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1.
José A. Navarro Manuel Hervás M. A. De la Rosa 《Journal of biological inorganic chemistry》1997,2(1):11-22
Cytochrome c
6 and plastocyanin are soluble metalloproteins that act as mobile carriers transferring electrons between the two membrane-embedded
photosynthetic complexes cytochrome b
6 f and photosystem I (PSI). First, an account of recent data on structural and functional features of these two membrane complexes
is presented. Afterwards, attention is focused on the mobile heme and copper proteins – and, in particular, on the structural
factors that allow recognition and confer molecular specificity and control the rates of electron transfer from and to the
membrane complexes. The interesting question of why plastocyanin has been chosen over the ancient heme protein is discussed
to place emphasis on the evolutionary aspects. In fact, cytochrome c
6 and plastocyanin are presented herein as an excellent case study of biological evolution, which is not only convergent (two
different structures but the same physiological function), but also parallel (two proteins adapting themselves to vary accordingly
to each other within the same organism).
Received: 4 July 1996 / Accepted: 16 September 1996 相似文献
2.
Yeast cells are often used as a model system in various experiments. Moreover, due to their high metabolic activity, yeast cells have a potential to be applied as elements in the design of biofuel cells and biosensors. However a wider application of yeast cells in electrochemical systems is limited due to high electric resistance of their cell wall. In order to reduce this problem we have polymerized conducting polymer polypyrrole (Ppy) directly in the cell wall and/or within periplasmic membrane. In this research the formation of Ppy was induced by [Fe(CN)6]3−ions, which were generated from K4[Fe(CN)6], which was initially added to polymerization solution. The redox process was catalyzed by oxido-reductases, which are present in the plasma membrane of yeast cells. The formation of Ppy was confirmed by spectrophotometry and atomic force microscopy. It was confirmed that the conducting polymer polypyrrole was formed within periplasmic space and/or within the cell wall of yeast cells, which were incubated in solution containing pyrrole, glucose and [Fe(CN)6]4−. After 24 h drying at room temperature we have observed that Ppy-modified yeast cell walls retained their initial spherical form. In contrast to Ppy-modified cells, the walls of unmodified yeast have wrinkled after 24 h drying. The viability of yeast cells in the presence of different pyrrole concentrations has been evaluated. 相似文献
3.
《Inorganica chimica acta》1986,111(1):39-43
Redox properties of the ion [Fe(CN)4NO]2− were studied electrochemically both in non-aqueous and aqueous media in the absence of free cyanide ions. It was found that while the reduction proceeds smoothly the oxidation is not observed at the electrode in the attainable potential range, and can be achieved only by Br2 oxidation taking place as oxidative addition. Aspects of the redox reactivity are discussed and the overall scheme of reactions of the tetracyanonitrosylferrate(2−) and derived species is given. 相似文献
4.
5.
Chang-An Yu Xiaowei Cen He-Wen Ma Ying Yin Linda Yu Lothar Esser Di Xia 《BBA》2008,1777(7-8):1038-1043
Intensive biochemical, biophysical and structural studies of the cytochrome (cyt) bc1 complex in the past have led to the formulation of the “protonmotive Q-cycle” mechanism for electron and proton transfer in this vitally important complex. The key step of this mechanism is the separation of electrons during the oxidation of a substrate quinol at the QP site with both electrons transferred simultaneously to ISP and cyt bL when the extrinsic domain of ISP (ISP-ED) is located at the b-position. Pre-steady state fast kinetic analysis of bc1 demonstrates that the reduced ISP-ED moves to the c1-position to reduce cyt c1 only after the reduced cyt bL is oxidized by cyt bH. However, the question of how the conformational switch of ISP-ED is initiated remains unanswered. The results obtained from analysis of inhibitory efficacy and binding affinity of two types of QP site inhibitors, Pm and Pf, under various redox states of the bc1 complex, suggest that the electron transfer from heme bL to bH is the driving force for the releasing of the reduced ISP-ED from the b-position to c1-position to reduce cyt c1. 相似文献
6.
Castellani M Havens J Kleinschroth T Millett F Durham B Malatesta F Ludwig B 《Biochimica et biophysica acta》2011,1807(11):1383-1389
The cytochrome bc(1) complex is a key component in several respiratory pathways. One of the characteristics of the eukaryotic complex is the presence of a small acidic subunit, which is thought to guide the interaction of the complex with its electron acceptor and facilitate electron transfer. Paracoccus denitrificans represents the only example of a prokaryotic organism in which a highly acidic domain is covalently fused to the cytochrome c(1) subunit. In this work, a deletion variant lacking this acidic domain has been produced and purified by affinity chromatography. The complex is fully intact as shown by its X-ray structure, and is a dimer (Kleinschroth et al., subm.) compared to the tetrameric (dimer-of-dimer) state of the wild-type. The variant complex is studied by steady-state kinetics and flash photolysis, showing wild type turnover and a virtually identical interaction with its substrate cytochrome c(552). 相似文献
7.
Kaige Liu Ruo Yuan Yaqin Chai Dianping Tang Haizhen An 《Bioprocess and biosystems engineering》2010,33(2):179-185
[AuCl4]− was initially deposited by electrochemical reduction on a glassy carbon electrode (GCE) to form porous nanogold layer, then
prussian blue (PB) was electrodeposited onto the as-prepared nanogold layer, and then secondary nanogold particles were fabricated
again on the PB surface by electrochemical reduction for the immobilization of anti-CEA antibodies. The presence of double-layer
porous gold nanoparticles enhanced the immobilized amount of biomolecules, and improved the sensitivity of the immunoassay.
PB, as a good redox probe, was facile to electrochemical analysis and measurement. Under optimal conditions, the developed
immunoassay exhibited dynamic range from 3.0 to 80.0 ng/mL with a detection limit of 0.9 ng/mL CEA (S/N = 3). Moreover, the
selectivity, reproducibility and stability of the immunosensor were acceptable. 相似文献
8.
Pinske C Krüger S Soboh B Ihling C Kuhns M Braussemann M Jaroschinsky M Sauer C Sargent F Sinz A Sawers RG 《Archives of microbiology》2011,193(12):893-903
Escherichia coli can both oxidize hydrogen and reduce protons. These activities involve three distinct [NiFe]-hydrogenases, termed Hyd-1, Hyd-2, and Hyd-3, each minimally comprising heterodimers of a large subunit, containing the [NiFe] active site, and a small subunit, bearing iron-sulfur clusters. Dihydrogen-oxidizing activity can be determined using redox dyes like benzyl viologen (BV); however, it is unclear whether electron transfer to BV occurs directly at the active site, or via an iron-sulfur center in the small subunit. Plasmids encoding Strep-tagged derivatives of the large subunits of the three E. coli [NiFe]-hydrogenases restored activity of the respective hydrogenase to strain FTD147, which carries in-frame deletions in the hyaB, hybC, and hycE genes encoding the large subunits of Hyd-1, Hyd-2, and Hyd-3, respectively. Purified Strep-HyaB was associated with the Hyd-1 small subunit (HyaA), and purified Strep-HybC was associated with the Hyd-2 small subunit (HybO), and a second iron-sulfur protein, HybA. However, Strep-HybC isolated from a hybO mutant had no other associated subunits and lacked BV-dependent hydrogenase activity. Mutants deleted separately for hyaA, hybO, or hycG (Hyd-3 small subunit) lacked BV-linked hydrogenase activity, despite the Hyd-1 and Hyd-2 large subunits being processed. These findings demonstrate that hydrogenase-dependent reduction of BV requires the small subunit. 相似文献
9.
Tomitake Tsukihara Koichi Homma Keiichi Fukuyama Yukiteru Katsube Toshiharu Hase Hiroshi Matsubara Nobuo Tanaka Masao Kakudo 《Journal of molecular biology》1981,152(4):821-823
A [4Fe4S] ferredoxin from Bacillus thermoproteolyticus has been crystallized. The space group is P1 with two molecules in the unit cell, with the dimensions . The Bijvoet-difference Patterson map of the native crystal shows up a prominent peak of [4Fe4S] cluster. 相似文献
10.
E. N. Frolov V. I. Goldanskii A. Birk F. Parak 《European biophysics journal : EBJ》1996,24(6):433-438
Interheme electrostatic interaction can explain the acceleration of the electron transfer (ET) rate from the highest potential heme (C38o) to the photooxidized bacteriochlorophyll dimer (P+) which takes place after the reduction of neighbouring heme(s) of the cytochrome subunit in the reaction center of Rps. viridis. The electrostatic interaction energies calculated for neighbouring hemes, 7.0 Å apart (edge-to-edge), and for two high potential hemes, 21.5 Å apart are found to be 0.110 eV and 0.040 eV respectively. The reorganisation energy of the C380-P+ transition of about 0.290±0.030 eV is calculated using the Marcus theory of electron tunneling. An empirical relation for the rate of ET is given. The low temperature restriction of the C380-+ transition is caused by an energetic inhibition which originates from an opposite shifting of the energy levels of C380 and P+ due to the freezing of protein dynamics and protein-bound water mobility. The freezing of the protein dynamics is revealed by the Mössbauer effect and correlates with the efficiency of the ET.Abbreviations RC
reaction center
- P+
cation-radical of bacteriochlorophyll dimer
- C380, C20, C310, C–60, hemes
indexed by the values of their individual redox potentials (in mV)
- ET
electron transfer 相似文献
11.
F. Bonomi Stefania Iametti Donald M. Kurtz Jr. Kimberly A. Richie E. Ragg 《Journal of biological inorganic chemistry》1998,3(6):595-605
The single Fe(II) in reduced rubredoxin from Clostridium pasteurianum was found to be quantitatively displaced by either Cd2+ or Zn2+ when a modest molar excess of the substituting metal salt was anaerobically incubated with the reduced rubredoxin under mild
conditions, namely, room temperature, pH 5.4–8.4, and no protein denaturants. Under the same conditions, cadmium-for-zinc substitution was also achieved upon aerobic incubation of the zinc-substituted
rubredoxin with a modest molar excess of Cd2+. Displacements of Fe(II) from the reduced rubredoxin were not observed upon anaerobic incubation with Ni2+, Co2+, or VO2+ salts, and no reaction with any of the divalent metal ions was observed for the oxidized [Fe(III)] rubredoxin. Fe(II) could
not be re-inserted into the Zn- or Cd-substituted rubredoxins without resorting to protein denaturation. 1H and 113Cd NMR experiments showed that the cadmium-substituted rubredoxin prepared by the non-denaturing substitution method retained
the pseudotetrahedral M(SCys)4 coordination geometry and secondary structural elements characteristic of the native rubredoxin, and that "unzipping" of
the β-sheet did not occur during metal substitution. Rates of Fe(II) displacement by M2+ (M=Cd or Zn) increased with increasing M2+/rubredoxin ratio, decreasing pH, and lower ionic strength. The substitution rates were faster for M=Cd than for M=Zn. Rates
of Cd2+ substitution into a V8A-mutated rubredoxin were significantly faster than for the wild-type protein. The side-chain of V8
is on the protein surface and close to the metal-ligating Cys42Sγ at the M(SCys)4 site. Therefore, the rate-limiting step in the substitution process is suggested to involve direct attack of the [M(SCys)4]2– site by the incoming M2+, without global unfolding of the protein. Implications of these results for metal ion incorporation into rubredoxins in vivo are discussed.
Received: 29 May 1998 / Accepted: 11 August 1998 相似文献
12.
Asymmetric distribution of cytochrome P-450 and NADPH–cytochrome P-450 (cytochrome c) reductase in vesicles from smooth endoplasmic reticulum of rat liver 总被引:2,自引:0,他引:2
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Michael B. Cooper John A. Craft Margaret R. Estall Brian R. Rabin 《The Biochemical journal》1980,190(3):737-746
1. The topography of cytochrome P-450 in vesicles from smooth endoplasmic reticulum of rat liver has been examined. Approx. 50% of the cytochrome is directly accessible to the action of trypsin in intact vesicles whereas the remainder is inaccessible and partitioned between luminal-facing or phospholipid-embedded loci. Analysis by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis reveals three major species of the cytochrome. Of these, the variant with a mol.wt. of 52000 is induced by phenobarbitone and this species is susceptible to trypsin. 2. After trypsin treatment of smooth membrane, some NADPH–cytochrome P-450 (cytochrome c) reductase activity remains and this remaining activity is enhanced by treatment with 0.05% deoxycholate, which renders the membranes permeable to macromolecules. In non-trypsin-treated control membranes the reductase activity is increased to a similar extent. These observations suggest an asymmetric distribution of NADPH–cytochrome P-450 (cytochrome c) reductase in the membrane. 3. As compared with dithionite, NADPH reduces only 44% of the cytochrome P-450 present in intact membranes. After tryptic digestion, none of the remaining cytochrome P-450 is reducible by NADPH. 4. In the presence of both a superoxide-generating system (xanthine plus xanthine oxidase) and NADPH, all the cytochrome P-450 in intact membrane (as judged by dithionite reducibility) is reduced. The cytochrome P-450 remaining after trypsin treatment of smooth vesicles cannot be reduced by this method. 5. The superoxide-dependent reduction of cytochrome P-450 is prevented by treatment of the membranes with mersalyl, which inhibits NADPH–cytochrome P-450 (cytochrome c) reductase. Thus the effect of superoxide may involve NADPH–cytochrome P-450 reductase and cytosolically orientated membrane factor(s). 相似文献
13.
14.
Parkinson’s disease (PD) is characterized by progressive degeneration of dopaminergic neurons in the nigrostriatal system
and dopamine (DA) depletion in the striatum. The most popular therapeutic medicine for treating PD, 3-(3,4-Dihydroxyphenyl)-l-alanine (L-DOPA), has adverse effects, such as dyskinesia and disease acceleration. As superoxide (·O2
−) and hydroxyl radical (·OH) have been implicated in the pathogenesis of PD, free radical scavenging and antioxidants have
attracted attention as agents to prevent disease progression. Rodents injected with 6-hydroxydopamine (6-OHDA) intracerebroventricularly
are considered to be a good animal model of PD. Zingerone and eugenol, essential oils extracted from ginger and cloves, are
known to have free radical scavenging and antioxidant effects. Therefore, we examined the effects of zingerone and eugenol
on the behavioral problems in mouse model and on the DA concentration and antioxidant activities in the striatum after 6-OHDA
administration and L-DOPA treatment. Daily oral administration of eugenol/zingerone and injection of L-DOPA intraperitoneally
for 4 weeks following a single 6-OHDA injection did not improve abnormal behaviors induced by L-DOPA treatment. 6-OHDA reduced
the DA level in the striatum; surprisingly, zingerone and eugenol enhanced the reduction of striatal DA and its metabolites.
Zingerone decreased catalase activity, and increased glutathione peroxidase activity and the oxidized L-ascorbate level in
the striatum. We previously reported that pre-treatment with zingerone or eugenol prevents 6-OHDA-induced DA depression by
preventing lipid peroxidation. However, the present study shows that post-treatment with these substances enhanced the DA
decrease. These substances had adverse effects dependent on the time of administration relative to model PD onset. These results
suggest that we should be wary of ingesting these spice elements after the onset of PD symptoms. 相似文献
15.
16.
The amino acid sequence of cytochrome c from Helix aspersa Müller (garden snail) 总被引:3,自引:3,他引:0
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R. H. Brown M. Richardson D. Boulter J. A. M. Ramshaw R. P. S. Jefferies 《The Biochemical journal》1972,128(4):971-974
The amino acid sequence of a snail cytochrome c has been determined. The molecule consists of a single polypeptide chain of 104 residues, and is homologous with other mitochondrial cytochromes c. Unlike the cytochromes c from vertebrates, there is no acetyl blocking group at the N-terminus. A change in an otherwise invariant position has been observed in position 87. Comparison with amino acid sequences of cytochromes c from other sources indicates that the point of divergence of the molluscs and the vertebrates in evolutionary time was 720 million years ago. Experimental details are given in a supplementary paper that has been deposited as Supplementary Publication SUP 50009 at the National Lending Library for Science and Technology, Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1972), 126, 5. 相似文献
17.
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19.
《Inorganica chimica acta》1986,121(1):33-37
The known complex [Et4N]3[Fe(MoS4)2] has been shown by EPR and visible spectral studies to react with both thiophenol and selenophenol. The reaction results in a change in the characteristic S=3/2 EPR spectrum of this species from a complex rhombic pattern to one of a very simple axial appearance. Although this effect is similar to that observed for reaction of these species with the iron- molybdenum cofactor of nitrogenase, a moiety known to consist of a FeMoS cluster species, the large excesses of reagents and the long reaction times required for complete formation of product indicate that these reactions are of questionable direct relevance to the biological system. The reaction corresponding to the EPR spectral change from rhombic to axial in the [Fe(MoS4)2]3−/PhSeH system has also been partially characterized by product isolation which indicates that attack by selenol of the two terminal MoS2 moieties in the starting material has occurred. 相似文献
20.
High-potential iron-sulfur protein (HiPIP) has been proposed to be involved in the iron respiratory electron transport chain in Acidithiobacillus ferrooxidans, which contains an [Fe(4)S(4)] cluster. We report here the assembly of an [Fe(4)S(4)] cluster in HiPIP from A. ferrooxidans ATCC 23270 in vitro in the presence of Fe(2+) and sulfide. The spectra and matrix-assisted laser desorption ionization-time of flight mass spectrometry results of holoHiPIP confirmed that the iron-sulfur cluster was correctly assembled into the protein. 相似文献