Homotropic cooperativity of monomeric cytochrome P450 3A4 in a nanoscale native bilayer environment

  • Baas B
  • Denisov I
  • Sligar S
  • 86

    Readers

    Mendeley users who have this article in their library.
  • 135

    Citations

    Citations of this article.

Abstract

Mechanistic studies of mammalian cytochrome P450s are often obscured by the phase heterogeneity of solubilized preparations of membrane enzymes. The various protein-protein aggregation states of microsomes, detergent solubilized cytochrome or a family of aqueous multimeric complexes can effect measured substrate binding events as well as subsequent steps in the reaction cycle. In addition, these P450 monooxygenases are normally found in a membrane environment and the bilayer composition and dynamics can also effect these catalytic steps. Here, we describe the structural and functional characterization of a homogeneous monomeric population of cytochrome P450 3A4 (CYP 3A4) in a soluble nanoscale membrane bilayer, or Nanodisc [Nano Lett. 2 (2002) 853]. Cytochrome P450 3A4:Nanodisc assemblies were formed and purified to yield a 1:1 ratio of CYP 3A4 to Nanodisc. Solution small angle X-ray scattering was used to structurally characterize this monomeric CYP 3A4 in the membrane bilayer. The purified CYP 3A4:Nanodiscs showed a heretofore undescribed high level of homotropic cooperativity in the binding of testosterone. Soluble CYP 3A4:Nanodisc retains its known function and shows prototypic hydroxylation of testosterone when driven by hydrogen peroxide. This represents the first functional characterization of a true monomeric preparation of cytochrome P450 monooxygenase in a phospholipid bilayer and elucidates new properties of the monomeric form. © 2004 Elsevier Inc. All rights reserved.

Author-supplied keywords

  • Cytochrome P450 monooxygenases
  • Homotropic cooperativity
  • Membrane scaffold protein
  • Nanodiscs
  • Small angle X-ray scattering

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Ilia DenisovUniversity of Illinois at Urbana-Champaign

    Follow
  • Bradley J. Baas

  • Stephen G. Sligar

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free