Funding Organization(s): French National Research Agency, European Research Council, Human Frontier Science Program, Russian Government Program of Competitive Growth of Kazan Federal University, National Institutes of Health
Primary Citation of Related Structures:   5FCI, 5FCJ
PubMed Abstract: 
The ribosome has been described as a ribozyme in which ribosomal RNA is responsible for peptidyl-transferase reaction catalysis. The W255C mutation of the universally conserved ribosomal protein uL3 has diverse effects on ribosome function (e.g., increased affinities for transfer RNAs, decreased rates of peptidyl-transfer), and cells harboring this mutation are resistant to peptidyl-transferase inhibitors (e.g., anisomycin). These observations beg the question of how a single amino acid mutation may have such wide ranging consequences. Here, we report the structure of the vacant yeast uL3 W255C mutant ribosome by X-ray crystallography, showing a disruption of the A-site side of the peptidyl-transferase center (PTC). An additional X-ray crystallographic structure of the anisomycin-containing mutant ribosome shows that high concentrations of this inhibitor restore a "WT-like" configuration to this region of the PTC, providing insight into the resistance mechanism of the mutant. Globally, our data demonstrate that ribosomal protein uL3 is structurally essential to ensure an optimal and catalytically efficient organization of the PTC, highlighting the importance of proteins in the RNA-centered ribosome.
Organizational Affiliation: 
Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS UMR7104, INSERM U964, 1 rue Laurent Fries, 67404 Illkirch-Graffenstaden, France. Electronic address: mailliot@igbmc.fr.