Cytosolic Intermediates for Cell Wall Biosynthesis and Degradation Control Inducible β-Lactam Resistance in Gram-Negative Bacteria

beta-lactam induction of chromosomal beta-lactamase in gram-negative bacteria requires the transcriptional regulator AmpR and the transport of murein breakdown products (muropeptides) into the cytoplasm. In vitro transcription shows that purified AmpR acts as an activator for ampC beta-lactamase synthesis. The murein precursor, UDP-MurNAc-pentapeptide, decreases AmpR-mediated transcriptional activation in vitro, but has no effect on an AmpR(G102E) mutant that mediates constitutive activation of ampC in vivo. Addition of the muropeptide, anhMurNAc-tripeptide, which accumulates in beta-lactamase-overproducing mutants, counteracts the negative effect of UDP-MurNAc-pentapeptide, restoring the innate ability of AmpR to induce ampC expression in vitro. Cytosolic intermediates of murein biosynthesis and degradation thus act antagonistically to control beta-lactamase expression, thereby operating as a cell-wall sensing device.

[1]  John F. Kennedy,et al.  Bacterial cell wall , 1996 .

[2]  J. Höltje,et al.  The negative regulator of beta-lactamase induction AmpD is a N-acetyl-anhydromuramyl-L-alanine amidase. , 1994, FEMS microbiology letters.

[3]  E. Goodell.  Recycling of murein by Escherichia coli , 1985, Journal of bacteriology.

[4]  Thomas J. White,et al.  PCR protocols: a guide to methods and applications. , 1990 .

[5]  F. Sanger,et al.  DNA sequencing with chain-terminating inhibitors. , 1977, Proceedings of the National Academy of Sciences of the United States of America.

[6]  J. Heijenoort,et al.  Cytoplasmic steps of peptidoglycan synthesis in Escherichia coli , 1982, Journal of bacteriology.

[7]  W. Gilbert,et al.  Sequencing end-labeled DNA with base-specific chemical cleavages. , 1980, Methods in enzymology.

[8]  M. Schell.  Molecular biology of the LysR family of transcriptional regulators. , 1993, Annual review of microbiology.

[9]  B. D. Beck,et al.  Activity of three murein hydrolases during the cell division cycle of Escherichia coli K-12 as measured in toluene-treated cells , 1976, Journal of bacteriology.

[10]  J. Heijenoort.  Chapter 3 Biosynthesis of the bacterial peptidoglycan unit , 1994 .

[11]  H. H. Martin,et al.  AmpG, a signal transducer in chromosomal β‐lactamase induction , 1993 .

[12]  W. Messer,et al.  Activity of murein hydrolases in synchronized cultures of Escherichia coli , 1977, Journal of bacteriology.

[13]  S Henikoff,et al.  A large family of bacterial activator proteins. , 1988, Proceedings of the National Academy of Sciences of the United States of America.

[14]  J. Höltje,et al.  The murein hydrolases of Escherichia coli: properties, functions and impact on the course of infections in vivo. , 1991, Journal of general microbiology.

[15]  John E. Coligan,et al.  Current Protocols in Protein Science , 1996 .

[16]  A. Geis,et al.  Phospho-N-acetylmuramoyl-pentapeptide-transferase of Escherichia coli K12. Properties of the membrane-bound and the extracted and partially purified enzyme. , 1978, Biochimica et biophysica acta.

[17]  L. Daneo-Moore,et al.  Cellular autolytic activity in synchronized populations of Streptococcus faecium , 1978, Journal of bacteriology.

[18]  M. M. Bradford.  A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. , 1976, Analytical biochemistry.

[19]  D. Mengin-Lecreulx,et al.  Identification of the mpl gene encoding UDP-N-acetylmuramate: L-alanyl-gamma-D-glutamyl-meso-diaminopimelate ligase in Escherichia coli and its role in recycling of cell wall peptidoglycan , 1996, Journal of bacteriology.

[20]  J. Frère,et al.  AmpD, essential for both β‐lactamase regulation and cell wall recycling, is a novel cytosolic N‐acetylmuramyl‐L‐alanine amidase , 1995, Molecular microbiology.

[21]  F. Bolivar,et al.  Plasmid vector pBR322 and its special-purpose derivatives--a review. , 1986, Gene.

[22]  D. Mengin-Lecreulx,et al.  Variations in UDP-N-acetylglucosamine and UDP-N-acetylmuramyl-pentapeptide pools in Escherichia coli after inhibition of protein synthesis , 1989, Journal of bacteriology.

[23]  S. Normark,et al.  Purification and mutant analysis of Citrobacter freundii AmpR, the regulator for chromosomal AmpC β‐lactamase , 1991, Molecular microbiology.

[24]  S. Long,et al.  The Rhizobium meliloti groELc locus is required for regulation of early nod genes by the transcription activator NodD. , 1995, Genes & development.

[25]  N. M. Kredich,et al.  In vitro interactions of CysB protein with the cysJIH promoter of Salmonella typhimurium: inhibitory effects of sulfide , 1990, Journal of bacteriology.

[26]  B. Rolfe,et al.  Clovers secrete specific phenolic compounds which either stimulate or repress nod gene expression in Rhizobium trifolii , 1987, The EMBO journal.

[27]  C. Sanders,et al.  ampG is essential for high-level expression of AmpC beta-lactamase in Enterobacter cloacae , 1989, Antimicrobial Agents and Chemotherapy.

[28]  S. Normark,et al.  Bacterial cell wall recycling provides cytosolic muropeptides as effectors for beta‐lactamase induction. , 1994, The EMBO journal.

[29]  F. Neidhart.  Escherichia coli and Salmonella. , 1996 .

[30]  U. Schwarz,et al.  Volume growth, murein synthesis, and murein cross-linkage during the division cycle of Escherichia coli PA3092 , 1982, Journal of bacteriology.

[31]  S. Normark,et al.  Regulatory components in Citrobacter freundii ampC beta-lactamase induction. , 1985, Proceedings of the National Academy of Sciences of the United States of America.

[32]  S. Lindquist,et al.  Binding of the Citrobacter freundii AmpR regulator to a single DNA site provides both autoregulation and activation of the inducible ampC beta-lactamase gene , 1989, Journal of bacteriology.

[33]  F. Studier,et al.  Use of T7 RNA polymerase to direct expression of cloned genes. , 1990, Methods in enzymology.

[34]  S. Lindquist,et al.  Inactivation of the ampD gene causes semiconstitutive overproduction of the inducible Citrobacter freundii beta-lactamase , 1987, Journal of bacteriology.

[35]  J. Weiner,et al.  Overproduction, solubilization, purification and DNA-binding properties of AmpR from Citrobacter freundii. , 1993, European journal of biochemistry.