Isolation, purification and characterization of hemerythrin from Methylococcus capsulatus (Bath)

Kao, Wei-Chun; Wang, Vincent C.‐C.; Huang, Yi-Che; Yu, Steve S.‐F.; Chang, Ta‐Chau; Chan, Sunney I.

doi:10.1016/j.jinorgbio.2008.02.008

Cited by 41 publications

(36 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2A). These features are reminiscent of the methemerythrin spectrum attributed to a μ-oxo bridged diferric metallocenter (22). Addition of sodium dithionite to oxidized UreA2B2 under anaerobic conditions caused bleaching of the spectrum, in parallel to the restoration of activity, consistent with direct reduction of the active site ferric ions (Fig.…”

Section: Effects Of Medium Supplementation With Metal Ions On Urea2b2mentioning

confidence: 74%

Iron-containing urease in a pathogenic bacterium

Carter¹,

Tronrud

Taber³

et al. 2011

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

View full text Add to dashboard Cite

Helicobacter mustelae, a gastric pathogen of ferrets, synthesizes a distinct iron-dependent urease in addition to its archetypical nickel-containing enzyme. The iron-urease is oxygen-labile, with the inactive protein exhibiting a methemerythrin-like electronic spectrum. Significantly, incubation of the oxidized protein with dithionite under anaerobic conditions leads to restoration of activity and bleaching of the spectrum. Structural analysis of the oxidized species reveals a dinuclear iron metallocenter bridged by a lysine carbamate, closely resembling the traditional nickelurease active site. Although the iron-urease is less active than the nickel-enzyme, its activity allows H. mustelae to survive the carnivore's low-nickel gastric environment.diiron | hydrolase | metalloprotein | isoenzyme | enzyme activation

show abstract

Section: Effects Of Medium Supplementation With Metal Ions On Urea2b2mentioning

confidence: 74%

Iron-containing urease in a pathogenic bacterium

Carter¹,

Tronrud

Taber³

et al. 2011

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

View full text Add to dashboard Cite

show abstract

“…The CLJU_c21940 flavoprotein has 60% identity to a C. acetobutylicum flavoprotein (CA_C2449) that has demonstrated oxidase activity and is reduced by NROR (see Table S4 in the supplemental material) (57). Hemerythrins are proteins that carry oxygen and/or convert oxygen to hydrogen peroxide (81,82). C. ljungdahlii also has an annotated superoxide dismutase (CLJU_c29780), but expression of the gene coding for it was low for both 8%-O 2 -exposed and anaerobically cultured cells (data not shown).…”

Section: Resultsmentioning

confidence: 99%

Metabolic Response of Clostridium ljungdahlii to Oxygen Exposure

Whitham

Tirado-Acevedo

Chinn

et al. 2015

Appl Environ Microbiol

View full text Add to dashboard Cite

cClostridium ljungdahlii is an important synthesis gas-fermenting bacterium used in the biofuels industry, and a preliminary investigation showed that it has some tolerance to oxygen when cultured in rich mixotrophic medium. Batch cultures not only continue to grow and consume H 2 , CO, and fructose after 8% O 2 exposure, but fermentation product analysis revealed an increase in ethanol concentration and decreased acetate concentration compared to non-oxygen-exposed cultures. In this study, the mechanisms for higher ethanol production and oxygen/reactive oxygen species (ROS) detoxification were identified using a combination of fermentation, transcriptome sequencing (RNA-seq) differential expression, and enzyme activity analyses. The results indicate that the higher ethanol and lower acetate concentrations were due to the carboxylic acid reductase activity of a more highly expressed predicted aldehyde oxidoreductase (CLJU_c24130) and that C. ljungdahlii's primary defense upon oxygen exposure is a predicted rubrerythrin (CLJU_c39340). The metabolic responses of higher ethanol production and oxygen/ ROS detoxification were found to be linked by cofactor management and substrate and energy metabolism. This study contributes new insights into the physiology and metabolism of C. ljungdahlii and provides new genetic targets to generate C. ljungdahlii strains that produce more ethanol and are more tolerant to syngas contaminants. Clostridium ljungdahlii is an anaerobic, motile, endosporeforming, Gram-positive, rod-shaped, acetogenic bacterium isolated from chicken yard waste and has application as a biocatalyst to transform syngas components (CO, CO 2 , and H 2 ) into more valuable chemicals (1-4). It was the first bacterium discovered to metabolize these syngas components and to produce ethanol with acetate as its primary fermentation product (1, 4). To reduce the amount of acetate and increase the amount of ethanol produced by C. ljungdahlii for its use in industrial solvent production, different reactor designs and agitation parameters, varied syngas component concentrations, increased gas flow rates and pressures, reduced nitrogen sources, addition of reducing agents to media, adjustment of growth medium pH, and addition of nanoparticles have all been evaluated (1,(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Some of these efforts have reportedly improved ethanol/ acetate product ratios from 1:20 to 2:1 in batch cultures and from 1:1 to 21:1 for cultures grown in continuously stirred reactors (8,9,16). More recent sequencing and genetic modification techniques have greatly enhanced our understanding of C. ljungdahlii's metabolism and increased production of ethanol as well as enabled production of other chemicals (e.g., acetone, butyrate, and butanol) (2, 3, 17-21).Despite these advancements, for C. ljungdahlii to be effectively used for industrial syngas transformation, some of its catalytic limitations related to gaseous headspace composition still require evaluation. Although steel mill waste gas was recently used as...

show abstract

“…Hemerythrins are characterized by a non-heme di-iron core that is not only bridged by the carboxylate side chains of Asp and Glu residues but also is μ-oxo bridged (Fe III -O-Fe III ) in the oxidized form (Kao et al ., 2008). The iron atoms are liganded by histidine residues, which are all conserved in HerA (Supporting Information Fig.…”

Section: Resultsmentioning

confidence: 99%

“…7A) showed two major absorption bands at 336 nm and 374 nm and a weaker feature around 500 nm, which represent ligand-to-metal charge transfer transitions from the μ-oxo bridge to Fe(III) within the di-iron core. These spectral features are diagnostic of the met form of hemerythrins (Kao et al ., 2008) where a hydroxide is liganded to one of the Fe(III) centres. Reduction of the met protein by dithionite resulted in the bleaching of each of these peaks (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…7A) to form the deoxy form of the protein, where a hydroxide bridges the di-iron binuclear centre, with each iron now in the Fe(II) form. Re-oxidation of the protein by oxygen from the reduced to the peroxy-Fe(III) liganded intermediate can be accompanied by an enhancement of the 500 nm feature, which is diagnostic of the oxy form of hemerythrins (Kao et al ., 2008) although we did not observe this in our experiments. However, when the as-isolated (met) form of the protein was treated with sodium azide, a characteristic broad absorbance around 450 nm developed (Fig.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Hemerythrins in the microaerophilic bacterium Campylobacter jejuni help protect key iron–sulphur cluster enzymes from oxidative damage

Kendall

Barrero-Tobon

Hendrixson

et al. 2013

Environmental Microbiology

View full text Add to dashboard Cite

Microaerophilic bacteria are adapted to low oxygen environments, but the mechanisms by which their growth in air is inhibited are not well understood. The citric acid cycle in the microaerophilic pathogen Campylobacter jejuni is potentially vulnerable, as it employs pyruvate and 2-oxoglutarate:acceptor oxidoreductases (Por and Oor), which contain labile (4Fe-4S) centres. Here, we show that both enzymes are rapidly inactivated after exposure of cells to a fully aerobic environment. We investigated the mechanisms that might protect enzyme activity and identify a role for the hemerythrin HerA (Cj0241). A herA mutant exhibits an aerobic growth defect and reduced Por and Oor activities after exposure to 21% (v/v) oxygen. Slow anaerobic recovery of these activities after oxygen damage was observed, but at similar rates in both wild-type and herA strains, suggesting the role of HerA is to prevent Fe-S cluster damage, rather than promote repair. Another hemerythrin (HerB; Cj1224) also plays a protective role. Purified HerA and HerB exhibited optical absorption, ligand binding and resonance Raman spectra typical of μ-oxo-bridged di-iron containing hemerythrins. We conclude that oxygen lability and poor repair of Por and Oor are major contributors to microaerophily in C. jejuni; hemerythrins help prevent enzyme damage microaerobically or during oxygen transients.

show abstract

Isolation, purification and characterization of hemerythrin from Methylococcus capsulatus (Bath)

Cited by 41 publications

References 23 publications

Iron-containing urease in a pathogenic bacterium

Iron-containing urease in a pathogenic bacterium

Metabolic Response of Clostridium ljungdahlii to Oxygen Exposure

Hemerythrins in the microaerophilic bacterium Campylobacter jejuni help protect key iron–sulphur cluster enzymes from oxidative damage

Contact Info

Product

Resources

About