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, Antonio V. Xavier

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

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.

Original languageEnglish
Pages (from-to)113-120
Number of pages8
JournalBBA - Bioenergetics
Volume1787
Issue number2
Early online date21 Nov 2008
DOIs
Publication statusPublished - 28 Feb 2009

Keywords / Materials (for Non-textual outputs)

  • Respiratory enzyme
  • Fumarate
  • Heme
  • NMR
  • Redox
  • Electrostatic interaction

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