Solid-state NMR reveals structural and dynamical properties of a membrane-anchored electron-carrier protein, cytochrome b5

J Am Chem Soc. 2007 May 30;129(21):6670-1. doi: 10.1021/ja069028m. Epub 2007 May 9.

Abstract

Cytochrome b5 (cyt b5) is a membrane-anchored electron-carrier protein containing a heme in its soluble domain. It enhances the enzymatic turnover of selected members of the cytochrome P450 superfamily of catabolic enzymes, localized in the endoplasmic reticulum of liver cells. Remarkably, its alpha-helical membrane-anchoring domain is indispensable for the cyt b5/cyt P450 interaction. Here, we present the first solid-state NMR studies on holo-cyt b5 in a membrane environment, namely, macroscopically oriented DMPC:DHPC bicelles. We have presented approaches to selectively investigate different domains of the protein using spectral editing NMR techniques that utilize the unique motional properties of each domain. Two-dimensional 1H-15N HIMSELF spectra showed PISA-wheel patterns reporting on the structure and dynamics of the membrane anchor of the protein.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cytochromes b5 / chemistry*
  • Lipid Bilayers / chemistry
  • Membrane Proteins / chemistry*
  • Models, Molecular
  • Nitrogen Isotopes
  • Nuclear Magnetic Resonance, Biomolecular
  • Rabbits

Substances

  • Lipid Bilayers
  • Membrane Proteins
  • Nitrogen Isotopes
  • Cytochromes b5