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Role of a novel disulfide bridge within the all-beta fold of soluble Rieske proteins.

Botelho, Hugo M. and Leal, Sónia S. and Veith, Andreas and Prosinecki, Vesna and Bauer, Christian and Fröhlich, Renate and Kletzin, Arnulf and Gomes, Cláudio M. (2010):
Role of a novel disulfide bridge within the all-beta fold of soluble Rieske proteins.
In: Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry, pp. 271-81, 15, (2), ISSN 1432-1327, [Article]

Abstract

Rieske proteins and Rieske ferredoxins are present in the three domains of life and are involved in a variety of cellular processes. Despite their functional diversity, these small Fe-S proteins contain a highly conserved all-beta fold, which harbors a [2Fe-2S] Rieske center. We have identified a novel subtype of Rieske ferredoxins present in hyperthermophilic archaea, in which a two-cysteine conserved SKTPCX((2-3))C motif is found at the C-terminus. We establish that in the Acidianus ambivalens representative, Rieske ferredoxin 2 (RFd2), these cysteines form a novel disulfide bond within the Rieske fold, which can be selectively broken under mild reducing conditions insufficient to reduce the [2Fe-2S] cluster or affect the secondary structure of the protein, as shown by visible circular dichroism, absorption, and attenuated total reflection Fourier transform IR spectroscopies. RFd2 presents all the EPR, visible absorption, and visible circular dichroism spectroscopic features of the [2Fe-2S] Rieske center. The cluster has a redox potential of +48 mV (25 degrees C and pH 7) and a pK (a) of 10.1 +/- 0.2. These shift to +77 mV and 8.9 +/- 0.3, respectively, upon reduction of the disulfide. RFd2 has a melting temperature near the boiling point of water (T(m) = 99 degrees C, pH 7.0), but it becomes destabilized upon disulfide reduction (DeltaT(m) = -9 degrees C, DeltaC(m) = -0.7 M guanidinium hydrochloride). This example illustrates how the incorporation of an additional structural element such as a disulfide bond in a highly conserved fold such as that of the Rieske domain may fine-tune the protein for a particular function or for increased stability.

Item Type: Article
Erschienen: 2010
Creators: Botelho, Hugo M. and Leal, Sónia S. and Veith, Andreas and Prosinecki, Vesna and Bauer, Christian and Fröhlich, Renate and Kletzin, Arnulf and Gomes, Cláudio M.
Title: Role of a novel disulfide bridge within the all-beta fold of soluble Rieske proteins.
Language: English
Abstract:

Rieske proteins and Rieske ferredoxins are present in the three domains of life and are involved in a variety of cellular processes. Despite their functional diversity, these small Fe-S proteins contain a highly conserved all-beta fold, which harbors a [2Fe-2S] Rieske center. We have identified a novel subtype of Rieske ferredoxins present in hyperthermophilic archaea, in which a two-cysteine conserved SKTPCX((2-3))C motif is found at the C-terminus. We establish that in the Acidianus ambivalens representative, Rieske ferredoxin 2 (RFd2), these cysteines form a novel disulfide bond within the Rieske fold, which can be selectively broken under mild reducing conditions insufficient to reduce the [2Fe-2S] cluster or affect the secondary structure of the protein, as shown by visible circular dichroism, absorption, and attenuated total reflection Fourier transform IR spectroscopies. RFd2 presents all the EPR, visible absorption, and visible circular dichroism spectroscopic features of the [2Fe-2S] Rieske center. The cluster has a redox potential of +48 mV (25 degrees C and pH 7) and a pK (a) of 10.1 +/- 0.2. These shift to +77 mV and 8.9 +/- 0.3, respectively, upon reduction of the disulfide. RFd2 has a melting temperature near the boiling point of water (T(m) = 99 degrees C, pH 7.0), but it becomes destabilized upon disulfide reduction (DeltaT(m) = -9 degrees C, DeltaC(m) = -0.7 M guanidinium hydrochloride). This example illustrates how the incorporation of an additional structural element such as a disulfide bond in a highly conserved fold such as that of the Rieske domain may fine-tune the protein for a particular function or for increased stability.

Journal or Publication Title: Journal of biological inorganic chemistry : JBIC : a publication of the Society of Biological Inorganic Chemistry
Volume: 15
Number: 2
Divisions: 10 Department of Biology > Sulfur Biochemistry and Microbial Bioenergetics
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10 Department of Biology
Date Deposited: 24 May 2011 08:06
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