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Research article2008Peer reviewed

Determining Rieske cluster reduction potentials

Brown, Eric N.; Friemann, Rosmarie; Karlsson, Andreas; Parales, Juan V.; Couture, Manon M.-J.; Eltis, Lindsay D.; Ramaswamy, S.

Abstract

The Rieske iron-sulfur proteins have reduction potentials ranging from -150 to +400 mV. This enormous range of potentials was first proposed to be due to differing solvent exposure or even protein structure. However, the increasing number of available crystal structures for Rieske iron-sulfur proteins has shown this not to be the case. Colbert and colleagues proposed in 2000 that differences in the electrostatic environment, and not structural differences, of a Rieske proteins are responsible for the wide range of reduction potentials observed. Using computational simulation methods and the newly determined structure of Pseudomonas sp. NCIB 9816-4 naphthalene dioxygenase Rieske ferredoxin (NDO-F(9816-4)), we have developed a model to predict the reduction potential of Rieske proteins given only their crystal structure. The reduction potential of NDO-F(9816-4), determined using a highly oriented pyrolytic graphite electrode, was - 150 +/- 2 mV versus the standard hydrogen electrode. The predicted reduction potentials correlate well with experimentally determined potentials. Given this model, the effect of protein mutations can be evaluated. Our results suggest that the reduction potential of new proteins can be estimated with good confidence from 3D structures of proteins. The structure of NDO-F(9816-4) is the most basic Rieske ferredoxin structure determined to date. Thus, the contributions of additional structural motifs and their effects on reduction potential can be compared with respect to this base structure.

Keywords

Electrochemistry; X-ray crystallography; Rieske ferredoxin

Published in

Journal of Biological Inorganic Chemistry
2008, Volume: 13, number: 8, pages: 1301-1313
Publisher: SPRINGER

      SLU Authors

    • Friemann, Rosmarie

      • Department of Molecular Biology, Swedish University of Agricultural Sciences

      • UKÄ Subject classification

      Biochemistry and Molecular Biology

      Publication identifier

      DOI: https://doi.org/10.1007/s00775-008-0413-4

      Permanent link to this page (URI)

      https://res.slu.se/id/publ/78138