Mechanistic studies of the agmatine deiminase from <i>Listeria monocytogenes</i>

Soares, Charles; Knuckley, Bryan

doi:10.1042/bcj20160221

Cited by 15 publications

(23 citation statements)

References 22 publications

(62 reference statements)

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“…A number of the genes that were differentially expressed after acid stress correspond to genes previously described as involved in the acid response of L. monocytogenes , namely the activation of the general stress response transcriptional regulator SigB, the Gad system, parts of the SOS response and the agmatine deiminase system [5,6,7,8,9,10,12,13,15].…”

Section: Resultsmentioning

confidence: 99%

“…Gad catalyzes the formation of γ-aminobutyric acid (GABA) from glutamate in a reaction that consumes protons [11]. Other known responses to acid shock in L. monocytogenes include the SOS response regulated by RecA [12,13], the LisRK two-component system [14], the agmatine deiminase system [15], proton consumption by acetoin production [2], and, in exponential growing cells, using the F 0 /F 1 -ATP synthase in reverse to pump protons from the cytosol to the extracellular space under the expense of ATP [16].…”

Section: Introductionmentioning

confidence: 99%

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Global Transcriptional Response of Three Highly Acid-Tolerant Field Strains of Listeria monocytogenes to HCl Stress

et al. 2019

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Tolerance to acid is of dual importance for the food-borne pathogen Listeria monocytogenes: acids are used as a preservative, and gastric acid is one of the first defenses within the host. There are considerable differences in the acid tolerance of strains. Here we present the transcriptomic response of acid-tolerant field strains of L. monocytogenes to HCl at pH 3.0. RNAseq revealed significant differential expression of genes involved in phosphotransferase systems, oxidative phosphorylation, cell morphology, motility, and biofilm formation. Genes in the acetoin biosynthesis pathway were upregulated, suggesting that L. monocytogenes shifts to metabolizing pyruvate to acetoin under organic acid stress. We also identified the formation of cell aggregates in microcolonies as a potential relief strategy. A motif search within the first 150 bp upstream of differentially expressed genes identified a novel potential regulatory sequence that may have a function in the regulation of virulence gene expression. Our data support a model where an excess of intracellular H+ ions is counteracted by pumping H+ out of the cytosol via cytochrome C under reduced activity of the ATP synthase. The observed morphological changes suggest that acid stress may cause cells to aggregate in biofilm microcolonies to create a more favorable microenvironment. Additionally, HCl stress in the host stomach may serve as (i) a signal to downregulate highly immunogenic flagella, and (ii) as an indicator for the imminent contact with host cells which triggers early stage virulence genes.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Global Transcriptional Response of Three Highly Acid-Tolerant Field Strains of Listeria monocytogenes to HCl Stress

et al. 2019

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“…The role of the GAD system is to increase pH i by converting extracellular glutamate to Γ-aminobutyrate (GABA) in an enzymatic reaction that reduces the intracellular proton concentration ( Cotter et al, 2001 ). The ADI and AgDI systems are both involved in the response of L. monocytogenes to extreme acidity ( Ryan et al, 2009 ; Soares and Knuckley, 2016 ). ADI imports arginine molecules from the extracellular environment, converting them to ornithine, CO 2 , ammonia (NH 3 ), and ATP.…”

Section: Resistance Of L Monocytogenes To Stress mentioning

confidence: 99%

Resistance of Listeria monocytogenes to Stress Conditions Encountered in Food and Food Processing Environments

Bucur

Grigore‐Gurgu

Crauwels³

et al. 2018

Front. Microbiol.

198

174

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Listeria monocytogenes is a human food-borne facultative intracellular pathogen that is resistant to a wide range of stress conditions. As a consequence, L. monocytogenes is extremely difficult to control along the entire food chain from production to storage and consumption. Frequent and recent outbreaks of L. monocytogenes infections illustrate that current measures of decontamination and preservation are suboptimal to control L. monocytogenes in food. In order to develop efficient measures to prevent contamination during processing and control growth during storage of food it is crucial to understand the mechanisms utilized by L. monocytogenes to tolerate the stress conditions in food matrices and food processing environments. Food-related stress conditions encountered by L. monocytogenes along the food chain are acidity, oxidative and osmotic stress, low or high temperatures, presence of bacteriocins and other preserving additives, and stresses as a consequence of applying alternative decontamination and preservation technologies such high hydrostatic pressure, pulsed and continuous UV light, pulsed electric fields (PEF). This review is aimed at providing a summary of the current knowledge on the response of L. monocytogenes toward these stresses and the mechanisms of stress resistance employed by this important food-borne bacterium. Circumstances when L. monocytogenes cells become more sensitive or more resistant are mentioned and existence of a cross-resistance when multiple stresses are present is pointed out.

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“…Although this p K a value (∼7.2) is lower than the p K a value of a free Cys (∼8.4), it is not surprising. In agmatine deiminase (AgD) from L. monocytogenes ( Listeria monocytogenes ), the p K a value of an active‐site Cys was reported to be ∼7.2 . Thus, the p K a value obtained in the pH dependent studies of H. pylori ADC suggests that the active‐site residue could be a Cys.…”

Section: Resultsmentioning

confidence: 99%

Biochemical and biophysical studies of Helicobacter pylori arginine decarboxylase, an enzyme important for acid adaptation in host

et al. 2018

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Despite importance of arginine decarboxylase (ADC: EC 4.1.1.19) of Helicobacter pylori (H. pylori) 26695 pathogenic strain for acid adaptation in host, the enzyme has not yet been studied at a molecular level. Using combined approaches that include kinetic assays, site-directed mutagenesis, circular dichroism, heat-induced denaturation, analytical gel-filtration, and homology modeling, we report here a detailed investigation of H. pylori ADC. The pyridoxal 5'-phosphate (PLP)-dependent enzyme exhibits higher catalytic activity in the presence of Mg ions at pH ∼8.5. Unlike other bacterial ADCs, this homolog exists as a hexamer. The higher thermal stability (T ∼65.8 ± 0.2 °C) of the enzyme observed from the heat-induced circular dichroism measurements indicates its secondary structural stabilization in the presence of PLP. The kinetic parameters K and k of the enzyme are determined to be 3.4 ± 0.2 mM and 55.2 ± 1.0 min , respectively. We elucidate that Cys487, a conserved residue located at the active-site, is involved in the catalysis, whose pK value was estimated to be ∼7.2. The homology model of the protein show conserved α/β TIM barrel and β-sandwich domains, which are characteristic features of fold III decarboxylases. A lower sequence identity (∼21%) of this enzyme compared with its human counterpart has enabled us to screen putative inhibitors of H. pylori ADC. We found that α-difluoromethylarginine inhibits the activity of the H. pylori enzyme competitively with a K value ∼118 µM and thus it can serve as a basis to design inhibitors with higher efficacy against this ADC. © 2018 IUBMB Life, 70(7):658-669, 2018.

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Mechanistic studies of the agmatine deiminase from Listeria monocytogenes

Abstract: Mechanistic and inhibition studies of the agmatine deiminase found in Listeria monocytogenes reveal a novel catalytic mechanism for the guanidinium-modifying enzyme superfamily. The results of the present study suggest that a new class of mechanism-based inactivators is needed.

Cited by 15 publications

References 22 publications

Global Transcriptional Response of Three Highly Acid-Tolerant Field Strains of Listeria monocytogenes to HCl Stress

Global Transcriptional Response of Three Highly Acid-Tolerant Field Strains of Listeria monocytogenes to HCl Stress

Resistance of Listeria monocytogenes to Stress Conditions Encountered in Food and Food Processing Environments

Biochemical and biophysical studies of Helicobacter pylori arginine decarboxylase, an enzyme important for acid adaptation in host

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