7TTU

50S ribosomal subunit from Staphylococcus aureus (Strain ATCC43300)

Summary for 7TTU

• Entry DOI: 10.2210/pdb7ttu/pdb
• EMDB information: 26124
• Descriptor: 50S ribosomal protein L19, 50S ribosomal protein L28, 50S ribosomal protein L29, ... (27 entities in total)
• Functional Keywords: 50s subunit, antibiotic resistance, ribosome
• Biological source: Staphylococcus aureus; More
• Total number of polymer chains: 27
• Total formula weight: 1307517.55

Authors

Belousoff, M.J.,Piper, S.,Johnson, R. (deposition date: 2022-02-01, release date: 2022-07-06, Last modification date: 2022-09-14)

Primary citation

Perlaza-Jimenez, L.,Tan, K.S.,Piper, S.J.,Johnson, R.M.,Bamert, R.S.,Stubenrauch, C.J.,Wright, A.,Lupton, D.,Lithgow, T.,Belousoff, M.J.
A Structurally Characterized Staphylococcus aureus Evolutionary Escape Route from Treatment with the Antibiotic Linezolid.
Microbiol Spectr, 10:e0058322-e0058322, 2022

PubMed Abstract: Methicillin-resistant Staphylococcus aureus (MRSA) is a bacterial pathogen that presents great health concerns. Treatment requires the use of last-line antibiotics, such as members of the oxazolidinone family, of which linezolid is the first member to see regular use in the clinic. Here, we report a short time scale selection experiment in which strains of MRSA were subjected to linezolid treatment. Clonal isolates which had evolved a linezolid-resistant phenotype were characterized by whole-genome sequencing. Linezolid-resistant mutants were identified which had accumulated mutations in the ribosomal protein uL3. Multiple clones which had two mutations in uL3 exhibited resistance to linezolid, 2-fold higher than the clinical breakpoint. Ribosomes from this strain were isolated and subjected to single-particle cryo-electron microscopic analysis and compared to the ribosomes from the parent strain. We found that the mutations in uL3 lead to a rearrangement of a loop that makes contact with Helix 90, propagating a structural change over 15 Å away. This distal change swings nucleotide U2504 into the binding site of the antibiotic, causing linezolid resistance. Antibiotic resistance poses a critical problem to human health and decreases the utility of these lifesaving drugs. Of particular concern is the "superbug" methicillin-resistant Staphylococcus aureus (MRSA), for which treatment of infection requires the use of last-line antibiotics, including linezolid. In this paper, we characterize the atomic rearrangements which the ribosome, the target of linezolid, undergoes during its evolutionary journey toward becoming drug resistant. Using cryo-electron microscopy, we describe a particular molecular mechanism which MRSA uses to become resistant to linezolid.

PubMed: 35736238
DOI: 10.1128/spectrum.00583-22

Experimental method

ELECTRON MICROSCOPY (3 Å)