1
|
Guengerich FP, McCarty KD, Tateishi Y, Liu L. Steroid 17α-hydroxylase/17, 20-lyase (cytochrome P450 17A1). Methods Enzymol 2023; 689:39-63. [PMID: 37802581 DOI: 10.1016/bs.mie.2023.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Cytochrome P450 (P450) 17A1 plays a key role in steroidogenesis, in that this enzyme catalyzes the 17α-hydroxylation of both pregnenolone and progesterone, followed by a lyase reaction to cleave the C-20 land C-21 carbons from each steroid. The reactions are important in the production of both glucocorticoids and androgens. The enzyme is critical in humans but is also a drug target in treatment of prostate cancer. Detailed methods are described for the heterologous expression of human P450 17A1 in bacteria, purification of the recombinant enzyme, reconstitution of the enzyme system in the presence of cytochrome b5, and chromatographic procedures for sensitive analyses of reaction products. Historic assay approaches are reviewed. Some information is also provided about outstanding questions in the research field, including catalytic mechanisms and searches for selective inhibitors.
Collapse
Affiliation(s)
- F Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, United States.
| | - Kevin D McCarty
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Yasuhiro Tateishi
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Lu Liu
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, United States
| |
Collapse
|
2
|
Lee SG, Kim V, Lee GH, Kim C, Jeong E, Guengerich FP, Kim D. Hydroxylation and lyase reactions of steroids catalyzed by mouse cytochrome P450 17A1 (Cyp17a1). J Inorg Biochem 2023; 240:112085. [PMID: 36640554 PMCID: PMC9892303 DOI: 10.1016/j.jinorgbio.2022.112085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/25/2022] [Accepted: 11/25/2022] [Indexed: 01/12/2023]
Abstract
Cytochrome P450 17A1 (CYP17A1) catalyzes 17α-hydroxylation and 17,20-lyase reactions with steroid hormones. Mice contain an orthologous Cyp17a1 enzyme in the genome, and its amino acid sequence has high similarity with human CYP17A1. We purified recombinant mouse Cyp17a1 and characterized its oxidation reactions with progesterone and pregnenolone. The open reading frame of the mouse Cyp17a1 gene was inserted and successfully expressed in Escherichia coli and then purified using Ni2+-nitrilotriacetic acid (NTA) affinity column chromatography. Purified mouse Cyp17a1 displayed typical Type I binding titration spectral changes upon the addition of progesterone, 17α-OH progesterone, pregnenolone, and 17α-OH pregnenolone, with similar binding affinities to those of human CYP17A1. Catalytic activities for 17α-hydroxylation and 17,20-lyase reactions were studied using ultra-performance liquid chromatography (UPLC)-mass spectrometry analysis. Mouse Cyp17a1 showed cytochrome b5 stimulation in catalysis. In comparison to human enzyme, much higher specificity constants (kcat/Km) were observed with mouse Cyp17a1. In the reactions of Δ4-steroids (progesterone and 17α-OH progesterone), the specificity constants were 2100 times higher than the human enzyme. The addition of cytochrome b5 produced significant stimulation of 17,20-lyase activities of mouse Cyp17a1. Two Arg mutants of mouse Cyp17a1 (R347H and R358Q) displayed a larger decrease in 17,20-lyase reaction (from 17α-OH pregnenolone to dehydroepiandrosterone, DHEA) than 17α-hydroxylation, indicating that -as in human CYP17A1-these basic residues in mouse Cyp17a1 are important in interacting with the cytochrome b5 protein in the lyase reactions.
Collapse
Affiliation(s)
- Sung-Gyu Lee
- Department of Biological Sciences, Konkuk University, Seoul 05025, Republic of Korea
| | - Vitchan Kim
- Department of Biological Sciences, Konkuk University, Seoul 05025, Republic of Korea
| | - Gyu-Hyeong Lee
- Department of Biological Sciences, Konkuk University, Seoul 05025, Republic of Korea
| | - Changmin Kim
- Department of Biological Sciences, Konkuk University, Seoul 05025, Republic of Korea
| | - Eunseo Jeong
- Department of Biological Sciences, Konkuk University, Seoul 05025, Republic of Korea
| | - F. Peter Guengerich
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232 USA
| | - Donghak Kim
- Department of Biological Sciences, Konkuk University, Seoul 05025, Republic of Korea.
| |
Collapse
|
3
|
Reed L, Indra R, Mrizova I, Moserova M, Schmeiser HH, Wolf CR, Henderson CJ, Stiborova M, Phillips DH, Arlt VM. Application of hepatic cytochrome b 5/P450 reductase null (HBRN) mice to study the role of cytochrome b 5 in the cytochrome P450-mediated bioactivation of the anticancer drug ellipticine. Toxicol Appl Pharmacol 2019; 366:64-74. [PMID: 30685480 PMCID: PMC6382462 DOI: 10.1016/j.taap.2019.01.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 01/14/2019] [Accepted: 01/22/2019] [Indexed: 01/30/2023]
Abstract
The anticancer drug ellipticine exerts its genotoxic effects after metabolic activation by cytochrome P450 (CYP) enzymes. The present study has examined the role of cytochrome P450 oxidoreductase (POR) and cytochrome b5 (Cyb5), electron donors to P450 enzymes, in the CYP-mediated metabolism and disposition of ellipticine in vivo. We used Hepatic Reductase Null (HRN) and Hepatic Cytochrome b5/P450 Reductase Null (HBRN) mice. HRN mice have POR deleted specifically in hepatocytes; HBRN mice also have Cyb5 deleted in the liver. Mice were treated once with 10 mg/kg body weight ellipticine (n = 4/group) for 24 h. Ellipticine-DNA adduct levels measured by 32P-postlabelling were significantly lower in HRN and HBRN livers than in wild-type (WT) livers; however no significant difference was observed between HRN and HBRN livers. Ellipticine-DNA adduct formation in WT, HRN and HBRN livers correlated with Cyp1a and Cyp3a enzyme activities measured in hepatic microsomes in the presence of NADPH confirming the importance of P450 enzymes in the bioactivation of ellipticine in vivo. Hepatic microsomal fractions were also utilised in incubations with ellipticine and DNA in the presence of NADPH, cofactor for POR, and NADH, cofactor for Cyb5 reductase (Cyb5R), to examine ellipticine-DNA adduct formation. With NADPH adduct formation decreased as electron donors were lost which correlated with the formation of the reactive metabolites 12- and 13-hydroxy-ellipticine in hepatic microsomes. No difference in adduct formation was observed in the presence of NADH. Our study demonstrates that Cyb5 contributes to the P450-mediated bioactivation of ellipticine in vitro, but not in vivo.
Collapse
Affiliation(s)
- Lindsay Reed
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - Radek Indra
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Iveta Mrizova
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Michaela Moserova
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - C Roland Wolf
- Division of Cancer Research, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom
| | - Colin J Henderson
- Division of Cancer Research, Jacqui Wood Cancer Centre, School of Medicine, University of Dundee, Ninewells Hospital, Dundee, United Kingdom
| | - Marie Stiborova
- Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - David H Phillips
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom
| | - Volker M Arlt
- Department of Analytical, Environmental and Forensic Sciences, MRC-PHE Centre for Environment and Health, King's College London, London, United Kingdom.
| |
Collapse
|
4
|
Ahsan F, Gardner QA, Rashid N, Towers GJ, Akhtar M. Preventing the N-terminal processing of human interferon α-2b and its chimeric derivatives expressed in Escherichia coli. Bioorg Chem 2018; 76:294-302. [PMID: 29223806 DOI: 10.1016/j.bioorg.2017.11.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 11/14/2017] [Accepted: 11/17/2017] [Indexed: 10/18/2022]
Abstract
We have previously shown that human interferon α-2b (IFN) produced in Escherichia coli (E. coli) is heterogeneous at the N-terminal, with three major species (Ahsan et al., 2014). These are: (a) the direct translation product of the gene retaining the N-terminal methionine, (b) a species from which the methionyl residue has been removed by E. coli methionyl aminopeptidase to give the native interferon α-2b and (c) in which the N-terminal Cys residue of the latter contains an acetyl group. In this paper we overcome this heterogeneity, using engineered interferon derivatives with phenylalanine residue directly downstream of the N-terminal methionine (Met-Phe-IFN). This modification not only prevented the removal of the N-terminal methionine by E. coli methionyl aminopeptidase but also the subsequent N-acetylation. Critically, Met-Phe-IFN had enhanced activity in a biological assay. N-terminal stabilization was also achieved by fusing human cytochrome b5 at the N-terminal of interferon (b5-IFN-chimera). In this case also, the protein was more active than a reciprocal chimera with cytochrome b5 at the C-terminal of interferon (Met-IFN-b5-chimera). This latter protein also had a heterogeneous N-terminal but addition of phenylalanine following Met, (Met-Phe-IFN-b5-chimera), resolved this problem and gave enhanced biological activity.
Collapse
Affiliation(s)
- Fatima Ahsan
- School of Biological Sciences, University of the Punjab, New Campus, Lahore 54590, Pakistan
| | | | - Naeem Rashid
- School of Biological Sciences, University of the Punjab, New Campus, Lahore 54590, Pakistan
| | - Greg J Towers
- Division of Infection and Immunity, University College London, London WC1E 6BT, UK
| | - Muhammad Akhtar
- School of Biological Sciences, University of the Punjab, New Campus, Lahore 54590, Pakistan; Biological Sciences, University of Southampton, SO17 1BJ, UK.
| |
Collapse
|
5
|
Samhan-Arias AK, Almeida RM, Ramos S, Cordas CM, Moura I, Gutierrez-Merino C, Moura JJG. Topography of human cytochrome b 5/cytochrome b 5 reductase interacting domain and redox alterations upon complex formation. Biochim Biophys Acta Bioenerg 2017; 1859:78-87. [PMID: 29111436 DOI: 10.1016/j.bbabio.2017.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 10/23/2017] [Accepted: 10/27/2017] [Indexed: 10/18/2022]
Abstract
Cytochrome b5 is the main electron acceptor of cytochrome b5 reductase. The interacting domain between both human proteins has been unidentified up to date and very little is known about its redox properties modulation upon complex formation. In this article, we characterized the protein/protein interacting interface by solution NMR and molecular docking. In addition, upon complex formation, we measured an increase of cytochrome b5 reductase flavin autofluorescence that was dependent upon the presence of cytochrome b5. Data analysis of these results allowed us to calculate a dissociation constant value between proteins of 0.5±0.1μM and a 1:1 stoichiometry for the complex formation. In addition, a 30mV negative shift of cytochrome b5 reductase redox potential in presence of cytochrome b5 was also measured. These experiments suggest that the FAD group of cytochrome b5 reductase increase its solvent exposition upon complex formation promoting an efficient electron transfer between the proteins.
Collapse
Affiliation(s)
- Alejandro K Samhan-Arias
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, NOVA, 2829-516 Caparica, Portugal.
| | - Rui M Almeida
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, NOVA, 2829-516 Caparica, Portugal
| | - Susana Ramos
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, NOVA, 2829-516 Caparica, Portugal
| | - Cristina M Cordas
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, NOVA, 2829-516 Caparica, Portugal
| | - Isabel Moura
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, NOVA, 2829-516 Caparica, Portugal
| | - Carlos Gutierrez-Merino
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, Institute of Molecular Pathology Biomarkers, University of Extremadura, 06006 Badajoz, Spain
| | - José J G Moura
- UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, NOVA, 2829-516 Caparica, Portugal.
| |
Collapse
|
6
|
Samhan-Arias AK, Maia LB, Cordas CM, Moura I, Gutierrez-Merino C, Moura JJG. Peroxidase-like activity of cytochrome b 5 is triggered upon hemichrome formation in alkaline pH. Biochim Biophys Acta Proteins Proteom 2017; 1866:373-378. [PMID: 28958890 DOI: 10.1016/j.bbapap.2017.09.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 10/18/2022]
Abstract
In alkaline media (pH12) a catalytic peroxidase activity of cytochrome b5 was found associated to a different conformational state. Upon incubation at this pH, cytochrome b5 electronic absorption spectrum was altered, with disappearance of characteristic bands of cytochrome b5 at pH7.0. The appearance of new electronic absorption bands and EPR measurements support the formation of a cytochrome b5 class B hemichrome with an acquired ability to bind polar ligands. This hemichrome is characterized by a negative formal redox potential and the same folding properties than cytochrome b5 at pH7. The acquired peroxidase-like activity of cytochrome b5 found at pH12, driven by a hemichrome formation, suggests a role of this protein in peroxidation products propagation.
Collapse
Affiliation(s)
- Alejandro K Samhan-Arias
- UCIBIO, REQUIMTE, Departamento de Quimica, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
| | - Luisa B Maia
- UCIBIO, REQUIMTE, Departamento de Quimica, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Cristina M Cordas
- UCIBIO, REQUIMTE, Departamento de Quimica, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Isabel Moura
- UCIBIO, REQUIMTE, Departamento de Quimica, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Carlos Gutierrez-Merino
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, University of Extremadura, 06006, Badajoz, Spain
| | - José J G Moura
- UCIBIO, REQUIMTE, Departamento de Quimica, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
| |
Collapse
|
7
|
Duggal R, Liu Y, Gregory MC, Denisov IG, Kincaid JR, Sligar SG. Evidence that cytochrome b5 acts as a redox donor in CYP17A1 mediated androgen synthesis. Biochem Biophys Res Commun 2016; 477:202-8. [PMID: 27297105 DOI: 10.1016/j.bbrc.2016.06.043] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 06/09/2016] [Indexed: 02/02/2023]
Abstract
Cytochrome P450 17A1 (CYP17A1) is an important drug target for castration resistant prostate cancer. It is a bi-functional enzyme, catalyzing production of glucocorticoid precursors by hydroxylation of pregnene-nucleus, and androgen biosynthesis by a second CC lyase step, at the expense of glucocorticoid production. Cytochrome b5 (cyt b5) is known to be a key regulator of the androgen synthesis reaction in vivo, by a mechanism that is not well understood. Two hypotheses have been proposed for the mechanism by which cyt b5 increases androgen biosynthesis. Cyt b5 could act as an allosteric effector, binding to CYP17A1 and either changing its selective substrate affinity or altering the conformation of the P450 to increase the catalytic rate or decrease unproductive uncoupling channels. Alternatively, cyt b5 could act as a redox donor for supply of the second electron in the P450 cycle, reducing the oxyferrous complex to form the reactive peroxo-intermediate. To understand the mechanism of lyase enhancement by cyt b5, we generated a redox-inactive form of cyt b5, in which the heme is replaced with a Manganese-protoporphyrin IX (Mn-b5), and investigated enhancement of androgen producing lyase reaction by CYP17A1. Given the critical significance of a stable membrane anchor for all of the proteins involved and the need for controlled stoichiometric ratios, we employed the Nanodisc system for this study. The redox inactive form was observed to have no effect on the lyase reaction, while reactions with the normal heme-iron containing cyt b5 were enhanced ∼5 fold as compared to reactions in the absence of cyt b5. We also performed resonance Raman measurements on ferric CYP17A1 bound to Mn-b5. Upon addition of Mn-b5 to Nanodisc reconstituted CYP17A1, we observed clear evidence for the formation of a b5-CYP17A1 complex, as noted by changes in the porphyrin modes and alteration in the proximal FeS vibrational frequency. Thus, although Mn-b5 binds to CYP17A1, it is unable to enhance the lyase reaction, strongly suggesting that cyt b5 has a redox effector role in enhancement of the CYP17A1 mediated lyase reaction necessary for androgen synthesis.
Collapse
|
8
|
Hatakeyama M, Kitaoka T, Ichinose H. Heterologous expression of fungal cytochromes P450 (CYP5136A1 and CYP5136A3) from the white-rot basidiomycete Phanerochaete chrysosporium: Functionalization with cytochrome b5 in Escherichia coli. Enzyme Microb Technol 2016; 89:7-14. [PMID: 27233123 DOI: 10.1016/j.enzmictec.2016.03.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 02/14/2016] [Accepted: 03/08/2016] [Indexed: 12/21/2022]
Abstract
Cytochromes P450 from the white-rot basidiomycete Phanerochaete chrysosporium, CYP5136A1 and CYP5136A3, are capable of catalyzing oxygenation reactions of a wide variety of exogenous compounds, implying their significant roles in the metabolism of xenobiotics by the fungus. It is therefore interesting to explore their biochemistry to better understand fungal biology and to enable the use of fungal enzymes in the biotechnology sector. In the present study, we developed heterologous expression systems for CYP5136A1 and CYP5136A3 using the T7 RNA polymerase/promoter system in Escherichia coli. Expression levels of recombinant P450s were dramatically improved by modifications and optimization of their N-terminal amino acid sequences. A CYP5136A1 reaction system was reconstructed in E. coli whole cells by coexpression of CYP5136A1 and a redox partner, NADPH-dependent P450 reductase (CPR). The catalytic activity of CYP5136A1 was significantly increased when cytochrome b5 (Cyt-b5) was further coexpressed with CPR, indicating that Cyt-b5 supports electron transfer reactions from NAD(P)H to CYP5136A1. Notably, P450 reaction occurred in E. coli cells that harbored CYP5136A1 and Cyt-b5 but not CPR, implying that the reducing equivalents required for the P450 catalytic cycle were transferred via a CPR-independent pathway. Such an "alternative" electron transfer system in CYP5136A1 reaction was also demonstrated using purified enzymes in vitro. The fungal P450 reaction system may be associated with sophisticated electron transfer pathways.
Collapse
Affiliation(s)
- Mayumi Hatakeyama
- Faculty of Agriculture, Kyushu University, 6-10-(1) Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
| | - Takuya Kitaoka
- Faculty of Agriculture, Kyushu University, 6-10-(1) Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
| | - Hirofumi Ichinose
- Faculty of Agriculture, Kyushu University, 6-10-(1) Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
| |
Collapse
|
9
|
Graham KM, Sparagano OAE, Finn RD. Isolation of the monooxygenase complex from Rhipicephalus (Boophilus) microplus - clues to understanding acaricide resistance. Ticks Tick Borne Dis 2016; 7:614-23. [PMID: 26850353 DOI: 10.1016/j.ttbdis.2016.01.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 12/16/2015] [Accepted: 01/19/2016] [Indexed: 11/26/2022]
Abstract
The monooxygenase complex is composed of three key proteins, a cytochrome P450 (CYP), the cytochrome P450 oxidoreductase (CPR) and cytochrome b5 and plays a key role in the metabolism and detoxification of xenobiotic substances, including pesticides. In addition, overexpression of these components has been linked to pesticide resistance in several important vectors of disease. Despite this, the monooxygenase complex has not been isolated from the Southern cattle tick Rhipicephalus (Boophilus) microplus, a major disease vector in livestock. Using bioinformatics 115 transcriptomic sequences were analyzed to identify putative pesticide metabolizing CYPs. RACE-PCR was used to amplify the full length sequence of one CYP; CYP3006G8 which displays a high degree of homology to members of the CYP6 and 9 subfamilies, known to metabolize pyrethroids. mRNA expression levels of CYP3006G8 were investigated in 11 strains of R. microplus with differing resistance profiles by qPCR, the results of which indicated a correlation with pyrethroid metabolic resistance. In addition to this gene, the sequences for CPR and cytochrome b5 were also identified and subsequently isolated from R. microplus using PCR. CYP3006G8 is only the third CYP gene isolated from R. microplus and the first to putatively metabolize pesticides. The initial results of expression analysis suggest that CYP3006G8 metabolizes pyrethroids but further biochemical characterization is required to confirm this. Differences in the kinetic parameters of human and mosquito CPR in terms of NADPH binding have been demonstrated and could potentially be used to design species specific pesticides. Similar differences in the tick CPR would confirm that this is a characteristic of heamatophagous arthropods.
Collapse
Affiliation(s)
- Kirsty M Graham
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University Newcastle, Ellison Building, Ellison Place, Newcastle Upon Tyne, NE1 8ST, UK.
| | - Olivier A E Sparagano
- Coventry University, Alan Berry Building, Coventry University, Priory Street, Coventry, CV1 5FB, UK.
| | - Robert D Finn
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University Newcastle, Ellison Building, Ellison Place, Newcastle Upon Tyne, NE1 8ST, UK.
| |
Collapse
|
10
|
Storbeck KH, Swart AC, Fox CL, Swart P. Cytochrome b5 modulates multiple reactions in steroidogenesis by diverse mechanisms. J Steroid Biochem Mol Biol 2015; 151:66-73. [PMID: 25446886 DOI: 10.1016/j.jsbmb.2014.11.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 11/02/2014] [Accepted: 11/21/2014] [Indexed: 12/18/2022]
Abstract
Cytochrome b5 (cyt-b5) is a relatively small haemoprotein which plays an important role in the regulation of mammalian steroidogenesis. This unique protein has the ability to modulate the activity of key steroidogenic enzymes via a number of diverse reaction mechanisms. Cyt-b5 can augment the 17,20-lyase activity of CYP17A1 by promoting the interaction of CYP17A1 and POR; enhance the 16-ene-synthase activity of CYP17A1 by acting as an electron donor; and enhance the activity of 3βHSD by increasing the affinity of 3βHSD for its cofactor NAD(+). We review the modulation of CYP17A1 and 3βHSD activity by cyt-b5 and discuss the reaction mechanisms associated with each activity. The physiological importance of cyt-b5 in regulating mammalian steroidogenesis is presented and the impact of inactivating cyt-b5 mutations are reviewed. This article is part of a Special Issue entitled 'Steroid/Sterol signaling'.
Collapse
Affiliation(s)
- Karl-Heinz Storbeck
- Department of Biochemistry, University of Stellenbosch, Stellenbosch 7600, South Africa
| | - Amanda C Swart
- Department of Biochemistry, University of Stellenbosch, Stellenbosch 7600, South Africa
| | - Cheryl L Fox
- Department of Biochemistry, University of Stellenbosch, Stellenbosch 7600, South Africa
| | - Pieter Swart
- Department of Biochemistry, University of Stellenbosch, Stellenbosch 7600, South Africa.
| |
Collapse
|
11
|
Abstract
A single enzyme, microsomal P450c17, catalyzes the 17α-hydroxylase activity needed to make cortisol and the subsequent 17,20 lyase activity needed to produce the 19-carbon precursors of sex steroids. The biochemical decision concerning whether P450c17 stops after 17α-hydroxylation or proceeds to 17,20 lyase activity is largely dependent on three post-translational factors. First, 17,20 lyase activity is especially sensitive to the molar abundance of the electron-transfer protein P450 oxidoreductase (POR). Second, cytochrome b5 strongly promotes 17,20 lyase activity, principally by acting as an allosteric factor promoting the interaction of P450c17 with POR, although a minor role as an alternative electron-transfer protein has not been wholly excluded. Third, the serine/threonine phosphorylation of P450c17 itself promotes 17,20 lyase activity, again apparently by promoting the interaction of P450c17 with POR. The principal kinase that phosphorylates P450c17 to confer 17,20 lyase activity appears to be p38α (MAPK14), which increases the maximum velocity of the 17,20 lyase reaction, while having no effect on the Michaelis constant for 17,20 lyase or any detectable effect on the 17α-hydroxylase reaction. Other kinases can also phosphorylate P450c17, but only p38α has been shown to affect its enzymology. Understanding the mechanisms regulating 17,20 lyase activity is essential for the understanding of hyperandrogenic disorders such as premature, exaggerated adrenarche and the polycystic ovary syndrome, and also for the design of selective 17,20 lyase inhibitors for use in hyperandrogenic states and in sex-steroid dependent cancers.
Collapse
Affiliation(s)
- Walter L Miller
- Department of Pediatrics, University of California, San Francisco, CA 94143-0978, USA.
| | - Meng Kian Tee
- Department of Pediatrics, University of California, San Francisco, CA 94143-0978, USA
| |
Collapse
|
12
|
Stiborová M, Moserová M, Černá V, Indra R, Dračínský M, Šulc M, Henderson CJ, Wolf CR, Schmeiser HH, Phillips DH, Frei E, Arlt VM. Cytochrome b5 and epoxide hydrolase contribute to benzo[a]pyrene-DNA adduct formation catalyzed by cytochrome P450 1A1 under low NADPH:P450 oxidoreductase conditions. Toxicology 2014; 318:1-12. [PMID: 24530354 DOI: 10.1016/j.tox.2014.02.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 01/31/2014] [Accepted: 02/04/2014] [Indexed: 10/25/2022]
Abstract
In previous studies we had administered benzo[a]pyrene (BaP) to genetically engineered mice (HRN) which do not express NADPH:cytochrome P450 oxidoreductase (POR) in hepatocytes and observed higher DNA adduct levels in livers of these mice than in wild-type mice. To elucidate the reason for this unexpected finding we have used two different settings for in vitro incubations; hepatic microsomes from control and BaP-pretreated HRN mice and reconstituted systems with cytochrome P450 1A1 (CYP1A1), POR, cytochrome b5, and epoxide hydrolase (mEH) in different ratios. In microsomes from BaP-pretreated mice, in which Cyp1a1 was induced, higher levels of BaP metabolites were formed, mainly of BaP-7,8-dihydrodiol. At a low POR:CYP1A1 ratio of 0.05:1 in the reconstituted system, the amounts of BaP diones and BaP-9-ol formed were essentially the same as at an equimolar ratio, but formation of BaP-3-ol was ∼ 1.6-fold higher. Only after addition of mEH were BaP dihydrodiols found. Two BaP-DNA adducts were formed in the presence of mEH, but only one when CYP1A1 and POR were present alone. At a ratio of POR:CYP1A1 of 0.05:1, addition of cytochrome b5 increased CYP1A1-mediated BaP oxidation to most of its metabolites indicating that cytochrome b5 participates in the electron transfer from NADPH to CYP1A1 required for enzyme activity of this CYP. BaP-9-ol was formed even by CYP1A1 reconstituted with cytochrome b5 without POR. Our results suggest that in livers of HRN mice Cyp1a1, cytochrome b5 and mEH can effectively activate BaP to DNA binding species, even in the presence of very low amounts of POR.
Collapse
Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic.
| | - Michaela Moserová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Věra Černá
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Radek Indra
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Martin Dračínský
- Institute of Organic Chemistry and Biochemistry, v.v.i. Academy of Sciences, Flemingovo n. 2, 166 10 Prague 6, Czech Republic
| | - Miroslav Šulc
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Colin J Henderson
- Division of Cancer Research, Medical Research Institute, Jacqui Wood Cancer Centre, University of Dundee, Dundee DD1 9SY, United Kingdom
| | - C Roland Wolf
- Division of Cancer Research, Medical Research Institute, Jacqui Wood Cancer Centre, University of Dundee, Dundee DD1 9SY, United Kingdom
| | - Heinz H Schmeiser
- Research Group Genetic Alterations in Carcinogenesis, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - David H Phillips
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, 150 Stamford Street, London SE1 9NH, United Kingdom
| | - Eva Frei
- Division of Preventive Oncology, National Center for Tumour Diseases, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, 150 Stamford Street, London SE1 9NH, United Kingdom
| |
Collapse
|
13
|
Keeling CI, Henderson H, Li M, Dullat HK, Ohnishi T, Bohlmann J. CYP345E2, an antenna-specific cytochrome P450 from the mountain pine beetle, Dendroctonus ponderosae Hopkins, catalyses the oxidation of pine host monoterpene volatiles. Insect Biochem Mol Biol 2013; 43:1142-1151. [PMID: 24139909 DOI: 10.1016/j.ibmb.2013.10.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 09/27/2013] [Accepted: 10/02/2013] [Indexed: 06/02/2023]
Abstract
The mountain pine beetle (MPB, Dendroctonus ponderosae Hopkins) is a significant pest of western North American pine forests. This beetle responds to pheromones and host volatiles in order to mass attack and thus overcome the terpenoid chemical defences of its host. The ability of MPB antennae to rapidly process odorants is necessary to avoid odorant receptor saturation and thus the enzymes responsible for odorant clearance are an important aspect of host colonization. An antenna-specific cytochrome P450, DponCYP345E2, is the most highly expressed transcript in adult MPB antenna. In in vitro assays with recombinant enzyme, DponCYP345E2 used several pine host monoterpenes as substrates, including (+)-(3)-carene, (+)-β-pinene, (-)-β-pinene, (+)-limonene, (-)-limonene, (-)-camphene, (+)-α-pinene, (-)-α-pinene, and terpinolene. The substrates were epoxidized or hydroxylated, depending upon the substrate. To complement DponCYP345E2, we also functionally characterized the NADPH-dependent cytochrome P450 reductase and the cytochrome b5 from MPB. DponCYP345E2 is the first cytochrome P450 to be functionally characterized in insect olfaction and in MPB.
Collapse
Affiliation(s)
- Christopher I Keeling
- Michael Smith Laboratories, University of British Columbia, 301-2185 East Mall, Vancouver, BC, Canada V6T 1A4.
| | | | | | | | | | | |
Collapse
|
14
|
Peng HM, Auchus RJ. Two surfaces of cytochrome b5 with major and minor contributions to CYP3A4-catalyzed steroid and nifedipine oxygenation chemistries. Arch Biochem Biophys 2013; 541:53-60. [PMID: 24256945 DOI: 10.1016/j.abb.2013.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 10/22/2013] [Accepted: 11/04/2013] [Indexed: 10/26/2022]
Abstract
Conserved human cytochrome b5 (b5) residues D58 and D65 are critical for interactions with CYP2E1 and CYP2C19, whereas E48 and E49 are essential for stimulating the 17,20-lyase activity of CYP17A1. Here, we show that b5 mutations E48G, E49G, D58G, and D65G have reduced capacity to stimulate CYP3A4-catalyzed progesterone and testosterone 6β-hydroxylation or nifedipine oxidation. The b5 double mutation D58G/D65G fails to stimulate these reactions, similar to CYP2E1 and CYP2C19, whereas mutation E48G/E49G retains 23-42% of wild-type stimulation. Neither mutation impairs the activity stimulation of wild-type b5, nor does mutation D58G/D65G impair the partial stimulation of mutations E48G or E48G/E49G. For assays reconstituted with a single phospholipid, phosphatidyl serine afforded the highest testosterone 6β-hydroxylase activity with wild-type b5 but the poorest activity with b5 mutation E48G/E49G, and the activity stimulation of mutation E48G/E49G was lost at [NaCl]>50mM. Cross-linking of CYP3A4 and b5 decreased in the order wild-type>E48G/E49G>D58G/D65G and varied with phospholipid. We conclude that two b5 acidic surfaces, primarily the domain including residues D58-D65, participate in the stimulation of CYP3A4 activities. Our data suggest that a minor population of CYP3A4 molecules remains sensitive to b5 mutation E48G/E49G, consistent with phospholipid-dependent conformational heterogeneity of CYP3A4.
Collapse
Affiliation(s)
- Hwei-Ming Peng
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, United States
| | - Richard J Auchus
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, United States.
| |
Collapse
|