Cross-linking of human cytochrome P450 2B6 to NADPH-cytochrome P450 reductase: Identification of a potential site of interaction

Namandjé N. Bumpus, Paul F. Hollenberg

Research output: Contribution to journalArticlepeer-review


The site(s) of interaction between human cytochrome P450 2B6 and NADPH-cytochrome P450 reductase (P450 reductase) have yet to be identified. To investigate this, the cross-linking agent 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC) was used to covalently link P450 2B6-P450 reductase. Following digestion with trypsin, the cross-linked peptides were identified by reconstituting the peptides in 18O-water based on the principle that the cross-linked peptides would be expected to incorporate twice as many 18O atoms as the non-cross-linked peptides. Subsequent mass spectrometric analyses of the resulting peptides led to the identification of one cross-linked peptide candidate. De novo sequencing of the peptide indicated that it is a complex between residues in the C-helix of the P450 (based upon solved X-ray crystal structures of P450 2B4) and the connecting domain of the P450 reductase. To confirm this experimentally, the P450 2B6 peptide identified through the cross-linking studies was synthesized and peptide competition studies were performed. In the presence of the synthetic peptide, P450 catalytic activity was decreased by up to 60% when compared to competition studies performed using a nonsense peptide. Taken together, these studies indicate that residues in the C-helix of P450 2B6 play a major role in the interaction with the P450 reductase.

Original languageEnglish (US)
Pages (from-to)485-488
Number of pages4
JournalJournal of Inorganic Biochemistry
Issue number4
StatePublished - Apr 2010
Externally publishedYes


  • Cross-linking
  • Cytochrome P450
  • Protein-protein interactions

ASJC Scopus subject areas

  • Biochemistry
  • Inorganic Chemistry


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