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Schulz V, Freibert SA, Boss L, Mühlenhoff U, Stehling O, Lill R. Mitochondrial [2Fe-2S] ferredoxins: new functions for old dogs. FEBS Lett 2023; 597:102-121. [PMID: 36443530 DOI: 10.1002/1873-3468.14546] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/23/2022] [Accepted: 11/23/2022] [Indexed: 12/02/2022]
Abstract
Ferredoxins (FDXs) comprise a large family of iron-sulfur proteins that shuttle electrons from NADPH and FDX reductases into diverse biological processes. This review focuses on the structure, function and specificity of mitochondrial [2Fe-2S] FDXs that are related to bacterial FDXs due to their endosymbiotic inheritance. Their classical function in cytochrome P450-dependent steroid transformations was identified around 1960, and is exemplified by mammalian FDX1 (aka adrenodoxin). Thirty years later the essential function in cellular Fe/S protein biogenesis was discovered for the yeast mitochondrial FDX Yah1 that is additionally crucial for the formation of haem a and ubiquinone CoQ6 . In mammals, Fe/S protein biogenesis is exclusively performed by the FDX1 paralog FDX2, despite the high structural similarity of both proteins. Recently, additional and specific roles of human FDX1 in haem a and lipoyl cofactor biosyntheses were described. For lipoyl synthesis, FDX1 transfers electrons to the radical S-adenosyl methionine-dependent lipoyl synthase to kickstart its radical chain reaction. The high target specificity of the two mammalian FDXs is contained within small conserved sequence motifs, that upon swapping change the target selection of these electron donors.
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Affiliation(s)
- Vinzent Schulz
- Institut für Zytobiologie, Philipps-Universität Marburg, Germany.,Zentrum für Synthetische Mikrobiologie Synmikro, Marburg, Germany
| | - Sven-A Freibert
- Institut für Zytobiologie, Philipps-Universität Marburg, Germany.,Zentrum für Synthetische Mikrobiologie Synmikro, Marburg, Germany
| | - Linda Boss
- Institut für Zytobiologie, Philipps-Universität Marburg, Germany.,Zentrum für Synthetische Mikrobiologie Synmikro, Marburg, Germany
| | - Ulrich Mühlenhoff
- Institut für Zytobiologie, Philipps-Universität Marburg, Germany.,Zentrum für Synthetische Mikrobiologie Synmikro, Marburg, Germany
| | - Oliver Stehling
- Institut für Zytobiologie, Philipps-Universität Marburg, Germany.,Zentrum für Synthetische Mikrobiologie Synmikro, Marburg, Germany
| | - Roland Lill
- Institut für Zytobiologie, Philipps-Universität Marburg, Germany.,Zentrum für Synthetische Mikrobiologie Synmikro, Marburg, Germany
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2
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Navakoudis E, Kotzabasis K. Polyamines: Α bioenergetic smart switch for plant protection and development. JOURNAL OF PLANT PHYSIOLOGY 2022; 270:153618. [PMID: 35051689 DOI: 10.1016/j.jplph.2022.153618] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/09/2022] [Accepted: 01/10/2022] [Indexed: 05/27/2023]
Abstract
The present review highlights the bioenergetic role of polyamines in plant protection and development and proposes a universal model for describing polyamine-mediated stress responses. Any stress condition induces an excitation pressure on photosystem II by reforming the photosynthetic apparatus. To control this phenomenon, polyamines act directly on the molecular structure and function of the photosynthetic apparatus as well as on the components of the chemiosmotic proton-motive force (ΔpH/Δψ), thus regulating photochemical (qP) and non-photochemical quenching (NPQ) of energy. The review presents the mechanistic characteristics that underline the key role of polyamines in the structure, function, and bioenergetics of the photosynthetic apparatus upon light adaptation and/or under stress conditions. By following this mechanism, it is feasible to make stress-sensitive plants to be tolerant by simply altering their polyamine composition (especially the ratio of putrescine to spermine), either chemically or by light regulation.
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Affiliation(s)
- Eleni Navakoudis
- Department of Biology, University of Crete, Voutes University Campus, 70013, Heraklion, Greece; Department of Chemical Engineering, Cyprus University of Technology, 3603, Limassol, Cyprus
| | - Kiriakos Kotzabasis
- Department of Biology, University of Crete, Voutes University Campus, 70013, Heraklion, Greece.
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3
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Bernhardt R, Neunzig J. Underestimated reactions and regulation patterns of adrenal cytochromes P450. Mol Cell Endocrinol 2021; 530:111237. [PMID: 33722664 DOI: 10.1016/j.mce.2021.111237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 02/18/2021] [Accepted: 02/27/2021] [Indexed: 11/20/2022]
Abstract
Although cytochrome P450 (CYP) systems including the adrenal ones are being investigated since many years, there are still reactions and regulation patterns that have been underestimated ever since. This review discusses neglected ones to bring them into the focus of investigators working in the field. Novel substrates and reactions described for adrenal CYPs recently point to the fact that different from what has been believed for many years, adrenal CYPs are less selective than previously thought. The conversion of steroid sulfates, intermediates of steroid biosynthesis as well as of exogenous compounds are being discussed here in more detail and consequences for further studies are drawn. Furthermore, it was shown that protein-protein interactions may have an important effect not only on the activity of adrenal CYPs, but also on the product pattern of the reactions. It was found that, as expected, the stoichiometry of CYP:redox partner plays an important role for tuning the activity. In addition, competition between different CYPs for the redox partner and for electrons and possible alterations by mutants in the efficiency of electron transfer play an important role for the activity and product pattern. Moreover, the influence of phosphorylation and small charged molecules like natural polyamines on the activity of adrenal systems has been demonstrated in-vitro indicating a possible regulation of adrenal CYP reactions by affecting redox partner recognition and binding affinity. Finally, an effect of the genetic background on the consequences of mutations in adrenal CYPs found in patients was suggested from corresponding in-vitro studies indicating that a different genetic background might be able to significantly affect the activity of a CYP mutant.
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Affiliation(s)
- Rita Bernhardt
- Department of Biochemistry, Campus B2.2, Saarland University, D-66123, Saarbrücken, Germany.
| | - Jens Neunzig
- Institute of Molecular Plant Biology, Campus A2.4, Saarland University, D-66123, Saarbrücken, Germany
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4
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Cho SY, Lee S, Yeom J, Kim HJ, Lee JH, Shin JW, Kwon MA, Lee KB, Jeong EM, Ahn HS, Shin DM, Kim K, Kim IG. Transglutaminase 2 mediates hypoxia-induced selective mRNA translation via polyamination of 4EBPs. Life Sci Alliance 2020; 3:3/3/e201900565. [PMID: 32075852 PMCID: PMC7032569 DOI: 10.26508/lsa.201900565] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 02/05/2020] [Accepted: 02/06/2020] [Indexed: 12/12/2022] Open
Abstract
This study highlights the role of transglutaminase 2 in selective mRNA translation of hypoxic cancer cells by polyamination-dependent modulation of 4EBPs, providing a target for cancer treatment. Hypoxia selectively enhances mRNA translation despite suppressed mammalian target of rapamycin complex 1 activity, contributing to gene expression reprogramming that promotes metastasis and survival of cancer cells. Little is known about how this paradoxical control of translation occurs. Here, we report a new pathway that links hypoxia to selective mRNA translation. Transglutaminase 2 (TG2) is a hypoxia-inducible factor 1–inducible enzyme that alters the activity of substrate proteins by polyamination or crosslinking. Under hypoxic conditions, TG2 polyaminated eukaryotic translation initiation factor 4E (eIF4E)-bound eukaryotic translation initiation factor 4E-binding proteins (4EBPs) at conserved glutamine residues. 4EBP1 polyamination enhances binding affinity for Raptor, thereby increasing phosphorylation of 4EBP1 and cap-dependent translation. Proteomic analyses of newly synthesized proteins in hypoxic cells revealed that TG2 activity preferentially enhanced the translation of a subset of mRNA containing G/C-rich 5′UTRs but not upstream ORF or terminal oligopyrimidine motifs. These results indicate that TG2 is a critical regulator in hypoxia-induced selective mRNA translation and provide a promising molecular target for the treatment of cancers.
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Affiliation(s)
- Sung-Yup Cho
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Korea .,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea.,Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Seungun Lee
- Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul, Korea
| | - Jeonghun Yeom
- Department of Convergence Medicine, Asan Medical Center, Seoul, Korea
| | - Hyo-Jun Kim
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Korea
| | - Jin-Haeng Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Korea
| | - Ji-Woong Shin
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Korea
| | - Mee-Ae Kwon
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Korea
| | - Ki Baek Lee
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Korea
| | - Eui Man Jeong
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Korea.,Institute of Human-Environment Interface Biology, Seoul National University College of Medicine, Seoul, Korea
| | - Hee Sung Ahn
- Department of Convergence Medicine, Asan Medical Center, Seoul, Korea
| | - Dong-Myung Shin
- Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul, Korea
| | - Kyunggon Kim
- Department of Biomedical Sciences, University of Ulsan College of Medicine, Seoul, Korea .,Department of Convergence Medicine, Asan Medical Center, Seoul, Korea
| | - In-Gyu Kim
- Department of Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Korea .,Institute of Human-Environment Interface Biology, Seoul National University College of Medicine, Seoul, Korea
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5
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Bitrián M, Tiburcio AF, Alcázar R. Determination of Posttranslational Modifications by 2D PAGE: Applications to Polyamines. Methods Mol Biol 2018; 1694:337-341. [PMID: 29080178 DOI: 10.1007/978-1-4939-7398-9_28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Polyamines not only affect transcription and translation but also may induce a number of posttranslational modifications. The identification of polyamine-induced posttranslational modifications can be performed by 2D PAGE analyses. Here, we provide a protocol for 2D-gel electrophoresis that has been optimized for plants. The combined use of this protocol with epitope-tagged proteins expressed in plants enables the detailed analysis of posttranslational modifications induced by different polyamines in vivo.
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Affiliation(s)
- Marta Bitrián
- Department of Biology, Healthcare and Environment, Faculty of Pharmacy and Food Sciences, Section of Plant Physiology, University of Barcelona, Avda. Joan XXIII 27-31, 08028, Barcelona, Spain.
| | - Antonio F Tiburcio
- Department of Biology, Healthcare and Environment, Faculty of Pharmacy and Food Sciences, Section of Plant Physiology, University of Barcelona, Avda. Joan XXIII 27-31, 08028, Barcelona, Spain
| | - Rubén Alcázar
- Department of Biology, Healthcare and Environment, Faculty of Pharmacy and Food Sciences, Section of Plant Physiology, University of Barcelona, Avda. Joan XXIII 27-31, 08028, Barcelona, Spain
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6
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Sang Q, Shan X, An Y, Shu S, Sun J, Guo S. Proteomic Analysis Reveals the Positive Effect of Exogenous Spermidine in Tomato Seedlings' Response to High-Temperature Stress. FRONTIERS IN PLANT SCIENCE 2017; 8:120. [PMID: 28220137 PMCID: PMC5292424 DOI: 10.3389/fpls.2017.00120] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/20/2017] [Indexed: 05/02/2023]
Abstract
Polyamines are phytohormones that regulate plant growth and development as well as the response to environmental stresses. To evaluate their functions in high-temperature stress responses, the effects of exogenous spermidine (Spd) were determined in tomato leaves using two-dimensional electrophoresis and MALDI-TOF/TOF MS. A total of 67 differentially expressed proteins were identified in response to high-temperature stress and/or exogenous Spd, which were grouped into different categories according to biological processes. The four largest categories included proteins involved in photosynthesis (27%), cell rescue, and defense (24%), protein synthesis, folding and degradation (22%), and energy and metabolism (13%). Exogenous Spd up-regulated most identified proteins involved in photosynthesis, implying an enhancement in photosynthetic capacity. Meanwhile, physiological analysis showed that Spd could improve net photosynthetic rate and the biomass accumulation. Moreover, an increased high-temperature stress tolerance by exogenous Spd would contribute to the higher expressions of proteins involved in cell rescue and defense, and Spd regulated the antioxidant enzymes activities and related genes expression in tomato seedlings exposed to high temperature. Taken together, these findings provide a better understanding of the Spd-induced high-temperature resistance by proteomic approaches, providing valuable insight into improving the high-temperature stress tolerance in the global warming epoch.
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Affiliation(s)
- Qinqin Sang
- Key Laboratory of Southern Vegetable Crop Genetic Improvement in Ministry of Agriculture, College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Xi Shan
- Key Laboratory of Southern Vegetable Crop Genetic Improvement in Ministry of Agriculture, College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Yahong An
- Key Laboratory of Southern Vegetable Crop Genetic Improvement in Ministry of Agriculture, College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Sheng Shu
- Key Laboratory of Southern Vegetable Crop Genetic Improvement in Ministry of Agriculture, College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Jin Sun
- Key Laboratory of Southern Vegetable Crop Genetic Improvement in Ministry of Agriculture, College of Horticulture, Nanjing Agricultural UniversityNanjing, China
- Nanjing Agricultural University (Suqian), Academy of Protected HorticultureSuqian, China
| | - Shirong Guo
- Key Laboratory of Southern Vegetable Crop Genetic Improvement in Ministry of Agriculture, College of Horticulture, Nanjing Agricultural UniversityNanjing, China
- Nanjing Agricultural University (Suqian), Academy of Protected HorticultureSuqian, China
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7
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Yuan Y, Zhong M, Shu S, Du N, Sun J, Guo S. Proteomic and Physiological Analyses Reveal Putrescine Responses in Roots of Cucumber Stressed by NaCl. FRONTIERS IN PLANT SCIENCE 2016; 7:1035. [PMID: 27471514 PMCID: PMC4945654 DOI: 10.3389/fpls.2016.01035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/01/2016] [Indexed: 05/03/2023]
Abstract
Soil salinity is a major environmental constraint that threatens agricultural productivity. Different strategies have been developed to improve crop salt tolerance, among which the effects of polyamines have been well-reported. To gain a better understanding of the cucumber (Cucumis sativus L.) responses to NaCl and unravel the underlying mechanism of exogenous putrescine (Put) alleviating salt-induced damage, comparative proteomic analysis was conducted on cucumber roots treated with NaCl, and/or Put for 7 days. The results showed that exogenous Put restored the root growth inhibited by NaCl. Sixty-two differentially expressed proteins implicated in various biological processes were successfully identified by MALDI-TOF/TOF MS. The four largest categories included proteins involved in defense response (24.2%), protein metabolism (24.2%), carbohydrate metabolism (19.4%), and amino acid metabolism (14.5%). Exogenous Put up-regulated most identified proteins involved in carbohydrate metabolism, implying an enhancement in energy generation. Proteins involved in defense response and protein metabolism were differently regulated by Put, which indicated the roles of Put in stress resistance and proteome rearrangement. Put also increased the abundance of proteins involved in amino acid metabolism. Meanwhile, physiological analysis showed that Put could further up-regulated the levels of free amino acids in salt stressed-roots. In addition, Put also improved endogenous polyamines contents by regulating the transcription levels of key enzymes in polyamine metabolism. Taken together, these results suggest that Put may alleviate NaCl-induced growth inhibition through degradation of misfolded/damaged proteins, activation of stress defense, and the promotion of carbohydrate metabolism to generate more energy.
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Affiliation(s)
- Yinghui Yuan
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Min Zhong
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Sheng Shu
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Nanshan Du
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural UniversityNanjing, China
| | - Jin Sun
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural UniversityNanjing, China
- Suqian Academy of Protected Horticulture, Nanjing Agricultural UniversitySuqian, China
| | - Shirong Guo
- Key Laboratory of Southern Vegetable Crop Genetic Improvement, Ministry of Agriculture, College of Horticulture, Nanjing Agricultural UniversityNanjing, China
- Suqian Academy of Protected Horticulture, Nanjing Agricultural UniversitySuqian, China
- *Correspondence: Shirong Guo
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8
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Magnes C, Fauland A, Gander E, Narath S, Ratzer M, Eisenberg T, Madeo F, Pieber T, Sinner F. Polyamines in biological samples: rapid and robust quantification by solid-phase extraction online-coupled to liquid chromatography-tandem mass spectrometry. J Chromatogr A 2014; 1331:44-51. [PMID: 24485539 PMCID: PMC3991419 DOI: 10.1016/j.chroma.2013.12.061] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 12/18/2013] [Accepted: 12/19/2013] [Indexed: 02/07/2023]
Abstract
Polyamines are ubiquitous active biogenic amines which contribute to basic cellular functions. Hence, their quantification in samples of diverse biological origins is essential for understanding how they function, especially in disease-relevant conditions. We present here a robust, high-throughput solid-phase extraction online coupled to a liquid chromatography-tandem mass spectrometry (SPE-LC/MS/MS) approach for the simultaneous quantification of eight polyamines in various biological samples. The polyamines include 1,3-diaminopropane, putrescine, cadaverin, N-acetyl-putrescine, spermidine, spermine, N(1)-acetyl-spermine, and l-ornithine. The novelty of the work is the use of two SPE columns online coupled to LC/MS/MS, which minimizes the sample pretreatment to a single derivatization step. The analysis is complete within 4min, making the method highly suitable for routine clinical analysis and high throughput screenings. The method was fully validated with serum samples. Dynamic ranges were 0.03 to 15μg/ml for ornithine and 1 to 500ng/ml for other polyamines, which cover physiological concentrations in serum samples. Lower limits of quantification (LLoQ) were found to be between 0.1 and 5ng/ml. As a proof of concept, we investigated gender differences in polyamine levels by analyzing the serum levels of 102 subjects.
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Affiliation(s)
- Christoph Magnes
- HEALTH—Institute for Biomedicine and Health Sciences, Joanneum Research, Forschungsgesellschaft m.b.H., Graz, Austria
| | - Alexander Fauland
- HEALTH—Institute for Biomedicine and Health Sciences, Joanneum Research, Forschungsgesellschaft m.b.H., Graz, Austria
| | - Edgar Gander
- HEALTH—Institute for Biomedicine and Health Sciences, Joanneum Research, Forschungsgesellschaft m.b.H., Graz, Austria
| | - Sophie Narath
- HEALTH—Institute for Biomedicine and Health Sciences, Joanneum Research, Forschungsgesellschaft m.b.H., Graz, Austria
| | - Maria Ratzer
- HEALTH—Institute for Biomedicine and Health Sciences, Joanneum Research, Forschungsgesellschaft m.b.H., Graz, Austria
| | - Tobias Eisenberg
- Institute of Molecular Biosciences, Karl-Franzens-University of Graz, Graz, Austria
| | - Frank Madeo
- Institute of Molecular Biosciences, Karl-Franzens-University of Graz, Graz, Austria
| | - Thomas Pieber
- HEALTH—Institute for Biomedicine and Health Sciences, Joanneum Research, Forschungsgesellschaft m.b.H., Graz, Austria
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Frank Sinner
- HEALTH—Institute for Biomedicine and Health Sciences, Joanneum Research, Forschungsgesellschaft m.b.H., Graz, Austria
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
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Neunzig J, Bernhardt R. Dehydroepiandrosterone sulfate (DHEAS) stimulates the first step in the biosynthesis of steroid hormones. PLoS One 2014; 9:e89727. [PMID: 24586990 PMCID: PMC3931814 DOI: 10.1371/journal.pone.0089727] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 01/22/2014] [Indexed: 11/18/2022] Open
Abstract
Dehydroepiandrosterone sulfate (DHEAS) is the most abundant circulating steroid in human, with the highest concentrations between age 20 and 30, but displaying a significant decrease with age. Many beneficial functions are ascribed to DHEAS. Nevertheless, long-term studies are very scarce concerning the intake of DHEAS over several years, and molecular investigations on DHEAS action are missing so far. In this study, the role of DHEAS on the first and rate-limiting step of steroid hormone biosynthesis was analyzed in a reconstituted in vitro system, consisting of purified CYP11A1, adrenodoxin and adrenodoxin reductase. DHEAS enhances the conversion of cholesterol by 26%. Detailed analyses of the mechanism of DHEAS action revealed increased binding affinity of cholesterol to CYP11A1 and enforced interaction with the electron transfer partner, adrenodoxin. Difference spectroscopy showed Kd-values of 40±2.7 µM and 24.8±0.5 µM for CYP11A1 and cholesterol without and with addition of DHEAS, respectively. To determine the Kd-value for CYP11A1 and adrenodoxin, surface plasmon resonance measurements were performed, demonstrating a Kd-value of 3.0±0.35 nM (with cholesterol) and of 2.4±0.05 nM when cholesterol and DHEAS were added. Kinetic experiments showed a lower Km and a higher kcat value for CYP11A1 in the presence of DHEAS leading to an increase of the catalytic efficiency by 75%. These findings indicate that DHEAS affects steroid hormone biosynthesis on a molecular level resulting in an increased formation of pregnenolone.
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Affiliation(s)
- Jens Neunzig
- Department of Biochemistry, Faculty of Technical and Natural Sciences III, Saarland University, Saarbrücken, Germany
| | - Rita Bernhardt
- Department of Biochemistry, Faculty of Technical and Natural Sciences III, Saarland University, Saarbrücken, Germany
- * E-mail:
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Mast N, Linger M, Pikuleva IA. Inhibition and stimulation of activity of purified recombinant CYP11A1 by therapeutic agents. Mol Cell Endocrinol 2013; 371:100-6. [PMID: 23089212 PMCID: PMC3568244 DOI: 10.1016/j.mce.2012.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Revised: 10/02/2012] [Accepted: 10/02/2012] [Indexed: 11/25/2022]
Abstract
In vertebrates, the biosynthesis of steroid hormones is initiated by cytochrome P450 CYP11A1 which converts cholesterol to pregnenolone. We investigated whether some of the experimental and FDA-approved therapeutic agents alter the activity of CYP11A1 in the reconstituted system in vitro. We found that under the experimental conditions used and when phospholipids are included, ketoconazole, posaconazole, carbenoxolone, and selegiline inhibit CYP11A1-mediated production of pregnenolone by at least 67%. Conversely, pemirolast, clobenpropit, desogestrel, dexmedetomidine, and tizanidine stimulate the enzyme activity by up to 70%. We then evaluated the identified inhibitors and activators for spectral binding to CYP11A1 and their effect on enzyme activity in the absence of phospholipids. The data obtained provide insight into how different drugs interact with CYP11A1 and demonstrate that P450 association with the lipid bilayer determines, in many cases, a drug's effect on enzyme activity.
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Affiliation(s)
| | | | - Irina A. Pikuleva
- Corresponding author. Address: Department of Ophthalmology and Visual Sciences, Case Western Reserve University, 2085 Adelbert Rd., r. 303a, Cleveland, OH 44106, USA. Tel.: + 1-216-368-3823; fax: + 1-216-368-3848.
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Shanmugasundararaj S, Zhou X, Neunzig J, Bernhardt R, Cotten JF, Ge R, Miller KW, Raines DE. Carboetomidate: an analog of etomidate that interacts weakly with 11β-hydroxylase. Anesth Analg 2013; 116:1249-56. [PMID: 23492967 DOI: 10.1213/ane.0b013e31828b3637] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Carboetomidate is a pyrrole etomidate analog that is 3 orders of magnitude less potent an inhibitor of in vitro cortisol synthesis than etomidate (an imidazole) and does not inhibit in vivo steroid production. Although carboetomidate's reduced functional effect on steroid synthesis is thought to reflect lower binding affinity to 11β-hydroxylase, differential binding to this enzyme has never been experimentally demonstrated. In the current study, we tested the hypothesis that carboetomidate and etomidate bind with differential affinity to 11β-hydroxylase by comparing their abilities to inhibit photoaffinity labeling of purified enzyme by a photoactivatable etomidate analog and to modify the enzyme's absorption spectrum in a way that is indicative of ligand binding. In addition, we made a preliminary exploration of the manner in which etomidate and carboetomidate might differentially interact with this site using spectroscopic methods as well as molecular modeling techniques to better understand the structural basis for their selectivity. METHODS The ability of azi-etomidate to inhibit cortisol synthesis was tested by assessing its ability to inhibit cortisol synthesis by H295R cells. The binding affinities of etomidate and carboetomidate to 11β-hydroxylase were compared by assessing their abilities to (1) inhibit photoincorporation of the photolabile etomidate analog [(3)H]azi-etomidate into the enzyme and (2) modify the absorption spectrum of the enzyme's heme group. In silico docking studies of etomidate, carboetomidate, and azi-etomidate binding to 11β-hydroxylase were performed using the computer software GOLD. RESULTS Similar to etomidate, azi-etomidate potently inhibits in vitro cortisol synthesis. Etomidate inhibited [(3)H]azi-etomidate photolabeling of 11β-hydroxylase in a concentration-dependent manner. At a concentration of 40 µM, etomidate reduced photoincorporation of [(3)H]azi-etomidate by 96% ± 1% whereas carboetomidate had no experimentally detectable effect. On addition of etomidate to 11β-hydroxylase, a type 2 difference spectrum was produced indicative of etomidate complexation with the enzyme's heme iron; carboetomidate had no effect whereas azi-etomidate produced a reverse type 1 spectrum. Computer modeling studies predicted that etomidate, carboetomidate, and azi-etomidate can fit into the heme-containing pocket that forms 11β-hydroxylase's active site and pose with their carbonyl oxygens interacting with the heme iron and their phenyl rings stacking with phenylalanine-80. However, additional unique poses were identified for etomidate and azi-etomidate that likely account for their higher affinities. CONCLUSIONS Carboetomidate's reduced ability to suppress in vitro and in vivo steroid synthesis as compared with etomidate reflects its lower binding affinity to 11β-hydroxylase and may be attributed to carboetomidate's inability to form a coordination bond with the heme iron located at the enzyme's active site.
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Abstract
The polyamines are ubiquitous polycationic compounds. Over the past 40 yr, investigation has shown that some of these, namely spermine, spermidine, and putrescine, are essential to male and female reproductive processes and to embryo/fetal development. Indeed, their absence is characterized by infertility and arrest in embryogenesis. Mammals synthesize polyamines de novo from amino acids or import these compounds from the diet. Information collected recently has shown that polyamines are essential regulators of cell growth and gene expression, and they have been implicated in both mitosis and meiosis. In male reproduction, polyamine expression correlates with stages of spermatogenesis, and polyamines appear to function in promoting sperm motility. There is evidence for polyamine involvement in ovarian follicle development and ovulation in female mammals, and polyamine synthesis is required for steroidogenesis in the ovary. Studies of the embryo indicate a polyamine requirement that can be met from maternal sources before implantation, whereas elimination of polyamine synthesis abrogates embryo development at gastrulation. Polyamines play roles in embryo implantation, in decidualization, and in placental formation and function, and polyamine privation during gestation results in intrauterine growth retardation. Emerging information implicates dietary arginine and dietary polyamines as nutritional regulators of fertility. The mechanisms by which polyamines regulate these multiple and diverse processes are not yet well explored; thus, there is fertile ground for further productive investigation.
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Affiliation(s)
- Pavine L C Lefèvre
- Centre de Recherche en Reproduction Animale, Faculté de Médecine Vétérinaire, Université de Montréal, 3200 rue Sicotte, Saint-Hyacinthe, Canada QC J2S 2M2
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Transient pockets on XIAP-BIR2: toward the characterization of putative binding sites of small-molecule XIAP inhibitors. J Mol Model 2011; 18:2031-42. [DOI: 10.1007/s00894-011-1217-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 08/09/2011] [Indexed: 10/17/2022]
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14
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Schiffler B, Zöllner A, Bernhardt R. Kinetic and optical biosensor study of adrenodoxin mutant AdxS112W displaying an enhanced interaction towards the cholesterol side chain cleavage enzyme (CYP11A1). EUROPEAN BIOPHYSICS JOURNAL: EBJ 2011; 40:1275-82. [PMID: 21526428 DOI: 10.1007/s00249-011-0703-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 03/18/2011] [Accepted: 03/26/2011] [Indexed: 10/18/2022]
Abstract
In mammals, steroid hormones are synthesized from cholesterol that is metabolized by the mitochondrial CYP11A1 system leading to pregnenolone. The reduction equivalents for this reaction are provided by NADPH, via a small electron transfer chain, consisting of adrenodoxin reductase (AdR) and adrenodoxin (Adx). The reaction partners are involved in a series of transient interactions to realize the electron transfer from NADPH to CYP11A1. Here, we compared the ionic strength effect on the AdR/Adx and Adx/CYP11A1 interactions for wild-type Adx and mutant AdxS112W. Using surface plasmon resonance measurements, stopped flow kinetic investigations and analyses of the product formation, we were able to obtain new insights into the mechanism of these interactions. The replacement of serine 112 by tryptophan was demonstrated to lead to a dramatically decreased k (off) rate of the Adx/CYP11A1 complex, resulting in a four-fold decreased K (d) value and indicating a much higher stability of the complex involving the mutant. Stopped flow analysis at various ionic strengths and in different mixing modes revealed that the binding of reduced Adx to CYP11A1 seems to display the limiting step for electron transfer to CYP11A1 with pre-reduced AdxS112W being much more efficient than wild-type Adx. Finally, the dramatic increase in pregnenolone formation at higher ionic strength using the mutant demonstrates that the interaction of CYP11A1 with Adx is the rate-limiting step in substrate conversion and that hydrophobic interactions may considerably improve this interaction and the efficiency of product formation. The data are discussed using published structural data of the complexes.
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Affiliation(s)
- Burkhard Schiffler
- Naturwissenschaftlich-Technische Fakultät III, Lehrstuhl für Biochemie, Universität des Saarlandes, Saarbrücken, Germany
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15
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Schuster I, Bernhardt R. Interactions of natural polyamines with mammalian proteins. Biomol Concepts 2011; 2:79-94. [DOI: 10.1515/bmc.2011.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
AbstractThe ubiquitously expressed natural polyamines putrescine, spermidine, and spermine are small, flexible cationic compounds that exert pleiotropic actions on various regulatory systems and, accordingly, are essentially involved in diverse life functions. These roles of polyamines result from their capability to interact with negatively charged regions of all major classes of biomolecules, which might act in response by changing their structures and functions. The present review deals with polyamine-protein interactions, thereby focusing on mammalian proteins. We discuss the various modes in which polyamines can interact with proteins, describe major types of affected functions illustrated by representative examples of involved proteins, and support information with respective structural evidence from elucidated three-dimensional structures. A specific focus is put on polyamine interactions at protein surfaces that can modulate the aggregation of proteins to organized structural networks as well as to toxic aggregates and, moreover, can play a role in important transient protein-protein interactions.
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Affiliation(s)
- Inge Schuster
- 1Institute for Theoretical Chemistry, University Vienna, A-1090 Vienna, Austria
| | - Rita Bernhardt
- 2Institute of Biochemistry, Saarland University, Campus B2.2, D-66123 Saarbrücken, Germany
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16
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Ewen KM, Kleser M, Bernhardt R. Adrenodoxin: the archetype of vertebrate-type [2Fe-2S] cluster ferredoxins. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1814:111-25. [PMID: 20538075 DOI: 10.1016/j.bbapap.2010.06.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 05/28/2010] [Accepted: 06/01/2010] [Indexed: 11/15/2022]
Abstract
Adrenodoxin is probably the best characterized member of the vertebrate-type [2Fe-2S]-cluster ferredoxins. It has been in the spotlight of scientific interest for many years due to its essential role in mammalian steroid hormone biosynthesis, where it acts as electron mediator between the NADPH-dependent adrenodoxin reductase and several mitochondrial cytochromes P450. In this review we will focus on the present knowledge about protein-protein recognition in the mitochondrial cytochrome P450 system and the modulation of the electron transfer between Adx and its redox partners, AdR and CYP(s). We also intend to point out the potential biotechnological applications of Adx as a versatile electron donor to different cytochromes P450, both in vitro and in vivo. Finally we will address the comparison between the mammalian cytochrome P450-associated adrenodoxin and ferredoxins involved in iron-sulfur-cluster biosynthesis. Despite their different functions, these proteins display an amazing similarity regarding their primary sequence, tertiary structure and biophysical features.
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Affiliation(s)
- Kerstin Maria Ewen
- Department of Biochemistry, Saarland University, D-66041 Saarbrücken, Germany
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