Summary information and primary citation
- PDB-id
-
11gg;
DSSR-derived features in text and
JSON formats; DNAproDB
- Class
- ribosome
- Method
- cryo-EM (3.02 Å)
- Summary
- Chimeric escherichia coli 70s ribosome containing an
evolved 16s rrna from pseudomonas aeruginosa (pa-st)
- Reference
-
Raskar T, Costello A, Badran AH, Fraser JS (2026):
"Structural
adaptations for enhanced translation kinetics in evolved
ribosomes." Biorxiv. doi: 10.64898/2026.03.05.706023.
- Abstract
- The ribosomal RNA sequence governs translation
dynamics, yet understanding how changes beyond the
conserved catalytic centers influence kinetics and protein
yield remains limited. Using orthogonal ribosome
phage-assisted continuous evolution (oRibo-PACE), we
recently reported chimeric ribosomes derived from
<i>Escherichia coli</i>, <i>Pseudomonas
aeruginosa</i>, and <i>Vibrio
cholerae</i> endowed with elevated translation rates
as compared to their starting counterparts. Here, we
structurally characterize these kinetically enhanced
ribosomes using cryo-electron microscopy and uncover a
potential relationship between 16S rRNA stability and
translation efficiency. Compared to their naive starting
points, evolved ribosomes exhibit extensive RNA structural
adaptation, often introduced by mismatches at key helical
junctions, which leads to local RNA-protein rearrangements
and destabilizes non-canonical base pairs. Compensatory
mutations that restore base-pairing stability and eliminate
flexibility reduced translational activity to wild-type
levels. Across trajectories, increased translational output
correlates with subtle, localized changes in the 16S rRNA
sequence that introduce limited structural destabilization
at specific elements. Taken together, our work provides new
insights into rRNA structural malleability and establishes
principles for engineering ribosomes with altered
translation properties.