QacR Is a Repressor Protein That Regulates Expression of theStaphylococcus aureus Multidrug Efflux Pump QacA*

@article{Grkovic1998QacRIA,
  title={QacR Is a Repressor Protein That Regulates Expression of theStaphylococcus aureus Multidrug Efflux Pump QacA*},
  author={Steve Grkovic and Melissa H. Brown and Natalie J. Roberts and Ian T. Paulsen and Ronald A. Skurray},
  journal={The Journal of Biological Chemistry},
  year={1998},
  volume={273},
  pages={18665 - 18673}
}
The Staphylococcus aureus QacA protein is a multidrug transporter that confers resistance to a broad range of antimicrobial agents via proton motive force-dependent efflux of the compounds. Primer extension analysis was performed to map the transcription start points of theqacA and divergently transcribed qacRmRNAs. Each gene utilized a single promoter element, the locations of which were confirmed by site-directed mutagenesis. Fusions of theqacA and qacR promoters to a chloramphenicol acetyl… 
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The Staphylococcal QacR Multidrug Regulator Binds a Correctly Spaced Operator as a Pair of Dimers

Analysis of a resultant cysteineless QacR derivative indicated that it retained full DNA-binding activities in vivo and in vitro and continued to be fully proficient for the mediation of induction of qacA expression in response to a range of structurally dissimilar multidrug transporter substrates.

Staphylococcal multidrug efflux protein QacA.

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The QacA multidrug exporter from Staphylococcus aureus mediates resistance to a wide array of monovalent or divalent cationic, lipophilic, antimicrobial compounds via a proton motive force-dependent antiport mechanism that conforms to classical Michaelis-Menten kinetics.

LfrR Is a Repressor That Regulates Expression of the Efflux Pump LfrA in Mycobacterium smegmatis

The results suggest that the LfrR repressor is able to bind to different compounds, which allows induction of LfrA multidrug efflux pump expression in response to these ones.

Conformational equilibrium defines the variable induction of the multidrug-binding transcriptional repressor QacR

It is revealed that the conformational equilibrium between the repressive and inducive conformations in QacR defines the induction level of the transporter gene, and it is shown that, in the known constitutively active QACR mutants, the equilibrium is shifted more toward the inducives conformation, even in the unligated state.

Domain Cross-talk during Effector Binding to the Multidrug Binding TTGR Regulator*

In vivo expression assays using a fusion of the promoter of ttgA to lacZ and antibiotic tolerance correlated with the in vitro observations, namely that mutant H67A leads to increased basal expression levels and enhances antibiotic tolerance, whereas mutants L66A and L66AV96A exhibit lower basalexpression levels and decreased resistance to antibiotics.

A Transcriptional Regulator of a Pristinamycin Resistance Gene inStreptomyces coelicolor *

Purified recombinant Pip was a dimer and displayed a high affinity for its palindromic binding motifs within theptr promoter and the upstream region of pep, encoding a major facilitator antiporter homologous to ptr.

CmeR Functions as a Transcriptional Repressor for the Multidrug Efflux Pump CmeABC in Campylobacter jejuni

Findings indicate that cmeR encodes a transcriptional repressor that directly interacts with the cmeABC promoter and modulates the expression of cme ABC, which leads to enhanced production of the MDR efflux pump.

LfrR Is a Repressor That Regulates Expression of the Efflux Pump LfrA in Mycobacterium smegmatis (cid:1)

R reverse transcription-PCR experiments showed that the two genes are organized as an operon, and lacZ reporter fusions were used to identify the lfrRA promoter region and it was found that some substrates of the multidrug transporter LfrA, e.g, acriflavine, enhance lfrA expression at a detectable level of transcription.

A real-time analysis of QacR-regulated multidrug resistance in Staphylococcus aureus.

Negative transcriptional regulation of the mce3 operon in Mycobacterium tuberculosis.

Results indicate that the mce3 operon is transcriptionally regulated and that under certain, unknown, conditions repression of gene expression could be lifted.
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