PT  - JOURNAL ARTICLE
AU  - Kaitlyn Tsai
AU  - Vanja Stojković
AU  - D. John Lee
AU  - Iris D. Young
AU  - Teresa Szal
AU  - Nora Vazquez-Laslop
AU  - Alexander S. Mankin
AU  - James S. Fraser
AU  - Danica Galonić Fujimori
TI  - Structural basis for context-specific inhibition of translation by oxazolidinone antibiotics
AID  - 10.1101/2021.08.10.455846
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.08.10.455846
4099  - http://biorxiv.org/content/early/2021/08/10/2021.08.10.455846.short
4100  - http://biorxiv.org/content/early/2021/08/10/2021.08.10.455846.full
AB  - The antibiotic linezolid, the first clinically approved member of the oxazolidinone class, inhibits translation of bacterial ribosomes by binding to the peptidyl transferase center. Recent work has demonstrated that linezolid does not inhibit peptide bond formation at all sequences but rather acts in a context-specific manner, namely when alanine occupies the penultimate position of the nascent chain. In this study, we determined that the second-generation oxazolidinone radezolid also induces stalling with alanine at the penultimate position. However, the molecular basis for context-specificity of these inhibitors has not been elucidated. In this study, we determined high-resolution cryo-EM structures of both linezolid and radezolid-stalled ribosome complexes. These structures reveal that the alanine side chain fits within a small hydrophobic crevice created by oxazolidinone, resulting in improved ribosome binding. Modification of the ribosome by the antibiotic resistance enzyme Cfr disrupts stalling by forcing the antibiotic to adopt a conformation that narrows the hydrophobic alanine pocket. Together, the structural and biochemical findings presented in this work provide molecular understanding of context-specific inhibition of translation by clinically important oxazolidinone antibiotics.Competing Interest StatementThe authors have declared no competing interest.