6bz8

Thermus thermophilus 70S containing 16S G347U point mutation and near-cognate ASL Leucine in A site

spinqualitylabelsall models 6bz8, resolution 3.74Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6bz8 is a 22 chain structure with sequence from Escherichia coli and Thermus thermophilus HB8. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.74Å Ligands: MG, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RS13_THET8 Located at the top of the head of the 30S subunit, it contacts several helices of the 16S rRNA. In the 70S ribosome structure it contacts the 23S rRNA (bridge B1a) and protein L5 of the 50S subunit (bridge B1b), connecting the top of the two subunits; these bridges are in contact with the A site and P site tRNAs respectively and are implicated in movement during ribosome translocation. Separately contacts the tRNAs in the A and P sites.[HAMAP-Rule:MF_01315] Publication Abstract from PubMed Decoding is thought to be governed by a conformational transition in the ribosome-open (off) to closed (on)-that occurs upon codon-anticodon pairing in the A site. Ribosomal ambiguity (ram) mutations increase miscoding and map to disparate regions, consistent with a role for ribosome dynamics in decoding, yet precisely how these mutations act has been unclear. Here, we solved crystal structures of 70S ribosomes harboring 16S ram mutations G299A and G347U in the absence A-site tRNA (A-tRNA) and in the presence of a near-cognate anticodon stem-loop (ASL). In the absence of an A-tRNA, each of the mutant ribosomes exhibits a partially closed (on) state. In the 70S-G347U structure, the 30S shoulder is rotated inward and intersubunit bridge B8 is disrupted. In the 70S-G299A structure, the 30S shoulder is rotated inward and decoding nucleotide G530 flips into the anti conformation. Both of these mutant ribosomes adopt the fully closed (on) conformation in the presence of near-cognate A-tRNA, just as they do with cognate A-tRNA. Thus, these ram mutations act by promoting the open (off) to closed (on) transition, albeit in somewhat distinct ways. This work reveals the functional importance of 30S shoulder rotation for productive aminoacylated-tRNA incorporation. Ribosomal ambiguity (ram) mutations promote the open (off) to closed (on) transition and thereby increase miscoding.,Hoffer ED, Maehigashi T, Fredrick K, Dunham CM Nucleic Acids Res. 2018 Nov 22. pii: 5198528. doi: 10.1093/nar/gky1178. PMID:30476222 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribosomal protein THX 3D structures Ribosome 3D structures

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