7qh4
From Proteopedia
Structure of the B. subtilis disome - collided 70S ribosome
Structural highlights
FunctionA0A063XCB6_BACIU One of the primary rRNA binding proteins. Required for association of the 30S and 50S subunits to form the 70S ribosome, for tRNA binding and peptide bond formation. It has been suggested to have peptidyltransferase activity; this is somewhat controversial. Makes several contacts with the 16S rRNA in the 70S ribosome.[HAMAP-Rule:MF_01320] Publication Abstract from PubMedRibosome rescue pathways recycle stalled ribosomes and target problematic mRNAs and aborted proteins for degradation(1,2). In bacteria, it remains unclear how rescue pathways distinguish ribosomes stalled in the middle of a transcript from actively translating ribosomes(3-6). Here, using a genetic screen in Escherichia coli, we discovered a new rescue factor that has endonuclease activity. SmrB cleaves mRNAs upstream of stalled ribosomes, allowing the ribosome rescue factor tmRNA (which acts on truncated mRNAs(3)) to rescue upstream ribosomes. SmrB is recruited to ribosomes and is activated by collisions. Cryo-electron microscopy structures of collided disomes from E. coli and Bacillus subtilis show distinct and conserved arrangements of individual ribosomes and the composite SmrB-binding site. These findings reveal the underlying mechanisms by which ribosome collisions trigger ribosome rescue in bacteria. Ribosome collisions induce mRNA cleavage and ribosome rescue in bacteria.,Saito K, Kratzat H, Campbell A, Buschauer R, Burroughs AM, Berninghausen O, Aravind L, Green R, Beckmann R, Buskirk AR Nature. 2022 Mar;603(7901):503-508. doi: 10.1038/s41586-022-04416-7. Epub 2022 , Mar 9. PMID:35264790[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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