Ferric iron reductase activity of LuxG from Photobacterium leiognathi

ABSTRACT Ferric iron reductase was purified from magnetotactic bacteriumMagnetospirillum (formerly Aquaspirillum)magnetotacticum (ATCC 31632) to an electrophoretically homogeneous state. The enzyme was loosely bound on the cytoplasmic face of the cytoplasmic membrane and was found more frequently in magnetic cells than in nonmagnetic cells. The molecular mass of the purified enzyme was calculated upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis to be about 36 kDa, almost the same as that calibrated by gel filtration analysis. The enzyme required NADH and flavin mononucleotide (FMN) as optimal electron donor and cofactor, respectively, and the activity was strongly inhibited by Zn2+ acting as a partial mixed-type inhibitor. TheKm values for NADH and FMN were 4.3 and 0.035 μM, respectively, and the Ki values for Zn2+ were 19.2 and 23.9 μM for NADH and FMN, respectively. When the bacterium was grown in the presence of ZnSO4, the magnetosome number in the cells and the ferric iron reductase activity declined in parallel with an increase in the ZnSO4 concentration of the medium, suggesting that the ferric iron reductase purified in the present study may participate in magnetite synthesis.

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The fission yeast ferric reductase gene frp1+ is required for ferric iron uptake and encodes a protein that is homologous to the gp91-phox subunit of the human NADPH phagocyte oxidoreductase

Molecular and Cellular Biology ◽

10.1128/mcb.13.7.4342-4350.1993 ◽

1993 ◽

Vol 13 (7) ◽

pp. 4342-4350

Author(s):

D G Roman ◽

A Dancis ◽

G J Anderson ◽

R D Klausner

Keyword(s):

Fission Yeast ◽

Iron Uptake ◽

Ferric Iron ◽

Reductase Activity ◽

Iron Acquisition ◽

Protein A ◽

Mutant Gene ◽

Predicted Amino Acid Sequence ◽

Mrna Levels ◽

Ferric Reductase

We have identified a cell surface ferric reductase activity in the fission yeast Schizosaccharomyces pombe. A mutant strain deficient in this activity was also deficient in ferric iron uptake, while ferrous iron uptake was not impaired. Therefore, reduction is a required step in cellular ferric iron acquisition. We have cloned frp1+, the wild-type allele of the mutant gene. frp1+ mRNA levels were repressed by iron addition to the growth medium. Fusion of 138 nucleotides of frp1+ promoter sequences to a reporter gene, the bacterial chloramphenicol acetyltransferase gene, conferred iron-dependent regulation upon the latter when introduced into S. pombe. The predicted amino acid sequence of the frp1+ gene exhibits hydrophobic regions compatible with transmembrane domains. It shows similarity to the Saccharomyces cerevisiae FRE1 gene product and the gp91-phox protein, a component of the human NADPH phagocyte oxidoreductase that is deficient in X-linked chronic granulomatous disease.

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Extracellular iron reductase activity produced by Listeria monocytogenes

Archives of Microbiology ◽

10.1007/s002030050354 ◽

1996 ◽

Vol 166 (1) ◽

pp. 51-57 ◽

Cited By ~ 30

Author(s):

Esau Barchini ◽

Richard E. Cowart

Keyword(s):

Listeria Monocytogenes ◽

Reductase Activity ◽

Iron Reductase

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Microevolution During Serial Mouse Passage Demonstrates FRE3 as a Virulence Adaptation Gene in Cryptococcus neoformans

mBio ◽

10.1128/mbio.00941-14 ◽

2014 ◽

Vol 5 (2) ◽

Cited By ~ 20

Author(s):

Guowu Hu ◽

Shu Hui Chen ◽

Jin Qiu ◽

John E. Bennett ◽

Timothy G. Myers ◽

...

Keyword(s):

Cryptococcus Neoformans ◽

Transcriptome Sequencing ◽

Molecular Mechanisms ◽

Reductase Activity ◽

The United States ◽

Microbial Pathogens ◽

Content Type ◽

Time To Death ◽

Expression Studies ◽

Iron Reductase

ABSTRACTPassage in mice of opportunistic pathogens such asCryptococcus neoformansis known to increase virulence, but little is known about the molecular mechanisms involved in virulence adaptation. Serial mouse passage of nine environmental strains of serotype AC. neoformansidentified two highly adapted virulent strains that showed a 4-fold reduction in time to death after four passages. Transcriptome sequencing expression studies demonstrated increased expression of aFRE3-encoded iron reductase in the two strains but not in a control strain that did not demonstrate increased virulence during mouse passage.FRE3was shown to express an iron reductase activity and to play a role in iron-dependent growth ofC. neoformans. Overexpression ofFRE3in the two original environmental strains increased growth in the macrophage cell line J774.16 and increased virulence. These data demonstrate a role forFRE3in the virulence ofC. neoformansand demonstrate how the increased expression of such a “virulence acquisition gene” during the environment-to-mammal transition, can optimize the virulence of environmental strains in mammalian hosts.IMPORTANCECryptococcus neoformansis a significant global fungal pathogen that also resides in the environment. Recent studies have suggested that the organism may undergo microevolution in the host. However, little is known about the permitted genetic changes facilitating the adaptation of environmental strains to mammalian hosts. The present studies subjected environmental strains isolated from several metropolitan areas of the United States to serial passages in mice. Transcriptome sequencing expression studies identified the increased expression of an iron reductase gene,FRE3, in two strains that adapted in mice to become highly virulent, and overexpression ofFRE3recapitulated the increased virulence after mouse passage. Iron reductase in yeast is important to iron uptake in a large number of microbial pathogens. These studies demonstrate the capacity ofC. neoformansto show reproducible changes in the expression levels of small numbers of genes termed “virulence adaptation genes” to effectively increase pathogenicity during the environment-to-mammal transition.

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Iron Deficiency Induced Changes in Iron Reductase Activity in Papaya Roots

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.127.2.184 ◽

2002 ◽

Vol 127 (2) ◽

pp. 184-187 ◽

Cited By ~ 6

Author(s):

Thomas E. Marler ◽

Ruben dela Cruz ◽

Andrea L. Blas

Keyword(s):

Glycine Max ◽

Iron Deficiency ◽

Carica Papaya ◽

Reductase Activity ◽

Fe Deficiency ◽

Root Tip ◽

Root Tips ◽

Soybean Line ◽

Induced Changes ◽

Iron Reductase

Four papaya (Carica papaya L.) cultivars were cultured aeroponically or in perlite to determine the magnitude, timing, and root locality of Fe reductase induced by Fe deficiency. Five soybean [Glycine max (L.) Merrill] lines with a known range of Fe-deficiency chlorosis scores were cultured in perlite for comparison. Speed of inducement of Fe reductase activity was determined in plants cultured without Fe for 0 to 17 days. Location of Fe reductase activity was determined by sectioning roots from the tip to 60 to 70 mm proximal to the root tip from plants cultured without Fe for 16 to 19 days. The Fe reductase system was induced in all papaya cultivars after 7 to 11 days without Fe, and activity increased through 17 days. Iron reductase activity in all papaya cultivars was comparable to the most tolerant soybean line. The zone of highest activity was the apical 10 mm of roots. These results indicate that papaya roots are highly efficient in induced Fe reductase activity. The highest activity in root tips underscores the importance of maintaining a healthy, continually growing root system with numerous growing points when culturing papaya in alkaline substrates.

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Reduction of ferric chelates by leaf plasma membrane preparations from Fe-deficient and Fe-sufficient sugar beet

Functional Plant Biology ◽

10.1071/pp99002 ◽

1999 ◽

Vol 26 (6) ◽

pp. 601 ◽

Cited By ~ 13

Author(s):

Elena B. González-Vallejo ◽

Anunciación Abadía ◽

Jose Antonio González-Reyes ◽

Javier Abadía ◽

Ana Flor López-Millán ◽

...

Keyword(s):

Plasma Membrane ◽

Citric Acid ◽

Sugar Beet ◽

Plasma Membranes ◽

Ferric Iron ◽

Reductase Activity ◽

Tetraacetic Acid ◽

Ferric Chelate Reductase ◽

Ferric Chelate Reductase Activity ◽

Optimal Ph

The ferric chelate reductase activities of leaf plasma membranes isolated from the leaves of Fe-deficient and Fe-sufficient sugar beet have been characterized. Substrates used were the complexes of ferric iron with ethylene diamine tetraacetic acid, citric acid and malic acid. Iron deficiency was associated with 1.5- to 2-fold increases in leaf plasma membrane ferric chelate reductase activity when rates were calculated on a protein basis. The natural complexes of ferric iron with citrate and especially with malate were good substrates for the ferric chelate reductase enzyme present in leaf plasma membrane preparations. The apparent affinities were higher for the ferric malate complex. The optimal pH for the activity of the ferric chelate reductase in sugar beet leaf plasma membranes was in the range 6.5–7.0. The ferric chelate reductase activity decreased by approximately 30% when the assay pH was decreased to 5.8 or increased to 7.5. Therefore, our data provide evidence against the hypothesis that changes in apoplastic pH could decrease markedly the activity of the ferric chelate reductase enzyme in plasma membrane preparations from the leaves of Fe-deficient plants.

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The fission yeast ferric reductase gene frp1+ is required for ferric iron uptake and encodes a protein that is homologous to the gp91-phox subunit of the human NADPH phagocyte oxidoreductase.

Molecular and Cellular Biology ◽

10.1128/mcb.13.7.4342 ◽

1993 ◽

Vol 13 (7) ◽

pp. 4342-4350 ◽

Cited By ~ 84

Author(s):

D G Roman ◽

A Dancis ◽

G J Anderson ◽

R D Klausner

Keyword(s):

Fission Yeast ◽

Iron Uptake ◽

Ferric Iron ◽

Reductase Activity ◽

Iron Acquisition ◽

Protein A ◽

Mutant Gene ◽

Predicted Amino Acid Sequence ◽

Mrna Levels ◽

Ferric Reductase

We have identified a cell surface ferric reductase activity in the fission yeast Schizosaccharomyces pombe. A mutant strain deficient in this activity was also deficient in ferric iron uptake, while ferrous iron uptake was not impaired. Therefore, reduction is a required step in cellular ferric iron acquisition. We have cloned frp1+, the wild-type allele of the mutant gene. frp1+ mRNA levels were repressed by iron addition to the growth medium. Fusion of 138 nucleotides of frp1+ promoter sequences to a reporter gene, the bacterial chloramphenicol acetyltransferase gene, conferred iron-dependent regulation upon the latter when introduced into S. pombe. The predicted amino acid sequence of the frp1+ gene exhibits hydrophobic regions compatible with transmembrane domains. It shows similarity to the Saccharomyces cerevisiae FRE1 gene product and the gp91-phox protein, a component of the human NADPH phagocyte oxidoreductase that is deficient in X-linked chronic granulomatous disease.

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Biochemical characterization of Serpula lacrymans iron-reductase enzymes in lignocellulose breakdown

Journal of Industrial Microbiology & Biotechnology ◽

10.1007/s10295-019-02238-7 ◽

2019 ◽

Vol 47 (1) ◽

pp. 145-154 ◽

Cited By ~ 3

Author(s):

Irnia Nurika ◽

Daniel C. Eastwood ◽

Timothy D. H. Bugg ◽

Guy C. Barker

Keyword(s):

Ferric Iron ◽

Biochemical Characterization ◽

Recombinant Enzymes ◽

Binding Domains ◽

Lignin Decomposition ◽

Pre Treatment ◽

Serpula Lacrymans ◽

Iron Reductase ◽

Ir Genes

AbstractPutative iron-reductase (IR) genes from Serpula lacrymans with similarity to the conserved iron-binding domains of cellobiose dehydrogenase (CDH) enzymes have been identified. These genes were cloned and expressed to functionally characterize their activity and role in the decomposition of lignocellulose. The results show that IR1 and IR2 recombinant enzymes have the ability to depolymerize both lignin and cellulose, are capable of the reduction of ferric iron to the ferrous form, and are capable of the degradation of nitrated lignin. Expression of these genes during wheat straw solid-state fermentation was shown to correlate with the release of compounds associated with lignin decomposition. The results suggest that both IR enzymes mediate a non-enzymatic depolymerisation of lignocellulose and highlight the potential of chelator-mediated Fenton systems in the industrial pre-treatment of biomass.

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Characterization and partial purification of a ferrireductase from human duodenal microvillus membranes

Biochemical Journal ◽

10.1042/bj3090745 ◽

1995 ◽

Vol 309 (3) ◽

pp. 745-748 ◽

Cited By ~ 58

Author(s):

H D Riedel ◽

A J Remus ◽

B A Fitscher ◽

W Stremmel

Keyword(s):

Ferrous Iron ◽

Iron Uptake ◽

Plasma Membranes ◽

Ferric Iron ◽

Reductase Activity ◽

Nitrilotriacetic Acid ◽

Iron Chelator ◽

Partial Purification ◽

Uptake System ◽

Ammonium Sulphate Precipitation

Reduction of ferric iron in the presence of HuTu 80 cells or duodenal microvillus membranes (MVMs) was investigated. With both systems, NADH-dependent reduction of Fe3+/NTA (nitrilotriacetic acid) was demonstrated, using the ferrous iron chelator ferrozine. Uptake of Fe3+ from Fe3+/NTA by HuTu 80 cells was strongly inhibited by addition of ferrozine, indicating that Fe2+ is the substrate for the iron uptake system. With isolated plasma membranes it is shown that the reductase activity is sensitive to trypsin and incubation at 65 degrees C. The reductase activity could be extracted from the plasma membrane and partially purified by ammonium sulphate precipitation and isoelectric focusing. From the purification and inhibition characteristics we conclude that reduction of ferric iron on the surface of duodenal plasma membranes is catalysed by a membrane protein.

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