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Updated: May 9, 2026

Single Molecule Fluorescence Energy Transfer Study of Ribosome Protein Synthesis
Published on: July 6, 2021
The ribosome triggers the stringent response by RelA via a highly distorted tRNA
Xabier Agirrezabala1, Israel S Fernández, Ann C Kelley
1CIC bioGUNE, Structural Biology Unit, Bldg 800, Biscay Technology Park, Derio 48160, Basque Country, Spain.
None:
The bacterial stringent response links nutrient starvation with the transcriptional control of genes. This process is initiated by the stringent factor RelA, which senses the presence of deacylated tRNA in the ribosome as a symptom of amino-acid starvation to synthesize the alarmone (p)ppGpp. Here we report a cryo-EM study of RelA bound to ribosomes bearing cognate, deacylated tRNA in the A-site. The data show that RelA on the ribosome stabilizes an unusual distorted form of the tRNA, with the acceptor arm making contact with RelA and far from its normal location in the peptidyl transferase centre.
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