5mdy

Structure of ArfA and TtRF2 bound to the 70S ribosome (pre-accommodated state)Structure of ArfA and TtRF2 bound to the 70S ribosome (pre-accommodated state)

5mdy, resolution 3.35Å Show:Asymmetric Unit Biological Assembly Structural highlights 5mdy is a 10 chain structure with sequence from Escherichia coli, Escherichia coli K-12 and Thermus thermophilus HB8. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 3.35Å Ligands: Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RS19_ECOLI In the E.coli 70S ribosome in the initiation state (PubMed:12809609) it has been modeled to contact the 23S rRNA of the 50S subunit forming part of bridge B1a; this bridge is broken in the model with bound EF-G. The 23S rRNA contact site in bridge B1a is modeled to differ in different ribosomal states (PubMed:12859903), contacting alternately S13 or S19. In the 3.5 angstroms resolved ribosome structures (PubMed:16272117) the contacts between L5, S13 and S19 bridge B1b are different, confirming the dynamic nature of this interaction. Bridge B1a is not visible in the crystallized ribosomes due to 23S rRNA disorder.[HAMAP-Rule:MF_00531] Protein S19 forms a complex with S13 that binds strongly to the 16S ribosomal RNA. Contacts the A site tRNA.[HAMAP-Rule:MF_00531] Publication Abstract from PubMed Ribosomes stall when they encounter the end of messenger RNA (mRNA) without an in-frame stop codon. In bacteria, these "nonstop" complexes can be rescued by alternative ribosome-rescue factor A (ArfA). We used electron cryomicroscopy to determine structures of ArfA bound to the ribosome with 3'-truncated mRNA, at resolutions ranging from 3.0 to 3.4 angstroms. ArfA binds within the ribosomal mRNA channel and substitutes for the absent stop codon in the A site by specifically recruiting release factor 2 (RF2), initially in a compact preaccommodated state. A similar conformation of RF2 may occur on stop codons, suggesting a general mechanism for release-factor-mediated translational termination in which a conformational switch leads to peptide release only when the appropriate signal is present in the A site. Translational termination without a stop codon.,James NR, Brown A, Gordiyenko Y, Ramakrishnan V Science. 2016 Dec 16;354(6318):1437-1440. Epub 2016 Dec 1. PMID:27934701 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribosome 3D structures