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Kato Y, Sugiura M, Oda A, Watanabe T. Spectroelectrochemical determination of the redox potential of pheophytin a, the primary electron acceptor in photosystem II. Proc Natl Acad Sci U S A 2009; 106:17365-70. [PMID: 19805064 PMCID: PMC2765088 DOI: 10.1073/pnas.0905388106] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Indexed: 02/07/2023] Open
Abstract
Thin-layer cell spectroelectrochemistry, featuring rigorous potential control and rapid redox equilibration within the cell, was used to measure the redox potential E(m)(Phe a/Phe a(-)) of pheophytin (Phe) a, the primary electron acceptor in an oxygen-evolving photosystem (PS) II core complex from a thermophilic cyanobacterium Thermosynechococcus elongatus. Interferences from dissolved O(2) and water reductions were minimized by airtight sealing of the sample cell added with dithionite and mercury plating on the gold minigrid working electrode surface, respectively. The result obtained at a physiological pH of 6.5 was E(m)(Phe a/Phe a(-)) = -505 + or - 6 mV vs. SHE, which is by approximately 100 mV more positive than the values measured approximately 30 years ago at nonphysiological pH and widely accepted thereafter in the field of photosynthesis research. Using the P680* - Phe a free energy difference, as estimated from kinetic analyses by previous authors, the present result would locate the E(m)(P680/P680(+)) value, which is one of the key parameters but still resists direct measurements, at approximately +1,210 mV. In view of these pieces of information, a renewed diagram is proposed for the energetics in PS II.
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Affiliation(s)
- Yuki Kato
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan; and
| | - Miwa Sugiura
- Cell-Free Science and Technology Research Center, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
| | - Akinori Oda
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan; and
| | - Tadashi Watanabe
- Institute of Industrial Science, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan; and
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Bernad S, Mäntele W. An innovative spectroelectrochemical reflection cell for rapid protein electrochemistry and ultraviolet/visible/infrared spectroscopy. Anal Biochem 2006; 351:214-8. [PMID: 16530718 DOI: 10.1016/j.ab.2005.12.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2005] [Revised: 12/16/2005] [Accepted: 12/16/2005] [Indexed: 11/24/2022]
Abstract
A novel electrochemical reflection cell combining electrochemical techniques and spectroscopy which uses a solid gold working electrode as an optical mirror is described. This cell can be used at path lengths as low as a few micrometers and thus is suitable for ultraviolet/visible (UV/Vis) and infrared spectroscopy even for aqueous solutions and suspensions. The cell was designed for small sample volumes of only a few microliters, thus reducing the effort for sample preparation. Due to the short path length of some micrometers, the entire volume is within the Nernst diffusion layer, hence resulting in fast equilibration. Evaluation of the technique is described with direct electrochemistry of horse heart cytochrome c at the gold electrode modified with 4,4'-dithiodipyridine. Cyclic voltammograms indicate rapid and reversible electrochemistry with the correct midpoint potential (52 mV vs Ag/AgCl/3 M KCl). Chronoamperometry and coulometry confirm rapid and complete oxidation and reduction; the cell volume can be entirely fully reduced within less than 10-20 s. Spectroscopy in the UV/Vis region, with potentials at the working electrode stepped between -390 and 390 mV, show perfect titration of the cytochrome c heme bands. A Nernst fit of the alpha band absorption, with redox potential Em and number of electrons n left as parameters, yields a midpoint potential of 49 mV and n=0.9. The potential of this cell in the investigation of biological electron transfer reactions and in the study of bioenergetic systems is discussed.
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Affiliation(s)
- Sophie Bernad
- Institut für Biophysik, Johann Wolfgang Goethe-Universität Frankfurt am Main, Max-von Laue-Strasse 1, D-60438 Frankfurt am Main, Germany.
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Neudeck A, Dunsch L. Microstructured electrode materials in UV-visible spectroelectrochemistry. J Electroanal Chem (Lausanne) 1995. [DOI: 10.1016/0022-0728(95)03824-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Affiliation(s)
- S Dong
- Changchun Institute of Applied Chemistry, Chinese Academy of Sciences
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An electrochemical cell for simultaneous electrochemical and spectroelectrochemical measurements under semi-infinite diffusion conditions and thin-layer conditions. J Electroanal Chem (Lausanne) 1992. [DOI: 10.1016/0022-0728(92)80297-h] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Taniguchi I, Fujiwara T, Tominaga M. New Simple Cell for In-situ Fluoroelectrochemical Measurements. CHEM LETT 1992. [DOI: 10.1246/cl.1992.1217] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Moss DA, Leonhard M, Bauscher M, Mäntele W. Electrochemical redox titration of cofactors in the reaction center from Rhodobacter sphaeroides. FEBS Lett 1991; 283:33-6. [PMID: 2037069 DOI: 10.1016/0014-5793(91)80547-g] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The electrochemical redox poising of the primary electron donor P and of the quinone electron acceptor(s) Q in isolated reaction centers from Rhodobacter sphaeroides in an ultra-thin-layer electrochemical cell, monitored by chronoamperometry and by spectroscopy in the visible/near-infrared region, is reported. Electrical application of a redox potential of +0.4 V (vs. Ag/AgCl/3 M KCl) leads to quantitative formation of the pi-cation radical of P within a few minutes. The oxidized product can be re-reduced to the neutral species by application of 0 V, and full reversibility is maintained over many cycles. By poising at a series of intermediate potentials, a titration curve for the 865 nm P band was obtained, which could be fitted to a Nernst function with Em = 0.485 vs. SHE and n = 0.96. By application of negative potentials (-0.2 V and -0.45 V vs. Ag/AgCl/3 M KCl), the quinone electron acceptors were reversibly reduced as demonstrated by the shift of bacteriopheophytin absorption and drastically changed kinetics of charge recombination. The use of this thin-layer electrochemical technique for the determination of midpoint potentials, for the investigation of redox-poised electron transfer reactions as well as for spectroscopy in the mid-infrared region is discussed.
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Affiliation(s)
- D A Moss
- Institut für Biophysik und Strahlenbiologie, Universität Freiburg, Germany
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Hirasawa M, Sung JD, Malkin R, Zilber A, Droux M, Knaff DB. Evidence for the presence of a [2Fe-2S] ferredoxin in bean sprouts. BIOCHIMICA ET BIOPHYSICA ACTA 1988; 934:169-76. [PMID: 3390451 DOI: 10.1016/0005-2728(88)90179-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
An iron-sulfur protein with properties similar to those of ferredoxins found in the leaves of higher plants has been isolated from bean sprouts--a non-photosynthetic plant tissue. The bean sprout protein has a molecular mass of 12.5 kDa and appears to contain a single [2Fe-2S] cluster. The absorbance and circular dichroism spectra of the bean sprout protein resemble those of spinach leaf ferredoxin and the bean sprout protein can replace spinach ferredoxin as an electron donor for NADP+ reduction, nitrite reduction and thioredoxin reduction by spinach leaf enzymes. Although the reduced bean sprout protein (Em = -440 mV) is a slightly stronger reductant than spinach ferredoxin and appears to be less acidic than spinach ferredoxin, the two proteins are similar enough so that the bean sprout protein is recognized by an antibody raised against spinach ferredoxin.
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Affiliation(s)
- M Hirasawa
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409-1061
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Daub J, Salbeck J, Aurbach I. CD-Spektroelektrochemie, eine Methode zur Charakterisierung chiraler Elektronentransferreagentien und chiraler Reaktionszwischenstufen. Angew Chem Int Ed Engl 1988. [DOI: 10.1002/ange.19881000215] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Daub J, Salbeck J, Aurbach I. CD Spectroelectrochemistry, a Method for the Characterization of Chiral Electron Transfer Reagents and Chiral Reaction Intermediates. ACTA ACUST UNITED AC 1988. [DOI: 10.1002/anie.198802911] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Erabi T, Yamashita Y, Nishimura K, Wada M. Spectroelectrochemical Determination of Redox Potential of Cytochrome c′ in Rhodospirillum rubrumChromatophores. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1987. [DOI: 10.1246/bcsj.60.2251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Wynn R, Redlinger TE, Foster JM, Blankenship RE, Fuller R, Shaw RW, Knaff DB. Electron-transport chains of phototrophically and chemotrophically grown Chloroflexus aurantiacus. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1987. [DOI: 10.1016/0005-2728(87)90217-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Kirchhoff JR, Deutsch E, Heineman WR. Characterization of technetium radiopharmaceuticals by thin-layer spectroelectrochemistry. J Pharm Biomed Anal 1986; 4:777-87. [PMID: 16867559 DOI: 10.1016/0731-7085(86)80088-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Optically transparent thin-layer electrode (OTTLE) techniques have been used to characterize technetium complexes of biomedical importance. Different Tc oxidation states have been generated at the electrodes and absorption spectra determined. Small cell volumes allow the study of materials available in small quantities, and a flow cell configuration has also been used. Heart and bone imaging agents have been studied.
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Affiliation(s)
- J R Kirchhoff
- Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA
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The membrane-bound electron-transfer components of aerobically grown Chromatium vinosum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 1985. [DOI: 10.1016/0005-2728(85)90030-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Fernández VM. An electrochemical cell for reduction of biochemicals: its application to the study of the effect of pH and redox potential on the activity of hydrogenases. Anal Biochem 1983; 130:54-9. [PMID: 6346946 DOI: 10.1016/0003-2697(83)90648-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Erabi T, Tanaka M. Cathodic Reduction of Ubiquinone-10 Dissolved in Carbon-paste Electrode. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1983. [DOI: 10.1246/bcsj.56.15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Anderson CW, Cushman MR, Kennedy SM, Wheeler JR. Dual-beam difference spectroelectrochemistry. Anal Biochem 1982; 127:413-7. [PMID: 6299133 DOI: 10.1016/0003-2697(82)90195-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Smith JM, Smith WH, Knaff DB. Electrochemical titrations of a ferredoxin-ferredoxin:NADP+ oxidoreductase complex. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 635:405-11. [PMID: 7236672 DOI: 10.1016/0005-2728(81)90038-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Potentiometric titrations employing an electrochemical thin-layer cell indicate that complex formation between ferredoxin and ferredoxin:NADP+ oxidoreductase alters the midpoint oxidation-reduction potentials of both proteins. The midpoint potential of ferredoxin the complex becomes 22 +/- 6 mV more negative compared to ferredoxin alone while the midpoint potential of ferredoxin:NADP+ oxidoreductase becomes 23 +/- 4 mV more positive on complex formation.
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Jursinic P. POLAROGRAPHIC DETECTION OF AN ENDOGENOUS REDUCTANT GENERATED DURING FLASH ILLUMINATION OF CHLOROPLASTS. Photochem Photobiol 1980. [DOI: 10.1111/j.1751-1097.1980.tb03986.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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310 - Optically transparent thin layer electrode techniques for the study of biological redox systems. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/0302-4598(79)80026-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Anderson CW, Halsall HB, Heineman WR. A small-volume thin-layer spectroelectrochemical cell for the study of biological components. Anal Biochem 1979; 93:366-72. [PMID: 223467 DOI: 10.1016/s0003-2697(79)80164-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Optically transparent thin layer electrode techniquesfor the study of biological redox systems. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/s0022-0728(79)81070-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Rickard LH, Landrum H, Hawkridge F. 261 - A Mediated Electrochemical Redox Study of Soluble Spinach Ferredoxin Using Optically Coupled Methods. ACTA ACUST UNITED AC 1978. [DOI: 10.1016/0302-4598(78)80008-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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