Peptidoglycan biosynthesis in Escherichia coli: variations in the metabolism of alanine and D-alanyl-D-alanine

Roubin, Marie-Renée De; Mengin‐Lecreulx, Dominique; Heijenoort, Jean van

doi:10.1099/00221287-138-8-1751

Cited by 11 publications

(10 citation statements)

References 23 publications

(20 reference statements)

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“…D‐cycloserine (DCS) is a structural analog of D‐alanine that inactivates Alr and Ddl, and causes rapid cell lysis (Neuhaus and Lynch, ; Wang et al, ; Prosser and de Carvalho, ; Azam and Jayaram, ). A concentration of 1 μg mL ‐1 DCS is sufficient to deplete the UDP‐MurNac‐pentapeptide pool in 30 minutes when E. coli is grown in minimal medium (Mengin‐lecreulx et al, ; de Roubin et al, ). Inhibition of the D‐ala:D‐ala ligase by DCS causes a 50‐fold accumulation of UDP‐MurNac‐tripeptide (de Roubin et al, ), suggests that E. coli cannot use UDP‐MurNac‐tripeptide to synthesize lipid II with a tripeptide side chain.…”

Section: Resultsmentioning

confidence: 99%

FtsW activity and lipid II synthesis are required for recruitment of MurJ to midcell during cell division in Escherichia coli

Liu

Meiresonne

Bouhss

et al. 2018

Molecular Microbiology

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Peptidoglycan (PG) is the unique cell shape-determining component of the bacterial envelope, and is a key target for antibiotics. PG synthesis requires the transmembrane movement of the precursor lipid II, and MurJ has been shown to provide this activity in Escherichia coli. However, how MurJ functions in vivo has not been reported. Here we show that MurJ localizes both in the lateral membrane and at midcell, and is recruited to midcell simultaneously with late-localizing divisome proteins and proteins MraY and MurG. MurJ septal localization is dependent on the presence of a complete and active divisome, lipid II synthesis and PBP3/FtsW activities. Inactivation of MurJ, either directly by mutation or through binding with MTSES, did not affect the midcell localization of MurJ. Our study visualizes MurJ localization in vivo and reveals a possible mechanism of MurJ recruitment during cell division.

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Section: Resultsmentioning

confidence: 99%

FtsW activity and lipid II synthesis are required for recruitment of MurJ to midcell during cell division in Escherichia coli

Liu

Meiresonne

Bouhss

et al. 2018

Molecular Microbiology

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“…The insertion mutant 22H12 was found to have a transpositional disruption of the rfa operon, specifically in waaL (rfaL), the gene encoding the O antigen ligase of the LPS biosynthetic gene cluster (50). The 25D9 and 40G5 mutants were both found to have insertions in or near the alanine racemase I gene, alr, whose product converts L-alanine into D-alanine for peptidoglycan synthesis (16). Thus, all four mutants contain disruptions of genes mediating PAMP biosynthesis.…”

Section: Methodsmentioning

confidence: 96%

Molecular Basis of UropathogenicEscherichia coliEvasion of the Innate Immune Response in the Bladder

Billips¹,

Schaeffer²,

Klumpp

2008

Infect Immun

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In the urinary tract, the innate immune system detects conserved bacterial components and responds to infection by activating the proinflammatory transcription factor NF-B, resulting in cytokine secretion and neutrophil recruitment. Uropathogenic Escherichia coli (UPEC), however, has been shown to evade the host innate immune response by suppressing NF-B activation in urothelial cells, which results in decreased cytokine secretion and increased urothelial apoptosis. To understand the molecular basis of UPEC modulation of inflammation, we performed a genetic screen with UPEC strain NU14 to identify genes which are required for modulation of urothelial cytokine secretion. Disruption of ampG (peptidoglycan permease), waaL (lipopolysaccharide O antigen ligase), or alr (alanine racemase) resulted in increased urothelial interleukin-8 (IL-8) and IL-6 release from urothelial cell cultures. Targeted deletion of these genes also resulted in elevated urothelial cytokine production during UPEC infection. Conditioned media from bacterial cultures of NU14 ⌬ampG and NU14 ⌬waaL contained a heat-stable factor(s) which stimulated greater urothelial IL-8 secretion than that in NU14-conditioned medium. In a mouse model of urinary tract infection, NU14 ⌬ampG, NU14 ⌬waaL, and NU14 ⌬alr were attenuated compared to wild-type NU14 and showed reduced fitness in competition experiments. Instillation of NU14 ⌬ampG or NU14 ⌬waaL increased bladder neutrophil recruitment, indicating that enhanced urothelial cytokine secretion during urinary tract infection results in an altered host response. Thus, UPEC evasion of innate immune detection of bacterial components, such as lipopolysaccharide and peptidoglycan fragments, is likely an important factor in the ability of UPEC to colonize the urinary tract.The host innate immune system utilizes a family of pattern recognition receptors (PRRs) that detect invading pathogens by recognition of evolutionarily conserved components. Recognition of these pathogen-associated molecular patterns (PAMPs) through PRR family members, including the Tolllike receptors (TLRs) and nucleotide binding and oligomerization domain-like receptors, results in activation of antimicrobial responses, such as the production of antimicrobial peptides and secretion of proinflammatory cytokines (18,29,45). Many bacterial pathogens, however, have evolved strategies for subverting the host innate immune system by evading detection by PRRs and/or disruption of the downstream cellular signaling pathways (8,30,38).Infection of the urinary tract by uropathogenic Escherichia coli (UPEC), the most frequent cause of urinary tract infection (UTI), is associated with a robust innate immune response characterized by the production of inflammatory cytokines and chemokines by the urothelium. The production of inflammatory cytokines and chemokines results in the rapid recruitment of neutrophils into the bladder lumen and in bacterial clearance (21,22,41). The activation of the innate immune response in the urinary tract is dependent upon PRR re...

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“…53, 54 The arrows correspond to metabolites with statistically significant (p < 0.05) concentration increases (up) or decreases (down) when comparing DCS treated cells to untreated cells. Circles indicate the metabolite concentration is similar (p > 0.05).…”

Section: Figurementioning

confidence: 99%

Metabolomics Analysis Identifies d-Alanine-d-Alanine Ligase as the Primary Lethal Target of d-Cycloserine in Mycobacteria

Halouska

Fenton²,

Zinniel³

et al. 2013

J. Proteome Res.

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D-cycloserine is an effective second line antibiotic used as a last resort to treat multi (MDR)- and extensively (XDR)- drug resistant strains of Mycobacterium tuberculosis. D-cycloserine interferes with the formation of peptidoglycan biosynthesis by competitive inhibition of Alanine racemase (Alr) and D-Alanine-D-alanine ligase (Ddl). Although, the two enzymes are known to be inhibited, the in vivo lethal target is still unknown. Our NMR metabolomics work has revealed that Ddl is the primary target of DCS, as cell growth is inhibited when the production of D-alanyl-D-alanine is halted. It is shown that inhibition of Alr may contribute indirectly by lowering the levels of D-alanine thus allowing DCS to outcompete D-alanine for Ddl binding. The NMR data also supports the possibility of a transamination reaction to produce D-alanine from pyruvate and glutamate, thereby bypassing Alr inhibition. Furthermore, the inhibition of peptidoglycan synthesis results in a cascading effect on cellular metabolism as there is a shift toward the catabolic routes to compensate for accumulation of peptidoglycan precursors.

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Peptidoglycan biosynthesis in Escherichia coli: variations in the metabolism of alanine and D-alanyl-D-alanine

Cited by 11 publications

References 23 publications

FtsW activity and lipid II synthesis are required for recruitment of MurJ to midcell during cell division in Escherichia coli

FtsW activity and lipid II synthesis are required for recruitment of MurJ to midcell during cell division in Escherichia coli

Molecular Basis of UropathogenicEscherichia coliEvasion of the Innate Immune Response in the Bladder

Metabolomics Analysis Identifies d-Alanine-d-Alanine Ligase as the Primary Lethal Target of d-Cycloserine in Mycobacteria

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