The kinetic properties of the carboxy terminal domain of the <i>Bacillus licheniformis</i> 749/I BlaR penicillin‐receptor shed a new light on the derepression of β‐lactamase synthesis

Duval, Valérie; Swinnen, M.; Lepage, Sophie; Brans, Alain; Granier, Benoit; Franssen, Colette; Frère, Jean‐Marie; Joris, Bernard

doi:10.1046/j.1365-2958.2003.03520.x

Cited by 29 publications

(33 citation statements)

References 27 publications

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“…This experiment yielded a homogeneous mass shift of 333 Da, corresponding closely to the expected mass shift of 334 Da for a benzylpenicillin adduct. Similar deletion mutants containing the sensor domain of BlaR1 have been expressed in E. coli previously for both S. aureus (38) and B. licheniformis (39) and have been shown to fully retain their activities as highly sensitive PBPs.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

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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“…Complete deacylation exceeds the doubling time for S. aureus (20-30 min), indicating that acylation must be an irreversible event [52]. The rate constants determined for the sensor domain from B. licheniformis are similar [53]. Three conserved sequence motifs defi ne the active site of all b-lactam serine transferases/hydrolases, including the class A, C and D b-lactamases and the cell wall transpeptidases [36].…”

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confidence: 95%

β-Lactam resistance in Staphylococcus aureus: the adaptive resistance of a plastic genome

Fuda

Fisher

Mobashery

2005

Cell. Mol. Life Sci.

182

162

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Staphylococci have two mechanisms for resistance to beta-lactam antibiotics. One is the production of beta-lactamases, enzymes that hydrolytically destroy beta-lactams. The other is the expression of penicillin-binding protein 2a (PBP 2a), which is not susceptible to inhibition by beta-lactam antibiotics. Strains of S. aureus exhibiting either beta-lactamase or PBP 2a-directed resistance (or both) have established a considerable ecological niche among human pathogens. The emergence and subsequent spread of bacterial strains designated as methicillin-resistant S. aureus (MRSA), from the 1960s to the present, has created clinical difficulties for nosocomial treatment on a global scale. The recent variants of MRSA that are resistant to glycopeptide antibiotics (such as vancomycin) have ushered in a new and disconcerting chapter in the evolution of this organism.

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“…This module belongs to the serine penicillinrecognizing protein family and can be overproduced in Escherichia coli as a water-soluble moiety that is efficiently acylated by penicillin and other ␤-lactam antibiotics (Fig. 1B) (13,14). The second-order acylation rate constants k 2 /KЈ ranged from 0.0017 to more than 1 M Ϫ1 s Ϫ1 , and the deacylation rate constants (k 3 ) were lower than 4 ϫ 10 Ϫ5 s Ϫ1 .…”

mentioning

confidence: 99%

Evidence of an Intramolecular Interaction between the Two Domains of the BlaR1 Penicillin Receptor during the Signal Transduction

Hanique

Colombo

Goormaghtigh

et al. 2004

Journal of Biological Chemistry

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The kinetic properties of the carboxy terminal domain of the Bacillus licheniformis 749/I BlaR penicillin‐receptor shed a new light on the derepression of β‐lactamase synthesis

Abstract: These authors contributed equally to this study.

Cited by 29 publications

References 27 publications

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

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

β-Lactam resistance in Staphylococcus aureus: the adaptive resistance of a plastic genome

Evidence of an Intramolecular Interaction between the Two Domains of the BlaR1 Penicillin Receptor during the Signal Transduction

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