Journal Article

Structural basis for PoxtA-mediated resistance to phenicol and oxazolidinone antibiotics

Pelechano, Vicent, Atkinson, Gemma C., Kasari, Marje, Huch, Susanne, Takada, Hiraku, Wilson, Daniel N., Nersisyan, Lilit, Sundsfjord, Arnfinn, Hegstad, Kristin, Turnbull, Kathryn Jane, Murina, Victoriia, Crowe-McAuliffe, Caillan, Hauryliuk, Vasili

2022

Overview

PoxtA and OptrA are ATP binding cassette (ABC) proteins of the F subtype (ABCF). They confer resistance to oxazolidinone and phenicol antibiotics, such as linezolid and chloramphenicol, which stall translating ribosomes when certain amino acids are present at a defined position in the nascent polypeptide chain. These proteins are often encoded on mobile genetic elements, facilitating their rapid spread amongst Gram-positive bacteria, and are thought to confer resistance by binding to the ribosome and dislodging the bound antibiotic. However, the mechanistic basis of this resistance remains unclear. Here we refine the PoxtA spectrum of action, demonstrate alleviation of linezolid-induced context-dependent translational stalling, and present cryo-electron microscopy structures of PoxtA in complex with the Enterococcus faecalis 70S ribosome. PoxtA perturbs the CCA-end of the P-site tRNA, causing it to shift by ∼4 Å out of the ribosome, corresponding to a register shift of approximately one amino acid for an attached nascent polypeptide chain. We postulate that the perturbation of the P-site tRNA by PoxtA thereby alters the conformation of the attached nascent chain to disrupt the drug binding site. PoxtA confers resistance to ribosome-targeting oxazolidinone (linezolid) and chloramphenicol antibiotics. Here, Crowe-McAuliffe et al. provide structural insights into how binding of PoxtA to the ribosome indirectly promotes drug dissociation.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 101/28 / 38/39 / 45/91 / 631/326/22/1290 / 631/326/22/1434 / 631/337/574/1789 / 631/535/1258/1259 / Amino acids / Anti-Bacterial Agents - pharmacology / Antibiotics / Bacteria / Binding sites / Biologi / Biological Sciences / Chains / Chloramphenicol / Chloromycetin / Conformation / Cryoelectron Microscopy / Drug Resistance, Bacterial - genetics / Electron microscopy / Enterococcus faecalis - genetics / Gram-positive bacteria / Humanities and Social Sciences / Linezolid / Linezolid - pharmacology / multidisciplinary / Natural Sciences / Naturvetenskap / Oxazolidinones - pharmacology / Perturbation / Polypeptides / Proteins / Ribosomes / RNA, Transfer - genetics / Science / Science (multidisciplinary) / Stalling / Transfer RNA / tRNA