6xz7
From Proteopedia
E. coli 50S ribosomal subunit in complex with dirithromycin, fMet-Phe-tRNA(Phe) and deacylated tRNA(iMet).
Structural highlights
FunctionRL5_ECOLI This is 1 of the proteins that binds and probably mediates the attachment of the 5S RNA into the large ribosomal subunit, where it forms part of the central protuberance. Its 5S rRNA binding is significantly enhanced in the presence of L18.[HAMAP-Rule:MF_01333_B] In the 70S ribosome in the initiation state (PubMed:12809609) was modeled to contact protein S13 of the 30S subunit (bridge B1b), connecting the 2 subunits; the protein-protein contacts between S13 and L5 in B1b change in the model with bound EF-G implicating this bridge in subunit movement (PubMed:12809609 and PubMed:18723842). In the two 3.5 A resolved ribosome structures (PubMed:16272117) the contacts between L5, S13 and S19 are different, confirming the dynamic nature of this interaction.[HAMAP-Rule:MF_01333_B] Contacts the P site tRNA; the 5S rRNA and some of its associated proteins might help stabilize positioning of ribosome-bound tRNAs.[HAMAP-Rule:MF_01333_B] Publication Abstract from PubMedMacrolides are one of the most successful and widely used classes of antibacterials, which kill or stop the growth of pathogenic bacteria by binding near the active site of the ribosome and interfering with protein synthesis. Dirithromycin is a derivative of the prototype macrolide erythromycin with additional hydrophobic side chain. In our recent study, we have discovered that the side chain of dirithromycin forms lone pair-pi stacking interaction with the aromatic imidazole ring of the His69 residue in ribosomal protein uL4 of the Thermus thermophilus 70S ribosome. In the current work, we found that neither the presence of the side chain, nor the additional contact with the ribosome, improve the binding affinity of dirithromycin to the ribosome. Nevertheless, we found that dirithromycin is a more potent inhibitor of in vitro protein synthesis in comparison with its parent compound, erythromycin. Using high-resolution cryo-electron microscopy, we determined the structure of the dirithromycin bound to the translating Escherichia coli 70S ribosome, which suggests that the better inhibitory properties of the drug could be rationalized by the side chain of dirithromycin pointing into the lumen of the nascent peptide exit tunnel, where it can interfere with the normal passage of the growing polypeptide chain. Insights into the improved macrolide inhibitory activity from the high-resolution cryo-EM structure of dirithromycin bound to the E. coli 70S ribosome.,Pichkur EB, Paleskava A, Tereshchenkov AG, Kasatsky P, Komarova ES, Shiriaev DI, Bogdanov AA, Dontsova OA, Osterman IA, Sergiev PV, Polikanov YS, Myasnikov AG, Konevega AL RNA. 2020 Jun;26(6):715-723. doi: 10.1261/rna.073817.119. Epub 2020 Mar 6. PMID:32144191[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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