6BZ7

Thermus thermophilus 70S containing 16S G299A point mutation and near-cognate ASL Leucine in A site.

This is a non-PDB format compatible entry.

Summary for 6BZ7

• Entry DOI: 10.2210/pdb6bz7/pdb
• Descriptor: 16S rRNA, 30S ribosomal protein S10, 30S ribosomal protein S11, ... (58 entities in total)
• Functional Keywords: protein biosynthesis, ribosomes, rna, trna, transfer rna, 30s, 50s, 70s, 16s, 23s, ribosomal subunit, bacterial proteins, codon, transfer, translational, ribosome
• Biological source: Thermus thermophilus HB8; More
• Total number of polymer chains: 112
• Total formula weight: 4487895.38

Authors

Hoffer, E.D.,Maehigashi, T.,Fagan, C.E.,Dunham, C.M. (deposition date: 2017-12-22, release date: 2018-11-14, Last modification date: 2023-10-04)

Primary citation

Hoffer, E.D.,Maehigashi, T.,Fredrick, K.,Dunham, C.M.
Ribosomal ambiguity (ram) mutations promote the open (off) to closed (on) transition and thereby increase miscoding.
Nucleic Acids Res., 47:1557-1563, 2019

PubMed Abstract: 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.

PubMed: 30476222
DOI: 10.1093/nar/gky1178

Experimental method

X-RAY DIFFRACTION (3.68 Å)