4TUB

Crystal structure of tRNA-Thr bound to Codon ACC-C on the Ribosome

This is a non-PDB format compatible entry.

Summary for 4TUB

• Entry DOI: 10.2210/pdb4tub/pdb
• Descriptor: 16S rRNA, 30S ribosomal protein S10, 30S ribosomal protein S11, ... (59 entities in total)
• Functional Keywords: protein biosynthesis, ribosome, rna, trna, transfer rna, 30s, 50s, 70s, 16s, 23s, ribosomal subunit, mrna frameshift
• Biological source: Thermus thermophilus HB8; More
• Total number of polymer chains: 112
• Total formula weight: 4440252.64

Authors

Fagan, C.E.,Dunham, C.M. (deposition date: 2014-06-24, release date: 2015-05-13, Last modification date: 2024-11-20)

Primary citation

Fagan, C.E.,Maehigashi, T.,Dunkle, J.A.,Miles, S.J.,Dunham, C.M.
Structural insights into translational recoding by frameshift suppressor tRNASufJ.
Rna, 20:1944-1954, 2014

PubMed Abstract: The three-nucleotide mRNA reading frame is tightly regulated during translation to ensure accurate protein expression. Translation errors that lead to aberrant protein production can result from the uncoupled movement of the tRNA in either the 5' or 3' direction on mRNA. Here, we report the biochemical and structural characterization of +1 frameshift suppressor tRNA(SufJ), a tRNA known to decode four, instead of three, nucleotides. Frameshift suppressor tRNA(SufJ) contains an insertion 5' to its anticodon, expanding the anticodon loop from seven to eight nucleotides. Our results indicate that the expansion of the anticodon loop of either ASL(SufJ) or tRNA(SufJ) does not affect its affinity for the A site of the ribosome. Structural analyses of both ASL(SufJ) and ASL(Thr) bound to the Thermus thermophilus 70S ribosome demonstrate both ASLs decode in the zero frame. Although the anticodon loop residues 34-37 are superimposable with canonical seven-nucleotide ASLs, the single C31.5 insertion between nucleotides 31 and 32 in ASL(SufJ) imposes a conformational change of the anticodon stem, that repositions and tilts the ASL toward the back of the A site. Further modeling analyses reveal that this tilting would cause a distortion in full-length A-site tRNA(SufJ) during tRNA selection and possibly impede gripping of the anticodon stem by 16S rRNA nucleotides in the P site. Together, these data implicate tRNA distortion as a major driver of noncanonical translation events such as frameshifting.

PubMed: 25352689
DOI: 10.1261/rna.046953.114

Experimental method

X-RAY DIFFRACTION (3.6 Å)