5kpx

Structure of RelA bound to ribosome in presence of A/R tRNA (Structure IV)Structure of RelA bound to ribosome in presence of A/R tRNA (Structure IV)

5kpx, resolution 3.90Å Show:Asymmetric Unit Biological Assembly Structural highlights 5kpx is a 10 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.9Å Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RL3_ECOLI One of two assembly inititator proteins, it binds directly near the 3'-end of the 23S rRNA, where it nucleates assembly of the 50S subunit.[HAMAP-Rule:MF_01325_B] Publication Abstract from PubMed Stringent response is a conserved bacterial stress response underlying virulence and antibiotic resistance. RelA/SpoT-homolog proteins synthesize transcriptional modulators (p)ppGpp, allowing bacteria to adapt to stress. RelA is activated during amino-acid starvation, when cognate deacyl-tRNA binds to the ribosomal A (aminoacyl-tRNA) site. We report four cryo-EM structures of E. coli RelA bound to the 70S ribosome, in the absence and presence of deacyl-tRNA accommodating in the 30S A site. The boomerang-shaped RelA with a wingspan of more than 100 A wraps around the A/R (30S A-site/RelA-bound) tRNA. The CCA end of the A/R tRNA pins the central TGS domain against the 30S subunit, presenting the (p)ppGpp-synthetase domain near the 30S spur. The ribosome and A/R tRNA are captured in three conformations, revealing hitherto elusive states of tRNA engagement with the ribosomal decoding center. Decoding-center rearrangements are coupled with the step-wise 30S-subunit 'closure', providing insights into the dynamics of high-fidelity tRNA decoding. Ribosome*RelA structures reveal the mechanism of stringent response activation.,Loveland AB, Bah E, Madireddy R, Zhang Y, Brilot AF, Grigorieff N, Korostelev AA Elife. 2016 Jul 19;5. pii: e17029. doi: 10.7554/eLife.17029. PMID:27434674 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribosome 3D structures