Oxazolidinone Antibiotics Target the P Site onEscherichiacoliRibosomes

作者：Hiroyuki Aoki, Lizhu Ke, Susan M. Poppe, Toni Jo Poel, Elizabeth A. Weaver, Robert C. Gadwood, Richard C. Thomas, Dean L. Shinabarger, Maria Clelia GANOZA · 发表于：Antimicrobial Agents and Chemotherapy · 年份：2002 · DOI：10.1128/aac.46.4.1080-1085.2002 · 被引用次数：129 · 研究领域：RNA and protein synthesis mechanisms、RNA modifications and cancer、Peptidase Inhibition and Analysis

The oxazolidinones are a novel class of antimicrobial agents that target protein synthesis in a wide spectrum of gram-positive and anaerobic bacteria. The oxazolidinone PNU-100766 (linezolid) inhibits the binding of fMet-tRNA to 70S ribosomes. Mutations to oxazolidinone resistance in Halobacterium halobium, Staphylococcus aureus, and Escherichia coli map at or near domain V of the 23S rRNA, suggesting that the oxazolidinones may target the peptidyl transferase region responsible for binding fMet-tRNA. This study demonstrates that the potency of oxazolidinones corresponds to increased inhibition of fMet-tRNA binding. The inhibition of fMet-tRNA binding is competitive with respect to the fMet-tRNA concentration, suggesting that the P site is affected. The fMet-tRNA reacts with puromycin to form peptide bonds in the presence of elongation factor P (EF-P), which is needed for optimum specificity and efficiency of peptide bond synthesis. Oxazolidinone inhibition of the P site was evaluated by first binding fMet-tRNA to the A site, followed by translocation to the P site with EF-G. All three of the oxazolidinones used in this study inhibited translocation of fMet-tRNA. We propose that the oxazolidinones target the ribosomal P site and pleiotropically affect fMet-tRNA binding, EF-P stimulated synthesis of peptide bonds, and, most markedly, EF-G-mediated translocation of fMet-tRNA into the P site.