title: Linezolid-dependent function and structure adaptation of ribosomes in a Staphylococcus epidermidis strain exhibiting linezolid dependence.
abstract: Linezolid-dependent growth was recently reported in Staphylococcus epidermidis clinical strains carrying mutations associated with linezolid resistance. To investigate this unexpected behavior at the molecular level, we isolated active ribosomes from one of the linezolid-dependent strains and we compared them with ribosomes isolated from a wild-type strain. Both strains were grown in the absence and presence of linezolid. Detailed biochemical and structural analyses revealed essential differences in the function and structure of isolated ribosomes which were assembled in the presence of linezolid. The catalytic activity of peptidyltransferase was found to be significantly higher in the ribosomes derived from the linezolid-dependent strain. Interestingly, the same ribosomes exhibited an abnormal ribosomal subunit dissociation profile on a sucrose gradient in the absence of linezolid, but the profile was restored after treatment of the ribosomes with an excess of the antibiotic. Our study suggests that linezolid most likely modified the ribosomal assembly procedure, leading to a new functional ribosomal population active only in the presence of linezolid. Therefore, the higher growth rate of the partially linezolid-dependent strains could be attributed to the functional and structural adaptations of ribosomes to linezolid.
authors.affiliation: Department of Biochemistry, School of Medicine, University of Patras, Patras, Greece.
authors.forename: Sofia
authors.initials: S
authors.lastname: Kokkori
authors.affiliation: Department of Biochemistry, School of Medicine, University of Patras, Patras, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Apostolidi
authors.affiliation: Department of Microbiology, Medical School, University of Athens, Athens, Greece.
authors.forename: Athanassios
authors.initials: A
authors.lastname: Tsakris
authors.affiliation: Department of Microbiology, Medical School, University of Athens, Athens, Greece.
authors.forename: Spyros
authors.initials: S
authors.lastname: Pournaras
authors.affiliation: Department of Biochemistry, School of Medicine, University of Patras, Patras, Greece cstath@med.upatras.gr dinosg@upatras.gr.
authors.forename: Constantinos
authors.initials: C
authors.lastname: Stathopoulos
authors.affiliation: Department of Biochemistry, School of Medicine, University of Patras, Patras, Greece cstath@med.upatras.gr dinosg@upatras.gr.
authors.forename: George
authors.initials: G
authors.lastname: Dinos
mesh_terms: D000081:Acetamides / Q000494:pharmacology*; D000222:Adaptation, Physiological; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002499:Centrifugation, Density Gradient; D024881:Drug Resistance, Bacterial / Q000235:genetics; D007700:Kinetics; D000069349:Linezolid; D023303:Oxazolidinones / Q000494:pharmacology*; D010458:Peptidyl Transferases / Q000235:genetics / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000187:drug effects; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D013212:Staphylococcus epidermidis / Q000737:chemistry / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D000081:Acetamides; D000900:Anti-Bacterial Agents; D023303:Oxazolidinones; D012269:Ribosomal Proteins; D010458:Peptidyl Transferases; D000069349:Linezolid