The pH dependence of the redox midpoint potential of the 2Fe2S cluster from cytochrome b6f complex (the 'Rieske centre')

Wolfgang Nitschke; Pierre Joliot; Ursula Liebl; A. William Rutherford; Günter Hauska; Adolf Müller; Astrid Riedel

doi:10.1016/0005-2728(92)90109-F

The pH dependence of the redox midpoint potential of the 2Fe2S cluster from cytochrome b₆f complex (the 'Rieske centre')

Wolfgang Nitschke, Pierre Joliot, Ursula Liebl, A. William Rutherford, Günter Hauska, Adolf Müller, Astrid Riedel

Research output: Contribution to journal › Article › peer-review

Abstract

The pH dependence of the redox midpoint potential (E_m) of the Rieske centre from spinach cytochrome b₆f complex was studied by EPR. The E_m was found to be independent of pH up to pH 8 and to decrease at higher pH values. The slope of the decrease above the pK value was roughly consistent with the involvement of a dissociable proton on the oxidized form of the cluster. The E_m in the pH-independent region (i.e. <pH 8) was determined to be +320 mV. This is in contrast to the original value (E_m = +290 mV) reported by Malkin and Aparicio (Biochem. Biophys. Res. Commun. 63 (1975) 1157-1160) and confirms the results reported more recently (E_m = 310-320 mV) by Malkin (FEBS Lett. 131 (1981) 169-172) and Nitschke et al. (Biochim. Biophys. Acta 974 (1989) 223-226).

Original language	English
Pages (from-to)	266-268
Number of pages	3
Journal	Biochimica et Biophysica Acta - Bioenergetics
Volume	1102
Issue number	2
DOIs	https://doi.org/10.1016/0005-2728(92)90109-F
Publication status	Published - 25 Sept 1992
Externally published	Yes

Keywords

Cytochrome bf complex
EPR
Iron-sulfur cluster
Redox potential
pH dependence

Access to Document

10.1016/0005-2728(92)90109-F

Cite this

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title = "The pH dependence of the redox midpoint potential of the 2Fe2S cluster from cytochrome b6f complex (the 'Rieske centre')",

abstract = "The pH dependence of the redox midpoint potential (Em) of the Rieske centre from spinach cytochrome b6f complex was studied by EPR. The Em was found to be independent of pH up to pH 8 and to decrease at higher pH values. The slope of the decrease above the pK value was roughly consistent with the involvement of a dissociable proton on the oxidized form of the cluster. The Em in the pH-independent region (i.e. m = +290 mV) reported by Malkin and Aparicio (Biochem. Biophys. Res. Commun. 63 (1975) 1157-1160) and confirms the results reported more recently (Em = 310-320 mV) by Malkin (FEBS Lett. 131 (1981) 169-172) and Nitschke et al. (Biochim. Biophys. Acta 974 (1989) 223-226).",

keywords = "Cytochrome bf complex, EPR, Iron-sulfur cluster, Redox potential, pH dependence",

author = "Wolfgang Nitschke and Pierre Joliot and Ursula Liebl and Rutherford, \{A. William\} and G{\"u}nter Hauska and Adolf M{\"u}ller and Astrid Riedel",

year = "1992",

month = sep,

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doi = "10.1016/0005-2728(92)90109-F",

language = "English",

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T1 - The pH dependence of the redox midpoint potential of the 2Fe2S cluster from cytochrome b6f complex (the 'Rieske centre')

AU - Nitschke, Wolfgang

AU - Joliot, Pierre

AU - Liebl, Ursula

AU - Rutherford, A. William

AU - Hauska, Günter

AU - Müller, Adolf

AU - Riedel, Astrid

PY - 1992/9/25

Y1 - 1992/9/25

N2 - The pH dependence of the redox midpoint potential (Em) of the Rieske centre from spinach cytochrome b6f complex was studied by EPR. The Em was found to be independent of pH up to pH 8 and to decrease at higher pH values. The slope of the decrease above the pK value was roughly consistent with the involvement of a dissociable proton on the oxidized form of the cluster. The Em in the pH-independent region (i.e. m = +290 mV) reported by Malkin and Aparicio (Biochem. Biophys. Res. Commun. 63 (1975) 1157-1160) and confirms the results reported more recently (Em = 310-320 mV) by Malkin (FEBS Lett. 131 (1981) 169-172) and Nitschke et al. (Biochim. Biophys. Acta 974 (1989) 223-226).

AB - The pH dependence of the redox midpoint potential (Em) of the Rieske centre from spinach cytochrome b6f complex was studied by EPR. The Em was found to be independent of pH up to pH 8 and to decrease at higher pH values. The slope of the decrease above the pK value was roughly consistent with the involvement of a dissociable proton on the oxidized form of the cluster. The Em in the pH-independent region (i.e. m = +290 mV) reported by Malkin and Aparicio (Biochem. Biophys. Res. Commun. 63 (1975) 1157-1160) and confirms the results reported more recently (Em = 310-320 mV) by Malkin (FEBS Lett. 131 (1981) 169-172) and Nitschke et al. (Biochim. Biophys. Acta 974 (1989) 223-226).

KW - Cytochrome bf complex

KW - EPR

KW - Iron-sulfur cluster

KW - Redox potential

KW - pH dependence

U2 - 10.1016/0005-2728(92)90109-F

DO - 10.1016/0005-2728(92)90109-F

M3 - Article

AN - SCOPUS:0026671755

SN - 0005-2728

VL - 1102

SP - 266

EP - 268

JO - Biochimica et Biophysica Acta - Bioenergetics

JF - Biochimica et Biophysica Acta - Bioenergetics

IS - 2