Structural basis for cooperative DNA binding by two dimers of the multidrug‐binding protein QacR

  title={Structural basis for cooperative DNA binding by two dimers of the multidrug‐binding protein QacR},
  author={Maria A. Schumacher and Marshall C. Miller and Steve Grkovic and Melissa H. Brown and Ronald A. Skurray and Richard G. Brennan},
  journal={The EMBO Journal},
The Staphylococcus aureus multidrug‐binding protein QacR represses transcription of the qacA multidrug transporter gene and is induced by multiple structurally dissimilar drugs. QacR is a member of the TetR/CamR family of transcriptional regulators, which share highly homologous N‐terminal DNA‐binding domains connected to seemingly non‐homologous ligand‐binding domains. Unlike other TetR members, which bind ∼15 bp operators, QacR recognizes an unusually long 28 bp operator, IR1, which it… 

Thermodynamics of Cooperative DNA Recognition at a Replication Origin and Transcription Regulatory Site

A positive, entropy-driven cooperativity upon binding of the protein to its cognate tandem double E2 site is determined, associated with a change in DNA structure, where the overall B conformation is maintained.

Structural mechanism of the simultaneous binding of two drugs to a multidrug‐binding protein

The crystal structure of the Staphylococcus aureus multidrug‐binding transcription repressor, QacR, bound simultaneously to ethidium (Et) and proflavin (Pf), underscores the plasticity of the multidrog‐binding pocket and reveals an alternative, Pf‐induced binding mode for Et.

Crystal Structures of QacR-Diamidine Complexes Reveal Additional Multidrug-binding Modes and a Novel Mechanism of Drug Charge Neutralization*

The Staphylococcus aureus multidrug-binding protein QacR represses transcription of the plasmid-encoded membrane protein QacA, a multidrug efflux transporter. QacR is induced by multiple structurally

Biochemical characterization of the multidrug regulator QacR distinguishes residues that are crucial to multidrug binding and induction of qacA transcription.

The functional significance of hydrophobic, aromatic, and polar residues characteristic of the rhodamine 6G pocket and the proximal Tyr(92), proposed to facilitate the transcriptionally active conformation, was examined and highlights the significant contribution of these residues to QacR-mediated derepression of qacA transcription following ligand binding in the distal subpocket and may be important for the general mechanism irrespective of the ligand bound.

Structural basis for antibiotic recognition by the TipA class of multidrug‐resistance transcriptional regulators

The classical globin fold is well adapted not only for accommodating its canonical cofactors, heme and other tetrapyrroles, but also for the recognition of a variety of antibiotics where ligand binding leads to transcriptional activation and drug resistance.

The protein–DNA contacts in RutR·carAB operator complexes

A model of the RutR·operator DNA complex based on the crystal structures of RutR and of the DNA-bound family member QacR is built and tested with site-directed mutagenesis of the helix–turn–helix DNA binding motif and in vitro binding studies with the cognate purified mutant RutR proteins.

Crystal structure of Pseudomonas aeruginosa transcriptional regulator PA2196 bound to its operator DNA.

The DNA binding domain of the Vibrio vulnificus SmcR transcription factor is flexible and binds diverse DNA sequences

X-ray crystallography and small angle X-ray scattering data support a model in which two mechanisms drive SmcR transcriptional activation: interaction with RNAP and a multi-conformational DNA binding domain that permits recognition of variable DNA sites.

Structural basis of cooperative DNA recognition by the plasmid conjugation factor, TraM

It is demonstrated that both DNA-binding specificity, as well as selective interactions between TraM and the C-terminal tail of its cognate TraD mediate conjugation specificity within the F-like family of plasmids.

Structural and functional basis of transcriptional regulation by TetR family protein CprB from S. coelicolor A3(2)

Experiments performed on a subset of DNA sequences from Streptomyces coelicolor A3(2) suggest that CprB is most likely a pleiotropic regulator, potentially a part of a network of proteins that modulates the γ-butyrolactone synthesis and antibiotic regulation pathways in S. coel Nicolor A 3(2).



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.

Crystal structure of a cobalt-activated diphtheria toxin repressor-DNA complex reveals a metal-binding SH3-like domain.

The crystal structure of wild-type DtxR, a 226 residue three-domain dimeric protein, activated by cobalt and bound to a 21 bp DNA duplex based on the consensus operator sequence is reported, revealing for the first time a metal-binding function for this class of domains.

Structural Mechanisms of QacR Induction and Multidrug Recognition

The Staphylococcus aureus multidrug binding protein QacR represses transcription of the qacA multidrug transporter gene and is induced by structurally diverse cationic lipophilic drugs. Here, we

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

Adding of diverse QacA substrates was shown to induce qacA expression in vivo, as well as inhibit binding of QacR to operator DNA in vitro, by using gel-mobility shift assays, which appears to interact directly with structurally dissimilar inducing compounds that are substrates of the Qac a multidrug efflux pump.

Residues important for the function of a multihelical DNA binding domain in the new transcription factor family of Cam and Tet repressors.

It is reported that some prokaryotic repressors including CamR and TetR belong to the same family and the DNA binding mode of this type of DBD and a general mechanism of regulating their DNA binding are discussed in reference to the crystal structure of TetR.

Staphylococcal multidrug efflux protein QacA.

  • M. BrownR. Skurray
  • Biology, Chemistry
    Journal of molecular microbiology and biotechnology
  • 2001
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.

DNA recognition by beta-sheets in the Arc repressor-operator crystal structure.

The co-crystal structure of this Arc tetramer-operator complex is reported at 2.6 A resolution and it is shown that each Arc dimer uses an antiparallel beta-sheet to recognize bases in the major groove.

Methyl groups of thymine bases are important for nucleic acid recognition by DtxR.

In addition to making base-specific hydrogen-bonding interactions to the DNA through its Gln43 residue, DtxR also recognizes methyl groups at certain positions in the DNA sequence with its Ser37 and Pro39 side chains, to achieve binding specificity toward its cognate operator sequences.

DNA recognition by β-sheets in the Arc represser–operator crystal structure

TRANSCRIPTION of the ant gene during lytic growth of bacteriophage P22 (ref. 1) is regulated by the cooperative binding of two Arc repressor dimers to a 21-base-pair operator site2,3. Here we report

Multidrug resistance proteins QacA and QacB from Staphylococcus aureus: membrane topology and identification of residues involved in substrate specificity.

QacA represents the first membrane transport protein shown to contain 14 transmembrane segments, and confirms that the major facilitator superfamily contains a family of proteins with 14 trans Membranes segments.