.
Domains are shown in different colors, the numbers denote approximate amino acid positions demarcating the domains. The view of the structures of RelA and A/R tRNA (green) in the lower panel shows …
(A) In the absence of A-site tRNA (Structure I), the C-terminal superdomain of RelA interacts with the intersubunit bridge B1a. The ACT domain interacts with the A-site finger (helix 38 of 23S rRNA) …
(A) Cryo-EM map (gray) and the structural model of the C-terminal ACT domain and its interaction with the bulged A896 of the A-site finger (ASF) of 23S ribosomal RNA (Structure III). The cryo-EM map …
(A) EMD-2373 (Agirrezabala et al., 2013) was segmented according to the atomic model for Structure IV. The segmentation reveals density for the RIS and ACT domains at the subunit interface, as …
(A) The 3´ CCA end of A/R tRNA pins the TGS domain against helix 5 of 16S rRNA. (B). Interactions of the terminal nucleotides of the A/R tRNA with the TGS domain. (C) Comparison of the TGS domain …
(A) The conformations of the TGS domain and interactions with the CCA end of A/R tRNA are similar in Structures II, III and IV. RelA TGS domains from Structures II, III, and IV (aa 404–487) were …
(A) Pseudo-hydrolase (PH; pink) and synthetase (Synth; red) domains are in the intersubunit space between the sarcin-ricin loop (SRL) of the 23S rRNA and the spur of the 16S rRNA. The N-terminal …
(A−F).Two predominant conformations of the N-terminal domains are shown, obtained by sub-classification of each Structure into three classes. In one class, the synthetase domain is in the vicinity …
(A) Position of the synthetase domain of RelA (red) in Structure IV near the tip of the spur of the 30S subunit (yellow). (B) Interaction of OAS1 (blue) with an RNA helix (magenta) results in …
(A) A/R tRNA settles into the decoding center of the 30S subunit between Structures II (grey) and IV (colored as in Figure 1). Structures II and IV were aligned on the 16S rRNA. RelA is not shown. …
(A) The position of A/R tRNA in Structure II (green) is compared with the A/T tRNA (purple) in E. coli 70S•EF-Tu•GDP•kirromycin•Phe-tRNAPhe complex (PDB: 5AFI; [Fischer et al., 2015]) and A/A tRNA …
(A) A view down on the 30S subunit from the inter-subunit interface shows the position of the decoding center (boxed). The 50S subunit (except for helix 69), small ribosomal proteins and RelA are …
Distances between Structures II, III and IV, reflecting the movement of the 30S shoulder domain from Structures II to III to IV, relative to the head and the body of the 30S subunit.
The 30S subunit adopts the most open conformation in Structure II, intermediate conformation in Structure III, and most closed conformation in Structure IV. In Structure IV, the shoulder of the 30S …
(A) Example of cryo-EM density near the decoding center in Structure III. The map was sharpened by applying a B-factor of -100 Å2 and is shown at 3.2 σ. (B) Example of cryo-EM density showing the …
(A) Cryo-EM density (shown as mesh) of the decoding center in Structure I. The map was sharpened by applying a B-factor of -120 Å2 and density is shown at 2.0 σ for mRNA, 4.0 σ for G530, 2.0 σ for …
The C-terminal domains of RelA, the RIS and the ACT, bind the ribosome at the intersubunit bridge B1a near the vacant A site, but the synthetase remains unbound and inactive. When deacyl-tRNA binds …
(A) In the absence of deacyl-tRNA, a RelA-bound 70S ribosome can accommodate EF-Tu ternary complex. Superposition of the 70S•RelA complex, Structure I, with the E. coli …
Three views (scenes) are shown: (1) A view of the complete 70S complex, as in Figure 1; two conformations of the N-terminal domain of RelA are shown for Structures II, III and IV. In Structure I, …