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Adzamli IK, Henderson RA, Ong H, Sykes AG, Cammack R, Rao KK. Identification of inner- and outer-sphere reaction pathways in the reduction of iron-sulphur proteins with a chromium (II)-macrocycle complex. Biochem Biophys Res Commun 1982; 105:1582-9. [PMID: 7103972 DOI: 10.1016/0006-291x(82)90969-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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52
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Rao KK, Rao BN, Balasundaram V, Venugopal N. "Primary mediastinal seminoma". Indian J Cancer 1981; 18:153-6. [PMID: 7309113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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53
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Johnson MK, Thomson AJ, Robinson AE, Rao KK, Hall DO. Low-temperature magnetic circular dichroism spectra and magnetisation curves of 4Fe clusters in iron-sulphur proteins from Chromatium and Clostridium pasteurianum. Biochim Biophys Acta 1981; 667:433-51. [PMID: 6260220 DOI: 10.1016/0005-2795(81)90209-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The magnetic circular dichroism (MCD) spectra of the 4Fe clusters in the iron-sulphur proteins high-potential iron protein from Chromatium and the 8Fe ferredoxin from Clostridium pasteurianum have been measured over the wavelength range 300-800 nm at temperatures between approx. 1.5 and 50 K and at magnetic fields up to 5 tesla. In both cases the proteins have been studied in the oxidized and reduced states. The reduced state of high-potential iron protein gives a temperature-independent MCD spectrum up to 20 K, confirming the diamagetism of this state at low temperature. The MCD spectrum of samples of oxidized ferredoxin invariably show the presence of a low concentration of a paramagnetic species, in agreement with the observation that the EPR spectrum always shows a signal at g = 2.01. The paramagnetic MCD spectrum runs across the whole of the wavelength range studied and therefore most probably originates from an iron-sulphur centre. The diamagnetic component of the MCD spectrum of oxidized ferredoxin is very similar to that of reduced high-potential iron protein. The low-temperature MCD spectra of oxidized high-potential iron protein and reduced ferredoxin reveal intense, temperature-dependent bands. The spectra are highly structured with that of high-potential iron protein showing a large number of electronic transitions across the visible region. The MCD spectra of the two different oxidation levels are quite distinctive and should provide a means of establishing the identity of these state of 4Fe clusters in more complex proteins. MCD magnetisation curves have been constructed from detailed studies of the field and temperature dependence of the MCD spectra of the two paramagnetic oxidation states. These plots can be satisfactorily fitted to the theoretically computed curves for an S = 1/2 ground state with the g factors experimentally determined by EPR spectroscopy. The low-temperature MCD spectra of the reduced 2Fe-2S ferredoxin from Spirulina maxima are also presented and MCD magnetisation curves plotted and fitted to the experimentally determined g factors.
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Abstract
Certain metalloproteins are common to all photosynthetic electron transfer chains. These include soluble proteins such as ferredoxins and cytochromes of the c2 type, and membrane-bound components such as cytochrome b, c1 and the Rieske iron-sulphur protein. The sequence of electron transfer Quinone leads to (cyt b, Fe-S, cyt c1) leads to cyt c2 indicates a common precursor to these systems and to the mitochondrial respiratory chain. In cyanobacteria the cytochrome c2 can be interchanged with the copper protein plastocyanin, and furthermore in chloroplasts of higher plants the latter is used exclusively. The ferredoxins in anaerobic photosynthetic bacteria are mostly of the [4Fe-4S] type, probably derived from those of the fermentative bacteria. These could readily be formed in the earliest cells from iron, sulphide and a very simple peptide. In the oxygen-evolving cyanobacteria and the aerobic halobacteria the [2Fe-2S] ferredoxins predominate. The electron transfer chains of the cyanobacteria have been incorporated almost unchanged into the chloroplasts of plants. The electron transfer chains of purple photosynthetic bacteria were probably the precursors of the mitochondrial respiratory chain, as shown by similarities of cytochromes c2 and succinate dehydrogenase. However a different origin of the eukaryotic cytoplasm is indicated by the presence of the copper/zinc superoxide dismutase.
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Abstract
1. The efficiencies of ferredoxins and flavodoxins from a range of sources as mediators in systems for hydrogen evolution were assessed. 2. In supporting electron transfer from dithionite to hydrogenase of the bacterium Clostridium pasteurianum, highest activity was shown by the ferredoxin from the cyanobacterium Chlorogloeopsis fritschii and flavodoxin from the bacterium Megasphaera elsdenii. The latter was some twenty times as active as comparable concentrations of Methyl Viologen. Ferredoxins from the cyanobacterium Anacystis nidulans and the red alga Porphyra umbilicalis also showed high activity. 3. In mediating electron transfer from chloroplast membranes to Clostridium pasteurianum hydrogenase the flavodoxin from Anacystis nidulans proved the most active with Nostoc strain MAC flavodoxin and Porphyra umbilicalis ferredoxin also being appreciably more active than other cyanobacterial and higher plant ferredoxins. 4. In both hydrogenase systems the ferredoxin and flavodoxin from the red alga Chondrus crispus and the ferredoxin from another red alga Gigartina stellata showed very low activity. 5. There appeared to be no apparent correlation of efficiency in supporting hydrogenase activity with midpoint redox potential (Em) of the mediators, though some correlation of Em with the efficiency of the mediators in supporting NADP+ photoreduction by chloroplasts, or pyruvate oxidation by a Clostridium pasteurianum system, was evident. 6. Activity of the mediators in the hydrogenase systems therefore primarily reflects differences in tertiary structure conferring differing affinities for the other components of the systems.
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Trivedi LS, Rao KK. Hydrolysis of cellulosic wastes by Aspergillus fumigatus cellulase. Indian J Exp Biol 1980; 18:425-7. [PMID: 6995286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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57
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Petersson L, Cammack R, Rao KK. Antiferromagnetic exchange interaction in the two-iron-two-sulphur ferredoxin from the blue-green alga Spirulina maxima studied with a highly sensitive magnetic balance. Biochim Biophys Acta 1980; 622:18-24. [PMID: 6244858 DOI: 10.1016/0005-2795(80)90154-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
1. A highly sensitive magnetic balance of the Faraday type is described. 2. The magnetic susceptibility of the oxidized and reduced forms of the two-iron-two-sulphur ferredoxin from the blue-green alga Spirulina maxima has been measured over a wide temperature range. 3. The results can be interpreted within a simple model involving antiferromagnetically coupled iron atoms at the active site. The coupling, expressed as --J, is estimated to be 182 +/- 20/cm and 98 +5/-10 /cm for the oxidized and reduced forms, respectively.
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Trivedi LS, Rao KK. Cellulase induction in Aspergillus fumigatus M 216. Indian J Exp Biol 1980; 18:240-2. [PMID: 6771206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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59
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Adams MW, Rao KK, Hall DO, Christou G, Garner CD. Biological activity of synthetic molybdenum-iron-sulphur, iron-sulphur and iron-selenium analogues of ferredoxin-type centres. Biochim Biophys Acta 1980; 589:1-9. [PMID: 7356974 DOI: 10.1016/0005-2728(80)90127-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The molybdenum-iron-sulphur cluster [Fe6Mo2S8(SCH2CH2OH)9]3-, which contains two Fe3MoS4 cubane-like centres, is the best plausible analogue available to date for the molybdenum site of the nitrogenase enzymes. The iron-sulphur cluster [Fe4S4(S . CH2CH2OH)4]2- and the iron-selenium cluster [Fe4Se4(S . CH2CH2OH)4]2- are structural analogues of the ferredoxin Fe4S4 active centre. All three clusters would replace ferredoxin and mediate electron transfer to Clostridium pasteurianum hydrogenase in a H2-evolving system with sodium dithionite as the electron donor. The clusters would not replace hydrogenases which themselves are unable to evolve H2 from reduced ferredoxins. The molybdenum-iron-sulphur cluster would also replace ferredoxin in a chloroplast-ferredoxin-hydrogenase H2 evolving system.
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Llama MJ, Serra JL, Rao KK, Hall DO. Separation and purification of two hydrogenase activities in Chromatium: kinetics and subunit analysis [proceedings]. Biochem Soc Trans 1979; 7:1117-8. [PMID: 510723 DOI: 10.1042/bst0071117a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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61
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Serra JL, Llama MJ, Rao KK, Hall DO. Properties of the monomeric and dimeric forms of Chromatium hydrogenase [proceedings]. Biochem Soc Trans 1979; 7:1119-20. [PMID: 510724 DOI: 10.1042/bst0071119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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62
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Llama MJ, Serra JL, Rao KK, Hall DO. Isolation and characterization of the hydrogenase activity from the non-heterocystous cyanobacterium Spirulina maxima. FEBS Lett 1979; 98:342-6. [PMID: 105936 DOI: 10.1016/0014-5793(79)80213-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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63
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Rupp H, Rao KK, Hall DO, Cammack R. Electron spin relaxation of iron-sulphur proteins studied by microwave power saturation. Biochim Biophys Acta 1978; 537:255-60. [PMID: 215217 DOI: 10.1016/0005-2795(78)90509-3] [Citation(s) in RCA: 169] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The electron-spin relaxation of iron-sulphur centres in a range of simple proteins (ferredoxin, high-potential iron-sulphur protein and rubredoxin) was investigated by means of the temperature dependence and microwave power saturation of the EPR signal. The proteins containing [2Fe-2S] centres all showed temperature optima higher than those for [4Fe-4S] centres, but the difference between the slowest-relaxing [4Fe-4S] protein (Chromatium high-potential iron-sulphur protein) and the fastest-relaxing [2Fe-2S] protein (Halobacterium halobium ferredoxin) was small. A greater distinction was seen in the power saturation behaviour at low temperature (10--20 K). The behaviour of the signal intensity as a function of microwave power was analyzed in terms of the power for half saturation P 1/2 and the degree of homogeneous/inhomogeneous broadening. The effect of distorting the protein structure by salts, organic solvents and urea was to decrease the electron-spin relaxation rate as shown by a decreased value of P 1/2. The addition of Ni2+ as a paramagnetic perturbing agent caused an increase in the electron-spin relaxation rate of all the proteins, with the exception of adrenal ferredoxin, as shown by an increased P 1/2 and, in a few cases, broadening of the linewidth. Ferricyanide, a commonly used oxidizing agent, has similar effects. These results are discussed in relation to the use of paramagnetic probes to determine whether iron-sulphur centres are near to a membrane surface. Spin-spin interactions between two paramagnetic centres in a protein molecule such as a 2[4Fe-4S] ferredoxin, lead to more rapid electron-spin relaxation. This method was used to detect a spin-spin interaction between molybdenum V and centre Fe-SI in xanthine oxidase.
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Stephens PJ, Thomson AJ, Keiderling TA, Rawlings J, Rao KK, Hall DO. Cluster characterization in iron-sulfur proteins by magnetic circular dichroism. Proc Natl Acad Sci U S A 1978; 75:5273-5. [PMID: 281679 PMCID: PMC392944 DOI: 10.1073/pnas.75.11.5273] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We report magnetic circular dichroism (MCD) spectra of 4-Fe iron-sulfur clusters in the iron-sulfur proteins Chromatium high-potential iron protein (HIPIP), Bacillus stearothermophilus ferredoxin and Clostridium pasteurianum ferredoxin. The MCD is found to vary significantly with cluster oxidation state but is relatively insensitive to the nature of the protein. The spectra obtained are compared with the corresponding spectra of iron-sulfur proteins containing 2-Fe clusters. It is concluded that MCD is useful for the characterization of iron-sulfur cluster type and oxidation state in iron-sulfur proteins and is superior for this purpose to absorption and natural circular dichroism spectroscopy.
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66
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Stephens PJ, Thomson AJ, Dunn JB, Keiderling TA, Rawlings J, Rao KK, Hall DO. Circular dichroism and magnetic circular dichroism of iron-sulfur proteins. Biochemistry 1978; 17:4770-8. [PMID: 728385 DOI: 10.1021/bi00615a026] [Citation(s) in RCA: 109] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Circular dichroism (CD) and magnetic circular dichroism (MCD) spectra are reported for the 2-Fe ferredoxins from Pseudomonas putida and Spirulina maxima, Chromatium HIPIP, the 4-Fe ferredoxin from Bacillus stearothermophilus, and the 8-Fe ferredoxin from Clostridium pasteurianum. The spectral range spans the near-infrared, visible, and near ultraviolet. In all cases except oxidized 2-Fe ferredoxins, electronic absorption is observed continuously from less than 5000 cm-1 to above 30,000 cm-1. The CD spectra of the two 2-Fe ferredoxins are similar. In contrast, the CD of the 4-Fe and 8-Fe proteins, for a given 4-Fe cluster oxidation level, varies considerable with protein. MCD is less sensitive to protein environment than is CD. In the 2-Fe proteins, MCD at 5 T is appreciably smaller than the CD; in the 4-Fe and 8-Fe proteins, MCD and CD are comparable in magnitude. Both CD and MCD are more highly structured than the corresponding absorption spectra. The CD and MCD spectra reported provide a broader base than heretofore available for the characterization of iron-sulfur proteins containing 2-Fe and 4-Fe clusters and for the evaluation of electronic structural models for these clusters.
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Hase T, Wakabayashi S, Matsubara H, Kerscher L, Oesterhelt D, Rao KK, Hall DO. Complete amino acid sequence of Halobacterium halobium ferredoxin containing an Nepsilon-acetyllysine residue. J Biochem 1978; 83:1657-70. [PMID: 670159 DOI: 10.1093/oxfordjournals.jbchem.a132078] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
1. The complete amino acid sequence of the 2Fe-2S ferredoxin from Halobacterium halobium was determined to be: (formula see text):2. The apoferredoxin chain consists of 128 amino acid residues and has a molecular weight of 14,330. 3. There are only four cysteines in this ferredoxin molecule; they should be involved in the binding of the two iron atoms at the active center. Ther relative positions of these cysteines are similar to those of the cysteines in chloroplast ferredoxins. 4. There is a high degree of homology between H. halobium ferredoxin and chloroplast ferredoxins, though the latter molecules contain only about 98 amino acid residues. 5. H. halobium ferredoxin contains a single residue of Nepsilon-acetyllysine.
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Abstract
An in vitro system containing isolated chloroplasts, ferredoxin and bacterial hydrogenase on illumination evolves H2 and O2 from water. Maximum rate of hydrogen production so far achieved is two litres H2 per g. chlorophyll per h. The rate of H2 evolution per mg chlorophyll is dependent on concentrations of chlorophyll and ferredoxin in the reaction mixture. The rates as well as duration of H2 production are enhanced by the presence of oxygen scavengers and bovine serum albumin in the system. Hydrogenases and ferredoxins vary in their degree of cross reactivity in the chloroplast system; with some hydrogenases the H2 evolution rates were increased by the presence of additional biological electron carriers. Attempts to couple algal hydrogenases to the chloroplasts system have not succeeded so far.
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Abstract
Midpoint potentials of plant-type ferredoxins from a range of sources were measured by redox titrations combined with electron-paramagnetic-resonance spectroscopy. For ferredoxins from higher plants, green algae and most red algae, the midpoint potentials (at pH 8.0) were between --390 and --425 mV. Values for the major ferredoxin fractions from blue-green algae were less negative (between --325 and --390 mV). In addition, Spirulina maxima and Nostoc strain MAC contain second minor ferredoxin components with a different potential, --305 mV (the highest so far measured for a plant-algal ferrodoxin) for Spirulina ferrodoxin II, and --455 mV (the lowest so far measured for a plant-algal ferredoxin) for Nostoc strain MAC ferredoxin II. However, two ferredoxins extracted from a variety of the higher plant Pisum sativum (pea) had midpoint potentials that were only slightly different from each other. These values are discussed in terms of possible roles for the ferredoxins in addition to their involvement in photosynthetic electron transport.
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Abstract
High concentration of inorganic phosphate in the culture medium of Aspergillus fumigatus inhibited ergot alkaloid synthesis. Addition of L-tryptophan but not mevalonate or 5-methyltryptophan to the above culture restored the alkaloid synthesis to the level found in normal cultures. The decrease in alkaloid synthesis in the fungus accompanies an increase in cell mass, cellular protein and sterol content. Aspartate aminotransferase and alanine aminotransferase activities were significantly increased in the high-phosphate culture.
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71
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Rivoal JC, Briat B, Cammack R, Hall DO, Rao KK, Douglas IN, Thomson AJ. The low temperature magnetic circular dichroism spectra of iron-sulphur proteins. I. Oxidised rubredoxin. Biochim Biophys Acta 1977; 493:122-31. [PMID: 880309 DOI: 10.1016/0005-2795(77)90265-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Variable temperature magnetic circular dichroism spectra have been measured on oxidised Clostridium pasteurianum rubredoxin. Evidence has been obtained for the presence of two one-electron charge-transfer transitions, sulphur to ferric ion, in the region 15 000 to 28 000 cm-1. The first moment of the lower energy band is consistent with it being the orbital transition t1 non-bonding sulphur orbital, to the 2 e ferric d-orbital. The magnitude of the spin-orbit coupling constant in the lower excited state has been determined and shown to be small compared with the axial distortion. The splitting of the low energy band observed in the absorption spectrum can therefore be equated directly with the axial distortion of the lowest excited charge-transfer state. Finally, the potential utility of making saturation experiments at very low temperatures has been examined.
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Thomson AJ, Cammack R, Hall DO, Rao KK, Briat B, Rivoal JC, Badoz J. The low temperature magnetic circular dichroism spectra of iron-sulphur proteins. II. Two-iron ferredoxins. Biochim Biophys Acta 1977; 493:132-41. [PMID: 880310 DOI: 10.1016/0005-2795(77)90266-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Variable temperature magnetic circular dichroism (MCD) spectra of a number of two-iron ferredoxins have been measured. The spectra of fully oxidised spinach and Spirulina maxima ferredoxin are independent of temperature between room temperature and 18 K, showing that no contribution to the room temperature MCD spectrum arises from the small population of low-lying excited states originating from the exchange coupling. However, the low temperature MCD spectra of the half-reduced proteins spinach and Spirulina maxima ferredoxin and adrenodoxin are all reasonably intense and temperature dependent. An interpretation of the spectrum of the charge-transfer region is suggested by starting with the assignments previously obtained from rubredoxin.
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73
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Gupta AR, Rao KK. Inhibition of tryptophan uptake in Aspergillus fumigatus by tryptamine. Experientia 1977; 33:853-4. [PMID: 330196 DOI: 10.1007/bf01951239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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74
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Rao KK, Gupta AR. Cell-pool tryptophan levels during ergot alkaloid formation in Aspergillus fumigatus. Indian J Exp Biol 1977; 15:588-9. [PMID: 340382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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75
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Rao KK, Mehta AM, Gupta AR. Phosphate uptake and involvement of binding protein in Tween-80 supplemented culture of Aspergillus fumigatus. Folia Microbiol (Praha) 1977; 22:216-21. [PMID: 18385 DOI: 10.1007/bf02885603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Tween-80 supplementation in submerged culture of Aspergillus fumigatus resulted in an increase of phosphate uptake. The uptake system was characterized as saturable, energy-dependent and operating against the concentration gradient. Control and Tween 80 cultures showed similar Km values for phosphate uptake (50 micrometer). Cold osmotic shock treatment of the cultures was found to cause considerable reduction in the ability to take up phosphorus with concomitant release of the binding protein into the shock fluid. Binding protein preparation from Tween-80 supplemented cells showed more activity than that from control cells.
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Gupta AR, Rao KK. Role of biotin in ergot alkaloid formation by aspergillus fumigatus. Indian J Biochem Biophys 1977; 14:84-5. [PMID: 336519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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77
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Cammack R, Rao KK, Hall DO, Moura JJ, Xavier AV, Bruschi M, Le Gall J, Deville A, Gayda JP. Spectroscopic studies of the oxidation-reduction properties of three forms of ferredoxin from Desulphovibrio gigas. Biochim Biophys Acta 1977; 490:311-21. [PMID: 189829 DOI: 10.1016/0005-2795(77)90006-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Electron paramagnetic resonance spectra were recorded of three forms of Desulphovibrio gigas ferredoxin, FdI, FdI' and FdII. The g = 1.94 signal seen in dithionite-reduced samples is strong in FdI, weaker in FdI' and very small in FdII. The g = 2.02 signal in the oxidized proteins is weak in FdI and strongest in FdII. It is concluded that most of the 4Fe-4S centres in FdI change between states C- and C2-; FdI' contain both types of centre. There is no evidence that any particular centre can change reversibly between all three oxidation states. Circular dichroism spectra show differences between FdI and FdII even in the diamagnetic C2- state. The redox potentials of the iron-sulphur centres of the three oligomers (forms) are different. After formation of the apo-protein of FdII and reconstitution with iron and sulphide, the protein behaves more like FdI, showing a strong g = 1.94 signal in the reduced states.
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78
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Tel-Or E, Cammack R, Rao KK, Rogers LJ, Stewart WD, Hall DO. Comparative immunochemistry of bacterial, algal and plant ferredoxins. Biochim Biophys Acta 1977; 490:120-31. [PMID: 836867 DOI: 10.1016/0005-2795(77)90112-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
1. Antibodies were produced in rabbits to the 4Fe-4S ferrodoxins from Bacillus stearothermophilus, the 2 [4Fe-4S] ferredoxin from Clostridium pasteurianum, and the 2Fe-2S ferredoxins from the blue-green algia Spirulina maxima, the green alga Scenedesmus obliquus, and the higher plant Beta vulgaris. The antibodies were tested for immunoprecipitation activity with seven bacterial, twelve blue-green algal, six eukaryotic algal and six higher plant ferredoxins. 2. Antibodies to the bacterial ferredoxins reacted to a significant extent only with their homologous proteins. On the other hand, antibodies to the plant and algal ferredoxins showed cross-reaction with other ferredoxins. There was a correlation between the degrees of immunoprecipitation and the similarity in amino acid sequences. These results suggest that the method can be used as a marker in taxonomic studies. 3. The interaction of the antibodies with the five native ferredoxins was compared with the reactions with their apoproteins. In each case the degree of interaction was different. This behaviour was interpreted as due to an influence of tertiary structure on the antibody-antigen interaction.
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Hase T, Ohmiya N, Matsubara H, Mullinger RN, Rao KK, Hall DO. Amino acid sequence of a four-iron-four-sulphur ferredoxin isolated from Bacillus stearothermophilus. Biochem J 1976; 159:55-63. [PMID: 999643 PMCID: PMC1164037 DOI: 10.1042/bj1590055] [Citation(s) in RCA: 40] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
1. The primary structure of a 4Fe-4S ferredoxin from Bacillus stearothermophilus was determined and shown to consist of a single polypeptide chain of 81 amino acid residues. The molecular weight of the holoprotein is about 9120. 2. There are only four cysteine residues in the molecule; three of these are located near the N-terminus as a Cys-X-X-Cys-X-X-Cys segment, and the fourth cysteine residue is followed by a proline and located in the C-terminal half. 3. The Fe-S chromophore in B. stearothermophilus ferredoxin was previously well characterized and was shown to consist of a single 4Fe-4S cluster. This ferredoxin sequence establishes for the first time the relative location of the four cysteine residues necessary to bind the 4Fe-4S cluster of a 4Fe ferredoxin, and is in agreement with the criteria for the relative positions of the cysteines proposed from X-ray-crystallographic studies on an 8Fe (two 4Fe-4S clusters) ferredoxin. 4. The sequence of B. stearothermophilus ferredoxin is homologous in many segments to that of other bacterial ferredoxins, the degree of homology being greater towards ferredoxins from Desulfovibrio gigas and photosynthetic bacteria than to Clostridial ferredoxins. 5. The presence of a relatively higher number of glutamic acid and lower number of cysteine residues in the molecule may explain the greater thermal stability and oxygen-insenstivity of this ferredoxin.
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Tanaka M, Haniu M, Yasunobu KT, Rao KK, Hall DO. Modification of the automated sequence determination as applied to the sequence determination of the Spirulina maxima ferredoxin. Biochemistry 1975; 14:5535-40. [PMID: 811255 DOI: 10.1021/bi00696a024] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The amino acid sequence of the Spirulina maxima ferredoxin was shown to be: H2N-Ala-Thr-Tyr-Lys-Val-Thr-Leu-Ile-Ser-Glu-Ala-Glu-Gly-Ile-Asn-Glu-Thr-Ile-Asp-Cys-Asp-Asp-Asp-Thr-Tyr-Ile-Leu-Asp-Ala-Ala-Glu-Glu-Ala-Gly-Leu-Asp-Leu-Pro-Tyr-Ser-Cys-Arg-Ala-Gly-Ala-Cys-Ser-Thr-Cys-Ala-Gly-Lys-Ile-Thr-Ser-Gly-Ser-Ile-Asp-Gln-Ser-Asp-Gln-Ser-Phe-Leu-Asp-Asp-asp-Gln-Ile-Gln-Ala-Gly-Tyr-Val-Leu-Thr-Cys-Val-Ala-Tyr-Pro-Thr-Ser-Asp-Cys-Thr-Ile-Gln-Thr-His-Gln-Glu-Glu-Gly-Leu-Tyr-COOH. The S. maxima ferredoxin is the first procaryote ferredoxin of the plant-algal type to be reported. A modification of the automated sequence determination of a peptide, which was extracted by the organic solvents used to remove excess reagents and the amino acid thiazoline, was utilized to complete the sequence of a 36 residue tryptic peptide.
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Mullinger RN, Cammack R, Rao KK, Hall DO, Dickson DP, Johnson CE, Rush JD, Simopoulos A. Physicochemical characterization of the four-iron-four-sulphide ferredoxin from Bacillus stearothermophilus. Biochem J 1975; 151:75-83. [PMID: 174558 PMCID: PMC1172327 DOI: 10.1042/bj1510075] [Citation(s) in RCA: 81] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
1. A stable ferredoxin was prepared from Bacillus stearothermophilus and purified by chromatography on DEAE-cellulose and by electrophoresis. 2. The minimum molecular weight determined from the amino acid composition was about 7900 and this was in reasonable agreement with a value of 8500 determined by polyacrylamide-gel electrophoresis. The ferredoxin contained four iron atoms and four labile sulphide groups per molecule. 3. The optical absorption, optical-rotatory-dispersion and circular-dichroism spectra are typical of ferredoxins containing 4Fe-4S clusters. 4. Oxidation-reduction titrations, combined with electron-paramagnetic-resonance (e.p.r.) spectroscopy, showed that the protein has a mid-point potential, at pH8, of -280 +/- 10mV, and that only one electron-accepting paramagnetic species is present. 5. The e.p.r. spectrum of the reduced ferredoxin is more readily saturated with microwave power at low temperatures than those of the eight-iron ferredoxins, indicating that there is another mechanism of electron-spin relaxation in the latter. 6. Mossbauer spectra of both redox states were observed over a range of temperatures and in magnetic fields. At high temperatures (77 degrees K and above) both redox states appear as quadrupole-split doublets; in the reduced state two resolved doublets are seen, suggesting appreciable localization of the additional reducing electron. 7. The average chemical shift indicates formal valences of two Fe3+ and two Fe2+ in the oxidized state and three Fe2+ and one Fe3+ in the reduced state. However, the spectra indicate that there are differing degrees of electron delocalization over the iron atoms. 8. At low temperatures (4.2 degrees K) the oxidized form shows no hyperfine magnetic interaction, even in an applied magnetic field, evidence that the oxidized ferredoxin is in a non-magnetic state as a result of antiferromagnetic coupling between the iron atoms. 9. At 4.2 degrees K the reduced form shows a broad asymmetric pattern resulting from magnetic hyperfine interaction. This contrasts with the reduced ferredoxin of Clostridium pasteurianum, which shows a doublet, suggesting that in the latter there may be interaction between the two 4Fe-4S centres. 10. In large applied magnetic fields, positive and negative hyperfine fields are seen in the Mossbauer spectra of the reduced ferredoxin, evidence for antiferromagnetic coupling between the iron atoms in the 4Fe-4S centre. The high-field spectra of the reduced ferredoxin of B. stearothermophilus are similar to those of the reduced ferredoxin of C. pasteurianum.
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Abstract
Tween 80, which caused increased biomass formation, also produced the highest increase in the uptake rate of all components of the medium. The fatty acid components of the respective Tweens, i.e. palmitic acid (Tween 40), stearic acid (Tween 60), and oleic acid (Tween 80), have no effect either on alkaloid production or on substrate uptake. The fatty acid composition was different in the cell membrane of the culture supplemented with Tween 60 and facilitated the transport of metabolites into the cells.
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Abstract
The X-ray photoelectron spectra of the 2p, 3s and 3p levels of iron in oxidized Clostridium pasteurianum ferredoxin indicate that the eight iron atoms in the molecule are indistinguishable. Their magnetic state is indicated both by core polarization splitting of the 3s electrons, and by "shake-up' satellites on the 2p lines. Similar satellites are observed in the 2p lines of reduced Chromatium high-potential iron-sulphur proteins and oxidized spinach ferredoxin, indicating that there too the iron atoms are magnetic. The low observed magnetic susceptibility of these proteins is therefore due to spin-coupling between the iron atoms in the active centre.
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88
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Rao KK, Gupta AR. Inhibition of Tryptophan Synthetase by Phosphate in Alkaloid-producing culture of Aspergillus fumigatus. Naturwissenschaften 1975; 62:394-5. [PMID: 1105205 DOI: 10.1007/bf00625354] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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89
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Tanaka M, Haniu M, Yasunobu KT, Evans MC, Rao KK. The amino acid sequence of ferredoxin II from Chlorobium limicola, a photosynthetic green bacterium. Biochemistry 1975; 14:1938-43. [PMID: 1125205 DOI: 10.1021/bi00680a021] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The amino acid sequence of ferredoxin II from the photosynthetic green sulfur-reducing bacterium, Chlorobium limicola, was deduced to be: Ala-His-Arg-Ile-Thr-Glu-Glu-Cys-Thr-Tyr-Cys-Ala-Ala-Cys-Glu-Pro-Glu-Cys-Pro-Val-Asn-Ala-Ile-Ser-Ala-Gly-Asp-Glu-Ile-Tyr-Ile-Val-Asp-Glu-Ser-Val-Cys-Thr-Asp-Cys-Glu-Gly-Tyr-Tyr-Asp-Glu-Pro-Ala-Cys-Val-Ala-Val-Cys-Pro-Val-Asp-Cys-Ile-Ile-Lys-Val. The ferredoxin was shown to consist of 61 amino acids in a single polypeptide chain. The presence of 8 g-atoms of Fe and 8 mol of sulfide led to a calculated molecular weight of 7289. In constract to the ferredoxin I from C. limicola, ferredoxin II contains basic amino acids in positions 2 and 3 and 60 from the NH(2)-terminal end of the protein. The sequences of all the various ferredoxins from photosynthetic bacteria reported to date are compared with one another.
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91
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Tanaka M, Haniu M, Zeitlin S, Yasunobu KT, Evans MC, Rao KK, Hall DO. Amino acid sequence of the Spirulina maxima ferredoxin, a ferredoxin from a procaryote. Biochem Biophys Res Commun 1975; 64:399-407. [PMID: 807207 DOI: 10.1016/0006-291x(75)90267-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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92
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Anderson RE, Anger G, Petersson L, Ehrenberg A, Cammack R, Hall DO, Mullinger R, Rao KK. The iron electron-nuclear double resonance (ENDOR) of 4-Fe clusters in iron-sulfur proteins from Chromatium and Clostridium pasteurianum. Biochim Biophys Acta 1975; 376:63-71. [PMID: 164903 DOI: 10.1016/0005-2728(75)90204-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Iron electron-nuclear double resonance (ENDOR) measurements were made of the 4-Fe clusters in oxidized Chromatium high-potential iron-sulfur protein, dithionite-reduced high-potential iron-sulfur protein in 80% dimethylsulphoxide, fully reduced Clostridium pasteurianum ferredoxin in aqueous solution and in 80% dimethylsulfoxide. The hyperfine couplings determined show that: i) the electron distribution in each case is nearly symmetric; ii) there are two types of iron in oxidized high potential iron-sulfur protein; iii) only one type of iron is observed in each fully reduced 4-Fe cluster; iv) the data also suggest a greater electron delocalization onto the ligands as compared to the 2-Fe ferredoxins.
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93
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Kagamiyama H, Rao KK, Hall DO, Cammack R, Matsubara H. Equisetum (horsetail) ferredoxin: characterization of the active centre and position of the four cysteine residues in this 2Fe-2S protein. Biochem J 1975; 145:121-3. [PMID: 1191250 PMCID: PMC1165194 DOI: 10.1042/bj1450121] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Analysis of the ferredoxin of the primitive vascular plant Equisetum indicates that the cysteine residue normally found at position 18 of plant-type ferredoxins is replaced by a valine, although the spectroscopic properties of the ferredoxins are unaffected. It is concluded that the iron--sulphur cluster in plant-type ferredoxins is attached to cysteine residues 39, 44, 47 and 77.
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94
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Rao KK, Patel VP. Effect of tryptophan and related compounds on alkaloid formation in Aspergillus fumigatus. Lloydia 1974; 37:608-10. [PMID: 4615230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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95
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Tanaka M, Haniu M, Yasunobu KT, Evans MC, Rao KK. Amino acid sequence of ferredoxin from a photosynthetic green bacterium, Chlorobium limicola. Biochemistry 1974; 13:2953-9. [PMID: 4407619 DOI: 10.1021/bi00711a026] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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96
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Hall DO, Cammack R, Rao KK. The iron-sulphur proteins: evolution of a ubiquitous protein from model systems to higher organisms. Orig Life 1974; 5:363-86. [PMID: 4416334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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97
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Dickson DP, Johnson CE, Cammack R, Evans MC, Hall DO, Rao KK. Mössbauer effect in the high-potential iron-sulphur protein from Chromatium. Evidence for the state of the iron atoms. Biochem J 1974; 139:105-8. [PMID: 4463936 PMCID: PMC1166256 DOI: 10.1042/bj1390105] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
1. The previous Mössbauer work on Chromatium high-potential iron-sulphur protein by Moss et al. (1968) and Evans et al. (1970) was extended to high applied magnetic fields. 2. Measurements of the reduced protein confirm that it is non-magnetic. 3. Spectra of the oxidized protein in applied magnetic fields clearly indicate that some iron atoms have a positive hyperfine field, which is evidence for antiferromagnetic coupling. 4. The spectra can be interpreted in terms of two types of iron atom with positive and negative hyperfine fields of 9 and 12T respectively. 5. A consideration of the chemical shifts and other evidence suggests formal valences of two Fe(3+) and two Fe(2+) atoms in the non-magnetic reduced state, and three Fe(3+) atoms and one Fe(2+) atom in the oxidized state. 6. However, no separate Fe(3+) and Fe(2+) spectra are seen, suggesting that the d electrons are not localized on particular iron atoms.
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98
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Thompson CL, Johnson CE, Dickson DP, Cammack R, Hall DO, Weser U, Rao KK. Mössbauer effect in the eight-iron ferredoxin from Clostridium pasterurianum. Evidence for the state of the iron atoms. Biochem J 1974; 139:97-103. [PMID: 4463952 PMCID: PMC1166255 DOI: 10.1042/bj1390097] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
1. Mössbauer spectra of both redox states of the eight-iron ferredoxin from Clostridium pasteurianum were observed over a range of temperatures and in magnetic fields. 2. At high temperatures (77 degrees K and above) the spectra of both states consist essentially of the superposition of two or more closely similar doublets. 3. The average chemical shift for the oxidized protein leads to the proposal that each of the two four-iron active centres consists formally of two Fe(3+) and two Fe(2+) atoms. 4. The average chemical shift and quadrupole splitting increase on reduction, consistent with there being one Fe(3+) and three Fe(2+) atoms per centre in the reduced molecule. 5. The spectral changes on reduction show that all the iron atoms are affected when one electron is added to each four-iron centre. 6. No separate Fe(3+) and Fe(2+) spectra were observed (as they were, for instance, in the reduced two-iron plant ferredoxins) suggesting that the d electrons are not localized on particular atoms, but are shared approximately equally by all four atoms in the four-iron centres. 7. At low temperatures (4 degrees K and below) no magnetic hyperfine interaction was observed in the oxidized protein even in an applied magnetic field, confirming the non-magnetic nature of the molecule in the oxidized state, and suggesting that the four iron atoms in each centre are antiferromagnetically coupled together to give zero spin. 8. Magnetic hyperfine interaction was observed in the reduced protein at low temperatures, and showed that all the iron atoms were magnetic. This demonstrates that one electron goes to each centre on reduction. 9. On application of a large magnetic field to the reduced protein at low temperatures, both positive and negative hyperfine fields were shown to be present, thus directly showing that antiferromagnetic coupling exists between the iron atoms in the reduced state.
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99
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Rao KK, Patel VP, Patel B. Alkaloid production by Aspergillus fumigatus as influenced by changes in substrate composition. Indian J Exp Biol 1974; 12:76-8. [PMID: 4609899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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100
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Hall DO, Cammack R, Rao KK. Ferredoxins in the evolution of photosynthetic systems from anaerobic bacteria to higher plants. Space Life Sci 1973; 4:455-68. [PMID: 4203768 DOI: 10.1007/bf00930357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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