Tuning of functional heme reduction potentials in Shewanella fumarate reductases

Miguel Pessanha, Emma L Rothery, Caroline S Miles, Graeme A Reid, Stephen K Chapman, Ricardo O Louro, David L Turner, Carlos A Salgueiro, António V Xavier

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    30 Citations (Scopus)

    Abstract

    The fumarate reductases from S. frigidimarina NCIMB400 and S. oneidensis MR-1 are soluble and monomeric enzymes located in the periplasm of these bacteria. These proteins display two redox active domains, one containing four c-type hemes and another containing FAD at the catalytic site. This arrangement of single-electron redox co-factors leading to multiple-electron active sites is widespread in respiratory enzymes. To investigate the properties that allow a chain of single-electron co-factors to sustain the activity of a multi-electron catalytic site, redox titrations followed by NMR and visible spectroscopies were applied to determine the microscopic thermodynamic parameters of the hemes. The results show that the redox behaviour of these fumarate reductases is similar and dominated by a strong interaction between hemes II and III. This interaction facilitates a sequential transfer of two electrons from the heme domain to FAD via heme IV. (C) 2008 Elsevier B.V. All rights reserved.

    Original languageEnglish
    Pages (from-to)113-120
    Number of pages8
    JournalBiochimica et Biophysica Acta - Bioenergetics
    Volume1787
    Issue number2
    DOIs
    Publication statusPublished - Feb 2009

    Keywords

    • WOLINELLA-SUCCINOGENES
    • THERMODYNAMIC CHARACTERIZATION
    • ENERGY TRANSDUCTION
    • Respiratory enzyme
    • Heme
    • REDOX BEHAVIOR
    • FRIGIDIMARINA
    • TETRAHEME CYTOCHROME
    • Fumarate
    • Redox
    • ELECTRON-TRANSFER MECHANISMS
    • Electrostatic interaction
    • NMR
    • FLAVOCYTOCHROME C(3)
    • CYTOCHROME C(3)

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