8c97
From Proteopedia
Cryo-EM captures early ribosome assembly in action
Structural highlights
FunctionRL14_ECOLI This protein binds directly to 23S ribosomal RNA. In the E.coli 70S ribosome (PubMed:12809609) it has been modeled to make two contacts with the 16S rRNA of the 30S subunit, forming part of bridges B5 and B8, connecting the 2 subunits. Although the protein undergoes significant rotation during the transition from an initiation to and EF-G bound state, the bridges remain stable. In the 3.5 A resolved structures (PubMed:16272117) L14 and L19 interact and together make contact with the 16S rRNA in bridges B5 and B8.[1] Can also interact with RsfA, in this case bridge B8 probably cannot form, and the 30S and 50S ribosomal subunits do not associate, which represses translation.[2] Publication Abstract from PubMedRibosome biogenesis is a fundamental multi-step cellular process in all domains of life that involves the production, processing, folding, and modification of ribosomal RNAs (rRNAs) and ribosomal proteins. To obtain insights into the still unexplored early assembly phase of the bacterial 50S subunit, we exploited a minimal in vitro reconstitution system using purified ribosomal components and scalable reaction conditions. Time-limited assembly assays combined with cryo-EM analysis visualizes the structurally complex assembly pathway starting with a particle consisting of ordered density for only ~500 nucleotides of 23S rRNA domain I and three ribosomal proteins. In addition, our structural analysis reveals that early 50S assembly occurs in a domain-wise fashion, while late 50S assembly proceeds incrementally. Furthermore, we find that both ribosomal proteins and folded rRNA helices, occupying surface exposed regions on pre-50S particles, induce, or stabilize rRNA folds within adjacent regions, thereby creating cooperativity. Cryo-EM captures early ribosome assembly in action.,Qin B, Lauer SM, Balke A, Vieira-Vieira CH, Burger J, Mielke T, Selbach M, Scheerer P, Spahn CMT, Nikolay R Nat Commun. 2023 Feb 17;14(1):898. doi: 10.1038/s41467-023-36607-9. PMID:36797249[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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