Ferric-reductase activities in Vibrio vulnificus biotypes 1 and 2

Mazoy, R

doi:10.1016/s0378-1097(99)00044-0

Cited by 3 publications

(4 citation statements)

References 16 publications

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“…These results told us that the Fe(III)nitrilotriacetic acid substrate together with FMN would best serve the purpose of activity measuring during enzymes purification. Contrary to some [8,13], but in accordance with other [10] previous research, our assay for the enzymes from P. denitrificans was not significantly sensitive to oxygen, as air removal from the reaction mixture with a stream of argon increased the rate of Fe(II)(ferrozine) 3 production by 10% maximum. Based on this finding, all further measurements could be performed under ambient oxygen pressure.…”

Section: Choice Of a Fe(iii) Substrate For The Enzyme Assaysupporting

confidence: 91%

“…Fe(III) reductases constitute a heterogeneous group of enzymes in respect to their biochemical properties. The majority of the known bacterial Fe(III) reductases resides in the cytoplasm, consists of one small polypeptide chain lacking any distinguishable prosthetic group, reduces Fe(III) at the expense of NADH or NADPH and requires flavin as an electron transfer mediator [6–13]. On the contrary, Fe(III) reductases of Fe(III) respirers are c ‐type cytochromes excreted into the medium or exposed at the cell surface where they can make direct contact with the solid metal oxides [14,15].…”

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confidence: 99%

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Isolation and biochemical characterization of two soluble iron(III) reductases from Paracoccus denitrificans

Mazoch

Tesařı́k

Sedláček

et al. 2004

European Journal of Biochemistry

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Two soluble enzymes (FerA and FerB) catalyzing the reduction of a number of iron(III) complexes by NADH, were purified to near homogeneity from the aerobically grown iron‐limited culture of Paracoccus denitrificans using a combination of anion‐exchange chromatography (Sepharose Q), chromatofocusing (Mono P), and gel permeation chromatography (Superose 12). FerA is a monomer with a molecular mass of 19 kDa, whereas FerB exhibited a molecular mass of about 55 kDa and consists of probably two identical subunits. FerA can be classified as an NADH:flavin oxidoreductase with a sequential reaction mechanism. It requires the addition of FMN or riboflavin for activity on Fe(III) substrates. In these reactions, the apparent substrate specificity of FerA seems to stem exclusively from different chemical reactivities of Fe(III) compounds with the free reduced flavin produced by the enzyme. Observations on reducibility of Fe(III) chelated by vicinal dihydroxy ligands support the view that FerA takes part in releasing iron from the catechol type siderophores synthesized by P. denitrificans. Contrary to FerA, the purified FerB contains a noncovalently bound redox‐active FAD coenzyme, can utilize NADPH in place of NADH, does not reduce free FMN at an appreciable rate, and gives a ping‐pong type kinetic pattern with NADH and Fe(III)‐nitrilotriacetate as substrates. FerB is able to reduce chromate, in agreement with the fact that its N‐terminus bears a homology to the previously described chromate reductase from Pseudomonas putida. Besides this, it also readily reduces quinones like ubiquinone‐0 (Q0) or unsubstituted p‐benzoquinone.

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Section: Choice Of a Fe(iii) Substrate For The Enzyme Assaysupporting

confidence: 91%

mentioning

confidence: 99%

Isolation and biochemical characterization of two soluble iron(III) reductases from Paracoccus denitrificans

Mazoch

Tesařı́k

Sedláček

et al. 2004

European Journal of Biochemistry

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“…Many bacterial ferric iron reductases have been described over the past 30 years from a variety of different bacteria including Agrobacterium tumefaciens [35], Azotobacter vinelandii [36], Bacillus megaterium [37], Bacillus subtilis [38,39], Escherichia coli [40–42], Legionella pneumophila [43,44], Listeria monocytogenes [45–47], Magnetospirillum magnetotacticum [48], Mycobacterium paratuberculosis [49], Mycobacterium smegmatis [50], Neisseria gonorrhoeae [51], Pseudomonas aeruginosa [52–54], Pseudomonas fluorescens [55], Rhodopseudomonas sphaeroides [56], Treponema denticola [57], and Vibrio vulnificus [58]. Only a few of these enzymes have been purified to homogeneity and characterized in detail.…”

Section: Assimilatory Ferric Iron Reductasesmentioning

confidence: 99%

Microbial ferric iron reductases

2003

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Almost all organisms require iron for enzymes involved in essential cellular reactions. Aerobic microbes living at neutral or alkaline pH encounter poor iron availability due to the insolubility of ferric iron. Assimilatory ferric reductases are essential components of the iron assimilatory pathway that generate the more soluble ferrous iron, which is then incorporated into cellular proteins. Dissimilatory ferric reductases are essential terminal reductases of the iron respiratory pathway in iron-reducing bacteria. While our understanding of dissimilatory ferric reductases is still limited, it is clear that these enzymes are distinct from the assimilatory-type ferric reductases. Research over the last 10 years has revealed that most bacterial assimilatory ferric reductases are flavin reductases, which can serve several physiological roles. This article reviews the physiological function and structure of assimilatory and dissimilatory ferric reductases present in the Bacteria, Archaea and Yeast. Ferric reductases do not form a single family, but appear to be distinct enzymes suggesting that several independent strategies for iron reduction may have evolved.

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“…Assessment of isogenic fur mutants has also allowed the identification of downstream proteins such as the 77-kDa putative V. vulnificus heme receptor, hupA (40), which is also downstream of HupR, a positive regulator of hupA transcription under low-iron conditions in the presence of heme. Finally V. vulnificus also utilizes ferric reductases to further facilitate iron acquisition from siderophores into the cell (45). These extensive observations reaffirm the role of iron in V. vulnificus's virulence.…”

Section: Iron and Pathogensmentioning

confidence: 66%

Hepcidin: the Missing Link between Hemochromatosis andInfections

Ashrafian

2003

Infect Immun

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The aphrodisiacal potential of oysters is the stuff of maritime folklore, having roots in tales of Aphrodite (literally "foam born"), the goddess of love, said to have arisen from the sea on an oyster shell. However, mariners' tales chronicling oysters' lethal potential, despite having abounded since the 5th century B.C., have received less attention. Vibrio vulnificus, originally described in 1979 (6; J. J. Farmer III, Letter, Lancet ii:903, 1979), is a particularly virulent, lactose-fermenting, motile gram-negative halophilic bacterium that inhabits temperate coastal waters, notably of the Gulf of Mexico. V. vulnificus is concentrated in fish and filter feeders such as oysters and clams (up to 50% culture positive) and crabs (up to 11% culture positive) (18,72), and infection associated with exposure to this organism may range from wound infections to fatal septicemic shock (38, 69). Moreover, as probably the leading cause of seafood-associated fatalities in the United States, this organism is considered a significant public health hazard, since despite early recognition, aggressive antibiotic therapy, and surgical debridement, the morbidity, mortality, and cost associated with V. vulnificus infections remain substantial (48,49).Risk factors for V. vulnificus infection include the V. vulnificus subtype (various genetically distinct subgroups of biotype 1 identified by randomly amplified polymorphic DNA PCR appear to be especially virulent), immunocompromised state (human immunodeficiency virus, cancer, bone marrow suppression, achlorhydria, and diabetes), end-stage renal impairment, liver impairment (particularly cirrhosis [infection risk, 200-fold]) (33), and hemochromatosis (primary or secondary such as the hemolytic anemias and thalassemias or porphyria cutanea tarda) (11,30,31,51,71). Interestingly, these same patients, especially those with iron overload, also have a striking predisposition to other aggressive bacteria, including Listeria monocytogenes, Klebsiella sp., and Yersinia sp. (the last of these, perhaps coincidentally, is also a potentially waterborne

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Ferric-reductase activities in Vibrio vulnificus biotypes 1 and 2

Cited by 3 publications

References 16 publications

Isolation and biochemical characterization of two soluble iron(III) reductases from Paracoccus denitrificans

Isolation and biochemical characterization of two soluble iron(III) reductases from Paracoccus denitrificans

Microbial ferric iron reductases

Hepcidin: the Missing Link between Hemochromatosis andInfections

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