@article {65009,
	title = {Ribosome{\textbullet}RelA structures reveal the mechanism of stringent response activation.},
	journal = {Elife},
	volume = {5},
	year = {2016},
	month = {2016 07 19},
	abstract = {<p>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 {\r 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 {\textquoteright}closure{\textquoteright}, providing insights into the dynamics of high-fidelity tRNA decoding.</p>
},
	keywords = {Cryoelectron Microscopy, Escherichia coli, Ligases, Protein Binding, Ribosomes, RNA, Transfer, Stress, Physiological},
	issn = {2050-084X},
	doi = {10.7554/eLife.17029},
	author = {Loveland, Anna B and Bah, Eugene and Madireddy, Rohini and Zhang, Ying and Brilot, Axel F and Grigorieff, Nikolaus and Korostelev, Andrei A}
}
