Figure 3. Interactions of the TGS domain of RelA with the A/R tRNA and 16S rRNA.
(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 bound with the CCA end of the A/R tRNA (this work) with the dimeric TGS domain from C. leptum RSH (Forouhar et al., 2009), showing that the A/R tRNA disrupts the dimerization surface of the isolated homologous TGS domain. Superposition was performed by the structural alignment of the all-atom models of the TGS domain (Structure IV) and the TGS dimer (PDB: 3HVZ). The TGS dimer is shown in blue; other molecules are labeled and colored as in Figure 1. Structure IV is shown in all panels.
Figure 3—figure supplement 1. Interactions of the TGS domain with the A/R tRNA.
(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 superimposed. The 30S subunit is not shown for clarity. (B) Cryo-EM density and interactions of the TGS domain with the CCA end of the A/R tRNA. The map for Structure III, which was sharpened by applying a B-factor of −120 Å2, is shown at 2.35 σ. Colors are as in Figure 1.