Electron transfer in nitrogenase catalysis

Lance C. Seefeldt*, Brian M. Hoffman, Dennis R. Dean

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

93 Scopus citations


Nitrogenase is a two-component enzyme that catalyzes the nucleotide-dependent reduction of N 2 to 2NH 3. This process involves three redox-active metal-containing cofactors including a [4Fe-4S] cluster, an eight-iron P cluster and a seven-iron plus molybdenum FeMo-cofactor, the site of substrate reduction. A deficit-spending model for electron transfer has recently been proposed that incorporates protein conformational gating that favors uni-directional electron transfer among the metalloclusters for the activation of the substrate-binding site. Also reviewed is a proposal that each of the metal clusters cycles through only two redox states of the metal-sulfur core as the system accumulates the multiple electrons required for substrate binding and reduction. In particular, it was suggested that as FeMo-cofactor acquires the four electrons necessary for optimal binding of N 2, each successive pair of electrons is stored as an Fe-H --Fe bridging hydride, with the FeMo-cofactor metal-ion core retaining its resting redox state. We here broaden the discussion of stable intermediates that might form when FeMo-cofactor receives an odd number of electrons.

Original languageEnglish (US)
Pages (from-to)19-25
Number of pages7
JournalCurrent Opinion in Chemical Biology
Issue number1-2
StatePublished - Apr 2012

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry


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