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Jecmen T, Tuzhilkin R, Sulc M. Photo-Methionine, Azidohomoalanine and Homopropargylglycine Are Incorporated into Newly Synthesized Proteins at Different Rates and Differentially Affect the Growth and Protein Expression Levels of Auxotrophic and Prototrophic E. coli in Minimal Medium. Int J Mol Sci 2023; 24:11779. [PMID: 37511538 PMCID: PMC10380393 DOI: 10.3390/ijms241411779] [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: 06/01/2023] [Revised: 07/06/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023] Open
Abstract
Residue-specific incorporation of non-canonical amino acids (ncAAs) introduces bio-orthogonal functionalities into proteins. As such, this technique is applied in protein characterization and quantification. Here, we studied protein expression with three methionine analogs, namely photo-methionine (pMet), azidohomoalanine (Aha) and homopropargylglycine (Hpg), in prototrophic E. coli BL-21 and auxotrophic E. coli B834 to maximize ncAA content, thereby assessing the effect of ncAAs on bacterial growth and the expression of cytochrome b5 (b5M46), green fluorescence protein (MBP-GFP) and phage shock protein A. In auxotrophic E. coli, ncAA incorporation ranged from 50 to 70% for pMet and reached approximately 50% for Aha, after 26 h expression, with medium and low expression levels of MBP-GFP and b5M46, respectively. In the prototrophic strain, by contrast, the protein expression levels were higher, albeit with a sharp decrease in the ncAA content after the first hours of expression. Similar expression levels and 70-80% incorporation rates were achieved in both bacterial strains with Hpg. Our findings provide guidance for expressing proteins with a high content of ncAAs, highlight pitfalls in determining the levels of methionine replacement by ncAAs by MALDI-TOF mass spectrometry and indicate a possible systematic bias in metabolic labeling techniques using Aha or Hpg.
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Affiliation(s)
- Tomas Jecmen
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 43 Prague, Czech Republic
| | - Roman Tuzhilkin
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 43 Prague, Czech Republic
| | - Miroslav Sulc
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 43 Prague, Czech Republic
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Stiborová M, Indra R, Moserová M, Šulc M, Hodek P, Frei E, Schmeiser HH, Arlt VM. NADPH- and NADH-dependent metabolism of and DNA adduct formation by benzo[ a]pyrene catalyzed with rat hepatic microsomes and cytochrome P450 1A1. MONATSHEFTE FUR CHEMIE 2016; 147:847-855. [PMID: 27110038 PMCID: PMC4828493 DOI: 10.1007/s00706-016-1713-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 02/11/2016] [Indexed: 11/11/2022]
Abstract
ABSTRACT Benzo[a]pyrene (BaP) is a human carcinogen that covalently binds to DNA after metabolic activation by cytochrome P450 (CYP) enzymes. Here we investigated the efficiencies of rat hepatic microsomes and rat recombinant CYP1A1 expressed with its reductase, NADPH:CYP oxidoreductase (POR), NADH:cytochrome b5 reductase, epoxide hydrolase and/or cytochrome b5 in Supersomes™ to metabolize this carcinogen. We also studied the effectiveness of coenzymes of two of the microsomal reductases, NADPH as a coenzyme of POR, and NADH as a coenzyme of NADH:cytochrome b5 reductase, to mediate BaP metabolism in these systems. Up to eight BaP metabolites and two DNA adducts were generated by the systems, both in the presence of NADPH and NADH. Among BaP metabolites, BaP-9,10-dihydrodiol, BaP-4,5-dihydrodiol, BaP-7,8-dihydrodiol, BaP-1,6-dione, BaP-3,6-dione, BaP-9-ol, BaP-3-ol, and a metabolite of unknown structure were formed by hepatic microsomes and rat CYP1A1. One of two DNA adducts formed by examined enzymatic systems (rat hepatic microsomes and rat CYP1A1) was characterized to be 10-(deoxyguanosin-N2-yl)-7,8,9-trihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene (dG-N2-BPDE), while another adduct has similar chromatographic properties on polyethylaneimine-cellulose thin layer chromatography to a guanine adduct derived from reaction with 9-hydroxy-BaP-4,5-oxide. In the presence of either of the reductase cofactors tested, NADPH or NADH, cytochrome b5 stimulated CYP1A1-mediated formation of both BaP-DNA adducts. The results demonstrate that NADH can act as a sole electron donor for both the first and the second reduction of CYP1A1 during its reaction cycle catalyzing oxidation of BaP, and suggest that the NADH:cytochrome b5 reductase as the NADH-dependent reductase might substitute POR in this enzymatic system. GRAPHICAL ABSTRACT
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Affiliation(s)
- Marie Stiborová
- />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
| | - Michaela Moserová
- />Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Miroslav Šulc
- />Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Petr Hodek
- />Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Eva Frei
- />Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Heinz H. Schmeiser
- />Division of Radiopharmaceutical Chemistry, 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, London, SE1 9NH UK
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Stiborová M, Moserová M, Mrízová I, Dračínská H, Martínek V, Indra R, Frei E, Adam V, Kizek R, Schmeiser HH, Kubáčková K, Arlt VM. Induced expression of microsomal cytochrome b5 determined at mRNA and protein levels in rats exposed to ellipticine, benzo[ a]pyrene, and 1-phenylazo-2-naphthol (Sudan I). MONATSHEFTE FUR CHEMIE 2016; 147:897-904. [PMID: 27110040 PMCID: PMC4828491 DOI: 10.1007/s00706-015-1636-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Accepted: 12/13/2015] [Indexed: 11/29/2022]
Abstract
ABSTRACT The microsomal protein cytochrome b5 , which is located in the membrane of the endoplasmic reticulum, has been shown to modulate many reactions catalyzed by cytochrome P450 (CYP) enzymes. We investigated the influence of exposure to the anticancer drug ellipticine and to two environmental carcinogens, benzo[a]pyrene (BaP) and 1-phenylazo-2-naphthol (Sudan I), on the expression of cytochrome b5 in livers of rats, both at the mRNA and protein levels. We also studied the effects of these compounds on their own metabolism and the formation of DNA adducts generated by their activation metabolite(s) in vitro. The relative amounts of cytochrome b5 mRNA, measured by real-time polymerase chain reaction analysis, were induced by the test compounds up to 11.7-fold in rat livers. Western blotting using antibodies raised against cytochrome b5 showed that protein expression was induced by up to sevenfold in livers of treated rats. Microsomes isolated from livers of exposed rats catalyzed the oxidation of ellipticine, BaP, and Sudan I and the formation of DNA adducts generated by their reactive metabolite(s) more effectively than hepatic microsomes isolated from control rats. All test compounds are known to induce CYP1A1. This induction is one of the reasons responsible for increased oxidation of these xenobiotics by microsomes. However, induction of cytochrome b5 can also contribute to their enhanced metabolism. GRAPHICAL ABSTRACT
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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
| | - Iveta Mrízová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Helena Dračínská
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Václav Martínek
- 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
| | - Eva Frei
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Vojtěch Adam
- Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, 613 00 Brno, Czech Republic
| | - René Kizek
- Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University in Brno, 613 00 Brno, Czech Republic
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Kateřina Kubáčková
- Department of Oncology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, V Uvalu 84, 150 06 Prague 5, Czech Republic
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London, SE1 9NH UK
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Stiborová M, Bárta F, Levová K, Hodek P, Schmeiser HH, Arlt VM, Martínek V. A Mechanism of O-Demethylation of Aristolochic Acid I by Cytochromes P450 and Their Contributions to This Reaction in Human and Rat Livers: Experimental and Theoretical Approaches. Int J Mol Sci 2015; 16:27561-75. [PMID: 26593908 PMCID: PMC4661905 DOI: 10.3390/ijms161126047] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 10/30/2015] [Accepted: 11/05/2015] [Indexed: 01/30/2023] Open
Abstract
Aristolochic acid I (AAI) is a plant alkaloid causing aristolochic acid nephropathy, Balkan endemic nephropathy and their associated urothelial malignancies. AAI is detoxified by cytochrome P450 (CYP)-mediated O-demethylation to 8-hydroxyaristolochic acid I (aristolochic acid Ia, AAIa). We previously investigated the efficiencies of human and rat CYPs in the presence of two other components of the mixed-functions-oxidase system, NADPH:CYP oxidoreductase and cytochrome b₅, to oxidize AAI. Human and rat CYP1A are the major enzymes oxidizing AAI. Other CYPs such as CYP2C, 3A4, 2D6, 2E1, and 1B1, also form AAIa, but with much lower efficiency than CYP1A. Based on velocities of AAIa formation by examined CYPs and their expression levels in human and rat livers, here we determined the contributions of individual CYPs to AAI oxidation in these organs. Human CYP1A2 followed by CYP2C9, 3A4 and 1A1 were the major enzymes contributing to AAI oxidation in human liver, while CYP2C and 1A were most important in rat liver. We employed flexible in silico docking methods to explain the differences in AAI oxidation in the liver by human CYP1A1, 1A2, 2C9, and 3A4, the enzymes that all O-demethylate AAI, but with different effectiveness. We found that the binding orientations of the methoxy group of AAI in binding centers of the CYP enzymes and the energies of AAI binding to the CYP active sites dictate the efficiency of AAI oxidation. Our results indicate that utilization of experimental and theoretical methods is an appropriate study design to examine the CYP-catalyzed reaction mechanisms of AAI oxidation and contributions of human hepatic CYPs to this metabolism.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2 CZ-12843, Czech Republic.
| | - František Bárta
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2 CZ-12843, Czech Republic.
| | - Kateřina Levová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2 CZ-12843, Czech Republic.
| | - Petr Hodek
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2 CZ-12843, Czech Republic.
| | - Heinz H Schmeiser
- Division of Radiopharmaceutical Chemistry, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg 69120, Germany.
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environment and Health, King's College London, London SE1 9NH, UK.
| | - Václav Martínek
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, Prague 2 CZ-12843, Czech Republic.
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Ječmen T, Ptáčková R, Černá V, Dračínská H, Hodek P, Stiborová M, Hudeček J, Šulc M. Photo-initiated crosslinking extends mapping of the protein-protein interface to membrane-embedded portions of cytochromes P450 2B4 and b₅. Methods 2015; 89:128-37. [PMID: 26235815 DOI: 10.1016/j.ymeth.2015.07.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 01/17/2023] Open
Abstract
Protein-protein interactions play a central role in the regulation of many biochemical processes (e.g. the system participating in enzyme catalysis). Therefore, a deeper understanding of protein-protein interactions may contribute to the elucidation of many biologically important mechanisms. For this purpose, it is necessary to establish the composition and stoichiometry of supramolecular complexes and to identify the crucial portions of the interacting molecules. This study is devoted to structure-functional relationships in the microsomal Mixed Function Oxidase (MFO) complex, which is responsible for biotransformation of many hydrophobic endogenous compounds and xenobiotics. In particular, the cytochrome b5 interaction with MFO terminal oxygenase cytochrome P-450 (P450) was studied. To create photolabile probes suitable for this purpose, we prepared cytochrome b5 which had a photolabile diazirine analog of methionine (pMet) incorporated into the protein sequence, employing recombinant expression in Escherichia coli. In addition to wild-type cytochrome b5, where three methionines (Met) are located at positions 96, 126, and 131, six mutants containing only one Met in the sequence were designed and expressed (see Table 1). In these mutants, a single Met was engineered into the catalytic domain (at positions 23, 41, or 46), into the linker between the protein domains (at position 96), or into the membrane region (at positions 126 or 131). These mutants should confirm or exclude these portions of cytochrome b5 which are involved in the interaction with P450. After UV irradiation, the pMet group(s) in the photolabile cytochrome b5 probe was(were) activated, producing covalent crosslinks with the interacting parts of P450 2B4 in the close vicinity. The covalent complexes were analyzed by the "bottom up" approach with high-accuracy mass spectrometry. The analysis provided an identification of the contacts in the supramolecular complex with low structural resolution. We found that all the above-mentioned cytochrome b5 Met residues can form intermolecular crosslinks and thus participate in the interaction. In addition, our results indicate the existence of at least two P450:cytochrome b5 complexes which differ in the orientation of individual proteins. The results demonstrate the advantages of the photo-initiated crosslinking technique which is able to map the protein-protein interfaces not only in the solvent exposed regions, but also in the membrane-embedded segments (compared to a typical crosslinking approach which generally only identifies crosslinks in solvent exposed regions).
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Affiliation(s)
- Tomáš Ječmen
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic; Institute of Microbiology v.v.i., Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ-14220 Prague 4, Czech Republic
| | - Renata Ptáčková
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic; Institute of Microbiology v.v.i., Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ-14220 Prague 4, Czech Republic
| | - Věra Černá
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic
| | - Helena Dračínská
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic
| | - Petr Hodek
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic
| | - Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic
| | - Jiří Hudeček
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic
| | - Miroslav Šulc
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic; Institute of Microbiology v.v.i., Academy of Sciences of the Czech Republic, Vídeňská 1083, CZ-14220 Prague 4, Czech Republic.
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Stiborová M, Černá V, Moserová M, Mrízová I, Arlt VM, Frei E. The anticancer drug ellipticine activated with cytochrome P450 mediates DNA damage determining its pharmacological efficiencies: studies with rats, Hepatic Cytochrome P450 Reductase Null (HRN™) mice and pure enzymes. Int J Mol Sci 2014; 16:284-306. [PMID: 25547492 PMCID: PMC4307247 DOI: 10.3390/ijms16010284] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Accepted: 12/17/2014] [Indexed: 12/30/2022] Open
Abstract
Ellipticine is a DNA-damaging agent acting as a prodrug whose pharmacological efficiencies and genotoxic side effects are dictated by activation with cytochrome P450 (CYP). Over the last decade we have gained extensive experience in using pure enzymes and various animal models that helped to identify CYPs metabolizing ellipticine. In this review we focus on comparison between the in vitro and in vivo studies and show a necessity of both approaches to obtain valid information on CYP enzymes contributing to ellipticine metabolism. Discrepancies were found between the CYP enzymes activating ellipticine to 13-hydroxy- and 12-hydroxyellipticine generating covalent DNA adducts and those detoxifying this drug to 9-hydroxy- and 7-hydroellipticine in vitro and in vivo. In vivo, formation of ellipticine-DNA adducts is dependent not only on expression levels of CYP3A, catalyzing ellipticine activation in vitro, but also on those of CYP1A that oxidize ellipticine in vitro mainly to the detoxification products. The finding showing that cytochrome b5 alters the ratio of ellipticine metabolites generated by CYP1A1/2 and 3A4 explained this paradox. Whereas the detoxification of ellipticine by CYP1A and 3A is either decreased or not changed by cytochrome b5, activation leading to ellipticine-DNA adducts increased considerably. We show that (I) the pharmacological effects of ellipticine mediated by covalent ellipticine-derived DNA adducts are dictated by expression levels of CYP1A, 3A and cytochrome b5, and its own potency to induce these enzymes in tumor tissues, (II) animal models, where levels of CYPs are either knocked out or induced are appropriate to identify CYPs metabolizing ellipticine in vivo, and (III) extrapolation from in vitro data to the situation in vivo is not always possible, confirming the need for these animal models.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic.
| | - Věra Černá
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic.
| | - Michaela Moserová
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic.
| | - Iveta Mrízová
- Department of Biochemistry, Faculty of Science, Charles University, Hlavova 2030, CZ-12843 Prague 2, Czech Republic.
| | - Volker M Arlt
- Analytical and Environmental Sciences Division, MRC-PHE Centre for Environmental & Health, King's College London, 150 Stamford Street, London SE1 9NH, UK.
| | - Eva Frei
- Division of Preventive Oncology, National Center for Tumor Diseases, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
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Jeřábek P, Florián J, Stiborová M, Martínek V. Flexible docking-based molecular dynamics/steered molecular dynamics calculations of protein-protein contacts in a complex of cytochrome P450 1A2 with cytochrome b5. Biochemistry 2014; 53:6695-705. [PMID: 25313797 DOI: 10.1021/bi500814t] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Formation of transient complexes of cytochrome P450 (P450) with another protein of the endoplasmic reticulum membrane, cytochrome b5 (cyt b5), dictates the catalytic activities of several P450s. Therefore, we examined formation and binding modes of the complex of human P450 1A2 with cyt b5. Docking of soluble domains of these proteins was performed using an information-driven flexible docking approach implemented in HADDOCK. Stabilities of the five unique binding modes of the P450 1A2-cyt b5 complex yielded by HADDOCK were evaluated using explicit 10 ns molecular dynamics (MD) simulations in aqueous solution. Further, steered MD was used to compare the stability of the individual P450 1A2-cyt b5 binding modes. The best binding mode was characterized by a T-shaped mutual orientation of the porphyrin rings and a 10.7 Å distance between the two redox centers, thus satisfying the condition for a fast electron transfer. Mutagenesis studies and chemical cross-linking, which, in the absence of crystal structures, were previously used to deduce specific P450-cyt b5 interactions, indicated that the negatively charged convex surface of cyt b5 binds to the positively charged concave surface of P450. Our simulations further elaborate structural details of this interface, including nine ion pairs between R95, R100, R138, R362, K442, K455, and K465 side chains of P450 1A2 and E42, E43, E49, D65, D71, and heme propionates of cyt b5. The universal heme-centric system of internal coordinates was proposed to facilitate consistent classification of the orientation of the two porphyrins in any protein complex.
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Affiliation(s)
- Petr Jeřábek
- Department of Biochemistry, Faculty of Science, Charles University in Prague , Albertov 2030, 128 43 Prague 2, Czech Republic
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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] [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.
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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
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Plitzko B, Ott G, Reichmann D, Henderson CJ, Wolf CR, Mendel R, Bittner F, Clement B, Havemeyer A. The involvement of mitochondrial amidoxime reducing components 1 and 2 and mitochondrial cytochrome b5 in N-reductive metabolism in human cells. J Biol Chem 2013; 288:20228-37. [PMID: 23703616 PMCID: PMC3711290 DOI: 10.1074/jbc.m113.474916] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 05/23/2013] [Indexed: 12/26/2022] Open
Abstract
The mitochondrial amidoxime reducing component mARC is a recently discovered molybdenum enzyme in mammals. mARC is not active as a standalone protein, but together with the electron transport proteins NADH-cytochrome b5 reductase (CYB5R) and cytochrome b5 (CYB5), it catalyzes the reduction of N-hydroxylated compounds such as amidoximes. The mARC-containing enzyme system is therefore considered to be responsible for the activation of amidoxime prodrugs. All hitherto analyzed mammalian genomes code for two mARC genes (also referred to as MOSC1 and MOSC2), which share high sequence similarities. By RNAi experiments in two different human cell lines, we demonstrate for the first time that both mARC proteins are capable of reducing N-hydroxylated substrates in cell metabolism. The extent of involvement is highly dependent on the expression level of the particular mARC protein. Furthermore, the mitochondrial isoform of CYB5 (CYB5B) is clearly identified as an essential component of the mARC-containing N-reductase system in human cells. The participation of the microsomal isoform (CYB5A) in N-reduction could be excluded by siRNA-mediated down-regulation in HEK-293 cells and knock-out in mice. Using heme-free apo-CYB5, the contribution of mitochondrial CYB5 to N-reductive catalysis was proven to strictly depend on heme. Finally, we created recombinant CYB5B variants corresponding to four nonsynonymous single nucleotide polymorphisms (SNPs). Investigated mutations of the heme protein seemed to have no significant impact on N-reductive activity of the reconstituted enzyme system.
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Affiliation(s)
- Birte Plitzko
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Gudrun Ott
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Debora Reichmann
- the Department of Plant Biology, Braunschweig University of Technology, 38023 Braunschweig, Germany, and
| | - Colin J. Henderson
- the University of Dundee Medical Research Institute, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, Dundee DD1 9SY, Scotland, United Kingdom
| | - C. Roland Wolf
- the University of Dundee Medical Research Institute, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, Dundee DD1 9SY, Scotland, United Kingdom
| | - Ralf Mendel
- the Department of Plant Biology, Braunschweig University of Technology, 38023 Braunschweig, Germany, and
| | - Florian Bittner
- the Department of Plant Biology, Braunschweig University of Technology, 38023 Braunschweig, Germany, and
| | - Bernd Clement
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
| | - Antje Havemeyer
- From the Department of Pharmaceutical and Medicinal Chemistry, Pharmaceutical Institute, Christian-Albrechts-University of Kiel, 24118 Kiel, Germany
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Stiborová M, Dračínská H, Martínek V, Svášková D, Hodek P, Milichovský J, Hejduková Ž, Brotánek J, Schmeiser HH, Frei E. Induced expression of cytochrome P450 1A and NAD(P)H:quinone oxidoreductase determined at mRNA, protein, and enzyme activity levels in rats exposed to the carcinogenic azo dye 1-phenylazo-2-naphthol (Sudan I). Chem Res Toxicol 2013; 26:290-9. [PMID: 23289503 DOI: 10.1021/tx3004533] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sudan I (1-phenylazo-2-hydroxynaphthol) is a suspected human carcinogen causing tumors in the livers and urinary bladders of rats, mice, and rabbits. Here, we investigated for the first time the influence of Sudan I exposure on the expression of several biotransformation enzymes in the livers, kidneys, and lungs of rats concomitantly at the mRNA and protein levels and assayed their enzymatic activities. We also studied its effect on the formation of Sudan I-derived DNA adducts in vitro. Sudan I increased the total amounts of cytochrome P450 (P450) in all organs tested. Western blots using antibodies raised against various P450s, NADPH:P450 reductase, and NAD(P)H:quinone oxidoreductase 1 (NQO1) showed that the expression of P450 1A1 and NQO1 was induced in the liver, kidney, and lung of rats treated with Sudan I. The higher protein levels correlated with increased enzyme activities of P450 1A1/2 and NQO1. Furthermore, 9.9-, 5.9-, and 2.8-fold increases in the formation of Sudan I oxidative metabolites catalyzed by microsomes isolated from the liver, kidney, and lung, respectively, of rats treated with Sudan I were found. The relative amounts of P450 1A and NQO1 mRNA, measured by real-time polymerase chain reaction (RT-PCR) analysis, demonstrated that Sudan I induced the expression of P450 1A1 and NQO1 mRNA in the liver, kidney, and lung, and of P450 1A2 mRNA in kidney and lung. Finally, microsomes isolated from livers, kidneys, and lungs of Sudan I exposed rats more effectively catalyzed the formation of Sudan I-DNA adducts than microsomes from organs of control rats. This was attributable to the higher P450 1A1 expression. Because P450 1A1 is playing a major role in the bioactivation of Sudan I in rat and human systems, its induction by Sudan I may have a profound effect on cancer risk by this azo dye. In addition, the induction of P450 1A1/2 and NQO1 enzymes can influence individual human susceptibility to other environmental carcinogens and have an effect on cancer risk.
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Affiliation(s)
- Marie Stiborová
- Department of Biochemistry, Faculty of Science, Charles University, Albertov 2030, 128 40 Prague 2, Czech Republic.
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11
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Stiborová M, Indra R, Moserová M, Černá V, Rupertová M, Martínek V, Eckschlager T, Kizek R, Frei E. Cytochrome b5 Increases Cytochrome P450 3A4-Mediated Activation of Anticancer Drug Ellipticine to 13-Hydroxyellipticine Whose Covalent Binding to DNA Is Elevated by Sulfotransferases and N,O-Acetyltransferases. Chem Res Toxicol 2012; 25:1075-85. [DOI: 10.1021/tx3000335] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marie Stiborová
- 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
| | - 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
| | - Martina Rupertová
- Department of Biochemistry,
Faculty of Science, Charles University,
Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Václav Martínek
- Department of Biochemistry,
Faculty of Science, Charles University,
Albertov 2030, 128 40 Prague 2, Czech Republic
| | - Tomáš Eckschlager
- Department of Pediatric Hematology
and Oncology, Charles University and University Hospital Motol, Prague, Czech Republic
| | - René Kizek
- Department of Chemistry and Biochemistry,
Faculty of Agronomy, Mendel University,
Brno, Czech Republic
| | - Eva Frei
- Division
of Preventive Oncology,
National Center for Tumor Diseases, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
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Cytochrome b5 shifts oxidation of the anticancer drug ellipticine by cytochromes P450 1A1 and 1A2 from its detoxication to activation, thereby modulating its pharmacological efficacy. Biochem Pharmacol 2011; 82:669-80. [DOI: 10.1016/j.bcp.2011.06.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 06/03/2011] [Accepted: 06/03/2011] [Indexed: 01/19/2023]
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13
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Cao Y, Xian M, Yang J, Xu X, Liu W, Li L. Heterologous expression of stearoyl-acyl carrier protein desaturase (S-ACP-DES) from Arabidopsis thaliana in Escherichia coli. Protein Expr Purif 2009; 69:209-14. [PMID: 19716420 DOI: 10.1016/j.pep.2009.08.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Revised: 08/16/2009] [Accepted: 08/24/2009] [Indexed: 11/30/2022]
Abstract
Fatty acid desaturases are enzymes that introduce double bonds into fatty acyl chains, among which stearoyl-acyl carrier protein desaturase (S-ACP-DES) was widely distributed in the plant kingdom. We cloned the cDNA coding for fab2/ssi2, an S-ACP-DES from Arabidopsis thaliana, into the vector pET30a and heterologously expressed this fatty acid desaturase in Escherichia coli BL21 (DE3). After being induced with IPTG, the fusion protein was efficiently expressed in a soluble form. The SSI2 desaturase was purified by nickel ion affinity chromatography and the product obtained showed a single band by SDS-PAGE analysis. The expression of ssi2 modified the fatty acid composition of the recombinant strain. The ratio of palmitic acid (16:0) decreased from 45.2% (the control strain) to 35.2% while palmitoleate (16:1Delta9) and cis-vaccenate (18:1Delta11) levels were enhanced to some extent. The desaturase enzymatic activity was measured in vivo when the enzyme substrate stearic acid was provided in the culture medium. A new fatty acid, oleic acid (18:1Delta9) was found in the recombinant strain which did not exist in wild-type E. coli. These results demonstrated that the cofactors of the host system can complement the requirement of the SSI2 desaturase.
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Affiliation(s)
- Yujin Cao
- Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, 266101 Qingdao, China
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