Influence of cobalt substitution on the activity of iron-type nitrile hydratase: Are cobalt type nitrile hydratases regulated by carbon monoxide?

Sari, Marie-Agnès; Jaouen, Maryse; Rao, Saroja Narsing; Artaud, Isabelle

doi:10.1016/j.jinorgbio.2006.12.005

Cited by 13 publications

(4 citation statements)

References 48 publications

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“…We first photoactivated the iron-containing NHase (Prozomix) derived from Rhodococcus erythropolis as per published protocols 34,36 and then employed an enzyme activity assay that converted 2-nitro-5-thiocyanatobenzoic acid (NTBA) into formamide and 5-mercapto-2-nitrobenzoic acid (ε 412 = 13 600 M −1 cm −1 ), whose appearance can be followed spectrophotometrically. 37 We confirmed the necessity of the catalytic sulfenic acid in the active site by adding the commonly used specific sulfenic acid trap, dimedone. At 1 mM of dimedone, only ∼40% of the original enzyme activity was observed; in the absence of dimedone or boron compounds, the rate constant for thiolate product formation is ∼0.033 min −1 under the experimental conditions (Table S3).…”

Section: See Si)mentioning

confidence: 54%

“…We first photoactivated the iron-containing NHase (Prozomix) derived from Rhodococcus erythropolis as per published protocols , and then employed an enzyme activity assay that converted 2-nitro-5-thiocyanatobenzoic acid (NTBA) into formamide and 5-mercapto-2-nitrobenzoic acid (ε 412 = 13 600 M –1 cm –1 ), whose appearance can be followed spectrophotometrically . We confirmed the necessity of the catalytic sulfenic acid in the active site by adding the commonly used specific sulfenic acid trap, dimedone.…”

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confidence: 83%

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Capturing a Sulfenic Acid with Arylboronic Acids and Benzoxaborole

Liu

Benkovic

2013

J. Am. Chem. Soc.

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Post-translational redox generation of cysteine-sulfenic acids (Cys-SOH) functions as an important reversible regulatory mechanism for many biological functions, such as signal transduction, balancing cellular redox states, catalysis, and gene transcription. Herein we show that arylboronic acids and cyclic benzoxaboroles can form adducts with sulfenic acids in aqueous medium and that these boron-based compounds can potentially be used to trap biologically significant sulfenic acids. As proof of principle we demonstrate that a benzoxaborole can inhibit the enzyme activity of an iron-containing nitrile hydratase, which requires a catalytic αCys114-SOH in the active site. The nature of the adduct and the effect of the boronic acid's pK(a)(B) on the stability constant of the adduct are discussed within.

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Section: See Si)mentioning

confidence: 54%

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confidence: 83%

Capturing a Sulfenic Acid with Arylboronic Acids and Benzoxaborole

Liu

Benkovic

2013

J. Am. Chem. Soc.

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“…Recent studies showed that cobalt toxicity in E. coli and S. enterica is mainly due to its direct competition with iron especially affecting the synthesis of Fe–S clusters (Ranquet et al 2007; Thorgersen and Downs 2007) or indirectly via cobalt-mediated oxidative depletion of free thiols pool (Thorgersen and Downs 2007). On the other hand, the concentrations of cobalt chloride ranging from 100 μM up to 400 μM were found suitable for optimal E. coli growth and expression of cobalt-substituted iron-type nitrile hydratase (Sari et al 2007). …”

Section: Introductionmentioning

confidence: 99%

Effect of cobalt on Escherichia coli metabolism and metalloporphyrin formation

2010

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Toxicity in Escherichia coli resulting from high concentrations of cobalt has been explained by competition of cobalt with iron in various metabolic processes including Fe–S cluster assembly, sulfur assimilation, production of free radicals and reduction of free thiol pool. Here we present another aspect of increased cobalt concentrations in the culture medium resulting in the production of cobalt protoporphyrin IX (CoPPIX), which was incorporated into heme proteins including membrane-bound cytochromes and an expressed human cystathionine beta-synthase (CBS). The presence of CoPPIX in cytochromes inhibited their electron transport capacity and resulted in a substantially decreased respiration. Bacterial cells adapted to the increased cobalt concentration by inducing a modified mixed acid fermentative pathway under aerobiosis. We capitalized on the ability of E. coli to insert cobalt into PPIX to carry out an expression of CoPPIX-substituted heme proteins. The level of CoPPIX-substitution increased with the number of passages of cells in a cobalt-containing medium. This approach is an inexpensive method to prepare cobalt-substituted heme proteins compared to in vitro enzyme reconstitution or in vivo replacement using metalloporphyrin heme analogs and seems to be especially suitable for complex heme proteins with an additional coenzyme, such as human CBS.

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“…In the present investigation, we used E. coli (DH5α) as a prokaryotic model system to investigate the Co 2+ -induced cytotoxicity in bacteria. Co at 400 μM is optimal for growth and over expression of proteins in E. coli 20 . MIC of Co for E. coli (DH5α) was proposed to be >1 mM for each strain of E. coli 21 .…”

Section: Discussionmentioning

confidence: 99%

Cobalt-Induced Cytotoxicity in E. coli (DH5α) is Mediated by Modulation of Cellular Phospholipid Composition

Sahu,

Parida,

Dalua

et al. 2016

J. Adv. Mircobiol.

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The mechanism of Co 2+ -induced cytotoxicity in bacteria was evaluated using E. coli (DH5α) as a model system. In E. coli (DH5α), Co 2+ -induced cytotoxicity was characterized by a dose-dependent (i) reduction of growth rate, (ii) decrease in catalase activity and (iii) decrease in cytosolic free iron content, showing that Co 2+ -induced cytotoxicity enhances oxidative stress in E. coli. Co 2+ induced lipotoxicity in E. coli (DH5α) as indicated by a dose-dependent enhancement of total cellular phospholipid content and increased lipid peroxidation. Lipid peroxidation was mediated through formation of conjugated diene and lipid hydoperoxides folds. A quantitative analysis of total phospholipids using 2D-TLC showed that Co 2+ -induced toxicity led to modulation of cellular phospholipid (PL) content in E. coli (DH5α). Sum total of phosphatidyl ethanolamine (PE) and phosphatidyl glycerol (PG) (PE+PG) content was increased by 15 % that was accompanied by ~2 fold increase in cardiolipin (CL) content. As CL is known to be augmented in multiple growth inhibitory conditions, we hypothesize that enhanced CL content is a regulatory mechanism of E. coli to survive Co 2+ -induced cytotoxicity.

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Influence of cobalt substitution on the activity of iron-type nitrile hydratase: Are cobalt type nitrile hydratases regulated by carbon monoxide?

Cited by 13 publications

References 48 publications

Capturing a Sulfenic Acid with Arylboronic Acids and Benzoxaborole

Capturing a Sulfenic Acid with Arylboronic Acids and Benzoxaborole

Effect of cobalt on Escherichia coli metabolism and metalloporphyrin formation

Cobalt-Induced Cytotoxicity in E. coli (DH5α) is Mediated by Modulation of Cellular Phospholipid Composition

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