Study of heme Fe(III) ligated by OH<sup>–</sup> in cytochrome <i>b</i>–559 and its low temperature photochemistry in intact chloroplasts

A study of the in vitro reconstitution of sugar beet cytochrome b(559) of the photosystem II is described. Both α and β cytochrome subunits were first cloned and expressed in Escherichia coli. In vitro reconstitution of this cytochrome was carried out with partially purified recombinant subunits from inclusion bodies. Reconstitution with commercial heme of both (αα) and (ββ) homodimers and (αβ) heterodimer was possible, the latter being more efficient. The absorption spectra of these reconstituted samples were similar to that of the native heterodimer cytochrome b(559) form. As shown by electron paramagnetic resonance and potentiometry, most of the reconstituted cytochrome corresponded to a low spin form with a midpoint redox potential +36 mV, similar to that from the native purified cytochrome b(559). Furthermore, during the expression of sugar beet and Synechocystis sp. PCC 6803 cytochrome b(559) subunits, part of the protein subunits were incorporated into the host bacterial inner membrane, but only in the case of the β subunit from the cyanobacterium the formation of a cytochrome b(559)-like structure with the bacterial endogenous heme was observed. The reason for that surprising result is unknown. This in vivo formed (ββ) homodimer cytochrome b(559)-like structure showed similar absorption and electron paramagnetic resonance spectral properties as the native purified cytochrome b(559). A higher midpoint redox potential (+126 mV) was detected in the in vivo formed protein compared to the in vitro reconstituted form, most likely due to a more hydrophobic environment imposed by the lipid membrane surrounding the heme.

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Reconstitution, spectroscopy, and redox properties of the photosynthetic recombinant cytochrome b 559 from higher plants

Luján

Martínez

Alonso

et al. 2012

Photosynth Res

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Correlated behavior of the EPR signal of cytochrome b‐559 heme Fe(III) ligated by OH⁻ and the multiline signal of the Mn cluster in PS‐II membrane fragments

Fiege

Шувалов

1996

FEBS Letters

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EPR signals of Cyt b‐559 heme Fe(III) ligated by OH− and the multiline signal of the Mn cluster in PS‐II membrane fragments have been investigated. In 2,3‐dicyano‐5,6‐dichloro‐p‐benzoquinone‐oxidized PS‐II membrane fragments the light‐induced decrease of the EPR signal of the heme Fe(III)‐OH− is accompanied by the appearance of the EPR multiline signal of the Mn cluster. Addition of F− ions, which act as a stronger ligand for heme Fe(III) than OH−, decreases to the same extent the dark‐ and light‐induced signal of the heme Fe(III)‐OH− and the light‐induced multiline signal of the Mn cluster. These results are discussed in terms of the light‐induced formation of a bound OH′ radical shared between the Cyt b‐559 heme Fe and the Mn cluster as a first step of water oxidation.

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Effects of lead on two green microalgae Chlorella and Scenedesmus: photosystem II activity and heterogeneity

Dao

Beardall

2016

Algal Research

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Study of heme Fe(III) ligated by OH^– in cytochrome b–559 and its low temperature photochemistry in intact chloroplasts

Cited by 9 publications

References 20 publications

Reconstitution, spectroscopy, and redox properties of the photosynthetic recombinant cytochrome b 559 from higher plants

Reconstitution, spectroscopy, and redox properties of the photosynthetic recombinant cytochrome b 559 from higher plants

Correlated behavior of the EPR signal of cytochrome b‐559 heme Fe(III) ligated by OH⁻ and the multiline signal of the Mn cluster in PS‐II membrane fragments

Effects of lead on two green microalgae Chlorella and Scenedesmus: photosystem II activity and heterogeneity

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Study of heme Fe(III) ligated by OH– in cytochrome b–559 and its low temperature photochemistry in intact chloroplasts

Cited by 9 publications

References 20 publications

Reconstitution, spectroscopy, and redox properties of the photosynthetic recombinant cytochrome b 559 from higher plants

Reconstitution, spectroscopy, and redox properties of the photosynthetic recombinant cytochrome b 559 from higher plants

Correlated behavior of the EPR signal of cytochrome b‐559 heme Fe(III) ligated by OH− and the multiline signal of the Mn cluster in PS‐II membrane fragments

Effects of lead on two green microalgae Chlorella and Scenedesmus: photosystem II activity and heterogeneity

Contact Info

Product

Resources

About

Study of heme Fe(III) ligated by OH^– in cytochrome b–559 and its low temperature photochemistry in intact chloroplasts

Correlated behavior of the EPR signal of cytochrome b‐559 heme Fe(III) ligated by OH⁻ and the multiline signal of the Mn cluster in PS‐II membrane fragments