scholarly journals Mutations in Ribosomal Protein L3 Are Associated with Oxazolidinone Resistance in Staphylococci of Clinical Origin

2009 ◽  
Vol 53 (12) ◽  
pp. 5275-5278 ◽  
Author(s):  
Jeffrey B. Locke ◽  
Mark Hilgers ◽  
Karen Joy Shaw
Keyword(s):  
Staphylococcus Aureus ◽  
Sequence Analysis ◽  
Ribosomal Protein ◽  
Binding Site ◽  
Staphylococcus Epidermidis ◽  
Peptidyl Transferase ◽  
Peptidyl Transferase Center ◽  
Ribosomal Protein L3

ABSTRACT Following recent reports of ribosomal protein L3 mutations in laboratory-derived linezolid-resistant (LZDr) Staphylococcus aureus, we investigated whether similar mutations were present in LZDr staphylococci of clinical origin. Sequence analysis of a variety of LZDr isolates revealed two L3 mutations, ΔSer145 (S. aureus NRS127) and Ala157Arg (Staphylococcus epidermidis 1653059), both occurring proximal to the oxazolidinone binding site in the peptidyl transferase center. The oxazolidinone torezolid maintained a ≥8-fold potency advantage over linezolid for both strains.

scholarly journals Resistance to the Peptidyl Transferase Inhibitor Tiamulin Caused by Mutation of Ribosomal Protein L3

2003 ◽  
Vol 47 (9) ◽  
pp. 2892-2896 ◽  
Author(s):  
Jacob Bøsling ◽  
Susan M. Poulsen ◽  
Birte Vester ◽  
Katherine S. Long
Keyword(s):  
Ribosomal Protein ◽  
Drug Binding ◽  
Mechanisms Of Resistance ◽  
Peptidyl Transferase ◽  
Peptidyl Transferase Center ◽  
Resistance Determinants ◽  
Drug Binding Site ◽  
Gene Coding ◽  
Bacterial Ribosome ◽  
Ribosomal Protein L3

ABSTRACT The antibiotic tiamulin targets the 50S subunit of the bacterial ribosome and interacts at the peptidyl transferase center. Tiamulin-resistant Escherichia coli mutants were isolated in order to elucidate mechanisms of resistance to the drug. No mutations in the rRNA were selected as resistance determinants using a strain expressing only a plasmid-encoded rRNA operon. Selection in a strain with all seven chromosomal rRNA operons yielded a mutant with an A445G mutation in the gene coding for ribosomal protein L3, resulting in an Asn149Asp alteration. Complementation experiments and sequencing of transductants demonstrate that the mutation is responsible for the resistance phenotype. Chemical footprinting experiments show a reduced binding of tiamulin to mutant ribosomes. It is inferred that the L3 mutation, which points into the peptidyl transferase cleft, causes tiamulin resistance by alteration of the drug-binding site. This is the first report of a mechanism of resistance to tiamulin unveiled in molecular detail.

scholarly journals The GTPase Nog1 co-ordinates the assembly, maturation and quality control of distant ribosomal functional centers

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Purnima Klingauf-Nerurkar ◽  
Ludovic C Gillet ◽  
Daniela Portugal-Calisto ◽  
Michaela Oborská-Oplová ◽  
Martin Jäger ◽  
...  
Keyword(s):  
Quality Control ◽  
Protein Folding ◽  
Atpase Activity ◽  
Ribosomal Protein ◽  
Peptidyl Transferase ◽  
Peptidyl Transferase Center ◽  
Eukaryotic Ribosome ◽  
Ribosomal Stalk ◽  
Exit Tunnel ◽  
Ribosome Formation

Eukaryotic ribosome precursors acquire translation competence in the cytoplasm through stepwise release of bound assembly factors, and proofreading of their functional centers. In case of the pre-60S, these steps include removal of placeholders Rlp24, Arx1 and Mrt4 that prevent premature loading of the ribosomal protein eL24, the protein-folding machinery at the polypeptide exit tunnel (PET), and the ribosomal stalk, respectively. Here, we reveal that sequential ATPase and GTPase activities license release factors Rei1 and Yvh1 to trigger Arx1 and Mrt4 removal. Drg1-ATPase activity removes Rlp24 from the GTPase Nog1 on the pre-60S; consequently, the C-terminal tail of Nog1 is extracted from the PET. These events enable Rei1 to probe PET integrity and catalyze Arx1 release. Concomitantly, Nog1 eviction from the pre-60S permits peptidyl transferase center maturation, and allows Yvh1 to mediate Mrt4 release for stalk assembly. Thus, Nog1 co-ordinates the assembly, maturation and quality control of distant functional centers during ribosome formation.

scholarly journals First Report of cfr-Mediated Resistance to Linezolid in Human Staphylococcal Clinical Isolates Recovered in the United States

2008 ◽  
Vol 52 (6) ◽  
pp. 2244-2246 ◽  
Author(s):  
Rodrigo E. Mendes ◽  
Lalitagauri M. Deshpande ◽  
Mariana Castanheira ◽  
Joseph DiPersio ◽  
Michael A. Saubolle ◽  
...  
Keyword(s):  
United States ◽  
Staphylococcus Aureus ◽  
Ribosomal Protein ◽  
Staphylococcus Epidermidis ◽  
The United States ◽  
Human Infection ◽  
Clinical Isolates ◽  
23S Rrna ◽  
First Report ◽  
Linezolid Resistance

ABSTRACT Linezolid resistance has dominantly been mediated by mutations in 23S rRNA or ribosomal protein L4 genes. Recently, cfr has demonstrated the ability to produce a phenotype of resistance to not only oxazolidinones, but also other antimicrobial classes (phenicols, lincosamides, pleuromutilins, and streptogramin A). We describe the first detection of cfr-mediated linezolid resistance in Staphylococcus aureus and Staphylococcus epidermidis recovered from human infection cases monitored during the 2007 LEADER Program.

scholarly journals Structure-Activity Relationships of Diverse Oxazolidinones for Linezolid-Resistant Staphylococcus aureus Strains Possessing the cfr Methyltransferase Gene or Ribosomal Mutations

2010 ◽  
Vol 54 (12) ◽  
pp. 5337-5343 ◽  
Author(s):  
Jeffrey B. Locke ◽  
John Finn ◽  
Mark Hilgers ◽  
Gracia Morales ◽  
Shahad Rahawi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Ribosomal Proteins ◽  
Resistance Mechanisms ◽  
Structural Basis ◽  
23S Rrna ◽  
Peptidyl Transferase ◽  
Peptidyl Transferase Center ◽  
Structure Activity ◽  
Methyltransferase Gene ◽  
Key Features

ABSTRACT Staphylococcal resistance to linezolid (LZD) is mediated through ribosomal mutations (23S rRNA or ribosomal proteins L3 and L4) or through methylation of 23S rRNA by the horizontally transferred Cfr methyltransferase. To investigate the structural basis for oxazolidinone activity against LZD-resistant (LZDr) strains, we compared structurally diverse, clinically relevant oxazolidinones, including LZD, radezolid (RX-1741), TR-700 (torezolid), and a set of TR-700 analogs (including novel CD-rings and various A-ring C-5 substituents), against a panel of laboratory-derived and clinical LZDr Staphylococcus aureus strains possessing a variety of resistance mechanisms. Potency against all strains was correlated with optimization of C- and D-rings, which interact with more highly conserved regions of the peptidyl transferase center binding site. Activity against cfr strains was retained with either hydroxymethyl or 1,2,3-triazole C-5 groups but was reduced by 2- to 8-fold in compounds with acetamide substituents. LZD, which possesses a C-5 acetamide group and lacks a D-ring substituent, demonstrated the lowest potency against all strains tested, particularly against cfr strains. These data reveal key features contributing to oxazolidinone activity and highlight structural tradeoffs between potency against susceptible strains and potency against strains with various resistance mechanisms.

scholarly journals Elevated Linezolid Resistance in Clinical cfr-Positive Staphylococcus aureus Isolates Is Associated with Co-Occurring Mutations in Ribosomal Protein L3

2010 ◽  
Vol 54 (12) ◽  
pp. 5352-5355 ◽  
Author(s):  
Jeffrey B. Locke ◽  
Gracia Morales ◽  
Mark Hilgers ◽  
Kedar G. C. ◽  
Shahad Rahawi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
23S Rrna ◽  
Hospital Outbreak ◽  
Linezolid Resistance ◽  
Ribosomal Protein L3

ABSTRACT Resistance to linezolid (LZD) occurs through mutations in 23S rRNA and ribosomal proteins L3 and L4 or through methylation of 23S rRNA by Cfr. Here we report novel L3 mutations, ΔSer145/His146Tyr and ΔMet169-Gly174, co-occurring with cfr in LZD-resistant Staphylococcus aureus isolates recovered from a hospital outbreak in Madrid, Spain. LZD MIC values (16, 32, or 64 μg/ml) correlated with the presence and severity of the L3 mutation. All isolates had TR-700 (torezolid) MIC values of ≤2 μg/ml.

scholarly journals NAC covers ribosome-associated nascent chains thereby forming a protective environment for regions of nascent chains just emerging from the peptidyl transferase center.

1995 ◽  
Vol 130 (3) ◽  
pp. 519-528 ◽  
Author(s):  
S Wang ◽  
H Sakai ◽  
M Wiedmann
Keyword(s):  
Amino Acids ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Peptidyl Transferase ◽  
Nascent Polypeptide ◽  
Peptidyl Transferase Center ◽  
Protease Resistance ◽  
Protective Environment ◽  
Cytosolic Factors

We demonstrate that nascent polypeptide-associated complex (NAC) is one of the first cytosolic factors that newly synthesized nascent chains encounter. When NAC is present, nascent chains are segregated from the cytosol until approximately 30 amino acids in length, a finding consistent with the well-documented protease resistance of short ribosome-associated nascent chains. When NAC is removed, the normally protected nascent chains are susceptible to proteolysis. Therefore NAC, by covering COOH-terminal segments of nascent chains on the ribosome, perhaps together with ribosomal proteins, forms a protective environment for regions of nascent chains just emerging from the peptidyl transferase center. Since NAC is not a core ribosomal protein, the emergence of nascent chains from the ribosome may be more dynamic than previously thought.

Sign in / Sign up

Export Citation Format

Share Document