Structural and functional effects of cytochrome b5 interactions with human cytochrome P450 enzymes

J Biol Chem. 2017 Dec 22;292(51):20818-20833. doi: 10.1074/jbc.RA117.000220. Epub 2017 Oct 27.

Abstract

The small heme-containing protein cytochrome b5 can facilitate, inhibit, or have no effect on cytochrome P450 catalysis, often in a P450-dependent and substrate-dependent manner that is not well understood. Herein, solution NMR was used to identify b5 residues interacting with different human drug-metabolizing P450 enzymes. NMR results revealed that P450 enzymes bound to either b5 α4-5 (CYP2A6 and CYP2E1) or this region and α2-3 (CYP2D6 and CYP3A4) and suggested variation in the affinity for b5 Mutations of key b5 residues suggest not only that different b5 surfaces are responsible for binding different P450 enzymes, but that these different complexes are relevant to the observed effects on P450 catalysis.

Keywords: cytochrome; cytochrome P450; membrane protein; nuclear magnetic resonance (NMR); protein-protein interaction.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Substitution
  • Biocatalysis
  • Cytochrome P-450 CYP2A6 / chemistry
  • Cytochrome P-450 CYP2A6 / genetics
  • Cytochrome P-450 CYP2A6 / metabolism
  • Cytochrome P-450 CYP2D6 / chemistry
  • Cytochrome P-450 CYP2D6 / genetics
  • Cytochrome P-450 CYP2D6 / metabolism
  • Cytochrome P-450 CYP2E1 / chemistry
  • Cytochrome P-450 CYP2E1 / genetics
  • Cytochrome P-450 CYP2E1 / metabolism
  • Cytochrome P-450 CYP3A / chemistry
  • Cytochrome P-450 CYP3A / genetics
  • Cytochrome P-450 CYP3A / metabolism
  • Cytochrome P-450 Enzyme System / chemistry*
  • Cytochrome P-450 Enzyme System / genetics
  • Cytochrome P-450 Enzyme System / metabolism*
  • Cytochromes b5 / chemistry*
  • Cytochromes b5 / metabolism*
  • Humans
  • Kinetics
  • Mutagenesis, Site-Directed
  • Mutation
  • Nuclear Magnetic Resonance, Biomolecular
  • Protein Conformation
  • Protein Interaction Domains and Motifs
  • Solutions
  • Substrate Specificity

Substances

  • Solutions
  • Cytochromes b5
  • Cytochrome P-450 Enzyme System
  • Cytochrome P-450 CYP2E1
  • CYP2A6 protein, human
  • Cytochrome P-450 CYP2A6
  • Cytochrome P-450 CYP2D6
  • Cytochrome P-450 CYP3A
  • CYP3A4 protein, human

Associated data

  • PDB/2I96
  • PDB/1Z10