Probing the Transmembrane Structure and Dynamics of Microsomal NADPH-cytochrome P450 oxidoreductase by Solid-State NMR

NADPH-cytochrome P450 oxidoreductase (CYPOR) is an essential redox partner of the cytochrome P450 (cyt P450) superfamily of metabolic enzymes. In the endoplasmic reticulum of liver cells, such enzymes metabolize ∼75% of the pharmaceuticals in use today. It is known that the transmembrane domain of C...

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Bibliographic Details
Published in:Biophysical journal 2014-05, Vol.106 (10), p.2126-2133
Main Authors: Huang, Rui, Yamamoto, Kazutoshi, Zhang, Meng, Popovych, Nataliya, Hung, Ivan, Im, Sang-Choul, Gan, Zhehong, Waskell, Lucy, Ramamoorthy, Ayyalusamy
Format: Article
Language:English
Subjects:
Animals
Binding sites
Cell Membrane - metabolism
Dynamics
Endoplasmic reticulum
Enzymes
Flavin Mononucleotide - metabolism
Fluctuation
Lipids
Liver
Magnetic Resonance Spectroscopy
Membrane Proteins - metabolism
Membranes
Metabolism
Microsomes - enzymology
Models, Molecular
NADPH-Ferrihemoprotein Reductase - chemistry
NADPH-Ferrihemoprotein Reductase - metabolism
Nuclear magnetic resonance
Protein Structure, Secondary
Protein Structure, Tertiary
Proteins
Rats
Rotational
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Summary:NADPH-cytochrome P450 oxidoreductase (CYPOR) is an essential redox partner of the cytochrome P450 (cyt P450) superfamily of metabolic enzymes. In the endoplasmic reticulum of liver cells, such enzymes metabolize ∼75% of the pharmaceuticals in use today. It is known that the transmembrane domain of CYPOR plays a crucial role in aiding the formation of a complex between CYPOR and cyt P450. Here we present the transmembrane structure, topology, and dynamics of the FMN binding domain of CYPOR in a native membrane-like environment. Our solid-state NMR results reveal that the N-terminal transmembrane domain of CYPOR adopts an α-helical conformation in the lipid membrane environment. Most notably, we also show that the transmembrane helix is tilted ∼13° from the lipid bilayer normal, and exhibits motions on a submillisecond timescale including rotational diffusion of the whole helix and fluctuation of the helical director axis. The approaches and the information reported in this study would enable further investigations on the structure and dynamics of the full-length NADPH-cytochrome P450 oxidoreductase and its interaction with other membrane proteins in a membrane environment.
ISSN:0006-3495
1542-0086
DOI:10.1016/j.bpj.2014.03.051