On the Transcriptional Regulation of Methicillin Resistance

García‐Castellanos, Raquel; Mallorqui-Fernandez, G.; Marrero, Aniebrys; Potempa, Jan; Coll, Miquel; Gomis‐Rüth, F. Xavier

doi:10.1074/jbc.m313123200

Cited by 69 publications

(92 citation statements)

References 44 publications

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“…In the case of MecI, the wing is known to undergo a conformational change upon binding to DNA. 31, 34 We speculate the flexibility of the wing could facilitate the conformational changes necessary for DNA-binding. The length of the first two helices also seems to be somewhat variable.…”

Section: Dna-binding Mechanismmentioning

confidence: 99%

Solution Structure of Escherichia coli PapI, a Key Regulator of the Pap Pili Phase Variation

Kawamura

Zhou

et al. 2007

Journal of Molecular Biology

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Pyelonephritis-associated pili (pap) allow uropathogenic Escherichia coli to bind to epithelial cells and play an important role in urinary tract infection. Expression of pap pili is controlled by a phasevariation mechanism, based on the two distinct heritable states that are the result of adenine N6-methylation in either of the two GATC sequences in its regulatory region. Methylation status of these two sequences is sensed by the action of two proteins, Lrp and PapI, and they play a central role in determining pap pili gene expression in both phase-ON and phase-OFF cells. We used modern nuclear magnetic resonance techniques to determine the solution structure and backbone dynamics of PapI. We found its overall fold closely resembles that of the winged helix-turn-helix family of DNA-binding proteins. We also determined that PapI possesses its own DNA-binding activity, albeit non-sequence specific, independent of Lrp. PapI appears to bind to DNA with a K d in the 10 µM range. Possible mechanisms by which PapI might participate in the regulation of the pap operon are discussed in light of these new findings.

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Section: Dna-binding Mechanismmentioning

confidence: 99%

Solution Structure of Escherichia coli PapI, a Key Regulator of the Pap Pili Phase Variation

Kawamura

Zhou

et al. 2007

Journal of Molecular Biology

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“…Crystal structures have been determined previously for the S. aureus repressor MecI (13,18) and the apo form of the BlaR1 sensor domain of Bacillus licheniformis (19). In addition, the NMR solution structure is available for the B. licheniformis BlaI DNA-binding domain (20).…”

mentioning

confidence: 99%

“…blaZ, blaI, and blaR1) is plasmid-borne, constitutive ␤-lactamase expression has been observed in S. aureus strains possessing normal penicillinase plasmids (11). Several explanations for this observation have been proposed, including the involvement of an as of yet unidentified chromosomally encoded regulatory component known as BlaR2 (12,13).…”

mentioning

confidence: 99%

Crystal Structures of the Apo and Penicillin-acylated Forms of the BlaR1 β-Lactam Sensor of Staphylococcus aureus

Wilke

Hills

Zhang

et al. 2004

Journal of Biological Chemistry

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Staphylococcus aureus is among the most prevalent and antibiotic-resistant of pathogenic bacteria. The resistance of S. aureus to prototypal ␤-lactam antibiotics is conferred by two mechanisms: (i) secretion of hydrolytic ␤-lactamase enzymes and (ii) production of ␤-lactam-insensitive penicillin-binding proteins (PBP2a). Despite their distinct modes of resistance, expression of these proteins is controlled by similar regulation systems, including a repressor (BlaI/MecI) and a multidomain transmembrane receptor (BlaR1/MecR1). Resistance is triggered in response to a covalent binding event between a ␤-lactam antibiotic and the extracellular sensor domain of BlaR1/MecR1 by transduction of the binding signal to an intracellular protease domain capable of repressor inactivation. This study describes the first crystal structures of the sensor domain of BlaR1 (BlaR S ) from S. aureus in both the apo and penicillin-acylated forms. The structures show that the sensor domain resembles the ␤-lactam-hydrolyzing class D ␤-lactamases, but is rendered a penicillin-binding protein due to the formation of a very stable acyl-enzyme. Surprisingly, conformational changes upon penicillin binding were not observed in our structures, supporting the hypothesis that transduction of the antibiotic-binding signal into the cytosol is mediated by additional intramolecular interactions of the sensor domain with an adjacent extracellular loop in BlaR1.The evolution and dissemination of antibiotic resistance in pathogenic bacteria are a growing concern. Many of the antimicrobial "wonder drugs" society has come to rely on for the treatment of bacterial infections have been neutralized by new strains equipped with a variety of molecular countermeasures. Methicillin-resistant Staphylococcus aureus is a prominent example of this (1-3). Although ␤-lactam antibiotics such as penicillin have long been the drugs of choice for infections of S. aureus, current therapies for methicillin-resistant S. aureus infections now depend on distinct antibiotic classes such as glycopeptides to counter the increased resistance to penicillin and its derivatives. The recent emergence of glycopeptide-resistant strains of S. aureus (4, 5) underscores the need not only for the development of novel therapeutics, but for better understanding of the molecular mechanisms involved in antibiotic resistance.␤-Lactam antibiotics kill bacteria by inhibiting the cell wall transpeptidases (also known as penicillin-binding proteins (PBPs) 1 ) that are responsible for the essential cross-linking of peptidoglycan during synthesis of the rigid bacterial cell wall. Resistance to ␤-lactam antibiotics in S. aureus can be conferred by two mechanisms. In one case, ␤-lactamase enzymes are secreted from the bacterium to hydrolytically inactivate ␤-lactam antibiotics. Resistance of this form is encoded by the blaZ gene and is carried by Ͼ95% of S. aureus isolates (3). The second resistance mechanism is expression of PBP2a, a cell wall transpeptidase with broad-spectrum insensitivity to ␤-lacta...

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“…Subsequent site-directed mutagenesis studies indicate that two inverted repeat sequences, TACAnnTGTA, positioned 61 and 30 base pairs before the transcription start site of the cop operon, are crucial to the protein-DNA interaction [21,22]. A very similar DNA motif serves as a binding site for BlaI (from Bacillus licheniformis) and MecI (from Staphylococcus aureus), structurally characterized [23][24][25] proteins from the b-lacatamase family. The N-terminus of CopY exhibits significant sequence similarity to the blactmase family [19,21] as well as to the DNA binding region of the phage k cro repressor [26].…”

Section: Regulation Of the Cop Operon And Copymentioning

confidence: 99%