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Ibrahim SS, Kouamo MFM, Muhammad A, Irving H, Riveron JM, Tchouakui M, Wondji CS. Functional Validation of Endogenous Redox Partner Cytochrome P450 Reductase Reveals the Key P450s CYP6P9a/- b as Broad Substrate Metabolizers Conferring Cross-Resistance to Different Insecticide Classes in Anopheles funestus. Int J Mol Sci 2024; 25:8092. [PMID: 39125661 PMCID: PMC11311542 DOI: 10.3390/ijms25158092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 06/10/2024] [Accepted: 06/13/2024] [Indexed: 08/12/2024] Open
Abstract
The versatility of cytochrome P450 reductase (CPR) in transferring electrons to P450s from other closely related species has been extensively exploited, e.g., by using An. gambiae CPR (AgCPR), as a homologous surrogate, to validate the role of An. funestus P450s in insecticide resistance. However, genomic variation between the AgCPR and An. funestus CPR (AfCPR) suggests that the full metabolism spectrum of An. funestus P450s might be missed when using AgCPR. To test this hypothesis, we expressed AgCPR and AfCPR side-by-side with CYP6P9a and CYP6P9b and functionally validated their role in the detoxification of insecticides from five different classes. Major variations were observed within the FAD- and NADP-binding domains of AgCPR and AfCPR, e.g., the coordinates of the second FAD stacking residue AfCPR-Y456 differ from that of AgCPR-His456. While no significant differences were observed in the cytochrome c reductase activities, when co-expressed with their endogenous AfCPR, the P450s significantly metabolized higher amounts of permethrin and deltamethrin, with CYP6P9b-AfCPR membrane metabolizing α-cypermethrin as well. Only the CYP6P9a-AfCPR membrane significantly metabolized DDT (producing dicofol), bendiocarb, clothianidin, and chlorfenapyr (bioactivation into tralopyril). This demonstrates the broad substrate specificity of An. funestus CYP6P9a/-b, capturing their role in conferring cross-resistance towards unrelated insecticide classes, which can complicate resistance management.
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Affiliation(s)
- Sulaiman S. Ibrahim
- Department of Biochemistry, Bayero University, Kano PMB 3011, Nigeria
- Center for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (M.F.M.K.); (J.M.R.); (M.T.)
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool L3 5QA, UK; (A.M.); (H.I.)
| | - Mersimine F. M. Kouamo
- Center for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (M.F.M.K.); (J.M.R.); (M.T.)
| | - Abdullahi Muhammad
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool L3 5QA, UK; (A.M.); (H.I.)
- Center of Biotechnology Research, Bayero University, Kano PMB 3011, Nigeria
| | - Helen Irving
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool L3 5QA, UK; (A.M.); (H.I.)
| | - Jacob M. Riveron
- Center for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (M.F.M.K.); (J.M.R.); (M.T.)
| | - Magellan Tchouakui
- Center for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (M.F.M.K.); (J.M.R.); (M.T.)
| | - Charles S. Wondji
- Center for Research in Infectious Diseases (CRID), Yaoundé P.O. Box 13591, Cameroon; (M.F.M.K.); (J.M.R.); (M.T.)
- Vector Biology Department, Liverpool School of Tropical Medicine (LSTM), Liverpool L3 5QA, UK; (A.M.); (H.I.)
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Kefi M, Konstantinos P, Balabanidou V, Sarafoglou C, Tsakireli D, Douris V, Monastirioti M, Maréchal JD, Feyereisen R, Vontas J. Insights into unique features of Drosophila CYP4G enzymes. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2024; 164:104041. [PMID: 38008364 DOI: 10.1016/j.ibmb.2023.104041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 11/12/2023] [Accepted: 11/19/2023] [Indexed: 11/28/2023]
Abstract
The cytochrome P450 enzymes of the CYP4G subfamily are some of the most intriguing insect P450s in terms of structure and function. In Drosophila, CYP4G1 is highly expressed in the oenocytes and is the last enzyme in the biosynthesis of cuticular hydrocarbons, while CYP4G15 is expressed in the brain and is of unknown function. Both proteins have a CYP4G-specific and characteristic amino acid sequence insertion corresponding to a loop between the G and H helices whose function is unclear. Here we address these enigmatic structural and functional features of Drosophila CYP4Gs. First, we used reverse genetics to generate D. melanogaster strains in which all or part of the CYP4G-specific loop was removed from CYP4G1. We showed that the full loop was not needed for proper folding of the P450, but it is essential for function, and that just a short stretch of six amino acids is required for the enzyme's ability to make hydrocarbons. Second, we confirmed by immunocytochemistry that CYP4G15 is expressed in the brain and showed that it is specifically associated with the cortex glia cell subtype. We then expressed CYP4G15 ectopically in oenocytes, revealing that it can produce of a blend of hydrocarbons, albeit to quantitatively lower levels resulting in only a partial rescue of CYP4G1 knockdown flies. The CYP4G1 structural variants studied here should facilitate the biochemical characterization of CYP4G enzymes. Our results also raise the question of the putative role of hydrocarbons and their synthesis by cortex glial cells.
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Affiliation(s)
- Mary Kefi
- Department of Biology, University of Crete, Vassilika Vouton, 70013, Heraklion, Greece; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece
| | - Parasyris Konstantinos
- Department of Biology, University of Crete, Vassilika Vouton, 70013, Heraklion, Greece; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece
| | - Vasileia Balabanidou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece
| | - Chara Sarafoglou
- Department of Biology, University of Crete, Vassilika Vouton, 70013, Heraklion, Greece; Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece
| | - Dimitra Tsakireli
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece; Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, Greece
| | - Vassilis Douris
- Department of Biological Applications and Technology, University of Ioannina, 45110, Ioannina, Greece; Biomedical Research Institute (BRI), Foundation for Research and Technology (FORTH), University Campus, 451 10, Ioannina, Greece
| | - Maria Monastirioti
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece
| | - Jean-Didier Maréchal
- Departament de Química, Universitat Autònoma de Barcelona, Edifici C.n., Cerdanyola del Vallès, 08193, Barcelona, Spain
| | - René Feyereisen
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Belgium.
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Nikolaou Plastira Street 100, 70013, Heraklion, Greece; Pesticide Science Laboratory, Department of Crop Science, Agricultural University of Athens, Greece.
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Burris-Hiday SD, Scott EE. Allosteric modulation of cytochrome P450 enzymes by the NADPH cytochrome P450 reductase FMN-containing domain. J Biol Chem 2023; 299:105112. [PMID: 37517692 PMCID: PMC10481364 DOI: 10.1016/j.jbc.2023.105112] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/18/2023] [Accepted: 07/21/2023] [Indexed: 08/01/2023] Open
Abstract
NADPH-cytochrome P450 reductase delivers electrons required by heme oxygenase, squalene monooxygenase, fatty acid desaturase, and 48 human cytochrome P450 enzymes. While conformational changes supporting reductase intramolecular electron transfer are well defined, intermolecular interactions with these targets are poorly understood, in part because of their transient association. Herein the reductase FMN domain responsible for interacting with targets was fused to the N-terminus of three drug-metabolizing and two steroidogenic cytochrome P450 enzymes to increase the probability of interaction. These artificial fusion enzymes were profiled for their ability to bind their respective substrates and inhibitors and to perform catalysis supported by cumene hydroperoxide. Comparisons with the isolated P450 enzymes revealed that even the oxidized FMN domain causes substantial and diverse effects on P450 function. The FMN domain could increase, decrease, or not affect total ligand binding and/or dissociation constants depending on both P450 enzyme and ligand. As examples, FMN domain fusion has no effect on inhibitor ketoconazole binding to CYP17A1 but substantially altered CYP21A2 binding of the same compound. FMN domain fusion to CYP21A2 resulted in differential effects dependent on whether the ligand was 17α-hydroxyprogesterone versus ketoconazole. Similar enzyme-specific effects were observed on steady-state kinetics. These observations are most consistent with FMN domain interacting with the proximal P450 surface to allosterically impact P450 ligand binding and metabolism separate from electron delivery. The variety of effects on different P450 enzymes and on the same P450 with different ligands suggests intricate and differential allosteric communication between the P450 active site and its proximal reductase-binding surface.
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Affiliation(s)
- Sarah D Burris-Hiday
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Emily E Scott
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan, USA; Departments of Pharmacology and Biological Chemistry and the Programs in Chemical Biology and Biophysics, University of Michigan, Ann Arbor, Michigan, USA.
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Esteves F, Almeida CMM, Silva S, Saldanha I, Urban P, Rueff J, Pompon D, Truan G, Kranendonk M. Single Mutations in Cytochrome P450 Oxidoreductase Can Alter the Specificity of Human Cytochrome P450 1A2-Mediated Caffeine Metabolism. Biomolecules 2023; 13:1083. [PMID: 37509119 PMCID: PMC10377444 DOI: 10.3390/biom13071083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 06/29/2023] [Accepted: 07/04/2023] [Indexed: 07/30/2023] Open
Abstract
A unique cytochrome P450 (CYP) oxidoreductase (CPR) sustains activities of human microsomal CYPs. Its function requires toggling between a closed conformation enabling electron transfers from NADPH to FAD and then FMN cofactors and open conformations forming complexes and transferring electrons to CYPs. We previously demonstrated that distinct features of the hinge region linking the FAD and FMN domain (FD) modulate conformer poses and their interactions with CYPs. Specific FD residues contribute in a CYP isoform-dependent manner to the recognition and electron transfer mechanisms that are additionally modulated by the structure of CYP-bound substrate. To obtain insights into the underlying mechanisms, we analyzed how hinge region and FD mutations influence CYP1A2-mediated caffeine metabolism. Activities, metabolite profiles, regiospecificity and coupling efficiencies were evaluated in regard to the structural features and molecular dynamics of complexes bearing alternate substrate poses at the CYP active site. Studies reveal that FD variants not only modulate CYP activities but surprisingly the regiospecificity of reactions. Computational approaches evidenced that the considered mutations are generally in close contact with residues at the FD-CYP interface, exhibiting induced fits during complexation and modified dynamics depending on caffeine presence and orientation. It was concluded that dynamic coupling between FD mutations, the complex interface and CYP active site exist consistently with the observed regiospecific alterations.
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Affiliation(s)
- Francisco Esteves
- ToxOmics, NOVA Medical School, Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisbon, Portugal
| | - Cristina M M Almeida
- iMed.UL (Institute for Medicines and Pharmaceutical Sciences, Portugal), Faculty of Pharmacy, University of Lisboa, Av. Prof. Gama Pinto, 2, 1649-003 Lisbon, Portugal
- Laboratory of Bromatology and Water Quality, Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 2, 1649-003 Lisbon, Portugal
| | - Sofia Silva
- Laboratory of Bromatology and Water Quality, Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 2, 1649-003 Lisbon, Portugal
| | - Inês Saldanha
- ToxOmics, NOVA Medical School, Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisbon, Portugal
| | - Philippe Urban
- TBI, Université de Toulouse, CNRS, INRAE, INSA, 135 Avenue de Rangueil, 31077 Toulouse, CEDEX 04, France
| | - José Rueff
- ToxOmics, NOVA Medical School, Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisbon, Portugal
| | - Denis Pompon
- TBI, Université de Toulouse, CNRS, INRAE, INSA, 135 Avenue de Rangueil, 31077 Toulouse, CEDEX 04, France
| | - Gilles Truan
- TBI, Université de Toulouse, CNRS, INRAE, INSA, 135 Avenue de Rangueil, 31077 Toulouse, CEDEX 04, France
| | - Michel Kranendonk
- ToxOmics, NOVA Medical School, Faculdade de Ciências Médicas, NMS|FCM, Universidade NOVA de Lisboa, Campo Mártires da Pátria 130, 1169-056 Lisbon, Portugal
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Nowrouzi B, Rios-Solis L. Redox metabolism for improving whole-cell P450-catalysed terpenoid biosynthesis. Crit Rev Biotechnol 2021; 42:1213-1237. [PMID: 34749553 DOI: 10.1080/07388551.2021.1990210] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The growing preference for producing cytochrome P450-mediated natural products in microbial systems stems from the challenging nature of the organic chemistry approaches. The P450 enzymes are redox-dependent proteins, through which they source electrons from reducing cofactors to drive their activities. Widely researched in biochemistry, most of the previous studies have extensively utilised expensive cell-free assays to reveal mechanistic insights into P450 functionalities in presence of commercial redox partners. However, in the context of microbial bioproduction, the synergic activity of P450- reductase proteins in microbial systems have not been largely investigated. This is mainly due to limited knowledge about their mutual interactions in the context of complex systems. Hence, manipulating the redox potential for natural product synthesis in microbial chassis has been limited. As the potential of redox state as crucial regulator of P450 biocatalysis has been greatly underestimated by the scientific community, in this review, we re-emphasize their pivotal role in modulating the in vivo P450 activity through affecting the product profile and yield. Particularly, we discuss the applications of widely used in vivo redox engineering methodologies for natural product synthesis to provide further suggestions for patterning on P450-based terpenoids production in microbial platforms.
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Affiliation(s)
- Behnaz Nowrouzi
- Institute for Bioengineering, School of Engineering, The University of Edinburgh, Edinburgh, UK.,Centre for Synthetic and Systems Biology (SynthSys), The University of Edinburgh, Edinburgh, UK
| | - Leonardo Rios-Solis
- Institute for Bioengineering, School of Engineering, The University of Edinburgh, Edinburgh, UK.,Centre for Synthetic and Systems Biology (SynthSys), The University of Edinburgh, Edinburgh, UK
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Esteves F, Urban P, Rueff J, Truan G, Kranendonk M. Interaction Modes of Microsomal Cytochrome P450s with Its Reductase and the Role of Substrate Binding. Int J Mol Sci 2020; 21:E6669. [PMID: 32933097 PMCID: PMC7555755 DOI: 10.3390/ijms21186669] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/07/2020] [Accepted: 09/10/2020] [Indexed: 02/07/2023] Open
Abstract
The activity of microsomal cytochromes P450 (CYP) is strictly dependent on the supply of electrons provided by NADPH cytochrome P450 oxidoreductase (CPR). The variant nature of the isoform-specific proximal interface of microsomal CYPs implies that the interacting interface between the two proteins is degenerated. Recently, we demonstrated that specific CPR mutations in the FMN-domain (FD) may induce a gain in activity for a specific CYP isoform. In the current report, we confirm the CYP isoform dependence of CPR's degenerated binding by demonstrating that the effect of four of the formerly studied FD mutants are indeed exclusive of a specific CYP isoform, as verified by cytochrome c inhibition studies. Moreover, the nature of CYP's substrate seems to have a modulating role in the CPR:CYP interaction. In silico molecular dynamics simulations of the FD evidence that mutations induces very subtle structural alterations, influencing the characteristics of residues formerly implicated in the CPR:CYP interaction or in positioning of the FMN moiety. CPR seems therefore to be able to form effective interaction complexes with its structural diverse partners via a combination of specific structural features of the FD, which are functional in a CYP isoform dependent manner, and dependent on the substrate bound.
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Affiliation(s)
- Francisco Esteves
- Center for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Human Toxicology, NOVA Medical School/Faculty of Medical Sciences, Universidade NOVA de Lisboa, 1169-056 Lisbon, Portugal;
| | - Philippe Urban
- TBI, Université de Toulouse, CNRS, INRAE, INSA, CEDEX 04, 31077 Toulouse, France; (P.U.); (G.T.)
| | - José Rueff
- Center for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Human Toxicology, NOVA Medical School/Faculty of Medical Sciences, Universidade NOVA de Lisboa, 1169-056 Lisbon, Portugal;
| | - Gilles Truan
- TBI, Université de Toulouse, CNRS, INRAE, INSA, CEDEX 04, 31077 Toulouse, France; (P.U.); (G.T.)
| | - Michel Kranendonk
- Center for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Human Toxicology, NOVA Medical School/Faculty of Medical Sciences, Universidade NOVA de Lisboa, 1169-056 Lisbon, Portugal;
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Esteves F, Campelo D, Gomes BC, Urban P, Bozonnet S, Lautier T, Rueff J, Truan G, Kranendonk M. The Role of the FMN-Domain of Human Cytochrome P450 Oxidoreductase in Its Promiscuous Interactions With Structurally Diverse Redox Partners. Front Pharmacol 2020; 11:299. [PMID: 32256365 PMCID: PMC7094780 DOI: 10.3389/fphar.2020.00299] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 02/28/2020] [Indexed: 12/18/2022] Open
Abstract
NADPH cytochrome P450 oxidoreductase (CPR) is the obligatory electron supplier that sustains the activity of microsomal cytochrome P450 (CYP) enzymes. The variant nature of the isoform-specific proximal interface of microsomal CYPs indicates that CPR is capable of multiple degenerated interactions with CYPs for electron transfer, through different binding mechanisms, and which are still not well-understood. Recently, we showed that CPR dynamics allows formation of open conformations that can be sampled by its structurally diverse redox partners in a CYP-isoform dependent manner. To further investigate the role of the CPR FMN-domain in effective binding of CPR to its diverse acceptors and to clarify the underlying molecular mechanisms, five different CPR-FMN-domain random mutant libraries were created. These libraries were screened for mutants with increased activity when combined with specific CYP-isoforms. Seven CPR-FMN-domain mutants were identified, supporting a gain in activity for CYP1A2 (P117H, G144C, A229T), 2A6 (P117L/L125V, G175D, H183Y), or 3A4 (N151D). Effects were evaluated using extended enzyme kinetic analysis, cytochrome b 5 competition, ionic strength effect on CYP activity, and structural analysis. Mutated residues were located either in or adjacent to several acidic amino acid stretches - formerly indicated to be involved in CPR:CYP interactions - or close to two tyrosine residues suggested to be involved in FMN binding. Several of the identified positions co-localize with mutations found in naturally occurring CPR variants that were previously shown to cause CYP-isoform-dependent effects. The mutations do not seem to significantly alter the geometry of the FMN-domain but are likely to cause very subtle alterations leading to improved interaction with a specific CYP. Overall, these data suggest that CYPs interact with CPR using an isoform specific combination of several binding motifs of the FMN-domain.
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Affiliation(s)
- Francisco Esteves
- Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Huma Toxicology, NOVA Medical School, Faculty of Medical Sciences, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Diana Campelo
- Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Huma Toxicology, NOVA Medical School, Faculty of Medical Sciences, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Bruno Costa Gomes
- Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Huma Toxicology, NOVA Medical School, Faculty of Medical Sciences, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Philippe Urban
- Centre National de la Recherche, Scientifique, Institut National de la Recherche Agronomique, Institut National des Sciences Appliqu es de Toulouse, Toulouse Biotechnology Institute, Universit de Toulouse, Toulouse, France
| | - Sophie Bozonnet
- Centre National de la Recherche, Scientifique, Institut National de la Recherche Agronomique, Institut National des Sciences Appliqu es de Toulouse, Toulouse Biotechnology Institute, Universit de Toulouse, Toulouse, France
| | - Thomas Lautier
- Centre National de la Recherche, Scientifique, Institut National de la Recherche Agronomique, Institut National des Sciences Appliqu es de Toulouse, Toulouse Biotechnology Institute, Universit de Toulouse, Toulouse, France
| | - José Rueff
- Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Huma Toxicology, NOVA Medical School, Faculty of Medical Sciences, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Gilles Truan
- Centre National de la Recherche, Scientifique, Institut National de la Recherche Agronomique, Institut National des Sciences Appliqu es de Toulouse, Toulouse Biotechnology Institute, Universit de Toulouse, Toulouse, France
| | - Michel Kranendonk
- Centre for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Huma Toxicology, NOVA Medical School, Faculty of Medical Sciences, Universidade NOVA de Lisboa, Lisbon, Portugal
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Biochemical and structural insights into the cytochrome P450 reductase from Candida tropicalis. Sci Rep 2019; 9:20088. [PMID: 31882753 PMCID: PMC6934812 DOI: 10.1038/s41598-019-56516-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/04/2019] [Indexed: 12/15/2022] Open
Abstract
Cytochrome P450 reductases (CPRs) are diflavin oxidoreductases that supply electrons to type II cytochrome P450 monooxygenases (CYPs). In addition, it can also reduce other proteins and molecules, including cytochrome c, ferricyanide, and different drugs. Although various CPRs have been functionally and structurally characterized, the overall mechanism and its interaction with different redox acceptors remain elusive. One of the main problems regarding electron transfer between CPRs and CYPs is the so-called “uncoupling”, whereby NAD(P)H derived electrons are lost due to the reduced intermediates’ (FAD and FMN of CPR) interaction with molecular oxygen. Additionally, the decay of the iron-oxygen complex of the CYP can also contribute to loss of reducing equivalents during an unproductive reaction cycle. This phenomenon generates reactive oxygen species (ROS), leading to an inefficient reaction. Here, we present the study of the CPR from Candida tropicalis (CtCPR) lacking the hydrophobic N-terminal part (Δ2–22). The enzyme supports the reduction of cytochrome c and ferricyanide, with an estimated 30% uncoupling during the reactions with cytochrome c. The ROS produced was not influenced by different physicochemical conditions (ionic strength, pH, temperature). The X-ray structures of the enzyme were solved with and without its cofactor, NADPH. Both CtCPR structures exhibited the closed conformation. Comparison with the different solved structures revealed an intricate ionic network responsible for the regulation of the open/closed movement of CtCPR.
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Ebrecht AC, van der Bergh N, Harrison STL, Smit MS, Sewell BT, Opperman DJ. Biochemical and structural insights into the cytochrome P450 reductase from Candida tropicalis. Sci Rep 2019; 9:20088. [PMID: 31882753 DOI: 10.1101/711317] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/04/2019] [Indexed: 05/28/2023] Open
Abstract
Cytochrome P450 reductases (CPRs) are diflavin oxidoreductases that supply electrons to type II cytochrome P450 monooxygenases (CYPs). In addition, it can also reduce other proteins and molecules, including cytochrome c, ferricyanide, and different drugs. Although various CPRs have been functionally and structurally characterized, the overall mechanism and its interaction with different redox acceptors remain elusive. One of the main problems regarding electron transfer between CPRs and CYPs is the so-called "uncoupling", whereby NAD(P)H derived electrons are lost due to the reduced intermediates' (FAD and FMN of CPR) interaction with molecular oxygen. Additionally, the decay of the iron-oxygen complex of the CYP can also contribute to loss of reducing equivalents during an unproductive reaction cycle. This phenomenon generates reactive oxygen species (ROS), leading to an inefficient reaction. Here, we present the study of the CPR from Candida tropicalis (CtCPR) lacking the hydrophobic N-terminal part (Δ2-22). The enzyme supports the reduction of cytochrome c and ferricyanide, with an estimated 30% uncoupling during the reactions with cytochrome c. The ROS produced was not influenced by different physicochemical conditions (ionic strength, pH, temperature). The X-ray structures of the enzyme were solved with and without its cofactor, NADPH. Both CtCPR structures exhibited the closed conformation. Comparison with the different solved structures revealed an intricate ionic network responsible for the regulation of the open/closed movement of CtCPR.
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Affiliation(s)
- Ana C Ebrecht
- Department of Microbial, Biochemical, and Food Biotechnology, University of the Free State, Bloemfontein, 9301, South Africa
- South African DST-NRF Centre of Excellence in Catalysis (c*Change), University of Cape Town, Private Bag, Rondebosch, Cape Town, 7701, South Africa
| | - Naadia van der Bergh
- Centre for Bioprocess Engineering Research (CeBER), Department of Chemical Engineering, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
- South African DST-NRF Centre of Excellence in Catalysis (c*Change), University of Cape Town, Private Bag, Rondebosch, Cape Town, 7701, South Africa
| | - Susan T L Harrison
- Centre for Bioprocess Engineering Research (CeBER), Department of Chemical Engineering, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
- South African DST-NRF Centre of Excellence in Catalysis (c*Change), University of Cape Town, Private Bag, Rondebosch, Cape Town, 7701, South Africa
| | - Martha S Smit
- Department of Microbial, Biochemical, and Food Biotechnology, University of the Free State, Bloemfontein, 9301, South Africa
- South African DST-NRF Centre of Excellence in Catalysis (c*Change), University of Cape Town, Private Bag, Rondebosch, Cape Town, 7701, South Africa
| | - B Trevor Sewell
- Structural Biology Research Unit, Department of Integrative Biomedical Sciences, Institute for Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, 7700, South Africa.
| | - Diederik J Opperman
- Department of Microbial, Biochemical, and Food Biotechnology, University of the Free State, Bloemfontein, 9301, South Africa.
- South African DST-NRF Centre of Excellence in Catalysis (c*Change), University of Cape Town, Private Bag, Rondebosch, Cape Town, 7701, South Africa.
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10
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Strohmaier SJ, Huang W, Baek JM, Hunter DJB, Gillam EMJ. Rational evolution of the cofactor-binding site of cytochrome P450 reductase yields variants with increased activity towards specific cytochrome P450 enzymes. FEBS J 2019; 286:4473-4493. [PMID: 31276316 DOI: 10.1111/febs.14982] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 04/30/2019] [Accepted: 07/02/2019] [Indexed: 12/22/2022]
Abstract
NADPH-cytochrome P450 reductase (CPR) is the natural redox partner of microsomal cytochrome P450 enzymes. CPR shows a stringent preference for NADPH over the less expensive cofactor, NADH, economically limiting its use as a biocatalyst. The complexity of cofactor-linked CPR protein dynamics and the incomplete understanding of the interaction of CPR with both cofactors and electron acceptors present challenges for the successful rational engineering of a CPR with enhanced activity with NADH. Here, we report a rational evolution approach to enhance the activity of CPR with NADH, in which mutations were introduced into the NADPH-binding flavin adenine dinucleotide (FAD) domain. Multiple CPR mutants that used NADH more effectively than the wild-type CPR in the reduction of the surrogate electron acceptor, cytochrome c were found. However, most were inactive in supporting P450 activity, arguing against the use of cytochrome c as a surrogate electron acceptor. Unexpectedly, several mutants showed significantly improved activity towards CYP2C9 (mutant 1-014) and/or CYP2A6 (mutants 1-014, 1-015, 1-053 and 1-077) using NADPH, even though the mutations were introduced at locations remote from the putative CPR-P450 interaction face. Therefore, mutations at sites in the FAD domain of CPR may be promising future engineering targets to enhance P450-mediated substrate turnover. ENZYMES: NADPH-cytochrome P450 reductase - EC 1.6.2.4; cytochrome P450 - EC 1.14.14.1.
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Affiliation(s)
- Silja J Strohmaier
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Weiliang Huang
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Jong-Min Baek
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Dominic J B Hunter
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Elizabeth M J Gillam
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
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11
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Mahajan M, Ravula T, Prade E, Anantharamaiah GM, Ramamoorthy A. Probing membrane enhanced protein-protein interactions in a minimal redox complex of cytochrome-P450 and P450-reductase. Chem Commun (Camb) 2019; 55:5777-5780. [PMID: 31041432 PMCID: PMC7467500 DOI: 10.1039/c9cc01630a] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Investigating the interplay in a minimal redox complex of cytochrome-P450 and its reductase is crucial for understanding cytochrome-P450's enzymatic activity. Probing the hotspots of dynamic structural interactions using NMR revealed the engagement of loop residues from P450-reductase to be responsible for the enhanced affinity of CYP450 towards its obligate redox partner.
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Affiliation(s)
- Mukesh Mahajan
- Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, MI 48109-1055, USA.
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12
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Xia C, Shen AL, Duangkaew P, Kotewong R, Rongnoparut P, Feix J, Kim JJP. Structural and Functional Studies of the Membrane-Binding Domain of NADPH-Cytochrome P450 Oxidoreductase. Biochemistry 2019; 58:2408-2418. [PMID: 31009206 PMCID: PMC6873807 DOI: 10.1021/acs.biochem.9b00130] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
NADPH-cytochrome P450 oxidoreductase (CYPOR), the essential flavoprotein of the microsomal cytochrome P450 monooxygenase system, is anchored in the phospholipid bilayer by its amino-terminal membrane-binding domain (MBD), which is necessary for efficient electron transfer to cytochrome P450. Although crystallographic and kinetic studies have established the structure of the soluble catalytic domain and the role of conformational motions in the control of electron transfer, the role of the MBD is largely unknown. We examined the role of the MBD in P450 catalysis through studies of amino-terminal deletion mutants and site-directed spin labeling. We show that the MBD spans the membrane and present a model for the orientation of CYPOR on the membrane capable of forming a complex with cytochrome P450. EPR power saturation measurements of CYPOR mutants in liposomes containing a lipid/Ni(II) chelate identified a region of the soluble domain interacting with the membrane. The deletion of more than 29 residues from the N-terminus of CYPOR decreases cytochrome P450 activity concomitant with alterations in electrophoretic mobility and an increased resistance to protease digestion. The altered kinetic properties of these mutants are consistent with electron transfer through random collisions rather than via formation of a stable CYPOR-P450 complex. Purified MBD binds weakly to cytochrome P450, suggesting that other interactions are also required for CYPOR-P450 complex formation. We propose that the MBD and flexible tether region of CYPOR, residues 51-63, play an important role in facilitating the movement of the soluble domain relative to the membrane and in promoting multiple orientations that permit specific interactions of CYPOR with its varied partners.
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Affiliation(s)
- Chuanwu Xia
- Department of Biochemistry , Medical College of Wisconsin , Milwaukee , Wisconsin 53226 , United States
| | - Anna L Shen
- McArdle Laboratory for Cancer Research , University of Wisconsin-Madison , Madison , Wisconsin 53706 , United States
| | - Panida Duangkaew
- Department of Biochemistry , Medical College of Wisconsin , Milwaukee , Wisconsin 53226 , United States
- Department of Biochemistry, Faculty of Science , Mahidol University , Bangkok 10400 , Thailand
| | - Rattanawadee Kotewong
- Department of Biochemistry , Medical College of Wisconsin , Milwaukee , Wisconsin 53226 , United States
- Department of Biochemistry, Faculty of Science , Mahidol University , Bangkok 10400 , Thailand
| | - Pornpimol Rongnoparut
- Department of Biochemistry, Faculty of Science , Mahidol University , Bangkok 10400 , Thailand
| | - Jimmy Feix
- Department of Biophysics , Medical College of Wisconsin , Milwaukee , Wisconsin 53226 , United States
| | - Jung-Ja P Kim
- Department of Biochemistry , Medical College of Wisconsin , Milwaukee , Wisconsin 53226 , United States
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13
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Hedison TM, Scrutton NS. Tripping the light fantastic in membrane redox biology: linking dynamic structures to function in ER electron transfer chains. FEBS J 2019; 286:2004-2017. [PMID: 30657259 PMCID: PMC6563164 DOI: 10.1111/febs.14757] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/16/2018] [Accepted: 01/15/2019] [Indexed: 12/19/2022]
Abstract
How the dynamics of proteins assist catalysis is a contemporary issue in enzymology. In particular, this holds true for membrane‐bound enzymes, where multiple structural, spectroscopic and biochemical approaches are needed to build up a comprehensive picture of how dynamics influence enzyme reaction cycles. Of note are the recent studies of cytochrome P450 reductases (CPR)–P450 (CYP) endoplasmic reticulum redox chains, showing the relationship between dynamics and electron flow through flavin and haem redox centres and the impact this has on monooxygenation chemistry. These studies have led to deeper understanding of mechanisms of electron flow, including the timing and control of electron delivery to protein‐bound cofactors needed to facilitate CYP‐catalysed reactions. Individual and multiple component systems have been used to capture biochemical behaviour and these have led to the emergence of more integrated models of catalysis. Crucially, the effects of membrane environment and composition on reaction cycle chemistry have also been probed, including effects on coenzyme binding/release, thermodynamic control of electron transfer, conformational coupling between partner proteins and vectorial versus ‘off pathway’ electron flow. Here, we review these studies and discuss evidence for the emergence of dynamic structural models of electron flow along human microsomal CPR–P450 redox chains.
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Affiliation(s)
- Tobias M Hedison
- Manchester Institute of Biotechnology and School of Chemistry, University of Manchester, UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology and School of Chemistry, University of Manchester, UK
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14
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Campelo D, Esteves F, Brito Palma B, Costa Gomes B, Rueff J, Lautier T, Urban P, Truan G, Kranendonk M. Probing the Role of the Hinge Segment of Cytochrome P450 Oxidoreductase in the Interaction with Cytochrome P450. Int J Mol Sci 2018; 19:ijms19123914. [PMID: 30563285 PMCID: PMC6321550 DOI: 10.3390/ijms19123914] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/04/2018] [Accepted: 12/05/2018] [Indexed: 01/08/2023] Open
Abstract
NADPH-cytochrome P450 reductase (CPR) is the unique redox partner of microsomal cytochrome P450s (CYPs). CPR exists in a conformational equilibrium between open and closed conformations throughout its electron transfer (ET) function. Previously, we have shown that electrostatic and flexibility properties of the hinge segment of CPR are critical for ET. Three mutants of human CPR were studied (S243P, I245P and R246A) and combined with representative human drug-metabolizing CYPs (isoforms 1A2, 2A6 and 3A4). To probe the effect of these hinge mutations different experimental approaches were employed: CYP bioactivation capacity of pre-carcinogens, enzyme kinetic analysis, and effect of the ionic strength and cytochrome b5 (CYB5) on CYP activity. The hinge mutations influenced the bioactivation of pre-carcinogens, which seemed CYP isoform and substrate dependent. The deviations of Michaelis-Menten kinetic parameters uncovered tend to confirm this discrepancy, which was confirmed by CYP and hinge mutant specific salt/activity profiles. CPR/CYB5 competition experiments indicated a less important role of affinity in CPR/CYP interaction. Overall, our data suggest that the highly flexible hinge of CPR is responsible for the existence of a conformational aggregate of different open CPR conformers enabling ET-interaction with structural varied redox partners.
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Affiliation(s)
- Diana Campelo
- Center for Toxicogenomics and Human Health, Genetics, Oncology and Human Toxicology, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, 1150-082 Lisbon, Portugal.
| | - Francisco Esteves
- Center for Toxicogenomics and Human Health, Genetics, Oncology and Human Toxicology, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, 1150-082 Lisbon, Portugal.
| | - Bernardo Brito Palma
- Center for Toxicogenomics and Human Health, Genetics, Oncology and Human Toxicology, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, 1150-082 Lisbon, Portugal.
| | - Bruno Costa Gomes
- Center for Toxicogenomics and Human Health, Genetics, Oncology and Human Toxicology, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, 1150-082 Lisbon, Portugal.
| | - José Rueff
- Center for Toxicogenomics and Human Health, Genetics, Oncology and Human Toxicology, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, 1150-082 Lisbon, Portugal.
| | - Thomas Lautier
- LISBP, Université de Toulouse, CNRS, INRA, INSA, 31077 Toulouse CEDEX 04, France.
| | - Philippe Urban
- LISBP, Université de Toulouse, CNRS, INRA, INSA, 31077 Toulouse CEDEX 04, France.
| | - Gilles Truan
- LISBP, Université de Toulouse, CNRS, INRA, INSA, 31077 Toulouse CEDEX 04, France.
| | - Michel Kranendonk
- Center for Toxicogenomics and Human Health, Genetics, Oncology and Human Toxicology, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, 1150-082 Lisbon, Portugal.
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15
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Arendse LB, Blackburn JM. Effects of polymorphic variation on the thermostability of heterogenous populations of CYP3A4 and CYP2C9 enzymes in solution. Sci Rep 2018; 8:11876. [PMID: 30089838 PMCID: PMC6082832 DOI: 10.1038/s41598-018-30195-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 07/23/2018] [Indexed: 12/11/2022] Open
Abstract
The effect of non-synonymous single nucleotide polymorphisms (SNPs) on cytochrome P450 (CYP450) drug metabolism is currently poorly understood due to the large number of polymorphisms, the diversity of potential substrates and the complexity of CYP450 function. Previously we carried out in silico studies to explore the effect of SNPs on CYP450 function, using in silico calculations to predict the effect of mutations on protein stability. Here we have determined the effect of eight CYP3A4 and seven CYP2C9 SNPs on the thermostability of proteins in solution to test these predictions. Thermostability assays revealed distinct CYP450 sub-populations with only 65–70% of wild-type CYP3A4 and CYP2C9 susceptible to rapid heat-induced P450 to P420 conversion. CYP3A4 mutations G56D, P218R, S222P, I223R, L373F and M445T and CYP2C9 mutations V76M, I359L and I359T were destabilising, increasing the proportion of protein sensitive to the rapid heat-induced P450 to P420 conversion and/or reducing the half-life of this conversion. CYP2C9 Q214L was the only stabilising mutation. These results corresponded well with the in silico protein stability calculations, confirming the value of these predictions and together suggest that the changes in thermostability result from destabilisation/stabilisation of the protein fold, changes in the haem-binding environment or effects on oligomer formation/conformation.
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Affiliation(s)
- Lauren B Arendse
- Institute for Infectious Disease & Molecular Medicine, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Observatory, 7925, South Africa
| | - Jonathan M Blackburn
- Institute for Infectious Disease & Molecular Medicine, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, University of Cape Town, Observatory, 7925, South Africa.
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16
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Askenasy I, Murray DT, Andrews RM, Uversky VN, He H, Stroupe ME. Structure-Function Relationships in the Oligomeric NADPH-Dependent Assimilatory Sulfite Reductase. Biochemistry 2018; 57:3764-3772. [PMID: 29787249 DOI: 10.1021/acs.biochem.8b00446] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The central step in the assimilation of sulfur is a six-electron reduction of sulfite to sulfide, catalyzed by the oxidoreductase NADPH-dependent assimilatory sulfite reductase (SiR). SiR is composed of two subunits. One is a multidomain flavin binding reductase (SiRFP) and the other an iron-containing oxidase (SiRHP). Both enzymes are primarily globular, as expected from their functions as redox enzymes. Consequently, we know a fair amount about their structures but not how they assemble. Curiously, both structures have conspicuous regions that are structurally undefined, leaving questions about their functions and raising the possibility that they are critical in forming the larger complex. Here, we used ultraviolet-visible and circular dichroism spectroscopy, isothermal titration calorimetry, proteolytic sensitivity tests, electrospray ionization mass spectrometry, and activity assays to explore the effect of altering specific amino acids in SiRFP on their function in the holoenzyme complex. Additionally, we used computational analysis to predict the propensity for intrinsic disorder within both subunits and found that SiRHP's N-terminus is predicted to have properties associated with intrinsic disorder. Both proteins also contained internal regions with properties indicative of intrinsic disorder. We showed that SiRHP's N-terminal disordered region is critical for complex formation. Together with our analysis of SiRFP amino acid variants, we show how molecular interactions outside the core of each SiR globular enzyme drive complex assembly of this prototypical oxidoreductase.
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Affiliation(s)
| | | | | | - Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine , University of South Florida , Tampa , Florida 33612 , United States.,Institute for Biological Instrumentation of the Russian Academy of Sciences , Institutskaya strasse, 7 , Pushchino , Moscow Region 142290 , Russia
| | - Huan He
- Translational Science Laboratory, College of Medicine , Florida State University , Tallahassee , Florida 32306 , United States
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17
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Šrejber M, Navrátilová V, Paloncýová M, Bazgier V, Berka K, Anzenbacher P, Otyepka M. Membrane-attached mammalian cytochromes P450: An overview of the membrane's effects on structure, drug binding, and interactions with redox partners. J Inorg Biochem 2018; 183:117-136. [DOI: 10.1016/j.jinorgbio.2018.03.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 02/16/2018] [Accepted: 03/01/2018] [Indexed: 01/08/2023]
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18
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Freeman SL, Martel A, Devos JM, Basran J, Raven EL, Roberts GCK. Solution structure of the cytochrome P450 reductase-cytochrome c complex determined by neutron scattering. J Biol Chem 2018; 293:5210-5219. [PMID: 29475945 PMCID: PMC5892573 DOI: 10.1074/jbc.ra118.001941] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 02/20/2018] [Indexed: 01/22/2023] Open
Abstract
Electron transfer in all living organisms critically relies on formation of complexes between the proteins involved. The function of these complexes requires specificity of the interaction to allow for selective electron transfer but also a fast turnover of the complex, and they are therefore often transient in nature, making them challenging to study. Here, using small-angle neutron scattering with contrast matching with deuterated protein, we report the solution structure of the electron transfer complex between cytochrome P450 reductase (CPR) and its electron transfer partner cytochrome c This is the first reported solution structure of a complex between CPR and an electron transfer partner. The structure shows that the interprotein interface includes residues from both the FMN- and FAD-binding domains of CPR. In addition, the FMN is close to the heme of cytochrome c but distant from the FAD, indicating that domain movement is required between the electron transfer steps in the catalytic cycle of CPR. In summary, our results reveal key details of the CPR catalytic mechanism, including interactions of two domains of the reductase with cytochrome c and motions of these domains relative to one another. These findings shed light on interprotein electron transfer in this system and illustrate a powerful approach for studying solution structures of protein-protein complexes.
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Affiliation(s)
- Samuel L Freeman
- From the Departments of Chemistry and.,Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble, France.,Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, United Kingdom and
| | - Anne Martel
- Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble, France
| | - Juliette M Devos
- Institut Laue-Langevin, 71 avenue des Martyrs, 38042 Grenoble, France
| | - Jaswir Basran
- From the Departments of Chemistry and.,Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, United Kingdom and.,Molecular and Cell Biology and
| | - Emma L Raven
- From the Departments of Chemistry and .,Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, United Kingdom and
| | - Gordon C K Roberts
- Leicester Institute of Structural and Chemical Biology, University of Leicester, Leicester LE1 7RH, United Kingdom and .,Molecular and Cell Biology and
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19
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Campelo D, Lautier T, Urban P, Esteves F, Bozonnet S, Truan G, Kranendonk M. The Hinge Segment of Human NADPH-Cytochrome P450 Reductase in Conformational Switching: The Critical Role of Ionic Strength. Front Pharmacol 2017; 8:755. [PMID: 29163152 PMCID: PMC5670117 DOI: 10.3389/fphar.2017.00755] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 10/04/2017] [Indexed: 11/18/2022] Open
Abstract
NADPH-cytochrome P450 reductase (CPR) is a redox partner of microsomal cytochromes P450 and is a prototype of the diflavin reductase family. CPR contains 3 distinct functional domains: a FMN-binding domain (acceptor reduction), a linker (hinge), and a connecting/FAD domain (NADPH oxidation). It has been demonstrated that the mechanism of CPR exhibits an important step in which it switches from a compact, closed conformation (locked state) to an ensemble of open conformations (unlocked state), the latter enabling electron transfer to redox partners. The conformational equilibrium between the locked and unlocked states has been shown to be highly dependent on ionic strength, reinforcing the hypothesis of the presence of critical salt interactions at the interface between the FMN and connecting FAD domains. Here we show that specific residues of the hinge segment are important in the control of the conformational equilibrium of CPR. We constructed six single mutants and two double mutants of the human CPR, targeting residues G240, S243, I245 and R246 of the hinge segment, with the aim of modifying the flexibility or the potential ionic interactions of the hinge segment. We measured the reduction of cytochrome c at various salt concentrations of these 8 mutants, either in the soluble or membrane-bound form of human CPR. All mutants were found capable of reducing cytochrome c yet with different efficiency and their maximal rates of cytochrome c reduction were shifted to lower salt concentration. In particular, residue R246 seems to play a key role in a salt bridge network present at the interface of the hinge and the connecting domain. Interestingly, the effects of mutations, although similar, demonstrated specific differences when present in the soluble or membrane-bound context. Our results demonstrate that the electrostatic and flexibility properties of the hinge segment are critical for electron transfer from CPR to its redox partners.
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Affiliation(s)
- Diana Campelo
- Center for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Human Toxicology, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Thomas Lautier
- LISBP, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Philippe Urban
- LISBP, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Francisco Esteves
- Center for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Human Toxicology, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Sophie Bozonnet
- LISBP, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Gilles Truan
- LISBP, Université de Toulouse, CNRS, INRA, INSA, Toulouse, France
| | - Michel Kranendonk
- Center for Toxicogenomics and Human Health (ToxOmics), Genetics, Oncology and Human Toxicology, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
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20
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Lemaire B, Karchner SI, Goldstone JV, Lamb DC, Drazen JC, Rees JF, Hahn ME, Stegeman JJ. Molecular adaptation to high pressure in cytochrome P450 1A and aryl hydrocarbon receptor systems of the deep-sea fish Coryphaenoides armatus. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1866:155-165. [PMID: 28694077 DOI: 10.1016/j.bbapap.2017.06.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/27/2017] [Accepted: 06/28/2017] [Indexed: 01/19/2023]
Abstract
Limited knowledge of the molecular evolution of deep-sea fish proteomes so far suggests that a few widespread residue substitutions in cytosolic proteins binding hydrophilic ligands contribute to resistance to the effects of high hydrostatic pressure (HP). Structure-function studies with additional protein systems, including membrane bound proteins, are essential to provide a more general picture of adaptation in these extremophiles. We explored molecular features of HP adaptation in proteins binding hydrophobic ligands, either in lipid bilayers (cytochrome P450 1A - CYP1A) or in the cytosol (the aryl hydrocarbon receptor - AHR), and their partners P450 oxidoreductase (POR) and AHR nuclear translocator (ARNT), respectively. Cloning studies identified the full-length coding sequence of AHR, CYP1A and POR, and a partial sequence of ARNT from Coryphaenoides armatus, an abyssal gadiform fish thriving down to 5000m depth. Inferred protein sequences were aligned with many non-deep-sea homologs to identify unique amino acid substitutions of possible relevance in HP adaptation. Positionally unique substitutions of various physicochemical properties were found in all four proteins, usually at sites of strong-to-absolute residue conservation. Some were in domains deemed important for protein-protein interaction or ligand binding. In addition, some involved removal or addition of beta-branched residues; local modifications of beta-branched residue patterns could be important to HP adaptation. In silico predictions further suggested that some unique substitutions might substantially modulate the flexibility of the polypeptide segment in which they are found. Repetitive motifs unique to the abyssal fish AHR were predicted to be rich in glycosylation sites, suggesting that post-translational changes could be involved in adaptation as well. Recombinant CYP1A and AHR showed functional properties (spectral characteristics, catalytic activity and ligand binding) that demonstrate proper folding at 1atm, indicating that they could be used as deep-sea fish protein models to further evaluate protein function under pressure. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone".
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Affiliation(s)
- Benjamin Lemaire
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02540, USA; Institut des Sciences de la Vie, Université Catholique de Louvain, Louvain-la-Neuve 1348, Belgium
| | - Sibel I Karchner
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02540, USA; Boston University Superfund Research Program, Boston University School of Public Health, Boston, MA, USA
| | - Jared V Goldstone
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02540, USA; Boston University Superfund Research Program, Boston University School of Public Health, Boston, MA, USA
| | - David C Lamb
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02540, USA; Institute of Life Science, Medical School, Swansea University, Singleton Park, Swansea SA2 8PP, UK
| | - Jeffrey C Drazen
- Department of Oceanography, University of Hawaii, Honolulu, HI 96822, USA
| | - Jean François Rees
- Institut des Sciences de la Vie, Université Catholique de Louvain, Louvain-la-Neuve 1348, Belgium
| | - Mark E Hahn
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02540, USA; Boston University Superfund Research Program, Boston University School of Public Health, Boston, MA, USA
| | - John J Stegeman
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02540, USA; Boston University Superfund Research Program, Boston University School of Public Health, Boston, MA, USA.
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21
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Ducharme J, Auclair K. Use of bioconjugation with cytochrome P450 enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017. [PMID: 28625736 DOI: 10.1016/j.bbapap.2017.06.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Bioconjugation, defined as chemical modification of biomolecules, is widely employed in biological and biophysical studies. It can expand functional diversity and enable applications ranging from biocatalysis, biosensing and even therapy. This review summarizes how chemical modifications of cytochrome P450 enzymes (P450s or CYPs) have contributed to improving our understanding of these enzymes. Genetic modifications of P450s have also proven very useful but are not covered in this review. Bioconjugation has served to gain structural information and investigate the mechanism of P450s via photoaffinity labeling, mechanism-based inhibition (MBI) and fluorescence studies. P450 surface acetylation and protein cross-linking have contributed to the investigation of protein complexes formation involving P450 and its redox partner or other P450 enzymes. Finally, covalent immobilization on polymer surfaces or electrodes has benefited the areas of biocatalysis and biosensor design. This article is part of a Special Issue entitled: Cytochrome P450 biodiversity and biotechnology, edited by Erika Plettner, Gianfranco Gilardi, Luet Wong, Vlada Urlacher, Jared Goldstone.
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Affiliation(s)
- Julie Ducharme
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Karine Auclair
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada.
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22
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Milhim M, Gerber A, Neunzig J, Hannemann F, Bernhardt R. A Novel NADPH-dependent flavoprotein reductase from Bacillus megaterium acts as an efficient cytochrome P450 reductase. J Biotechnol 2016; 231:83-94. [DOI: 10.1016/j.jbiotec.2016.05.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 05/20/2016] [Accepted: 05/25/2016] [Indexed: 02/02/2023]
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23
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Manoj KM, Parashar A, Gade SK, Venkatachalam A. Functioning of Microsomal Cytochrome P450s: Murburn Concept Explains the Metabolism of Xenobiotics in Hepatocytes. Front Pharmacol 2016; 7:161. [PMID: 27445805 PMCID: PMC4918403 DOI: 10.3389/fphar.2016.00161] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 05/31/2016] [Indexed: 11/13/2022] Open
Abstract
Using oxygen and NADPH, the redox enzymes cytochrome P450 (CYP) and its reductase (CPR) work in tandem to carry out the phase I metabolism of a vast majority of drugs and xenobiotics. As per the erstwhile understanding of the catalytic cycle, binding of the substrate to CYP's heme distal pocket allows CPR to pump electrons through a CPR-CYP complex. In turn, this trigger (a thermodynamic push of electrons) leads to the activation of oxygen at CYP's heme-center, to give Compound I, a two-electron deficient enzyme reactive intermediate. The formation of diffusible radicals and reactive oxygen species (DROS, hitherto considered an undesired facet of the system) was attributed to the heme-center. Recently, we had challenged these perceptions and proposed the murburn ("mured burning" or "mild unrestricted burning") concept to explain heme enzymes' catalytic mechanism, electron-transfer phenomena and the regulation of redox equivalents' consumption. Murburn concept incorporates a one-electron paradigm, advocating obligatory roles for DROS. The new understanding does not call for high-affinity substrate-binding at the heme distal pocket of the CYP (the first and the most crucial step of the erstwhile paradigm) or CYP-CPR protein-protein complexations (the operational backbone of the erstwhile cycle). Herein, the dynamics of reduced nicotinamide nucleotides' consumption, peroxide formation and depletion, product(s) formation, etc. was investigated with various controls, by altering reaction variables, environments and through the incorporation of diverse molecular probes. In several CYP systems, control reactions lacking the specific substrate showed comparable or higher peroxide in milieu, thereby discrediting the foundations of the erstwhile hypothesis. The profiles obtained by altering CYP:CPR ratios and the profound inhibitions observed upon the incorporation of catalytic amounts of horseradish peroxidase confirm the obligatory roles of DROS in milieu, ratifying murburn as the operative concept. The mechanism of uncoupling (peroxide/water formation) was found to be dependent on multiple one and two electron equilibriums amongst the reaction components. The investigation explains the evolutionary implications of xenobiotic metabolism, confirms the obligatory role of diffusible reactive species in routine redox metabolism within liver microsomes and establishes that a redox enzyme like CYP enhances reaction rates (achieves catalysis) via a novel (hitherto unknown) modality.
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Affiliation(s)
| | - Abhinav Parashar
- Hemoproteins Lab, School of Bio Sciences and Technology, VIT University Vellore, India
| | - Sudeep K Gade
- Hemoproteins Lab, School of Bio Sciences and Technology, VIT University Vellore, India
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24
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Tanvir S, Thuróczy G, Selmaoui B, Silva Pires Antonietti V, Sonnet P, Arnaud-Cormos D, Lévêque P, Pulvin S, de Seze R. Effects of 3G cell phone exposure on the structure and function of the human cytochrome P450 reductase. Bioelectrochemistry 2016; 111:62-9. [PMID: 27243445 DOI: 10.1016/j.bioelechem.2016.05.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 05/10/2016] [Accepted: 05/10/2016] [Indexed: 11/29/2022]
Abstract
Cell phones increase exposure to radiofrequency (RF) electromagnetic fields (EMFs). Whether EMFs exert specific effects on biological systems remains debatable. This study investigated the effect of cell phone exposure on the structure and function of human NADPH-cytochrome P450 reductase (CPR). CPR plays a key role in the electron transfer to cytochrome P450, which takes part in a wide range of oxidative metabolic reactions in various organisms from microbes to humans. Human CPR was exposed for 60min to 1966-MHz RF inside a transverse electromagnetic cell (TEM-cell) placed in an incubator. The specific absorption rate (SAR) was 5W·kg(-1). Conformation changes have been detected through fluorescent spectroscopy of flavin and tryptophan residues, and investigated through circular dichroism, dynamic light scattering and microelectrophoresis. These showed that CPR was narrowed. By using cytochrome C reductase activity to assess the electron flux through the CPR, the Michaelis Menten constant (Km) and the maximum initial velocity (Vmax) decreased by 22% as compared with controls. This change was due to small changes in the tertiary and secondary structures of the protein at 37°C. The relevance of these findings to an actual RF exposure scenario demands further biochemical and in-vivo confirmation.
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Affiliation(s)
- Shazia Tanvir
- Sorbonne Universités, Université de Technologie de Compiègne, Laboratoire de Génie Enzymatique et Cellulaire, FRE CNRS 3580, CS60319, 60203 Compiègne Cedex. France
| | - György Thuróczy
- Unité de toxicologie expérimentale TOXI-PériTox UMR-I 01, Institut National de l'Environnement Industriel et des RISques (INERIS), Parc ALATA BP2, 60 550, Verneuil-en-Halatte, France; PériTOX, UPJV, Faculté de Médecine, 80 000 Amiens, France
| | - Brahim Selmaoui
- Unité de toxicologie expérimentale TOXI-PériTox UMR-I 01, Institut National de l'Environnement Industriel et des RISques (INERIS), Parc ALATA BP2, 60 550, Verneuil-en-Halatte, France; PériTOX, UPJV, Faculté de Médecine, 80 000 Amiens, France
| | - Viviane Silva Pires Antonietti
- Université de Picardie Jules Verne, Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources, UMR CNRS 7378, UFR de Pharmacie, 80 037, Amiens, France
| | - Pascal Sonnet
- Université de Picardie Jules Verne, Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources, UMR CNRS 7378, UFR de Pharmacie, 80 037, Amiens, France
| | | | - Philippe Lévêque
- Université de Limoges, CNRS, XLIM, UMR 7252, F-87000, Limoges, France
| | - Sylviane Pulvin
- Sorbonne Universités, Université de Technologie de Compiègne, Laboratoire de Génie Enzymatique et Cellulaire, FRE CNRS 3580, CS60319, 60203 Compiègne Cedex. France
| | - René de Seze
- Unité de toxicologie expérimentale TOXI-PériTox UMR-I 01, Institut National de l'Environnement Industriel et des RISques (INERIS), Parc ALATA BP2, 60 550, Verneuil-en-Halatte, France; PériTOX, UPJV, Faculté de Médecine, 80 000 Amiens, France.
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25
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A well-balanced preexisting equilibrium governs electron flux efficiency of a multidomain diflavin reductase. Biophys J 2016; 108:1527-1536. [PMID: 25809265 DOI: 10.1016/j.bpj.2015.01.032] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 12/24/2014] [Accepted: 01/21/2015] [Indexed: 01/11/2023] Open
Abstract
Diflavin reductases are bidomain electron transfer proteins in which structural reorientation is necessary to account for the various intramolecular and intermolecular electron transfer steps. Using small-angle x-ray scattering and nuclear magnetic resonance data, we describe the conformational free-energy landscape of the NADPH-cytochrome P450 reductase (CPR), a typical bidomain redox enzyme composed of two covalently-bound flavin domains, under various experimental conditions. The CPR enzyme exists in a salt- and pH-dependent rapid equilibrium between a previously described rigid, locked state and a newly characterized, highly flexible, unlocked state. We further establish that maximal electron flux through CPR is conditioned by adjustable stability of the locked-state domain interface under resting conditions. This is rationalized by a kinetic scheme coupling rapid conformational sampling and slow chemical reaction rates. Regulated domain interface stability associated with fast stochastic domain contacts during the catalytic cycle thus provides, to our knowledge, a new paradigm for improving our understanding of multidomain enzyme function.
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26
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Bostick CD, Hickey KM, Wollenberg LA, Flora DR, Tracy TS, Gannett PM. Immobilized Cytochrome P450 for Monitoring of P450-P450 Interactions and Metabolism. ACTA ACUST UNITED AC 2016; 44:741-9. [PMID: 26961240 DOI: 10.1124/dmd.115.067637] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 03/09/2016] [Indexed: 11/22/2022]
Abstract
Cytochrome P450 (P450) protein-protein interactions have been shown to alter their catalytic activity. Furthermore, these interactions are isoform specific and can elicit activation, inhibition, or no effect on enzymatic activity. Studies show that these effects are also dependent on the protein partner cytochrome P450 reductase (CPR) and the order of protein addition to purified reconstituted enzyme systems. In this study, we use controlled immobilization of P450s to a gold surface to gain a better understanding of P450-P450 interactions between three key drug-metabolizing isoforms (CYP2C9, CYP3A4, and CYP2D6). Molecular modeling was used to assess the favorability of homomeric/heteromeric P450 complex formation. P450 complex formation in vitro was analyzed in real time utilizing surface plasmon resonance. Finally, the effects of P450 complex formation were investigated utilizing our immobilized platform and reconstituted enzyme systems. Molecular modeling shows favorable binding of CYP2C9-CPR, CYP2C9-CYP2D6, CYP2C9-CYP2C9, and CYP2C9-CYP3A4, in rank order.KDvalues obtained via surface plasmon resonance show strong binding, in the nanomolar range, for the above pairs, with CYP2C9-CYP2D6 yielding the lowestKD, followed by CYP2C9-CYP2C9, CYP2C9-CPR, and CYP2C9-CYP3A4. Metabolic incubations show that immobilized CYP2C9 metabolism was activated by homomeric complex formation. CYP2C9 metabolism was not affected by the presence of CYP3A4 with saturating CPR concentrations. CYP2C9 metabolism was activated by CYP2D6 at saturating CPR concentrations in solution but was inhibited when CYP2C9 was immobilized. The order of addition of proteins (CYP2C9, CYP2D6, CYP3A4, and CPR) influenced the magnitude of inhibition for CYP3A4 and CYP2D6. These results indicate isoform-specific P450 interactions and effects on P450-mediated metabolism.
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Affiliation(s)
- Chris D Bostick
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, West Virginia (C.D.B., K.M.H.); Array BioPharma, Boulder, Colorado (L.A.W.); Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota (D.R.F.); College of Pharmacy, University of Kentucky, Lexington, Kentucky (T.S.T.); and Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Ft. Lauderdale, Florida (P.M.G.)
| | - Katherine M Hickey
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, West Virginia (C.D.B., K.M.H.); Array BioPharma, Boulder, Colorado (L.A.W.); Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota (D.R.F.); College of Pharmacy, University of Kentucky, Lexington, Kentucky (T.S.T.); and Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Ft. Lauderdale, Florida (P.M.G.)
| | - Lance A Wollenberg
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, West Virginia (C.D.B., K.M.H.); Array BioPharma, Boulder, Colorado (L.A.W.); Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota (D.R.F.); College of Pharmacy, University of Kentucky, Lexington, Kentucky (T.S.T.); and Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Ft. Lauderdale, Florida (P.M.G.)
| | - Darcy R Flora
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, West Virginia (C.D.B., K.M.H.); Array BioPharma, Boulder, Colorado (L.A.W.); Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota (D.R.F.); College of Pharmacy, University of Kentucky, Lexington, Kentucky (T.S.T.); and Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Ft. Lauderdale, Florida (P.M.G.)
| | - Timothy S Tracy
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, West Virginia (C.D.B., K.M.H.); Array BioPharma, Boulder, Colorado (L.A.W.); Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota (D.R.F.); College of Pharmacy, University of Kentucky, Lexington, Kentucky (T.S.T.); and Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Ft. Lauderdale, Florida (P.M.G.)
| | - Peter M Gannett
- Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University, Morgantown, West Virginia (C.D.B., K.M.H.); Array BioPharma, Boulder, Colorado (L.A.W.); Department of Experimental and Clinical Pharmacology, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota (D.R.F.); College of Pharmacy, University of Kentucky, Lexington, Kentucky (T.S.T.); and Department of Pharmaceutical Sciences, College of Pharmacy, Nova Southeastern University, Ft. Lauderdale, Florida (P.M.G.)
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27
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Quehl P, Hollender J, Schüürmann J, Brossette T, Maas R, Jose J. Co-expression of active human cytochrome P450 1A2 and cytochrome P450 reductase on the cell surface of Escherichia coli. Microb Cell Fact 2016; 15:26. [PMID: 26838175 PMCID: PMC4736170 DOI: 10.1186/s12934-016-0427-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 01/19/2016] [Indexed: 11/23/2022] Open
Abstract
Background Human cytochrome P450 (CYP) enzymes mediate the first step in the breakdown of most drugs and are strongly involved in drug–drug interactions, drug clearance and activation of prodrugs. Their biocatalytic behavior is a key parameter during drug development which requires preparative synthesis of CYP related drug metabolites. However, recombinant expression of CYP enzymes is a challenging bottleneck for drug metabolite biosynthesis. Therefore, we developed a novel approach by displaying human cytochrome P450 1A2 (CYP1A2) and cytochrome P450 reductase (CPR) on the surface of Escherichia coli. Results To present human CYP1A2 and CPR on the surface, we employed autodisplay. Both enzymes were displayed on the surface which was demonstrated by protease and antibody accessibility tests. CPR activity was first confirmed with the protein substrate cytochrome c. Cells co-expressing CYP1A2 and CPR were capable of catalyzing the conversion of the known CYP1A2 substrates 7-ethoxyresorufin, phenacetin and the artificial substrate luciferin-MultiCYP, which would not have been possible without interaction of both enzymes. Biocatalytic activity was strongly influenced by the composition of the growth medium. Addition of 5-aminolevulinic acid was necessary to obtain a fully active whole cell biocatalyst and was superior to the addition of heme. Conclusion We demonstrated that CYP1A2 and CPR can be co-expressed catalytically active on the cell surface of E. coli. It is a promising step towards pharmaceutical applications such as the synthesis of drug metabolites. Electronic supplementary material The online version of this article (doi:10.1186/s12934-016-0427-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Paul Quehl
- Institut für Pharmazeutische und Medizinische Chemie, PharmaCampus, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany.
| | - Joel Hollender
- Institut für Pharmazeutische und Medizinische Chemie, PharmaCampus, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany. .,Autodisplay Biotech GmbH, Merowingerplatz 1a, 40225, Düsseldorf, Germany.
| | - Jan Schüürmann
- Institut für Pharmazeutische und Medizinische Chemie, PharmaCampus, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany.
| | - Tatjana Brossette
- Autodisplay Biotech GmbH, Merowingerplatz 1a, 40225, Düsseldorf, Germany.
| | - Ruth Maas
- Autodisplay Biotech GmbH, Merowingerplatz 1a, 40225, Düsseldorf, Germany.
| | - Joachim Jose
- Institut für Pharmazeutische und Medizinische Chemie, PharmaCampus, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, 48149, Münster, Germany.
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28
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Estrada DF, Laurence JS, Scott EE. Cytochrome P450 17A1 Interactions with the FMN Domain of Its Reductase as Characterized by NMR. J Biol Chem 2015; 291:3990-4003. [PMID: 26719338 DOI: 10.1074/jbc.m115.677294] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Indexed: 11/06/2022] Open
Abstract
To accomplish key physiological processes ranging from drug metabolism to steroidogenesis, human microsomal cytochrome P450 enzymes require the sequential input of two electrons delivered by the FMN domain of NADPH-cytochrome P450 reductase. Although some human microsomal P450 enzymes can instead accept the second electron from cytochrome b5, for human steroidogenic CYP17A1, the cytochrome P450 reductase FMN domain delivers both electrons, and b5 is an allosteric modulator. The structural basis of these key but poorly understood protein interactions was probed by solution NMR using the catalytically competent soluble domains of each protein. Formation of the CYP17A1·FMN domain complex induced differential line broadening of the NMR signal for each protein. Alterations in the exchange dynamics generally occurred for residues near the surface of the flavin mononucleotide, including 87-90 (loop 1), and for key CYP17A1 active site residues. These interactions were modulated by the identity of the substrate in the buried CYP17A1 active site and by b5. The FMN domain outcompetes b5 for binding to CYP17A1 in the three-component system. These results and comparison with previous NMR studies of the CYP17A1·b5 complex suggest a model of CYP17A1 enzyme regulation.
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Affiliation(s)
- D Fernando Estrada
- From the Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66045 and
| | - Jennifer S Laurence
- the Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047
| | - Emily E Scott
- From the Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66045 and
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29
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Hlavica P. Mechanistic basis of electron transfer to cytochromes p450 by natural redox partners and artificial donor constructs. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 851:247-97. [PMID: 26002739 DOI: 10.1007/978-3-319-16009-2_10] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cytochromes P450 (P450s) are hemoproteins catalyzing oxidative biotransformation of a vast array of natural and xenobiotic compounds. Reducing equivalents required for dioxygen cleavage and substrate hydroxylation originate from different redox partners including diflavin reductases, flavodoxins, ferredoxins and phthalate dioxygenase reductase (PDR)-type proteins. Accordingly, circumstantial analysis of structural and physicochemical features governing donor-acceptor recognition and electron transfer poses an intriguing challenge. Thus, conformational flexibility reflected by togging between closed and open states of solvent exposed patches on the redox components was shown to be instrumental to steered electron transmission. Here, the membrane-interactive tails of the P450 enzymes and donor proteins were recognized to be crucial to proper orientation toward each other of surface sites on the redox modules steering functional coupling. Also, mobile electron shuttling may come into play. While charge-pairing mechanisms are of primary importance in attraction and complexation of the redox partners, hydrophobic and van der Waals cohesion forces play a minor role in docking events. Due to catalytic plasticity of P450 enzymes, there is considerable promise in biotechnological applications. Here, deeper insight into the mechanistic basis of the redox machinery will permit optimization of redox processes via directed evolution and DNA shuffling. Thus, creation of hybrid systems by fusion of the modified heme domain of P450s with proteinaceous electron carriers helps obviate the tedious reconstitution procedure and induces novel activities. Also, P450-based amperometric biosensors may open new vistas in pharmaceutical and clinical implementation and environmental monitoring.
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Affiliation(s)
- Peter Hlavica
- Walther-Straub-Institut für Pharmakologie und Toxikologie der LMU, Goethestrasse 33, 80336, München, Germany,
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30
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Miyamoto M, Yamashita T, Yasuhara Y, Hayasaki A, Hosokawa Y, Tsujino H, Uno T. Membrane Anchor of Cytochrome P450 Reductase Suppresses the Uncoupling of Cytochrome P450. Chem Pharm Bull (Tokyo) 2015; 63:286-94. [DOI: 10.1248/cpb.c15-00034] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - Taku Yamashita
- School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women’s University
| | - Yuki Yasuhara
- Graduate School of Pharmaceutical Sciences, Osaka University
| | | | - Yukari Hosokawa
- Graduate School of Pharmaceutical Sciences, Osaka University
| | | | - Tadayuki Uno
- Graduate School of Pharmaceutical Sciences, Osaka University
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31
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Huang R, Zhang M, Rwere F, Waskell L, Ramamoorthy A. Kinetic and structural characterization of the interaction between the FMN binding domain of cytochrome P450 reductase and cytochrome c. J Biol Chem 2014; 290:4843-4855. [PMID: 25512382 DOI: 10.1074/jbc.m114.582700] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cytochrome P450 reductase (CPR) is a diflavin enzyme that transfers electrons to many protein partners. Electron transfer from CPR to cyt c has been extensively used as a model reaction to assess the redox activity of CPR. CPR is composed of multiple domains, among which the FMN binding domain (FBD) is the direct electron donor to cyt c. Here, electron transfer and complex formation between FBD and cyt c are investigated. Electron transfer from FBD to cyt c occurs at distinct rates that are dependent on the redox states of FBD. When compared with full-length CPR, FBD reduces cyt c at a higher rate in both the semiquinone and hydroquinone states. The NMR titration experiments reveal the formation of dynamic complexes between FBD and cyt c on a fast exchange time scale. Chemical shift mapping identified residues of FBD involved in the binding interface with cyt c, most of which are located in proximity to the solvent-exposed edge of the FMN cofactor along with other residues distributed around the surface of FBD. The structural model of the FBD-cyt c complex indicates two possible orientations of complex formation. The major complex structure shows a salt bridge formation between Glu-213/Glu-214 of FBD and Lys-87 of cyt c, which may be essential for the formation of the complex, and a predicted electron transfer pathway mediated by Lys-13 of cyt c. The findings provide insights into the function of CPR and CPR-cyt c interaction on a structural basis.
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Affiliation(s)
- Rui Huang
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and
| | - Meng Zhang
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and
| | - Freeborn Rwere
- Department of Anesthesiology, University of Michigan and Veterans Affairs Medical Center, Ann Arbor, Michigan 48105
| | - Lucy Waskell
- Department of Anesthesiology, University of Michigan and Veterans Affairs Medical Center, Ann Arbor, Michigan 48105
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry and Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055 and.
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32
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Abstract
NOSs are homodimeric multidomain enzymes responsible for producing NO. In mammals, NO acts as an intercellular messenger in a variety of signaling reactions, as well as a cytotoxin in the innate immune response. Mammals possess three NOS isoforms--inducible, endothelial, and neuronal NOS--that are composed of an N-terminal oxidase domain and a C-terminal reductase domain. Calmodulin (CaM) activates NO synthesis by binding to the helical region connecting these two domains. Although crystal structures of isolated domains have been reported, no structure is available for full-length NOS. We used high-throughput single-particle EM to obtain the structures and higher-order domain organization of all three NOS holoenzymes. The structures of inducible, endothelial, and neuronal NOS with and without CaM bound are similar, consisting of a dimerized oxidase domain flanked by two separated reductase domains. NOS isoforms adopt many conformations enabled by three flexible linkers. These conformations represent snapshots of the continuous electron transfer pathway from the reductase domain to the oxidase domain, which reveal that only a single reductase domain participates in electron transfer at a time, and that CaM activates NOS by constraining rotational motions and by directly binding to the oxidase domain. Direct visualization of these large conformational changes induced during electron transfer provides significant insight into the molecular underpinnings governing NO formation.
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33
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Structural basis for the electron transfer from an open form of NADPH-cytochrome P450 oxidoreductase to heme oxygenase. Proc Natl Acad Sci U S A 2014; 111:2524-9. [PMID: 24550278 DOI: 10.1073/pnas.1322034111] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
NADPH-cytochrome P450 oxidoreductase (CPR) supplies electrons to various heme proteins including heme oxygenase (HO), which is a key enzyme for heme degradation. Electrons from NADPH flow first to flavin adenine dinucleotide, then to flavin mononucleotide (FMN), and finally to heme in the redox partner. For electron transfer from CPR to its redox partner, the ''closed-open transition'' of CPR is indispensable. Here, we demonstrate that a hinge-shortened CPR variant, which favors an open conformation, makes a stable complex with heme-HO-1 and can support the HO reaction, although its efficiency is extremely limited. Furthermore, we determined the crystal structure of the CPR variant in complex with heme-HO-1 at 4.3-Å resolution. The crystal structure of a complex of CPR and its redox partner was previously unidentified. The distance between heme and FMN in this complex (6 Å) implies direct electron transfer from FMN to heme.
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34
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Suwanchaichinda C, Brattsten LB. Genomic and bioinformatic analysis of NADPH-cytochrome P450 reductase in Anopheles stephensi (Diptera: Culicidae). JOURNAL OF INSECT SCIENCE (ONLINE) 2014; 14:165. [PMID: 25368081 PMCID: PMC5443604 DOI: 10.1093/jisesa/ieu027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 03/18/2013] [Indexed: 06/04/2023]
Abstract
The cytochrome P450 monooxygenase (P450) enzyme system is a major mechanism of xenobiotic biotransformation. The nicotinamide adenine dinucleotide phosphate (NADPH)-cytochrome P450 reductase (CPR) is required for transfer of electrons from NADPH to P450. One CPR gene was identified in the genome of the malaria-transmitting mosquito Anopheles stephensi Liston (Diptera: Culicidae). The gene encodes a polypeptide containing highly conserved flavin mononucleotide-, flavin adenine dinucleotide-, and NADPH-binding domains, a unique characteristic of the reductase. Phylogenetic analysis revealed that the A. stephensi and other known mosquito CPRs belong to a monophyletic group distinctly separated from other insects in the same order, Diptera. Amino acid residues of CPRs involved in binding of P450 and cytochrome c are conserved between A. stephensi and the Norway rat Rattus norvegicus Berkenhout (Rodentia: Muridae). However, gene structure particularly within the coding region is evidently different between the two organisms. Such difference might arise during the evolution process as also seen in the difference of P450 families and isoforms found in these organisms. CPR in the mosquito A. stephensi is expected to be active and serve as an essential component of the P450 system.
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Affiliation(s)
- C Suwanchaichinda
- Department of Entomology, Rutgers University, New Brunswick, NJ 08901
| | - L B Brattsten
- Department of Entomology, Rutgers University, New Brunswick, NJ 08901
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35
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Simtchouk S, Eng JL, Meints CE, Makins C, Wolthers KR. Kinetic analysis of cytochrome P450 reductase from Artemisia annua reveals accelerated rates of NADH-dependent flavin reduction. FEBS J 2013; 280:6627-42. [PMID: 24299267 DOI: 10.1111/febs.12567] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 09/06/2013] [Accepted: 10/09/2013] [Indexed: 11/26/2022]
Abstract
Cytochrome P450 reductase from Artemisia annua (aaCPR) is a diflavin enzyme that has been employed for the microbial synthesis of artemisinic acid (a semi-synthetic precursor of the anti-malarial drug, artemisinin) based on its ability to transfer electrons to the cytochrome P450 monooxygenase, CYP71AV1. We have isolated recombinant aaCPR (with the N-terminal transmembrane motif removed) from Escherichia coli and compared its kinetic and thermodynamic properties with other CPR orthologues, most notably human CPR. The FAD and FMN redox potentials and the macroscopic kinetic constants associated with cytochrome c(3+) reduction for aaCPR are comparable to that of other CPR orthologues, with the exception that the apparent binding affinity for the oxidized coenzyme is ~ 30-fold weaker compared to human CPR. CPR from A. annua shows a 3.5-fold increase in uncoupled NADPH oxidation compared to human CPR and a strong preference (85 100-fold) for NADPH over NADH. Strikingly, reduction of the enzyme by the first and second equivalent of NADPH is much faster in aaCPR, with rates of > 500 and 17 s(-1) at 6 °C. We also optically detect a charge-transfer species that rapidly forms in < 3 ms and then persists during the reductive half reaction. Additional stopped-flow kinetic studies with NADH and (R)-[4-(2) H]NADPH suggest that the accelerated rate of flavin reduction is attributed to the relatively weak binding affinity of aaCPR for NADP(+) .
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Affiliation(s)
- Svetlana Simtchouk
- Department of Chemistry, University of British Columbia, Kelowna, BC, Canada
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Huang WC, Ellis J, Moody P, Raven E, Roberts G. Redox-linked domain movements in the catalytic cycle of cytochrome p450 reductase. Structure 2013; 21:1581-9. [PMID: 23911089 PMCID: PMC3763376 DOI: 10.1016/j.str.2013.06.022] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Revised: 06/24/2013] [Accepted: 06/26/2013] [Indexed: 11/17/2022]
Abstract
NADPH-cytochrome P450 reductase is a key component of the P450 mono-oxygenase drug-metabolizing system. There is evidence for a conformational equilibrium involving large-scale domain motions in this enzyme. We now show, using small-angle X-ray scattering (SAXS) and small-angle neutron scattering, that delivery of two electrons to cytochrome P450 reductase leads to a shift in this equilibrium from a compact form, similar to the crystal structure, toward an extended form, while coenzyme binding favors the compact form. We present a model for the extended form of the enzyme based on nuclear magnetic resonance and SAXS data. Using the effects of changes in solution conditions and of site-directed mutagenesis, we demonstrate that the conversion to the extended form leads to an enhanced ability to transfer electrons to cytochrome c. This structural evidence shows that domain motion is linked closely to the individual steps of the catalytic cycle of cytochrome P450 reductase, and we propose a mechanism for this.
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Affiliation(s)
- Wei-Cheng Huang
- Henry Wellcome Laboratories for Structural Biology, Department of Biochemistry, University of Leicester, Henry Wellcome Building, Leicester LE1 9HN, UK
| | - Jacqueline Ellis
- Henry Wellcome Laboratories for Structural Biology, Department of Biochemistry, University of Leicester, Henry Wellcome Building, Leicester LE1 9HN, UK
| | - Peter C.E. Moody
- Henry Wellcome Laboratories for Structural Biology, Department of Biochemistry, University of Leicester, Henry Wellcome Building, Leicester LE1 9HN, UK
| | - Emma L. Raven
- Department of Chemistry, University of Leicester, Leicester LE1 7RH, UK
| | - Gordon C.K. Roberts
- Henry Wellcome Laboratories for Structural Biology, Department of Biochemistry, University of Leicester, Henry Wellcome Building, Leicester LE1 9HN, UK
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Pandey AV, Flück CE. NADPH P450 oxidoreductase: structure, function, and pathology of diseases. Pharmacol Ther 2013; 138:229-54. [PMID: 23353702 DOI: 10.1016/j.pharmthera.2013.01.010] [Citation(s) in RCA: 168] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Accepted: 12/26/2012] [Indexed: 01/18/2023]
Abstract
Cytochrome P450 oxidoreductase (POR) is an enzyme that is essential for multiple metabolic processes, chiefly among them are reactions catalyzed by cytochrome P450 proteins for metabolism of steroid hormones, drugs and xenobiotics. Mutations in POR cause a complex set of disorders that often resemble defects in steroid metabolizing enzymes 17α-hydroxylase, 21-hydroxylase and aromatase. Since our initial reports of POR mutations in 2004, more than 200 different mutations and polymorphisms in POR gene have been identified. Several missense variations in POR have been tested for their effect on activities of multiple steroid and drug metabolizing P450 proteins. Mutations in POR may have variable effects on different P450 partner proteins depending on the location of the mutation. The POR mutations that disrupt the binding of co-factors have negative impact on all partner proteins, while mutations causing subtle structural changes may lead to altered interaction with specific partner proteins and the overall effect may be different for each partner. This review summarizes the recent discoveries related to mutations and polymorphisms in POR and discusses these mutations in the context of historical developments in the discovery and characterization of POR as an electron transfer protein. The review is focused on the structural, enzymatic and clinical implications of the mutations linked to newly identified disorders in humans, now categorized as POR deficiency.
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Affiliation(s)
- Amit V Pandey
- Department of Pediatrics, Division of Pediatric Endocrinology and Diabetology, University Children's Hospital Bern, and Department of Clinical Research, University of Bern, 3004 Bern, Switzerland.
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Iyanagi T, Xia C, Kim JJP. NADPH-cytochrome P450 oxidoreductase: prototypic member of the diflavin reductase family. Arch Biochem Biophys 2012; 528:72-89. [PMID: 22982532 PMCID: PMC3606592 DOI: 10.1016/j.abb.2012.09.002] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 09/01/2012] [Accepted: 09/03/2012] [Indexed: 12/31/2022]
Abstract
NADPH-cytochrome P450 oxidoreductase (CYPOR) and nitric oxide synthase (NOS), two members of the diflavin oxidoreductase family, are multi-domain enzymes containing distinct FAD and FMN domains connected by a flexible hinge. FAD accepts a hydride ion from NADPH, and reduced FAD donates electrons to FMN, which in turn transfers electrons to the heme center of cytochrome P450 or NOS oxygenase domain. Structural analysis of CYPOR, the prototype of this enzyme family, has revealed the exact nature of the domain arrangement and the role of residues involved in cofactor binding. Recent structural and biophysical studies of CYPOR have shown that the two flavin domains undergo large domain movements during catalysis. NOS isoforms contain additional regulatory elements within the reductase domain that control electron transfer through Ca(2+)-dependent calmodulin (CaM) binding. The recent crystal structure of an iNOS Ca(2+)/CaM-FMN construct, containing the FMN domain in complex with Ca(2+)/CaM, provided structural information on the linkage between the reductase and oxgenase domains of NOS, making it possible to model the holo iNOS structure. This review summarizes recent advances in our understanding of the dynamics of domain movements during CYPOR catalysis and the role of the NOS diflavin reductase domain in the regulation of NOS isozyme activities.
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Affiliation(s)
- Takashi Iyanagi
- Department of Biochemistry, Medical College of Wisconsin, USA
- Department of Life Science, The Himeji Institute of Technology, University of Hyogo, Japan
| | - Chuanwu Xia
- Department of Biochemistry, Medical College of Wisconsin, USA
| | - Jung-Ja P. Kim
- Department of Biochemistry, Medical College of Wisconsin, USA
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Abstract
Diflavin reductases are essential proteins capable of splitting the two-electron flux from reduced pyridine nucleotides to a variety of one electron acceptors. The primary sequence of diflavin reductases shows a conserved domain organization harboring two catalytic domains bound to the FAD and FMN flavins sandwiched by one or several non-catalytic domains. The catalytic domains are analogous to existing globular proteins: the FMN domain is analogous to flavodoxins while the FAD domain resembles ferredoxin reductases. The first structural determination of one member of the diflavin reductases family raised some questions about the architecture of the enzyme during catalysis: both FMN and FAD were in perfect position for interflavin transfers but the steric hindrance of the FAD domain rapidly prompted more complex hypotheses on the possible mechanisms for the electron transfer from FMN to external acceptors. Hypotheses of domain reorganization during catalysis in the context of the different members of this family were given by many groups during the past twenty years. This review will address the recent advances in various structural approaches that have highlighted specific dynamic features of diflavin reductases.
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Affiliation(s)
- Louise Aigrain
- Gene Machines Group, Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford OX1 3PU, UK; E-Mail:
| | - Fataneh Fatemi
- Institut de Chimie des Substances Naturelles, CNRS, UPR 2301, Centre de Recherche de Gif, 1 Av. de la Terrasse, 91198 Gif-sur-Yvette Cedex, France; E-Mails: (F.F.); (O.F.); (E.L.)
| | - Oriane Frances
- Institut de Chimie des Substances Naturelles, CNRS, UPR 2301, Centre de Recherche de Gif, 1 Av. de la Terrasse, 91198 Gif-sur-Yvette Cedex, France; E-Mails: (F.F.); (O.F.); (E.L.)
| | - Ewen Lescop
- Institut de Chimie des Substances Naturelles, CNRS, UPR 2301, Centre de Recherche de Gif, 1 Av. de la Terrasse, 91198 Gif-sur-Yvette Cedex, France; E-Mails: (F.F.); (O.F.); (E.L.)
| | - Gilles Truan
- Université de Toulouse; INSA, UPS, INP; LISBP, 135 Avenue de Rangueil, F-31077 Toulouse, France
- INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31400 Toulouse, France
- CNRS, UMR5504, F-31400 Toulouse, France
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +33-567048813; Fax: +33-567048814
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Lin HL, Kenaan C, Zhang H, Hollenberg PF. Reaction of human cytochrome P450 3A4 with peroxynitrite: nitrotyrosine formation on the proximal side impairs its interaction with NADPH-cytochrome P450 reductase. Chem Res Toxicol 2012; 25:2642-53. [PMID: 23016756 DOI: 10.1021/tx3002753] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The reaction of peroxynitrite (PN) with purified human cytochrome P450 3A4 (CYP3A4) resulted in the loss of the reduced-CO difference spectrum, but the absolute absorption spectrum of the heme was not significantly altered. The loss of 7-benzyloxy-4-(trifluoromethyl)coumarin (BFC) O-debenzylation activity of CYP3A4 was concentration-dependent with respect to PN, and the loss of BFC activity supported by NADPH-cytochrome P450 reductase (CPR) was much greater than that supported by tert-butyl hydroperoxide. Moreover, the PN-treated CYP3A4 exhibited a reduced-CO spectrum when reduced by CPR that was much smaller than when it was reduced by dithionite. These results suggest that modification of CYP3A4 by PN may impair its interaction with CPR, leading to the loss of catalytic activity. Tyrosine nitration, as measured by an increase in mass of 45 Da due to the addition of a nitro group, was used as a biomarker for protein modification by PN. PN-treated CYP3A4 was digested by trypsin and endoproteinase Glu C, and nitrotyrosine formation was then determined by using electrospray ionization-liquid chromatography-tandem mass spectrometry. Tyr residues 99, 307, 347, 430, and 432 were found to be nitrated. Using the GRAMM-X docking program, the structure for the CYP3A4-CPR complex shows that Tyr99, Tyr347, and Tyr430 are on the proximal side of CYP3A4 and are in close contact with three acidic residues in the FMN domain of CPR, suggesting that modification of one or more of these tyrosine residues by PN may influence CPR binding or the transfer of electrons to CYP3A4. Mutagenesis of Tyr430 to Phe or Val revealed that both the aromatic and the hydroxyl groups of Tyr are required for CPR-dependent catalytic activity and thus support the idea that the proximal side Tyr participates in the 3A4-CPR interaction. In conclusion, modification of tyrosine residues by PN and their subsequent identification can be used to enhance our knowledge of the structure/function relationships of the P450s with respect to the electron transfer steps, which are critical for P450 activity.
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Affiliation(s)
- Hsia-lien Lin
- Department of Pharmacology, University of Michigan, 2301 MSRB III, 1150 West Medical Center Drive, Ann Arbor, Michigan 48109-5632, United States
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41
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The closed and compact domain organization of the 70-kDa human cytochrome P450 reductase in its oxidized state as revealed by NMR. J Mol Biol 2012; 420:296-309. [PMID: 22543241 DOI: 10.1016/j.jmb.2012.03.022] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 02/29/2012] [Accepted: 03/23/2012] [Indexed: 11/20/2022]
Abstract
The NADPH cytochrome P450 reductase (CPR), a diflavin enzyme, catalyzes the electron transfer (ET) from NADPH to the substrate P450. The crystal structures of mammalian and yeast CPRs show a compact organization for the two domains containing FMN (flavin mononucleotide) and FAD (flavin adenine dinucleotide), with a short interflavin distance consistent with fast ET from the NADPH-reduced FAD to the second flavin FMN. This conformation, referred as "closed", contrasts with the alternative opened or extended domain arrangements recently described for partially reduced or mutant CPR. Internal domain flexibility in this enzyme is indeed necessary to account for the apparently conflicting requirements of having FMN flavin accessible to both the FAD and the substrate P450 at the same interface. However, how interdomain dynamics influence internal and external ETs in CPR is still largely unknown. Here, we used NMR techniques to explore the global, domain-specific and residue-specific structural and dynamic properties of the nucleotide-free human CPR in solution in its oxidized state. Based on the backbone resonance assignment of this 70-kDa protein, we collected residue-specific (15)N relaxation and (1)H-(15)N residual dipolar couplings. Surprisingly and in contrast with previous studies, the analysis of these NMR data revealed that the CPR exists in a unique and predominant conformation that highly resembles the closed conformation observed in the crystalline state. Based on our findings and the previous observations of conformational equilibria of the CPR in partially reduced states, we propose that the large-scale conformational transitions of the CPR during the catalytic cycle are tightly controlled to ensure optimal electron delivery.
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42
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Pudney CR, Heyes DJ, Khara B, Hay S, Rigby SEJ, Scrutton NS. Kinetic and spectroscopic probes of motions and catalysis in the cytochrome P450 reductase family of enzymes. FEBS J 2012; 279:1534-44. [PMID: 22142452 DOI: 10.1111/j.1742-4658.2011.08442.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There is a mounting body of evidence to suggest that enzyme motions are linked to function, although the design of informative experiments aiming to evaluate how this motion facilitates reaction chemistry is challenging. For the family of diflavin reductase enzymes, typified by cytochrome P450 reductase, accumulating evidence suggests that electron transfer is somehow coupled to large-scale conformational change and that protein motions gate the electron transfer chemistry. These ideas have emerged from a variety of experimental approaches, including structural biology methods (i.e. X-ray crystallography, electron paramagnetic/NMR spectroscopies and solution X-ray scattering) and advanced spectroscopic techniques that have employed the use of variable pressure kinetic methodologies, together with solvent perturbation studies (i.e. ionic strength, deuteration and viscosity). Here, we offer a personal perspective on the importance of motions to electron transfer in the cytochrome P450 reductase family of enzymes, drawing on the detailed insight that can be obtained by combining these multiple structural and biophysical approaches.
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Affiliation(s)
- Christopher R Pudney
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, Manchester, UK
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43
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Pudney CR, Khara B, Johannissen LO, Scrutton NS. Coupled motions direct electrons along human microsomal P450 Chains. PLoS Biol 2011; 9:e1001222. [PMID: 22205878 PMCID: PMC3243717 DOI: 10.1371/journal.pbio.1001222] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 11/08/2011] [Indexed: 11/22/2022] Open
Abstract
Protein domain motion is often implicated in biological electron transfer, but the general significance of motion is not clear. Motion has been implicated in the transfer of electrons from human cytochrome P450 reductase (CPR) to all microsomal cytochrome P450s (CYPs). Our hypothesis is that tight coupling of motion with enzyme chemistry can signal "ready and waiting" states for electron transfer from CPR to downstream CYPs and support vectorial electron transfer across complex redox chains. We developed a novel approach to study the time-dependence of dynamical change during catalysis that reports on the changing conformational states of CPR. FRET was linked to stopped-flow studies of electron transfer in CPR that contains donor-acceptor fluorophores on the enzyme surface. Open and closed states of CPR were correlated with key steps in the catalytic cycle which demonstrated how redox chemistry and NADPH binding drive successive opening and closing of the enzyme. Specifically, we provide evidence that reduction of the flavin moieties in CPR induces CPR opening, whereas ligand binding induces CPR closing. A dynamic reaction cycle was created in which CPR optimizes internal electron transfer between flavin cofactors by adopting closed states and signals "ready and waiting" conformations to partner CYP enzymes by adopting more open states. This complex, temporal control of enzyme motion is used to catalyze directional electron transfer from NADPH→FAD→FMN→heme, thereby facilitating all microsomal P450-catalysed reactions. Motions critical to the broader biological functions of CPR are tightly coupled to enzyme chemistry in the human NADPH-CPR-CYP redox chain. That redox chemistry alone is sufficient to drive functionally necessary, large-scale conformational change is remarkable. Rather than relying on stochastic conformational sampling, our study highlights a need for tight coupling of motion to enzyme chemistry to give vectorial electron transfer along complex redox chains.
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Affiliation(s)
- Christopher R. Pudney
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Basile Khara
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
| | - Linus O. Johannissen
- Manchester Interdisciplinary Biocentre, School of Chemical Engineering and Analytical Sciences, University of Manchester, Manchester, United Kingdom
| | - Nigel S. Scrutton
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom
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Lah L, Podobnik B, Novak M, Korošec B, Berne S, Vogelsang M, Kraševec N, Zupanec N, Stojan J, Bohlmann J, Komel R. The versatility of the fungal cytochrome P450 monooxygenase system is instrumental in xenobiotic detoxification. Mol Microbiol 2011; 81:1374-89. [PMID: 21810122 DOI: 10.1111/j.1365-2958.2011.07772.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Cytochromes P450 (CYPs) catalyse diverse reactions and are key enzymes in fungal primary and secondary metabolism, and xenobiotic detoxification. CYP enzymatic properties and substrate specificity determine the reaction outcome. However, CYP-mediated reactions may also be influenced by their redox partners. Filamentous fungi with numerous CYPs often possess multiple microsomal redox partners, cytochrome P450 reductases (CPRs). In the plant pathogenic ascomycete Cochliobolus lunatus we recently identified two CPR paralogues, CPR1 and CPR2. Our objective was to functionally characterize two endogenous fungal cytochrome P450 systems and elucidate the putative physiological roles of CPR1 and CPR2. We reconstituted both CPRs with CYP53A15, or benzoate 4-hydroxylase from C. lunatus, which is crucial in the detoxification of phenolic plant defence compounds. Biochemical characterization using RP-HPLC shows that both redox partners support CYP activity, but with different product specificities. When reconstituted with CPR1, CYP53A15 converts benzoic acid to 4-hydroxybenzoic acid, and 3-methoxybenzoic acid to 3-hydroxybenzoic acid. However, when the redox partner is CPR2, both substrates are converted to 3,4-dihydroxybenzoic acid. Deletion mutants and gene expression in mycelia grown on media with inhibitors indicate that CPR1 is important in primary metabolism, whereas CPR2 plays a role in xenobiotic detoxification.
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Affiliation(s)
- Ljerka Lah
- National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia.
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45
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Leferink NGH, Pudney CR, Brenner S, Heyes DJ, Eady RR, Samar Hasnain S, Hay S, Rigby SEJ, Scrutton NS. Gating mechanisms for biological electron transfer: integrating structure with biophysics reveals the nature of redox control in cytochrome P450 reductase and copper-dependent nitrite reductase. FEBS Lett 2011; 586:578-84. [PMID: 21762695 DOI: 10.1016/j.febslet.2011.07.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 07/01/2011] [Accepted: 07/04/2011] [Indexed: 11/16/2022]
Abstract
Biological electron transfer is a fundamentally important reaction. Despite the apparent simplicity of these reactions (in that no bonds are made or broken), their experimental interrogation is often complicated because of adiabatic control exerted through associated chemical and conformational change. We have studied the nature of this control in several enzyme systems, cytochrome P450 reductase, methionine synthase reductase and copper-dependent nitrite reductase. Specifically, we review the evidence for conformational control in cytochrome P450 reductase and methionine synthase reductase and chemical control i.e. proton coupled electron transfer in nitrite reductase. This evidence has accrued through the use and integration of structural, spectroscopic and advanced kinetic methods. This integrated approach is shown to be powerful in dissecting control mechanisms for biological electron transfer and will likely find widespread application in the study of related biological redox systems.
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Affiliation(s)
- Nicole G H Leferink
- Manchester Interdisciplinary Biocentre, Faculty of Life Sciences, University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
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46
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Kenaan C, Zhang H, Shea EV, Hollenberg PF. Uncovering the role of hydrophobic residues in cytochrome P450-cytochrome P450 reductase interactions. Biochemistry 2011; 50:3957-67. [PMID: 21462923 DOI: 10.1021/bi1020748] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cytochrome P450 (CYP or P450)-mediated drug metabolism requires the interaction of P450s with their redox partner, cytochrome P450 reductase (CPR). In this work, we have investigated the role of P450 hydrophobic residues in complex formation with CPR and uncovered novel roles for the surface-exposed residues V267 and L270 of CYP2B4 in mediating CYP2B4--CPR interactions. Using a combination of fluorescence labeling and stopped-flow spectroscopy, we have investigated the basis for these interactions. Specifically, in order to study P450--CPR interactions, a single reactive cysteine was introduced in to a genetically engineered variant of CYP2B4 (C79SC152S) at each of seven strategically selected surface-exposed positions. Each of these cysteine residues was modified by reaction with fluorescein-5-maleimide (FM), and the CYP2B4-FM variants were then used to determine the K(d) of the complex by monitoring fluorescence enhancement in the presence of CPR. Furthermore, the intrinsic K(m) values of the CYP2B4 variants for CPR were measured, and stopped-flow spectroscopy was used to determine the intrinsic kinetics and the extent of reduction of the ferric P450 mutants to the ferrous P450--CO adduct by CPR. A comparison of the results from these three approaches reveals that the sites on P450 exhibiting the greatest changes in fluorescence intensity upon binding CPR are associated with the greatest increases in the K(m) values of the P450 variants for CPR and with the greatest decreases in the rates and extents of reduced P450--CO formation.
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Affiliation(s)
- Cesar Kenaan
- Chemical Biology Doctoral Program, The University of Michigan, Ann Arbor, Michigan 48109, United States
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47
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Xia C, Hamdane D, Shen AL, Choi V, Kasper CB, Pearl NM, Zhang H, Im SC, Waskell L, Kim JJP. Conformational changes of NADPH-cytochrome P450 oxidoreductase are essential for catalysis and cofactor binding. J Biol Chem 2011; 286:16246-60. [PMID: 21345800 DOI: 10.1074/jbc.m111.230532] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The crystal structure of NADPH-cytochrome P450 reductase (CYPOR) implies that a large domain movement is essential for electron transfer from NADPH via FAD and FMN to its redox partners. To test this hypothesis, a disulfide bond was engineered between residues Asp(147) and Arg(514) in the FMN and FAD domains, respectively. The cross-linked form of this mutant protein, designated 147CC514, exhibited a significant decrease in the rate of interflavin electron transfer and large (≥90%) decreases in rates of electron transfer to its redox partners, cytochrome c and cytochrome P450 2B4. Reduction of the disulfide bond restored the ability of the mutant to reduce its redox partners, demonstrating that a conformational change is essential for CYPOR function. The crystal structures of the mutant without and with NADP(+) revealed that the two flavin domains are joined by a disulfide linkage and that the relative orientations of the two flavin rings are twisted ∼20° compared with the wild type, decreasing the surface contact area between the two flavin rings. Comparison of the structures without and with NADP(+) shows movement of the Gly(631)-Asn(635) loop. In the NADP(+)-free structure, the loop adopts a conformation that sterically hinders NADP(H) binding. The structure with NADP(+) shows movement of the Gly(631)-Asn(635) loop to a position that permits NADP(H) binding. Furthermore, comparison of these mutant and wild type structures strongly suggests that the Gly(631)-Asn(635) loop movement controls NADPH binding and NADP(+) release; this loop movement in turn facilitates the flavin domain movement, allowing electron transfer from FMN to the CYPOR redox partners.
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Affiliation(s)
- Chuanwu Xia
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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48
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Zhou X, Li M, Sheng C, Qiu X. NADPH-cytochrome P450 oxidoreductase from the chicken (Gallus gallus): sequence characterization, functional expression and kinetic study. Comp Biochem Physiol C Toxicol Pharmacol 2011; 153:53-9. [PMID: 20728568 DOI: 10.1016/j.cbpc.2010.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 08/09/2010] [Accepted: 08/10/2010] [Indexed: 12/16/2022]
Abstract
Cytochrome P450 monooxygenases have been well known to be responsible for the synthesis of endogenous compounds and the metabolism of exogenous compounds in almost all living organisms, which require NADPH-cytochrome P450 oxidoreductase (POR) as an electron donor to function. In this study, a 2031 bp open reading frame of POR gene was cloned from 35-day-old Roman hen liver, encoding an enzyme of 676 amino acids. Sequence analysis showed that chicken POR shares high homology with other vertebrates PORs and possesses the conserved binding domains of FAD, FMN, and NADPH. The genomic sequences of POR genes from chicken and other four vertebrates have highly conserved exon/intron organization structure. By fusion with bacterial signal peptide, chicken POR gene was functionally expressed in E. coli membrane and showed activities in reduction of cytochrome c and oxidation of NADPH. The Km values for cytochrome c and NADPH were 21.9 ± 2.3 μM and 2.4 ± 0.3 μM respectively. A Ping-Pong mechanism was proposed for chicken POR.
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Affiliation(s)
- Xiaojie Zhou
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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49
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Tah18 transfers electrons to Dre2 in cytosolic iron-sulfur protein biogenesis. Nat Chem Biol 2010; 6:758-65. [PMID: 20802492 DOI: 10.1038/nchembio.432] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 08/03/2010] [Indexed: 11/09/2022]
Abstract
Cytosolic and nuclear iron-sulfur (Fe-S) proteins play key roles in processes such as ribosome maturation, transcription and DNA repair-replication. For biosynthesis of their Fe-S clusters, a dedicated cytosolic Fe-S protein assembly (CIA) machinery is required. Here, we identify the essential flavoprotein Tah18 as a previously unrecognized CIA component and show by cell biological, biochemical and spectroscopic approaches that the complex of Tah18 and the CIA protein Dre2 is part of an electron transfer chain functioning in an early step of cytosolic Fe-S protein biogenesis. Electrons are transferred from NADPH via the FAD- and FMN-containing Tah18 to the Fe-S clusters of Dre2. This electron transfer chain is required for assembly of target but not scaffold Fe-S proteins, suggesting a need for reduction in the generation of stably inserted Fe-S clusters. The pathway is conserved in eukaryotes, as human Ndor1-Ciapin1 proteins can functionally replace yeast Tah18-Dre2.
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Ivanov AS, Gnedenko OV, Molnar AA, Archakov AI, Podust LM. FMN binding site of yeast NADPH-cytochrome P450 reductase exposed at the surface is highly specific. ACS Chem Biol 2010; 5:767-76. [PMID: 20557022 DOI: 10.1021/cb100055v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
NADPH-cytochrome P450 reductase (CPR) transfers two reducing equivalents derived from NADPH via FAD and FMN to microsomal P450 monooxygenases in one-electron transfer steps. The crystal structure of yeast CPR (yCPR) contains a surface-exposed FMN binding site (FMN2 site) at the interface of the FMN binding and connecting domains, in addition to the single buried site that has been observed in rat CPR. This finding provides a testable hypothesis of how intramolecular (between FAD and FMN) and intermolecular (between FMN and P450) electron transfer may occur in CPR. To verify that occupancy of the FMN2 site is not an artifact of crystallization, a surface plasmon resonance (SPR) biosensor technique has been applied to probe the selectivity of this site under functional conditions. A series of kinetic and equilibrium binding experiments involving yCPR immobilized on different sensor chip surfaces was performed using FMN and FAD, as well as FMN-derived compounds, including riboflavin, dimethylalloxazine, and alloxazine, and other molecules that resemble the planar isoalloxazine ring structure. Only FMN and FAD showed stoichiometric binding responses. Binding affinity for FMN was in the submicromolar range, 30 times higher than that for FAD. Association kinetic rates for the yCPR/FMN complex were up to 60-fold higher than for the yCPR/FAD complex. Taken together, these data indicate that (i) the surface-exposed site in yCPR is highly selective toward binding flavins, (ii) binding of FMN in this site is notably favored, and finally, (iii) both the phosphate group and the isoalloxazine ring of FMN are essential for binding.
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Affiliation(s)
- Alexis S. Ivanov
- Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, Moscow 119121, Russia
| | - Oksana V. Gnedenko
- Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, Moscow 119121, Russia
| | - Andrey A. Molnar
- Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, Moscow 119121, Russia
| | - Alexander I. Archakov
- Institute of Biomedical Chemistry, Russian Academy of Medical Sciences, Moscow 119121, Russia
| | - Larissa M. Podust
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94143
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