The E. coli β-lactamase attenuator mediates growth rate-dependent regulation

Jaurin, Bengtåke; Grundström, Thomas; Edlund, Thomas; Normark, Staffan

doi:10.1038/290221a0

Cited by 180 publications

(132 citation statements)

References 28 publications

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“…Anti-termination is occasionally achieved when the translational apparatus couples with a ribosome-binding sequence in nascent ampC transcripts [20]. Since ribosome biogenesis is independently coordinated with growth rate by the Stringent Response, AmpC expression is coordinated with growth rate by the amp/l attenuator [20]. The ampC gene is not induced by fl-lactam compounds and, in the absence of rare mutations that lead to AmpC overproduction, is not normally an agent offl-lactam resistance [21,22].…”

Section: Growth Rate Control Of Ampc Syn-thesis and Murein Structurementioning

confidence: 99%

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

Bishop¹,

Weiner²

1992

FEBS Letters

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In the periplasmic space of F.sche~'ichia coil, the (L)-m-A,pm-(D)-m-A,pm pcptid¢, the lipoprotein, and the AmpC fl-lactamas¢ are controlled by growth rate. To explain this coordinate regulation, it is proposed that the AmpC protein functions as an LD-endopeptidase in addition to its known function as a fl-lactamas¢. As LD-peptides, vo-peptides and fl-lactams are structurally similar, to-peptidases may belong to the larger family of DD-peptidases and serine ~-lactamases. In contrast to K coll. many related bacteria possess an inducible AmpC protein. Several gene systems necessary for AmpC induction are known to affect various aspects of peptidoglyean metabolism, It is proposed that AmpC induction ¢o=urs indirectly via a recyclabl¢ e¢ll wall pcptid¢.

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Section: Growth Rate Control Of Ampc Syn-thesis and Murein Structurementioning

confidence: 99%

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

Bishop¹,

Weiner²

1992

FEBS Letters

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“…By subcloning, ampC was localized to a 1370-base-pair (bp)-long DNA fragment (17,18). We have reported (19) a characterization of the regulatory region that precedes ampC. The expression from ampC was decreased by the presence of a terminator that caused a marked attenuation oftranscription.…”

mentioning

confidence: 99%

“…The expression from ampC was decreased by the presence of a terminator that caused a marked attenuation oftranscription. Mutations in both the promoter and the attenuator for ampC can confer increased ampC ,B lactamase production (19).…”

mentioning

confidence: 99%

ampC cephalosporinase of Escherichia coli K-12 has a different evolutionary origin from that of beta-lactamases of the penicillinase type.

Jaurin¹,

Grundström²

1981

Proc. Natl. Acad. Sci. U.S.A.

364

177

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A 1536-nucleotide-long sequence that carries the ampC fi-lactamase gene of the Escherichia coli K-12 chromosome has been determined. This gene codes for a protein of 377 amino acids, of which the first 19 amino acids form a signal peptide. The molecular weight of the mature enzyme was determined to be 39,600. The ampC P-lactamase with a substrate specificity for cephalosporins showed no significant sequence homologies with (-lactamases of the penicillinase type or with D-alanine carboxypeptidases. However, because the region around serine-80 of the ampC f3-lactamase has extensive homology with an active-site fragment ofthe Pseudomonas aeruginosa cephalosporinase, we suggest that the ampC cephalosporinase as well as related cephalosporinases form a distinct group of serine P-lactamases that have an evolutionary origin different from that of the serine penicillinases and thus constitute a new class of 13-lactamases. f3Lactamases of chromosomal or plasmid origin have been found in a large number of Gram-positive and Gram-negative bacteria (1). These enzymes have been classified according to such properties as substrate profile, isoelectric point, and molecular weight. The protein sequence has been determined for ,-lactamases from Staphylococcus aureus PC1 (2), Bacillus ltcheniformis 749/C (3, 4), and Escherichia coli/R6K, R-TEM (5).Nearly the entire sequence ofthe B. cereus 569/H P-lactamase has also been elucidated (6, 7). In addition, the amino acid sequence of the ,B-lactamase encoded by the plasmid pBR322 has been deduced from its nucleotide sequence (8). The two plasmid-mediated TEM P-lactamases from Gram-negative species differ only by one amino acid residue (5, 8).These 3-lactamases of known sequence all show substrate specificity for penicillins and have therefore been termed "penicillinases" (1). The molecular weight ofthese enzymes is around 29,000 (7). They show significant sequence homologies with each other (7) as well as with regions of D-alanine carboxypeptidases from B. stearothermophilus and B. subtilis (9). By the use of substrate analogues, the active site has been determined for three penicillinases and two carboxypeptidases (9-13). They have been referred to as "serine enzymes" because the reagents react with a serine residue. ,3-Lactamases ofthe metalloenzyme type have also been identified. From incomplete sequence data it is suggested that this class has a different evolutionary origin from that of the serine penicillinases of known sequence (7).The chromosomally encoded ,B-lactamases of Gram-negative enterobacteria in general are basic proteins with a substrate specificity for cephalosporins (14). One such cephalosporinase is encoded by the ampC gene of E. coli K-12. This gene, which is located at 93.8 min on the E. coli linkage map (15), was isolated from a gene bank containing E. coli chromosomal DNA (16,17). By subcloning, ampC was localized to a 1370-base-pair (bp)-long DNA fragment (17, 18). We have reported (19) a characterization of the regulatory region that precedes ampC. T...

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“…None of our monoclonal antibodies showed cross-reactivities with j?-lactamases of various bacterial species including species-specific cephalosporinases. Jaurin and Grundstrom suggested the existence of sequence homology among the species-specific cephalosporinases of gram-negative bacteria [28] and the cross-reactivities of some polyclonal antibodies implied that the sequence homology gave some structural similarities between cephalosporinases. Even if cephalosporinase of P. aeruginosa shared some structural similarities with those of other bacteria, our monoclonal antibodies did not recognize the similarities and were highly specific to P. aeruginosa cephalosporinase.…”

Section: Cephalosporinase-producingmentioning

confidence: 99%

Monoclonal antibodies against species-specific cephalosporinase of Pseudomonas aeruginosa

Murakami

Yoshida

1985

Eur J Biochem

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Ten hybridomas which produced monoclonal antibodies against species-specific cephalosporinase of Pseudomonas aeruginosa were constructed by somatic cell fusion of SP-2/0 myeloma cells with spleen cells from hyperimmunized BALB/c mice and intraperitoneally injected into mice. Monoclonal antibodies were partially purified from ascites fluids. All ten antibodies thus prepared were IgG immunoglobulins. In a solid-phase immunoassay the antibodies gave positive reactions which could be prevented by the presence of free cephalosporinase. When the antibodies were precipitated with anti-(mouse IgG), the cephalosporinase activity was co-precipitated. Also, these antibodies were co-eluted with cephalosporinase activity in gel filtration. Nine of the monoclonal antibody preparations elevated the cephalosporinase activity by about 6 -40% and only one inhibited it by about 50%. All the monoclonal antibodies were highly specific to P. aeruginosa cephalosporinase and showed no cross-reaction with nine cephalosporinases and four penicillinases of other gram-negative bacteria.The main mechanism of bacterial resistance to /3-lactam antibiotics is the production of /3-lactamase which cleaves the b-lactam rings of the antibiotics rendering them inactive [l, 21. They are produced in many bacterial species and differ from each other in their enzymological and physicochemical properties. Although several classifications of /3-lactamases have been proposed [2-41, the enzymes can be generally classified into the two groups of R-plasmid-mediated /3-lactamases and species-specific /3-lactamases. The /3-lactamase of Pseudomonas aeruginosa used in this study is a species-specific cephalosporinase which is more active against cephalosporins.Anti-serum against /3-lactamase was used to identify or classify /?-lactamases based on its specific reaction with the enzymes [5 -91. Monoclonal antibodies are useful probes for assessing the structural similarities between macromolecules such as /I-lactamases [lo]. Thus, a monoclonal antibody against /$-lactamase can be expected to reveal some interspecies similarities and intraspecies differences of the enzymes or to be a good reagent for detecting the enzyme. In the present investigation, we have prepared a set of monoclonal antibodies against the cephalosporinase of P. aeruginosa by the hybridoma technique [l 11 and characterized them. kindly supplied by T. Sawai (Chiba University, Japan). Enterobacter cloacae 214 [14], E. cloacae 53 [5], and E. coli W3110 (RTEM) which carries R-plasmid RTEM [I 51 were obtained from M. H. Richmond (University of Bristol, England). Other bacterial strains used were clinical isolates stocked in our laboratories. Pseudomonas aeruginosa SR24-12 produces cephalosporinase constitutively and is a mutant of strain SR24 which produces the enzyme inducibly. MATERIALS AND METHODS AntibioticsPurijkation of the cephalosporinase P. aeruginosa SR24-12 was cultured in 34 1 of heart infusion broth (Eiken, Tokyo, Japan) at 37°C for 6 h with aeration. About 69 g (wet weight) of cells we...

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The E. coli β-lactamase attenuator mediates growth rate-dependent regulation

Cited by 180 publications

References 28 publications

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

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

ampC cephalosporinase of Escherichia coli K-12 has a different evolutionary origin from that of beta-lactamases of the penicillinase type.

Monoclonal antibodies against species-specific cephalosporinase of Pseudomonas aeruginosa

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