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PLoS One. 2015 Nov 20;10(11):e0141252. doi: 10.1371/journal.pone.0141252. eCollection 2015.

Mechanistic Scrutiny Identifies a Kinetic Role for Cytochrome b5 Regulation of Human Cytochrome P450c17 (CYP17A1, P450 17A1).

Author information

1
School of Chemistry, Monash University, Clayton, Victoria, Australia.
2
ACRF Rational Drug Discovery Centre, St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.
3
School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.
4
Department of Physiology and Membrane Biology, School of Medicine, University of California Davis, Davis, California, United States of America.
5
Boreskov Institute of Catalysis, Prospekt Lavrentieva 5, Novosibirsk, Russia.
6
Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America.
7
Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia.
8
Discipline of Obstetrics and Gynaecology, School of Paediatrics and Reproductive Health, Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia.

Abstract

Cytochrome P450c17 (P450 17A1, CYP17A1) is a critical enzyme in the synthesis of androgens and is now a target enzyme for the treatment of prostate cancer. Cytochrome P450c17 can exhibit either one or two physiological enzymatic activities differentially regulated by cytochrome b5. How this is achieved remains unknown. Here, comprehensive in silico, in vivo and in vitro analyses were undertaken. Fluorescence Resonance Energy Transfer analysis showed close interactions within living cells between cytochrome P450c17 and cytochrome b5. In silico modeling identified the sites of interaction and confirmed that E48 and E49 residues in cytochrome b5 are essential for activity. Quartz crystal microbalance studies identified specific protein-protein interactions in a lipid membrane. Voltammetric analysis revealed that the wild type cytochrome b5, but not a mutated, E48G/E49G cyt b5, altered the kinetics of electron transfer between the electrode and the P450c17. We conclude that cytochrome b5 can influence the electronic conductivity of cytochrome P450c17 via allosteric, protein-protein interactions.

PMID:
26587646
PMCID:
PMC4654539
DOI:
10.1371/journal.pone.0141252
[Indexed for MEDLINE]
Free PMC Article

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