NirJ, a radical SAM family member of the d1 heme biogenesis cluster

Amanda A. Brindley, Richard Zajicek, Martin J. Warren, Stuart J. Ferguson, Stephen E.J. Rigby

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25 Citations (Scopus)


NirJ is involved in the transformation of precorrin-2 into heme d1, although its precise role in the process has not been established. The purified protein was found to contain a 4Fe-4S centre, in line with the prediction that it belongs to the radical SAM class of enzymes. This was further confirmed by binding of S-adenosyl-l-methionine (SAM) to dithionite-reduced NirJ, which resulted in a decrease in the signal intensity and in a shift to higher field of the [4Fe-4S]1+ EPR signal. Significantly, though, this approach also led to the appearance of a small but reproducible organic radical signal that was associated with about 2% of the NirJ molecules and was affected by the incorporation of SAM deuterated at the 5' adenosyl group.

Original languageEnglish
Pages (from-to)2461-2466
Number of pages6
JournalFEBS Letters
Issue number11
Publication statusPublished - Jun 2010


  • Biosynthesis
  • Heme d1
  • Iron-sulfur centre
  • NirJ
  • Radical SAM
  • Tetrapyrrole

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