Coordinate regulation of murein peptidase activity and AmpC β‐lactamase synthesis in <i>Escherichia coli</i>

Bishop, Russell E.; Weiner, Joël H.

doi:10.1016/0014-5793(92)80598-b

Cited by 21 publications

(24 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been proposed that structural similarities between both substrate (the b-lactam antibiotics vs. D-Ala-D-Ala peptidoglycan side chain) and enzyme (class A and C b-lactamases vs. DD-peptidases) could indicate an in vivo interaction of b-lactamases with cellwall components (Bishop and Weiner 1992;Morosini et al 2000). Marginal peptidase activity of b-lactamases as well as b-lactamase activity of DD-peptidases has been described in vitro (Rhazi et al 1999).…”

Section: Discussionmentioning

confidence: 99%

“…It has been hypothesized, however, that class C b-lactamases could participate in recycling of cell-wall components due to the structural similarity between b-lactam antibiotics and the DD-peptide bond found in the peptidoglycan layer (Bishop and Weiner 1992). A fitness cost associated with expression of the class C b-lactamase AmpC from Enterobacter cloacae in Salmonella enterica serotype Typhimurium has been documented (Morosini et al 2000).…”

mentioning

confidence: 99%

See 1 more Smart Citation

A Fitness Cost Associated With the Antibiotic Resistance Enzyme SME-1 β-Lactamase

2007

View full text Add to dashboard Cite

The bla TEM-1 b-lactamase gene has become widespread due to the selective pressure of b-lactam use and its stable maintenance on transferable DNA elements. In contrast, bla SME-1 is rarely isolated and is confined to the chromosome of carbapenem-resistant Serratia marcescens strains. Dissemination of bla SME-1 via transfer to a mobile DNA element could hinder the use of carbapenems. In this study, bla SME-1 was determined to impart a fitness cost upon Escherichia coli in multiple genetic contexts and assays. Genetic screens and designed SME-1 mutants were utilized to identify the source of this fitness cost. These experiments established that the SME-1 protein was required for the fitness cost but also that the enzyme activity of SME-1 was not associated with the fitness cost. The genetic screens suggested that the SME-1 signal sequence was involved in the fitness cost. Consistent with these findings, exchange of the SME-1 signal sequence for the TEM-1 signal sequence alleviated the fitness cost while replacing the TEM-1 signal sequence with the SME-1 signal sequence imparted a fitness cost to TEM-1 b-lactamase. Taken together, these results suggest that fitness costs associated with some b-lactamases may limit their dissemination.

show abstract

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

A Fitness Cost Associated With the Antibiotic Resistance Enzyme SME-1 β-Lactamase

2007

View full text Add to dashboard Cite

show abstract

“…Interestingly, at least two Shigella species, S. flexneri and S. dysenteriae, also lack the ampC gene, as demonstrated by Maurelli et al (25). The presence of the ampC gene, together with its exquisite transcriptional regulation (19) in most enterobacterial species, has suggested that AmpC might be involved in cell wall recycling (3).…”

mentioning

confidence: 97%

Biological Cost of AmpC Production for Salmonella enterica Serotype Typhimurium

Morosini

Ayala

Baquero

et al. 2000

Antimicrob Agents Chemother

View full text Add to dashboard Cite

Chromosomally mediated AmpC-type ␤-lactamases are frequently found among Enterobacteriaceae. Hyperproduction of AmpC ␤-lactamase results in high-level resistance to ␤-lactam antibiotics. One striking feature of Salmonella is the absence of the structural ampC gene, encoding AmpC ␤-lactamase, in contrast with other members in the Enterobacteriaceae family, such as Escherichia, Citrobacter, or Enterobacter. The horizontal acquisition of ampC genes is one of the causes of the increased resistance to extended-spectrum cephalosporins and ␤-lactamase inhibitors among gram-negative rods. Nevertheless, despite the high number of ␤-lactamresistant Salmonella isolates so far described, only two strains expressing resistance to cephalosporin and ␤-lactamase inhibitors which is mediated by AmpC-type enzymes have been found. In this work, data are provided which support the possibility that the maintenance and expression of the ampC gene may represent an unbearable cost for Salmonella in terms of reduction of some of its lifestyle attributes, such as growth rate and invasiveness. The deleterious AmpC burden can be eliminated by decreasing the production of AmpC when both the regulatory gene, ampR, and ampC are present in Salmonella. Thus, it is suggested that the two genes have to be acquired together by Salmonella, leading to an inducible ␤-lactam resistance phenotype. AmpC synthesis did not produce major variations in the peptidoglycan composition of Salmonella.

show abstract

“…The AmpD, PbpA and FtsZ gene products control aspects of cell-wall metabolism, whereas the AmpE and AmpG proteins share amino-acidsequence similarities with various membrane transport proteins (reviewed in Bishop and Weiner, 1992). Additionally, mutations in the ampR gene can suppress the ampG mutation, which suggests that the AmpR and AmpG proteins may interact physically (Bartowsky and Normark, 1991).…”

mentioning

confidence: 99%

Overproduction, solubilization, purification and DNA‐binding properties of AmpR from Citrobacter freundii

Bishop

Weiner

1993

European Journal of Biochemistry

Self Cite

View full text Add to dashboard Cite

AmpR belongs to the LysR family of prokaryotic DNA‐binding transcriptional regulators and controls induction of the enterobacterial ampCβ‐lactamase gene. The ampR gene of Citrobacter freundii was deregulated by employing the polymerase chain reaction to introduce an efficient ribosome‐binding sequence and suitable restriction enzyme sites for cloning into a chemically inducible tac‐promoter expression vector. When induced in Escherichia coli, the modified ampR gene rapidly overproduced the AmpR protein as an insoluble aggregate. The AmpR protein could be solubilized with 1.32 M guanidine/HCl and remained soluble when dialyzed against 0.5 M NaCl. The solubility properties of AmpR were exploited to selectively precipitate and resolubilize the protein in a nearly homogenous state. AmpR was then purified by a single gel‐filtration chromatography step which demonstrated that AmpR exists in solution as a monodisperse homodimeric protein. Several milligrams of purified AmpR could be obtained routinely from a 1‐l culture of induced bacteria. A DNA‐binding assay buffer containing 300 mM potassium glutamate and 30% glycerol was found to stabilize AmpR and used to demonstrate sequence‐specific DNA‐binding. Additionally, purified AmpR binds a half‐operator DNA with an inverted‐repeat sequence which competes with binding by the wild‐type operator. These findings are discussed in terms of the helix‐turn‐helix DNA‐binding motif, whereby AmpR is proposed to interact with its wild‐type operator as a dimer of dimers.

show abstract

Coordinate regulation of murein peptidase activity and AmpC β‐lactamase synthesis in Escherichia coli

Cited by 21 publications

References 52 publications

A Fitness Cost Associated With the Antibiotic Resistance Enzyme SME-1 β-Lactamase

A Fitness Cost Associated With the Antibiotic Resistance Enzyme SME-1 β-Lactamase

Biological Cost of AmpC Production for Salmonella enterica Serotype Typhimurium

Overproduction, solubilization, purification and DNA‐binding properties of AmpR from Citrobacter freundii

Contact Info

Product

Resources

About