Isolation and properties of the complex nonheme-iron-containing cytochrome b557 (bacterioferritin) from pseudomonas aeruginosa

Moore, Geoffrey R.; Mann, Stephen; Bannister, J.V.

doi:10.1016/0162-0134(86)80097-6

Cited by 72 publications

(50 citation statements)

References 25 publications

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“…The resulting spectrum at 4.2 K is shown in Fig. 2C; component 1, 6 = 1.32(5) mm/s, AEQ = 2.99(6) mm/s, 65.4(9)'/, of total absorption area; component 2, 6 = 0.42(6), AEQ = l.11(7), 34.6(8)% of total absorption area. Isomer shifts and quadrupole splittings of the reduced membrane sample fit well to those of whole cells at logarithmic growth.…”

Section: Resultsmentioning

confidence: 99%

Iron metabolism of Escherichia coli studied by Mössbauer spectroscopy and biochemical methods

Matzanke

Bill

et al. 1989

European Journal of Biochemistry

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To date it has barely been recognized that the nature of about 75% of the Escherichiu coli iron pool is unknown. Here we report the isolation of two iron species representing major components of iron metabolism in various growth states of E. coli. In vivo Mossbauer spectroscopy was applied to obtain information on the intracellular distribution pattern of iron in E. coli K12 W3110. Only two types of iron could be detected in the cell spectra: hexacoordinated Fe2+ and Fe3 + high-spin complexes. Other iron-requiring compounds are at least one order of magnitude less abundant in E. coli. The Mossbauer parameters of these complexcs fit neither cytochromes nor iron-sulfur proteins nor ferric holo-bacterioferritin. They are sensitive to metabolic changes and inhibitors. The ratio of Fe/subunit, Fe2 '/Fe3 + interconversion, chromatographic and electrophoretic data exclude bacterioferritin as the main iron metabolite in E. coli. Bacterioferritin can be observed only at very high ferric ion concentrations in the medium. The 55Fe fluorograms of both cytoplasmic and membrane fractions exhibit two exclusive bands with apparent molecular masses of 17 and 15 kDa, respectively. The two bands comprised 70% ofthe applied radioactivity. In gel filtration the main iron peak elutes at 155 kDa yielding two bands with apparent molecular masses of 17 and 15 kDa on SDS/PAGE. We therefore conclude that the iron species form a protein with an apparent molecular mass of 155 kDa containing 37-kDa and 15-kDa subunits. The iron content of the protein is 44 pg Fe/mg protein which corresponds to approximately 13 iron ions/subunit. No iron protein cxhibiting the observed features has been described so far. Additional Mossbauer experiments suggest that these novel iron proteins are not restricted to E. coli but that similar components are detectable in several bacterial and fungal systems, thus pointing to a general occurrcnce.Knowledge of the intracellular iron metabolism of both higher and microbial organisms is fragmentary. For Escherichiu coli, the following data are documented (values given per gram cells): total iron content 59-168 pg, nonheme iron in membranes 3.8 -15 pg, heme iron 0.52-0.56 pg [I, 21. Thus, the state of 75% of the E. coli iron pool remains obscure. The quantitative distribution of the metal within the various non-respiratory enzymes and bacterioferritin has not yet been determined. This paper provides evidence that the niain fraction of intracellular iron is associatud with novel components of iron metabolism in E. coli.Prcviously we have shown that in viiw Mossbauer spectroscopy furnishes detailed information on the oxidation state and to some extent on the intracellular distribution pattern of iron in various microbial systems [3 -61. In the present study this technique has been utilized to gain novel insights into the bacterial iron metabolism of E. coli K12 wild-type strain W313 0. In order to achieve specific and controlled uptake of "Fe, we have exploited one feature which E. coli has in common with many microorgan...

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Section: Resultsmentioning

confidence: 99%

Iron metabolism of Escherichia coli studied by Mössbauer spectroscopy and biochemical methods

Matzanke

Bill

et al. 1989

European Journal of Biochemistry

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“…Its cytoplasmic location indicates that bacterioferritin could have a similar function to mammalian ferritin in iron storage, as is widely assumed [6, [8][9][10][11][13][14][15][16][17]. However, there have been few reported studies aimed at addressing this question.…”

Section: Conditionsmentioning

confidence: 74%

“…The intracellular sequestration and mobilisation of iron have received little attention but a potential iron store which has been identified in Azotobacter vinelandii [6] [6,9, 101. N-terminal amino acid sequences of bacterioferritin polypeptides are highly similar [lo-141 and the molecular properties of these proteins indicate that they form a closely related family.…”

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confidence: 99%

“…Bacterioferritin is a multimeric protein with molecular mass approximately 440 kDa and is composed of 24 subunits [6,9,101. N-terminal amino acid sequences of bacterioferritin polypeptides are highly similar [lo-141 and the molecular properties of these proteins indicate that they form a closely related family.…”

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confidence: 99%

“…Iron is an essential element for the growth of almost all bacteria and many of the molecular details of iron uptake have been established [l -51. The intracellular sequestration and mobilisation of iron have received little attention but a potential iron store which has been identified in Azotobacter vinelandii [6], Azotobacter chroococcum [7], Escherichia coli [S], Pseudomonas aeruginosa [9], Nitrobacter winogradskyi [lo], the cyanobacterium Synechocystis PCC 6803 [ll] and Mycobacterium paratuberculosis [12] is bacterioferritin. Bacterioferritin is a multimeric protein with molecular mass approximately 440 kDa and is composed of 24 subunits [6,9,101.…”

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Iron metabolism in Rhodobacter capsulatus

Ringeling

Davy

Monkara

et al. 1994

European Journal of Biochemistry

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The water-soluble cytochrome b,,, from the photosynthetic bacterium Rhodobacter capsulatus was purified and shown to have the properties of the iron-storage protein bacterioferritin. The molecular mass of R. capsulatus bacterioferritin is 428 kDa and it is composed of a single type of 18-kDa subunit. The N-terminal amino acid sequence of the bacterioferritin subunit shows 70% identity to the sequence of bacterioferritin subunits from Escherichia coli, Nitrobacter winogradskyi, Azotobacter vinelandii and Synechocystis PCC 6803. The absorbance spectrum of reduced bacterioferritin shows absorbance maxima at 557 nm (a band), 526 nm @ band) and 417 nm (Soret band) from the six haem groups/molecule. Antibody assays reveal that bacterioferritin is located in the cytoplasm of R. capsulatus, and its levels stay relatively constant during batch growth under aerobic conditions when the iron concentration in the medium is kept constant. Iron deficiency leads to a decrease in bacterioferritin and iron overload leads to an increase. Bacterioferritin from R. capsulatus has an amorphous iron-oxide core with a high phosphate content (900-1000 Fe atoms and approximately 600 phosphateshacterioferritin molecule). Mossbauer spectroscopy indicates that in both aerobically and anaerobically (phototrophically) grown cells bacterioferritin with an Fe'+ core is formed, suggesting that iron-core formation in vivo may not always require molecular oxygen.Iron is an essential element for the growth of almost all bacteria and many of the molecular details of iron uptake have been established [l -51. The intracellular sequestration and mobilisation of iron have received little attention but a potential iron store which has been identified in Azotobacter vinelandii [6] [6,9, 101. N-terminal amino acid sequences of bacterioferritin polypeptides are highly similar [lo-141 and the molecular properties of these proteins indicate that they form a closely related family. Bacterioferritin, like its animal counterpart ferritin, is organised as a hollow protein shell which can contain a non-haem iron in its central cavity [6,[15][16][17]. Unlike mammalian ferritin, in which the non-haem iron core is crystalline ferrihydrite [16, 181, bacterioferritin has an amorphous iron core with a high phosphate content [19]. Another difference between mammalian fenitins and bacterioferritins is that the latter contain intrinsic haem groups while the former do not. It is the presence of haem in purified Alternative bacterial iron-storage systems to bacterioferritin exist. Fenitin of the non-haem type, with a relatively high sequence similarity to animal fenitin, has been isolated from Helicobacter pylori [21] and Bacteroides fragilis [22], and its gene has been cloned from E. coli [23]. Furthermore, the 57Fe Mossbauer spectroscopy study of intact E. coli cells reported by Matzanke et al. [24] clearly identified two ironrich species present in greater quantity than bacterioferritin that might constitute a novel iron-storage system.No iron-storage protein has been pr...

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Iron Proteins for Storage & Transport & Their Synthetic Analogs

Lewin

Brun

Moore

2005

Encyclopedia of Inorganic Chemistry

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This article reviews proteins involved in iron metabolism. Brief descriptions are given of the biological contexts for the proteins discussed but the main emphasis is on chemical and structural aspects of them. Iron is essential to almost all forms of life, but its low bioavailability and toxicity mean that they require sophisticated mechanisms to transport it. Mammals acquire heme and nonheme iron via proteins in the gut wall, and transport it around the body using serum transferrin, for ferric iron, and hemopexin, for heme. Microbes have an active iron uptake mechanism involving small iron chelators called siderophores, for example, ferrichrome in Escherichia coli . Ferrichrome enters the cell via FhuA, a β‐barrel in the outer membrane. The periplasmic protein FhuD then transfers it to the FhuBC complex in the cytoplasmic membrane. FhuB forms a channel through which the ferric siderophore passes using energy supplied by FhuC. Once inside the cytoplasm the iron is removed from the ligand, possibly via reduction by FhuF. Some pathogenic bacteria have a similar system for heme uptake, secreting hemophores such as HasA, which can remove heme from hemoglobin. Other pathogens have outer membrane receptors that remove ferric iron from transferrin and transport it into the periplasm, where it is bound by ferric binding proteins that closely resemble a single lobe of transferrin. Following its acquisition, iron needs to be stored safely. The most widespread form of iron storage is the ferritin superfamily, which includes ferritin, bacterioferritin, and Dps. Ferritin is found in bacteria, plants, and animals and is a large shell made up of 24 subunits within which up to 4,500 ferric ions can be stored as a ferrihydrite mineral core. Bacterioferritin is found in bacteria and is closely related to ferritin, but contains up to 12 heme groups bound between pairs of subunits, which may play a role in iron release or electron storage. The bacterial protein Dps is smaller than ferritin, with 12 subunits forming the protein shell, and can hold up to 500 ferric ions. All of these proteins contain dinuclear iron sites that catalyze the oxidation of ferrous iron. An alternative form of iron storage is frataxin, found in mitochondria. Although not related to ferritin, this protein has the ability to form large aggregates that can store up to 50 ferric ions per monomer in a mineral core resembling those of ferritins.

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Isolation and properties of the complex nonheme-iron-containing cytochrome b557 (bacterioferritin) from pseudomonas aeruginosa

Cited by 72 publications

References 25 publications

Iron metabolism of Escherichia coli studied by Mössbauer spectroscopy and biochemical methods

Iron metabolism of Escherichia coli studied by Mössbauer spectroscopy and biochemical methods

Iron metabolism in Rhodobacter capsulatus

Iron Proteins for Storage & Transport & Their Synthetic Analogs

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