7y7h
Structure of the Bacterial Ribosome with human tRNA Tyr(GalQ34) and mRNA(UAC)
Structural highlights
FunctionRS19_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 PubMedTransfer RNA (tRNA) modifications are critical for protein synthesis. Queuosine (Q), a 7-deaza-guanosine derivative, is present in tRNA anticodons. In vertebrate tRNAs for Tyr and Asp, Q is further glycosylated with galactose and mannose to generate galQ and manQ, respectively. However, biogenesis and physiological relevance of Q-glycosylation remain poorly understood. Here, we biochemically identified two RNA glycosylases, QTGAL and QTMAN, and successfully reconstituted Q-glycosylation of tRNAs using nucleotide diphosphate sugars. Ribosome profiling of knockout cells revealed that Q-glycosylation slowed down elongation at cognate codons, UAC and GAC (GAU), respectively. We also found that galactosylation of Q suppresses stop codon readthrough. Moreover, protein aggregates increased in cells lacking Q-glycosylation, indicating that Q-glycosylation contributes to proteostasis. Cryo-EM of human ribosome-tRNA complex revealed the molecular basis of codon recognition regulated by Q-glycosylations. Furthermore, zebrafish qtgal and qtman knockout lines displayed shortened body length, implying that Q-glycosylation is required for post-embryonic growth in vertebrates. Glycosylated queuosines in tRNAs optimize translational rate and post-embryonic growth.,Zhao X, Ma D, Ishiguro K, Saito H, Akichika S, Matsuzawa I, Mito M, Irie T, Ishibashi K, Wakabayashi K, Sakaguchi Y, Yokoyama T, Mishima Y, Shirouzu M, Iwasaki S, Suzuki T, Suzuki T Cell. 2023 Dec 7;186(25):5517-5535.e24. doi: 10.1016/j.cell.2023.10.026. Epub , 2023 Nov 21. PMID:37992713[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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