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Lee TE, Ko YJ, Shin KC, Oh DK. Biotransformation of docosahexaenoic acid into 10R,17S-dihydroxydocosahexaenoic acid as protectin DX 10-epimer by serial reactions of arachidonate 8R- and 15S-lipoxygenases. World J Microbiol Biotechnol 2024; 40:219. [PMID: 38809492 DOI: 10.1007/s11274-024-04032-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 05/22/2024] [Indexed: 05/30/2024]
Abstract
Protectins, 10,17-dihydroxydocosahexaenoic acids (10,17-DiHDHAs), are belonged to specialized pro-resolving mediators (SPMs). Protectins are generated by polymorphonuclear leukocytes in humans and resolve inflammation and infection in trace amounts. However, the quantitative production of protectin DX 10-epimer (10-epi-PDX, 10R,17S-4Z,7Z,11E,13Z,15E,19Z-DiHDHA) has been not attempted to date. In this study, 10-epi-PDX was quantitatively produced from docosahexaenoic acid (DHA) by serial whole-cell biotransformation of Escherichia coli expressing arachidonate (ARA) 8R-lipoxygenase (8R-LOX) from the coral Plexaura homomalla and E. coli expressing ARA 15S-LOX from the bacterium Archangium violaceum. The optimal bioconversion conditions to produce 10R-hydroxydocosahexaenoic acid (10R-HDHA) and 10-epi-PDX were pH 8.0, 30 °C, 2.0 mM DHA, and 4.0 g/L cells; and pH 8.5, 20 °C, 1.4 mM 10R-HDHA, and 1.0 g/L cells, respectively. Under these optimized conditions, 2.0 mM (657 mg/L) DHA was converted into 1.2 mM (433 mg/L) 10-epi-PDX via 1.4 mM (482 mg/L) 10R-HDHA by the serial whole-cell biotransformation within 90 min, with a molar conversion of 60% and volumetric productivity of 0.8 mM/h (288 mg/L/h). To the best of our knowledge, this is the first quantitative production of 10-epi-PDX. Our results contribute to the efficient biocatalytic synthesis of SPMs.
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Affiliation(s)
- Tae-Eui Lee
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, 05029, Republic of Korea
| | - Yoon-Joo Ko
- National Center for Inter-University Research facilities (NCIRF), Seoul National University, Seoul, 08826, Republic of Korea
| | - Kyung-Chul Shin
- Department of Bioscience and Biotechnology, Hankuk University of Foreign Studies, Yongin, 17035, Republic of Korea.
| | - Deok-Kun Oh
- Department of Bioscience and Biotechnology, Konkuk University, Seoul, 05029, Republic of Korea.
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2
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Palmer MA, Benatzy Y, Brüne B. Murine Alox8 versus the human ALOX15B ortholog: differences and similarities. Pflugers Arch 2024:10.1007/s00424-024-02961-w. [PMID: 38637408 DOI: 10.1007/s00424-024-02961-w] [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: 02/16/2024] [Revised: 03/30/2024] [Accepted: 04/03/2024] [Indexed: 04/20/2024]
Abstract
Human arachidonate 15-lipoxygenase type B is a lipoxygenase that catalyzes the peroxidation of arachidonic acid at carbon-15. The corresponding murine ortholog however has 8-lipoxygenase activity. Both enzymes oxygenate polyunsaturated fatty acids in S-chirality with singular reaction specificity, although they generate a different product pattern. Furthermore, while both enzymes utilize both esterified fatty acids and fatty acid hydro(pero)xides as substrates, they differ with respect to the orientation of the fatty acid in their substrate-binding pocket. While ALOX15B accepts the fatty acid "tail-first," Alox8 oxygenates the free fatty acid with its "head-first." These differences in substrate orientation and thus in regio- and stereospecificity are thought to be determined by distinct amino acid residues. Towards their biological function, both enzymes share a commonality in regulating cholesterol homeostasis in macrophages, and Alox8 knockdown is associated with reduced atherosclerosis in mice. Additional roles have been linked to lung inflammation along with tumor suppressor activity. This review focuses on the current knowledge of the enzymatic activity of human ALOX15B and murine Alox8, along with their association with diseases.
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Affiliation(s)
- Megan A Palmer
- Institute of Biochemistry I, Faculty of Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
| | - Yvonne Benatzy
- Institute of Biochemistry I, Faculty of Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
| | - Bernhard Brüne
- Institute of Biochemistry I, Faculty of Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany
- Frankfurt Cancer Institute, Goethe University Frankfurt, Frankfurt, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Frankfurt, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt, Frankfurt, Germany
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3
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Functional Characterization of Novel Bony Fish Lipoxygenase Isoforms and Their Possible Involvement in Inflammation. Int J Mol Sci 2022; 23:ijms232416026. [PMID: 36555666 PMCID: PMC9787790 DOI: 10.3390/ijms232416026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 12/10/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Eicosanoids and related compounds are pleiotropic lipid mediators, which are biosynthesized in mammals via three distinct metabolic pathways (cyclooxygenase pathway, lipoxygenase pathway, epoxygenase pathway). These mediators have been implicated in the pathogenesis of inflammatory diseases and drugs interfering with eicosanoid signaling are currently available as antiphlogistics. Eicosanoid biosynthesis has well been explored in mammals including men, but much less detailed information is currently available on eicosanoid biosynthesis in other vertebrates including bony fish. There are a few reports in the literature describing the expression of arachidonic acid lipoxygenases (ALOX isoforms) in several bony fish species but except for two zebrafish ALOX-isoforms (zfALOX1 and zfALOX2) bony fish eicosanoid biosynthesizing enzymes have not been characterized. To fill this gap and to explore the possible roles of ALOX15 orthologs in bony fish inflammation we cloned and expressed putative ALOX15 orthologs from three different bony fish species (N. furzeri, P. nyererei, S. formosus) as recombinant N-terminal his-tag fusion proteins and characterized the corresponding enzymes with respect to their catalytic properties (temperature-dependence, activation energy, pH-dependence, substrate affinity and substrate specificity with different polyenoic fatty acids). Furthermore, we identified the chemical structure of the dominant oxygenation products formed by the recombinant enzymes from different free fatty acids and from more complex lipid substrates. Taken together, our data indicate that functional ALOX isoforms occur in bony fish but that their catalytic properties are different from those of mammalian enzymes. The possible roles of these ALOX-isoforms in bony fish inflammation are discussed.
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Oh CW, Kim SE, Lee J, Oh DK. Bioconversion of C20- and C22-polyunsaturated fatty acids into 9S,15S- and 11S,17S-dihydroxy fatty acids by Escherichia coli expressing double-oxygenating 9S-lipoxygenase from Sphingopyxis macrogoltabida. J Biosci Bioeng 2022; 134:14-20. [PMID: 35466059 DOI: 10.1016/j.jbiosc.2022.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 03/30/2022] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
Abstract
Double-oxygenating lipoxygenase (LOX) converted C20- and C22-polyunsaturated fatty acids (PUFAs) into C20 dihydroxy fatty acids (DiHFAs) as inflammatory mediators and C22 DiHFAs as specialized pro-resolving mediators, which are involved in the resolution of inflammation and infection in humans, and their isomers, respectively. However, the quantitative bioconversion of C20- and C22-PUFAs into 9S,15S- and 11S,17S-DiHFAs has been not attempted to date, respectively. Here, we performed the efficient quantitative production of 9S,15S- and 11S,17S-DiHFAs by Escherichia coli expressing 9S-LOX from Sphingopyxis macrogoltabida. The optimal bioconversion conditions of the C20 PUFA arachidonic acid or the C22-PUFA docosahexaenoic acid were pH 8.5, 35 °C, 6 mM substrate, and 5 g dry cells/L for C20 PUFAs or 7 g dry cells/L for C22 PUFAs, respectively. Under these conditions, E. coli expressing double-oxygenating 9S-LOX from S. macrogoltabida converted arachidonic acid, eicosapentaenoic acid, docosapentaenoic acidn-3, and docosahexaenoic acid into 5.85 mM 9S,15S-dihydroxyeicosatetraenoic acid, 5.79 mM 9S,15S-dihydroxyeicosapentaenoic acid, 5.89 mM 11S,17S-hydroxydocosapentaenoic acidn-3, and 5.24 mM 11S,17S-dihydroxydocosahexaenoic acid in 40, 30, 50, and 60 min, with conversion yields of 97.5%, 96.5%, 98.1%, and 87.3%; and volumetric productivities of 8.78, 11.6, 7.07, and 5.24 mM/h, respectively. To date, these are the highest concentrations, conversion yields, and volumetric productivities reported in the bioconversion of C20- and C22-PUFAs into DiHFAs.
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Affiliation(s)
- Chae-Won Oh
- Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea
| | - Seong-Eun Kim
- Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea
| | - Jin Lee
- Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea
| | - Deok-Kun Oh
- Department of Bioscience and Biotechnology, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143-701, Korea.
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Identification of a novel enzyme from E. pacifica that acts as an eicosapentaenoic 8R-LOX and docosahexaenoic 10R-LOX. Sci Rep 2020; 10:20592. [PMID: 33244101 PMCID: PMC7693274 DOI: 10.1038/s41598-020-77386-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 11/09/2020] [Indexed: 01/20/2023] Open
Abstract
North Pacific krill (Euphausia pacifica) contain 8R-hydroxy-eicosapentaenoic acid (8R-HEPE), 8R-hydroxy-eicosatetraenoic acid (8R-HETE) and 10R-hydroxy-docosahexaenoic acid (10R-HDHA). These findings indicate that E. pacifica must possess an R type lipoxygenase, although no such enzyme has been identified in krill. We analyzed E. pacifica cDNA sequence using next generation sequencing and identified two lipoxygenase genes (PK-LOX1 and 2). PK-LOX1 and PK-LOX2 encode proteins of 691 and 686 amino acids, respectively. Recombinant PK-LOX1 was generated in Sf9 cells using a baculovirus expression system. PK-LOX1 metabolizes eicosapentaenoic acid (EPA) to 8R-HEPE, arachidonic acid (ARA) to 8R-HETE and docosahexaenoic acid (DHA) to 10R-HDHA. Moreover, PK-LOX1 had higher activity for EPA than ARA and DHA. In addition, PK-LOX1 also metabolizes 17S-HDHA to 10R,17S-dihydroxy-docosahexaenoic acid (10R,17S-DiHDHA). PK-LOX1 is a novel lipoxygenase that acts as an 8R-lipoxygenase for EPA and 10R-lipoxygenase for DHA and 17S-HDHA. Our findings show PK-LOX1 facilitates the enzymatic production of hydroxy fatty acids, which are of value to the healthcare sector.
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Kuhn H, Humeniuk L, Kozlov N, Roigas S, Adel S, Heydeck D. The evolutionary hypothesis of reaction specificity of mammalian ALOX15 orthologs. Prog Lipid Res 2018; 72:55-74. [PMID: 30237084 DOI: 10.1016/j.plipres.2018.09.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 09/04/2018] [Accepted: 09/13/2018] [Indexed: 02/07/2023]
Affiliation(s)
- Hartmut Kuhn
- Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Charitéplatz 1, CCO- Building, Virchowweg 6, D-10117 Berlin, Germany.
| | - Lia Humeniuk
- Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Charitéplatz 1, CCO- Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Nikita Kozlov
- Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Charitéplatz 1, CCO- Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Sophie Roigas
- Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Charitéplatz 1, CCO- Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Susan Adel
- Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Internal Medicine, Division of Hepathology and Gastroenterology, Augustenburger Platz 1, D-13353 Berlin, Germany
| | - Dagmar Heydeck
- Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biochemistry, Charitéplatz 1, CCO- Building, Virchowweg 6, D-10117 Berlin, Germany
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7
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Regiospecificity of a novel bacterial lipoxygenase from Myxococcus xanthus for polyunsaturated fatty acids. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:823-833. [DOI: 10.1016/j.bbalip.2018.04.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/13/2018] [Accepted: 04/18/2018] [Indexed: 11/17/2022]
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8
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Gilbert NC, Neau DB, Newcomer ME. Expression of an 8R-Lipoxygenase From the Coral Plexaura homomalla. Methods Enzymol 2018; 605:33-49. [PMID: 29909831 DOI: 10.1016/bs.mie.2018.02.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Methods are presented for the use of the coral 8R-lipoxygenase from the Caribbean sea whip coral Plexaura homomalla as a model enzyme for structural studies of animal lipoxygenases. The 8R-lipoxygenase is remarkably stable and can be stored at 4°C for 3 months with virtually no loss of activity. In addition, an engineered "pseudo wild-type" enzyme is soluble in the absence of detergents, which helps facilitate the preparation of enzyme:substrate complexes.
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Affiliation(s)
| | - David B Neau
- Cornell University, Northeastern Collaborative Access Team, Argonne National Laboratory, Argonne, IL, United States
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An JU, Song YS, Kim KR, Ko YJ, Yoon DY, Oh DK. Biotransformation of polyunsaturated fatty acids to bioactive hepoxilins and trioxilins by microbial enzymes. Nat Commun 2018; 9:128. [PMID: 29317615 PMCID: PMC5760719 DOI: 10.1038/s41467-017-02543-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 12/08/2017] [Indexed: 12/18/2022] Open
Abstract
Hepoxilins (HXs) and trioxilins (TrXs) are involved in physiological processes such as inflammation, insulin secretion and pain perception in human. They are metabolites of polyunsaturated fatty acids (PUFAs), including arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid, formed by 12-lipoxygenase (LOX) and epoxide hydrolase (EH) expressed by mammalian cells. Here, we identify ten types of HXs and TrXs, produced by the prokaryote Myxococcus xanthus, of which six types are new, namely, HXB5, HXD3, HXE3, TrXB5, TrXD3 and TrXE3. We succeed in the biotransformation of PUFAs into eight types of HXs (>35% conversion) and TrXs (>10% conversion) by expressing M. xanthus 12-LOX or 11-LOX with or without EH in Escherichia coli. We determine 11-hydroxy-eicosatetraenoic acid, HXB3, HXB4, HXD3, TrXB3 and TrXD3 as potential peroxisome proliferator-activated receptor-γ partial agonists. These findings may facilitate physiological studies and drug development based on lipid mediators. Hepoxilins (HXs) and trioxilins (TrXs) are lipid metabolites with roles in inflammation and insulin secretion. Here, the authors discover a prokaryotic source of HXs and TrXs, identify the biosynthetic enzymes and heterologously express HXs and TrXs in E. coli.
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Affiliation(s)
- Jung-Ung An
- Department of Integrative Bioscience and Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, Republic of Korea
| | - Yong-Seok Song
- Department of Integrative Bioscience and Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, Republic of Korea
| | - Kyoung-Rok Kim
- Department of Integrative Bioscience and Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, Republic of Korea
| | - Yoon-Joo Ko
- National Center for Inter-University Research Facilities (NCIRF), Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826, Republic of Korea
| | - Do-Young Yoon
- Department of Integrative Bioscience and Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, Republic of Korea
| | - Deok-Kun Oh
- Department of Integrative Bioscience and Biotechnology, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul, 05029, Republic of Korea.
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Kalms J, Banthiya S, Galemou Yoga E, Hamberg M, Holzhutter HG, Kuhn H, Scheerer P. The crystal structure of Pseudomonas aeruginosa lipoxygenase Ala420Gly mutant explains the improved oxygen affinity and the altered reaction specificity. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:463-473. [PMID: 28093240 DOI: 10.1016/j.bbalip.2017.01.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 01/03/2017] [Accepted: 01/12/2017] [Indexed: 12/30/2022]
Abstract
Secreted LOX from Pseudomonas aeruginosa (PA-LOX) has previously been identified as arachidonic acid 15S-lipoxygenating enzyme. Here we report that the substitution of Ala420Gly in PA-LOX leads to an enzyme variant with pronounced dual specificity favoring arachidonic acid 11R-oxygenation. When compared with other LOX-isoforms the molecular oxygen affinity of wild-type PA-LOX is 1-2 orders of magnitude lower (Km O2 of 0.4mM) but Ala420Gly exchange improved the molecular oxygen affinity (Km O2 of 0.2mM). Experiments with stereo-specifically deuterated linoleic acid indicated that the formation of both 13S- and 9R-HpODE involves abstraction of the proS-hydrogen from C11 of the fatty acid backbone. To explore the structural basis for the observed functional changes (altered specificity, improved molecular oxygen affinity) we solved the crystal structure of the Ala420Gly mutant of PA-LOX at 1.8Å resolution and compared it with the wild-type enzyme. Modeling of fatty acid alignment at the catalytic center suggested that in the wild-type enzyme dioxygen is directed to C15 of arachidonic acid by a protein tunnel, which interconnects the catalytic center with the protein surface. Ala420Gly exchange redirects intra-enzyme O2 diffusion by bifurcating this tunnel so that C11 of arachidonic acid also becomes accessible for O2 insertion.
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Affiliation(s)
- Jacqueline Kalms
- Institute of Medical Physics and Biophysics (CC2), Group Protein X-ray Crystallography and Signal Transduction, Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Swathi Banthiya
- Institute for Biochemistry (CC2), Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Etienne Galemou Yoga
- Institute of Medical Physics and Biophysics (CC2), Group Protein X-ray Crystallography and Signal Transduction, Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Mats Hamberg
- Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden
| | - Hermann-Georg Holzhutter
- Institute for Biochemistry (CC2), Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Hartmut Kuhn
- Institute for Biochemistry (CC2), Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany.
| | - Patrick Scheerer
- Institute of Medical Physics and Biophysics (CC2), Group Protein X-ray Crystallography and Signal Transduction, Charité - University Medicine Berlin, Charitéplatz 1, 10117 Berlin, Germany.
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Banthiya S, Kalms J, Galemou Yoga E, Ivanov I, Carpena X, Hamberg M, Kuhn H, Scheerer P. Structural and functional basis of phospholipid oxygenase activity of bacterial lipoxygenase from Pseudomonas aeruginosa. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1681-1692. [PMID: 27500637 DOI: 10.1016/j.bbalip.2016.08.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 07/29/2016] [Accepted: 08/03/2016] [Indexed: 01/18/2023]
Abstract
Pseudomonas aeruginosa expresses a secreted LOX-isoform (PA-LOX, LoxA) capable of oxidizing polyenoic fatty acids to hydroperoxy derivatives. Here we report high-level expression of this enzyme in E. coli and its structural and functional characterization. Recombinant PA-LOX oxygenates polyenoic fatty acids including eicosapentaenoic acid and docosahexaenoic acid to the corresponding (n-6)S-hydroperoxy derivatives. This reaction involves abstraction of the proS-hydrogen from the n-8 bisallylic methylene. PA-LOX lacks major leukotriene synthase activity but converts 5S-HETE and 5S,6R/S-DiHETE to anti-inflammatory and pro-resolving lipoxins. It also exhibits phospholipid oxygenase activity as indicated by the formation of a specific pattern of oxygenation products from different phospholipid subspecies. Multiple mutagenesis studies revealed that PA-LOX does not follow classical concepts explaining the reaction specificity of mammalian LOXs. The crystal structure of PA-LOX was solved with resolutions of up to 1.48Å and its polypeptide chain is folded as single domain. The substrate-binding pocket consists of two fatty acid binding subcavities and lobby. Subcavity-1 contains the catalytic non-heme iron. A phosphatidylethanolamine molecule occupies the substrate-binding pocket and its sn1 fatty acid is located close to the catalytic non-heme iron. His377, His382, His555, Asn559 and the C-terminal Ile685 function as direct iron ligands and a water molecule (hydroxyl) completes the octahedral ligand sphere. Although the biological relevance of PA-LOX is still unknown its functional characteristics (lipoxin synthase activity) implicate this enzyme in a bacterial evasion strategy aimed at downregulating the hosts' immune system.
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Affiliation(s)
- Swathi Banthiya
- Institut für Biochemie, Charité - Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Jacqueline Kalms
- Institut für Medizinische Physik und Biophysik, Group Protein X-ray Crystallography and Signal Transduction, Charité - Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Etienne Galemou Yoga
- Institut für Medizinische Physik und Biophysik, Group Protein X-ray Crystallography and Signal Transduction, Charité - Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Igor Ivanov
- Institut für Biochemie, Charité - Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Xavi Carpena
- Institut de Biologia Molecular de Barcelona (IBMB-CSIC), Parc Científic de Barcelona, 08028 Barcelona, Spain; XALOC beamline, ALBA synchrotron (CELLS), 08290 Cerdanyola del Vallès, Spain
| | - Mats Hamberg
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Hartmut Kuhn
- Institut für Biochemie, Charité - Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany.
| | - Patrick Scheerer
- Institut für Medizinische Physik und Biophysik, Group Protein X-ray Crystallography and Signal Transduction, Charité - Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany.
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12
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Ivanov I, Kuhn H, Heydeck D. Structural and functional biology of arachidonic acid 15-lipoxygenase-1 (ALOX15). Gene 2015; 573:1-32. [PMID: 26216303 PMCID: PMC6728142 DOI: 10.1016/j.gene.2015.07.073] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/26/2015] [Accepted: 07/21/2015] [Indexed: 12/14/2022]
Abstract
Lipoxygenases (LOX) form a family of lipid peroxidizing enzymes, which have been implicated in a number of physiological processes and in the pathogenesis of inflammatory, hyperproliferative and neurodegenerative diseases. They occur in two of the three domains of terrestrial life (bacteria, eucarya) and the human genome involves six functional LOX genes, which encode for six different LOX isoforms. One of these isoforms is ALOX15, which has first been described in rabbits in 1974 as enzyme capable of oxidizing membrane phospholipids during the maturational breakdown of mitochondria in immature red blood cells. During the following decades ALOX15 has extensively been characterized and its biological functions have been studied in a number of cellular in vitro systems as well as in various whole animal disease models. This review is aimed at summarizing the current knowledge on the protein-chemical, molecular biological and enzymatic properties of ALOX15 in various species (human, mouse, rabbit, rat) as well as its implication in cellular physiology and in the pathogenesis of various diseases.
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Affiliation(s)
- Igor Ivanov
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Hartmut Kuhn
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany.
| | - Dagmar Heydeck
- Institute of Biochemistry, Charité - University Medicine Berlin, Charitéplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
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Teder T, Lõhelaid H, Boeglin WE, Calcutt WM, Brash AR, Samel N. A Catalase-related Hemoprotein in Coral Is Specialized for Synthesis of Short-chain Aldehydes: DISCOVERY OF P450-TYPE HYDROPEROXIDE LYASE ACTIVITY IN A CATALASE. J Biol Chem 2015; 290:19823-32. [PMID: 26100625 DOI: 10.1074/jbc.m115.660282] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Indexed: 11/06/2022] Open
Abstract
In corals a catalase-lipoxygenase fusion protein transforms arachidonic acid to the allene oxide 8R,9-epoxy-5,9,11,14-eicosatetraenoic acid from which arise cyclopentenones such as the prostanoid-related clavulones. Recently we cloned two catalase-lipoxygenase fusion protein genes (a and b) from the coral Capnella imbricata, form a being an allene oxide synthase and form b giving uncharacterized polar products (Lõhelaid, H., Teder, T., Tõldsepp, K., Ekins, M., and Samel, N. (2014) PloS ONE 9, e89215). Here, using HPLC-UV, LC-MS, and NMR methods, we identify a novel activity of fusion protein b, establishing its role in cleaving the lipoxygenase product 8R-hydroperoxy-eicosatetraenoic acid into the short-chain aldehydes (5Z)-8-oxo-octenoic acid and (3Z,6Z)-dodecadienal; these primary products readily isomerize in an aqueous medium to the corresponding 6E- and 2E,6Z derivatives. This type of enzymatic cleavage, splitting the carbon chain within the conjugated diene of the hydroperoxide substrate, is known only in plant cytochrome P450 hydroperoxide lyases. In mechanistic studies using (18)O-labeled substrate and incubations in H2(18)O, we established synthesis of the C8-oxo acid and C12 aldehyde with the retention of the hydroperoxy oxygens, consistent with synthesis of a short-lived hemiacetal intermediate that breaks down spontaneously into the two aldehydes. Taken together with our initial studies indicating differing gene regulation of the allene oxide synthase and the newly identified catalase-related hydroperoxide lyase and given the role of aldehydes in plant defense, this work uncovers a potential pathway in coral stress signaling and a novel enzymatic activity in the animal kingdom.
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Affiliation(s)
- Tarvi Teder
- From the Department of Chemistry, Tallinn University of Technology, 12618 Tallinn, Estonia, Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, and
| | - Helike Lõhelaid
- From the Department of Chemistry, Tallinn University of Technology, 12618 Tallinn, Estonia
| | - William E Boeglin
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, and
| | - Wade M Calcutt
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee
| | - Alan R Brash
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, and
| | - Nigulas Samel
- From the Department of Chemistry, Tallinn University of Technology, 12618 Tallinn, Estonia,
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14
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Audran G, Brémond P, Marque SR, Siri D, Santelli M. Energetics of the biosynthesis of cyclopentenones from unsaturated fatty acids. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.09.056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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Muñoz-Garcia A, Thomas CP, Keeney DS, Zheng Y, Brash AR. The importance of the lipoxygenase-hepoxilin pathway in the mammalian epidermal barrier. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1841:401-8. [PMID: 24021977 PMCID: PMC4116325 DOI: 10.1016/j.bbalip.2013.08.020] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 08/27/2013] [Accepted: 08/30/2013] [Indexed: 01/22/2023]
Abstract
This review covers the background to discovery of the two key lipoxygenases (LOX) involved in epidermal barrier function, 12R-LOX and eLOX3, and our current views on their functioning. In the outer epidermis, their consecutive actions oxidize linoleic acid esterified in ω-hydroxy-ceramide to a hepoxilin-related derivative. The relevant background to hepoxilin and trioxilin biochemistry is briefly reviewed. We outline the evidence that linoleate in the ceramide is the natural substrate of the two LOX enzymes and our proposal for its importance in construction of the epidermal water barrier. Our hypothesis is that the oxidation promotes hydrolysis of the oxidized linoleate moiety from the ceramide. The resulting free ω-hydroxyl of the ω-hydroxyceramide is covalently bound to proteins on the surface of the corneocytes to form the corneocyte lipid envelope, a key barrier component. Understanding the role of the LOX enzymes and their hepoxilin products should provide rational approaches to ameliorative therapy for a number of the congenital ichthyoses involving compromised barrier function. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias.
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Affiliation(s)
- Agustí Muñoz-Garcia
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Christopher P Thomas
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Diane S Keeney
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Yuxiang Zheng
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Alan R Brash
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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16
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Jin J, Zheng Y, Boeglin WE, Brash AR. Biosynthesis, isolation, and NMR analysis of leukotriene A epoxides: substrate chirality as a determinant of the cis or trans epoxide configuration. J Lipid Res 2012; 54:754-761. [PMID: 23242647 DOI: 10.1194/jlr.m033746] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Leukotriene (LT)A₄ and closely related allylic epoxides are pivotal intermediates in lipoxygenase (LOX) pathways to bioactive lipid mediators that include the leukotrienes, lipoxins, eoxins, resolvins, and protectins. Although the structure and stereochemistry of the 5-LOX product LTA₄ is established through comparison to synthetic standards, this is the exception, and none of these highly unstable epoxides has been analyzed in detail from enzymatic synthesis. Understanding of the mechanistic basis of the cis or trans epoxide configuration is also limited. To address these issues, we developed methods involving biphasic reaction conditions for the LOX-catalyzed synthesis of LTA epoxides in quantities sufficient for NMR analysis. As proof of concept, human 15-LOX-1 was shown to convert 15S-hydroperoxy-eicosatetraenoic acid (15S-HPETE) to the LTA analog 14S,15S-trans-epoxy-eicosa-5Z,8Z,10E,12E-tetraenoate, confirming the proposed structure of eoxin A₄. Using this methodology we then showed that recombinant Arabidopsis AtLOX1, an arachidonate 5-LOX, converts 5S-HPETE to the trans epoxide LTA₄ and converts 5R-HPETE to the cis epoxide 5-epi-LTA₄, establishing substrate chirality as a determinant of the cis or trans epoxide configuration. The results are reconciled with a mechanism based on a dual role of the LOX nonheme iron in LTA epoxide biosynthesis, providing a rational basis for understanding the stereochemistry of LTA epoxide intermediates in LOX-catalyzed transformations.
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Affiliation(s)
- Jing Jin
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232
| | - Yuxiang Zheng
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232
| | - William E Boeglin
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232
| | - Alan R Brash
- Department of Pharmacology and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232
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Joo YC, Oh DK. Lipoxygenases: Potential starting biocatalysts for the synthesis of signaling compounds. Biotechnol Adv 2012; 30:1524-32. [DOI: 10.1016/j.biotechadv.2012.04.004] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 03/26/2012] [Accepted: 04/10/2012] [Indexed: 12/11/2022]
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18
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Jin J, Boeglin WE, Cha JK, Brash AR. 8R-Lipoxygenase-catalyzed synthesis of a prominent cis-epoxyalcohol from dihomo-γ-linolenic acid: a distinctive transformation compared with S-lipoxygenases. J Lipid Res 2011; 53:292-9. [PMID: 22158855 DOI: 10.1194/jlr.m022863] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Conversion of fatty acid hydroperoxides to epoxyalcohols is a well known secondary reaction of lipoxygenases, described for S-specific lipoxygenases forming epoxyalcohols with a trans-epoxide configuration. Here we report on R-specific lipoxygenase synthesis of a cis-epoxyalcohol. Although arachidonic and dihomo-γ-linolenic acids are metabolized by extracts of the Caribbean coral Plexaura homomalla via 8R-lipoxygenase and allene oxide synthase activities, 20:3ω6 forms an additional prominent product, identified using UV, GC-MS, and NMR in comparison to synthetic standards as 8R,9S-cis-epoxy-10S-erythro-hydroxy-eicosa-11Z,14Z-dienoic acid. Both oxygens of (18)O-labeled 8R-hydroperoxide are retained in the product, indicating a hydroperoxide isomerase activity. Recombinant allene oxide synthase formed only allene epoxide from 8R-hydroperoxy-20:3ω6, whereas two different 8R-lipoxygenases selectively produced the epoxyalcohol.A biosynthetic scheme is proposed in which a partial rotation of the reacting intermediate is required to give the observed erythro epoxyalcohol product. This characteristic and the synthesis of cis-epoxy epoxyalcohol may be a feature of R-specific lipoxygenases.
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Affiliation(s)
- Jing Jin
- Department of Pharmacology, and the Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
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19
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Applications of stereospecifically-labeled Fatty acids in oxygenase and desaturase biochemistry. Lipids 2011; 47:101-16. [PMID: 21971646 DOI: 10.1007/s11745-011-3612-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 08/30/2011] [Indexed: 10/17/2022]
Abstract
Oxygenation and desaturation reactions are inherently associated with the abstraction of a hydrogen from the fatty acid substrate. Since the first published application in 1965, stereospecific placement of a labeled hydrogen isotope (deuterium or tritium) at the reacting carbons has proven a highly effective strategy for investigating the chemical mechanisms catalyzed by lipoxygenases, hemoprotein fatty acid dioxygenases including cyclooxygenases, cytochromes P450, and also the desaturases and isomerases. This review presents a synopsis of all published studies through 2010 on the synthesis and use of stereospecifically labeled fatty acids (71 references), and highlights some of the mechanistic insights gained by application of stereospecifically labeled fatty acids.
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20
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AmbLOXe--an epidermal lipoxygenase of the Mexican axolotl in the context of amphibian regeneration and its impact on human wound closure in vitro. Ann Surg 2011; 253:410-8. [PMID: 21183847 DOI: 10.1097/sla.0b013e318207f39c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The Mexican axolotl (Ambystoma mexicanum) is a well-characterized example for intrinsic regeneration. As lipoxygenase signaling is of crucial importance to scarless mammalian wound healing, we postulated that lipoxygenases might be expressed during amphibian regeneration and they might also influence human cells under appropriate conditions. In this study we identified an amphibian lipoxygenase and evaluated its impact on human cells in an in vitro wound model. METHODS cDNA encoding for amphibian epidermal lipoxygenase (AmbLOXe) was polymerase chain reaction amplified and sequenced followed by phylogenic classification based on T-coffee alignment. Distribution of AmbLOXe was examined in various Ambystoma tissues, using polymerase chain reaction and in situ hybridization. Lipoxgenase influence was investigated using an outgrowth model of amphibian epidermal cells. Human osteosarcoma, as well as keratinocyte cell lines expressing AmbLOXe, were tested concerning in vitro wound closure in a monolayer scratch model. RESULTS We isolated AmbLOXe from Ambystoma limb bud blastema identified as a homologue of human epidermal lipoxygenase. Amphibian epidermal lipoxygenase is expressed in Axolotl limb blastema and in epidermal cells which show decreased cell migration and proliferation rates when treated with LOX inhibitors. Furthermore, human osteosarcoma and keratinocyte cells showed increased rates of cell migration if transfected with AmbLOXe. CONCLUSION In this study, AmbLOXe, a new effector of amphibian regeneration is described. In consideration of the presented data, AmbLOXe is important for amphibian epidermal cell proliferation and migration. As AmbLOXe expressing human osteosarcoma and keratinocyte cell lines showed increased rates of in vitro wound closure, an influence of amphibian mediators on human cells could be described for the first time.
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21
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Vogel R, Jansen C, Roffeis J, Reddanna P, Forsell P, Claesson HE, Kuhn H, Walther M. Applicability of the triad concept for the positional specificity of mammalian lipoxygenases. J Biol Chem 2009; 285:5369-76. [PMID: 20026599 DOI: 10.1074/jbc.m109.057802] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The nomenclature of lipoxygenases (LOXs) is partly based on the positional specificity of arachidonic acid oxygenation, but there is no unifying concept explaining the mechanistic basis of this enzyme property. According to the triad model, Phe-353, Ile-418, and Ile-593 of the rabbit 12/15-LOX form the bottom of the substrate-binding pocket, and introduction of less space-filling residues at either of these positions favors arachidonic acid 12-lipoxygenation. The present study was aimed at exploring the validity of the triad concept for two novel primate 12/15-LOX (Macaca mulatta and Pongo pygmaeus) and for five known members of the mammalian LOX family (human 12/15-LOX, mouse 12/15-LOX, human 15-LOX2, human platelet type 12-LOX, and mouse (12R)-LOX). The enzymes were expressed as N-terminal His tag fusion proteins in E. coli, the potential sequence determinants were mutated, and the specificity of arachidonic acid oxygenation was quantified. Taken together, our data indicate that the triad concept explains the positional specificity of all 12/15-LOXs tested (rabbit, human, M. mulatta, P. pygmaeus, and mouse). For the new enzymes of M. mulatta and P. pygmaeus, the concept had predictive value because the positional specificity predicted on the basis of the amino acid sequence was confirmed experimentally. The specificity of the platelet 12-LOX was partly explained by the triad hypothesis, but the concept was not applicable for 15-LOX2 and (12R)-LOX.
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Affiliation(s)
- Robert Vogel
- Institute of Biochemistry, University Medicine Berlin-Charité, Monbijoustrasse 2, D-10117 Berlin, Germany
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22
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Stabilization of an enzymatic extract from Penicillium camemberti containing lipoxygenase and hydroperoxide lyase activities. Process Biochem 2008. [DOI: 10.1016/j.procbio.2007.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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23
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Abstract
The dioxygenation of PUFAs (polyunsaturated fatty acids) in plants is mainly catalysed by members of the LOX (lipoxygenase) enzyme family. LOX products may be further metabolized, and are known as signalling substances in plant development and in responses to wounding and pathogen attack. In contrast with the situation in eukaryotes, information on the relevance of lipid peroxide metabolism in prokaryotic organisms is scarce. Therefore, we aimed to analyse LOXs and oxylipin patterns of cyanobacterial origin. A search of the genomic sequence of the cyanobacterium Nostoc sp. PCC 7120 suggested an open reading frame encoding a putative LOX named NspLOX that harboured an N-terminal extension. Individual analysis of recombinant C-terminal domain revealed enzymatic activity as a linoleate (9R)-LOX. Analysis of the full-length NspLOX protein, however, revealed linoleate diol synthase activity, generating (10E,12E)-9,14-dihydroxy-10,12-octadecadienoic acid as the main product from LA (linoleic acid) and (10E,12E,14E)-9,16-dihydroxy-10,12,14-octadecatrienoic acid as the main product from ALA (α-LA) substrates respectively, with ALA as preferred substrate. The enzyme exhibited a broad pH optimum between pH 7 and pH 10. Soluble extracts of Nostoc sp. contain more 9-LOX-derived hydroperoxides in sonified than in non-sonified cells, but products of full-length NspLOX were not detectable under the conditions used. As no other LOX-like sequence was identified in the genome of Nostoc sp. PCC 7120, the results presented suggest that (9R)-LOX-derived oxylipins may represent the endogenous products of NspLOX. Based on the biochemical results of NspLOX, we suggest that this bifunctional enzyme may represent a more ancient way to control the intracellular amount of oxylipins in this cyanobacterium.
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24
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Zheng Y, Boeglin WE, Schneider C, Brash AR. A 49-kDa mini-lipoxygenase from Anabaena sp. PCC 7120 retains catalytically complete functionality. J Biol Chem 2007; 283:5138-47. [PMID: 18070874 DOI: 10.1074/jbc.m705780200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Anabaena sp. PCC 7120 is one of the few prokaryotes harboring a lipoxygenase (LOX) gene. The sequence resides in an open reading frame encoding a fusion protein of a catalase-like hemoprotein with an unusually short LOX (approximately 49 kDa) at the C terminus. The recombinant mini-LOX contains a non-heme iron in the active site and is highly active with linoleic and alpha-linolenic acids (which occur naturally in Anabaena) giving the respective 9R-hydroperoxides, the mirror image of the 9S-LOX products of plants. Using stereospecifically labeled [11-(3)H]linoleic acids we show that reaction is catalyzed via a typical antarafacial relationship of initial hydrogen abstraction and oxygenation. The mini-LOX oxygenated C16/C18:2-phosphatidylcholine with 9R specificity, suggesting a "tail first" mode of fatty acid binding. Site-directed mutagenesis of an active site Ala (Ala215), typically conserved as Gly in R-LOX, revealed that substitution with Gly retained 9R specificity, whereas the larger Val substitution switched oxygenation to 13S, implying that Ala215 represents the functional equivalent of the Gly in other R-LOX. Metabolism studies using a synthetic fatty acid with extended double bond conjugation, 9E,11Z,14Z-20:3omega6, showed that the mini-LOX can control oxygenation two positions further along the fatty acid carbon chain. We conclude that the mini-LOX, despite lacking the beta-barrel domain and much additional sequence, is catalytically complete. Interestingly, animal and plant LOX, which undoubtedly share a common ancestor, are related in sequence only in the catalytic domain; it is possible that the prokaryotic LOX represents a common link and that the beta-barrel domain was then acquired independently in the animal and plant kingdoms.
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Affiliation(s)
- Yuxiang Zheng
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-6602, USA
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25
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Schneider C, Pratt DA, Porter NA, Brash AR. Control of oxygenation in lipoxygenase and cyclooxygenase catalysis. ACTA ACUST UNITED AC 2007; 14:473-88. [PMID: 17524979 PMCID: PMC2692746 DOI: 10.1016/j.chembiol.2007.04.007] [Citation(s) in RCA: 222] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 04/03/2007] [Accepted: 04/10/2007] [Indexed: 12/16/2022]
Abstract
Lipoxygenases (LOX) and cyclooxygenases (COX) react an achiral polyunsaturated fatty acid with oxygen to form a chiral peroxide product of high regio- and stereochemical purity. Both enzymes employ free radical chemistry reminiscent of hydrocarbon autoxidation but execute efficient control during catalysis to form a specific product over the multitude of isomers found in the nonenzymatic reaction. Exactly how both dioxygenases achieve this positional and stereo control is far from clear. We present four mechanistic models, not mutually exclusive, that could account for the specific reactions of molecular oxygen with a fatty acid in the LOX or COX active site.
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Affiliation(s)
- Claus Schneider
- Department of Pharmacology, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, U.S.A
| | - Derek A. Pratt
- Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, U.S.A
- Department of Chemistry, Queen’s University, Kingston, Ontario, Canada K7L 3N6
| | - Ned A. Porter
- Department of Chemistry, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, U.S.A
| | - Alan R. Brash
- Department of Pharmacology, Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, U.S.A
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26
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Lang I, Feussner I. Oxylipin formation in Nostoc punctiforme (PCC73102). PHYTOCHEMISTRY 2007; 68:1120-7. [PMID: 17412376 DOI: 10.1016/j.phytochem.2007.02.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Revised: 02/14/2007] [Accepted: 02/21/2007] [Indexed: 05/14/2023]
Abstract
The dioxygenation of polyunsaturated fatty acids is mainly catalyzed by members of the lipoxygenase enzyme family in flowering plants and mosses. Lipoxygenase products can be metabolized further and are known as signalling substances that play a role in plant development as well as in plant responses to wounding and pathogen attack. Apart from accumulating data in mammals, flowering and non-flowering plants, information on the relevance of lipid peroxide metabolism in prokaryotic organisms is scarce. Thus we aimed to isolate and analyze lipoxygenases and oxylipin patterns from cyanobacterial origin. DNA isolated from Nostoc punctiforme strain PCC73102 yielded sequences for at least two different lipoxygenases. These have been cloned as cDNAs and named NpLOX1 and NpLOX2. Both proteins were identified as linoleate 13-lipoxygenases by expression in E. coli. NpLOX1 was characterized in more detail: It showed a broad pH optimum ranging from pH 4.5 to pH 8.5 with a maximum at pH 8.0 and alpha-linolenic acid was the preferred substrate. Bacterial extracts contain more 13-lipoxygenase-derived hydroperoxides in wounded than in non-wounded cells with a 30-fold excess of non-esterified over esterified oxylipins. 9-Lipoxygenase-derived derivatives were not detectable. 13-Lipoxygenase-derived hydroperoxides in esterified lipids were present at almost equal amounts compared to non-esterified hydroperoxides in non-wounded cells. These results suggest that 13-lipoxygenases acting on free fatty acids dominate in N. punctiforme strain PCC73102 upon wounding.
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Affiliation(s)
- Imke Lang
- Georg-August-University of Göttingen, Albrecht-von-Haller-Institute of Plant Sciences, Department of Plant Biochemistry, Justus-von-Liebig-Weg 11, D-37085 Göttingen, Germany
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27
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Casey R, Hughes RK. Recombinant Lipoxygenases and Oxylipin Metabolism in Relation to Food Quality. FOOD BIOTECHNOL 2007. [DOI: 10.1081/fbt-200025673] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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28
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Fukuzumi S. Proton-Coupled Electron Transfer of Unsaturated Fatty Acids and Mechanistic Insight into Lipoxygenase. Helv Chim Acta 2006. [DOI: 10.1002/hlca.200690223] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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29
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Roopashree S, Singh S, Gowda L, Rao A. Dual-function protein in plant defence: seed lectin from Dolichos biflorus (horse gram) exhibits lipoxygenase activity. Biochem J 2006; 395:629-39. [PMID: 16441240 PMCID: PMC1462680 DOI: 10.1042/bj20051889] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Plant-pathogen interactions play a vital role in developing resistance to pests. Dolichos biflorus (horse gram), a leguminous pulse crop of the subtropics, exhibits amazing defence against attack by pests/pathogens. Investigations to locate the possible source of the indomitable pest resistance of D. biflorus, which is the richest source of LOX (lipoxygenase) activity, have led to a molecule that exhibits LOX-like functions. The LOX-like activity associated with the molecule, identified by its structure and stability to be a tetrameric lectin, was found to be unusual. The evidence for the lectin protein with LOX activity has come from (i) MALDI-TOF (matrix-assisted laser-desorption ionization-time-of-flight) MS, (ii) N-terminal sequencing, (iii) partial sequencing of the tryptic fragments of the protein, (iv) amino acid composition, and (v) the presence of an Mn2+ ion. A hydrophobic binding site of the tetrameric lectin, along with the presence of an Mn2+ ion, accounts for the observed LOX like activity. This is the first ever report of a protein exhibiting both haemagglutination and LOX-like activity. The two activities are associated with separate loci on the same protein. LOX activity associated with this molecule adds a new dimension to our understanding of lectin functions. This observation has wide implications for the understanding of plant defence mechanisms against pests and the cellular complexity in plant-pathogen interactions that may lead to the design of transgenics with potential to impart pest resistance to other crops.
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Affiliation(s)
- Subbaiah Roopashree
- Department of Protein Chemistry and Technology, Central Food Technological Research Institute, Mysore 570020, India
| | - Sridevi Annapurna Singh
- Department of Protein Chemistry and Technology, Central Food Technological Research Institute, Mysore 570020, India
| | - Lalitha R. Gowda
- Department of Protein Chemistry and Technology, Central Food Technological Research Institute, Mysore 570020, India
| | - A. G. Appu Rao
- Department of Protein Chemistry and Technology, Central Food Technological Research Institute, Mysore 570020, India
- To whom correspondence should be addressed (email )
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30
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Kühn H, O'Donnell VB. Inflammation and immune regulation by 12/15-lipoxygenases. Prog Lipid Res 2006; 45:334-56. [PMID: 16678271 DOI: 10.1016/j.plipres.2006.02.003] [Citation(s) in RCA: 291] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2005] [Revised: 01/19/2006] [Accepted: 02/06/2006] [Indexed: 12/22/2022]
Abstract
12/15-Lipoxygenases (12/15-LOX) are members of the LOX family, which are expressed in mammals by monocytes and macrophages following induction by the T helper type 2 cytokines, interleukins-4 and -13. They oxygenate free polyenoic fatty acids but also ester lipids and even complex lipid-protein assemblies such as biomembranes and lipoproteins. The primary oxidation products are either reduced by glutathione peroxidases to corresponding hydroxy derivatives or metabolized into secondary oxidized lipids including leukotrienes, lipoxins and hepoxilins, which act as lipid mediators. Examination of knockout and transgenic animals revealed important roles for 12/15-LOX in inflammatory diseases, including atherosclerosis, cancer, osteoporosis, angiotension II-dependent hypertension and diabetes. In vitro studies suggested 12/15-LOX products as coactivators of peroxisomal proliferator activating-receptors (PPAR), regulators of cytokine generation, and modulators of gene expression related to inflammation resolution. Despite much work in this area, the biochemical mechanisms by which 12/15-LOX regulates physiological and pathological immune cell function are not fully understood. This review will summarize the biochemistry and tissue expression of 12/15-LOX and will describe the current knowledge regarding its immunobiology and regulation of inflammation.
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Affiliation(s)
- Hartmut Kühn
- Institute of Biochemistry, Monbijoustrasse 2, University Medicine Berlin -- Charité, Germany
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Maskrey BH, Taylor GW, Rowley AF. The identification and role of a novel eicosanoid in the reproductive behaviour of barnacles (Balanus balanus). J Exp Biol 2006; 209:558-66. [PMID: 16424106 DOI: 10.1242/jeb.02037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
SUMMARY
Post-copulatory behaviour in barnacles involves a violent rocking movement of the opercular valves, which is thought to contribute to the expulsion of oocytes through the oviduct into the mantle cavity where they are fertilised. We demonstrate in this study that the seminal vesicles/testis of the subtidal barnacle Balanus balanus produce a biologically active factor,barnacle muscle stimulatory factor (BMSF), which causes a significant increase in cirral and body muscular activity. BMSF was identified using a combination of high performance liquid chromatography and mass spectrometry as a novel eicosanoid/oxylipin, 8,13-dihydroxyeicosapentaenoic acid. This is rapidly inactivated under mild acid conditions to form a complex range of triene and pentaene chromophore-containing products that have only been partially identified. Injection of purified BMSF into the mantle cavity of barnacles caused the rocking movements of the opercular valves as reported following fertilisation. In excised barnacles, it also caused muscular contractions of the whole body mass. The breakdown products of BMSF, however, were without such activities. The function of BMSF in facilitating fertilisation in barnacles is comparable to the role of other eicosanoids in human reproduction, reinforcing the view that these compounds have conserved activities in both invertebrates and vertebrates.
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Affiliation(s)
- Ben H Maskrey
- Department of Biological Sciences and Institute of Environmental Sustainability, University of Wales Swansea, Swansea, SA2 8PP, UK
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Mortimer M, Järving R, Brash AR, Samel N, Järving I. Identification and characterization of an arachidonate 11R-lipoxygenase. Arch Biochem Biophys 2006; 445:147-55. [PMID: 16321357 DOI: 10.1016/j.abb.2005.10.023] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2005] [Revised: 10/22/2005] [Accepted: 10/28/2005] [Indexed: 11/16/2022]
Abstract
11R-Lipoxygenase (11R-LOX) activity has been detected in several marine invertebrates, and here we report the first cloning and expression of the enzyme. The cDNA encoding a protein of 77kDa was isolated by RT-PCR from the soft coral Gersemia fruticosa and expressed in Escherichia coli. Incubations of recombinant enzyme with arachidonic acid yielded a single product, identified by RP-HPLC, GC-MS, and chiral phase-HPLC as 11R-hydroperoxyeicosatetraenoic acid. Other C18, C20, and C22 substrates are also oxygenated, preferentially at the omega10 position. Significantly, both Ca(2+)-ions and a membrane fraction are required for catalytic activity. Calcium effects translocation of the soluble 11R-LOX to the membrane and this association is reversible by Ca(2+) chelation. The enzyme sequence contains some conserved amino acids implicated in calcium activation of mammalian 5-LOX, and with its obligate requirement for membrane interaction the 11R-LOX may thus provide a new model for further analysis of this aspect of lipoxygenase activation.
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Affiliation(s)
- Monika Mortimer
- Department of Chemistry, Tallinn University of Technology, Akadeemia tee 15, Tallinn 12618, Estonia
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33
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Meruvu S, Walther M, Ivanov I, Hammarström S, Fürstenberger G, Krieg P, Reddanna P, Kuhn H. Sequence determinants for the reaction specificity of murine (12R)-lipoxygenase: targeted substrate modification and site-directed mutagenesis. J Biol Chem 2005; 280:36633-41. [PMID: 16129665 DOI: 10.1074/jbc.m508260200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Mammalian lipoxygenases (LOXs) are categorized with respect to their positional specificity of arachidonic acid oxygenation. Site-directed mutagenesis identified sequence determinants for the positional specificity of these enzymes, and a critical amino acid for the stereoselectivity was recently discovered. To search for sequence determinants of murine (12R)-LOX, we carried out multiple amino acid sequence alignments and found that Phe(390), Gly(441), Ala(455), and Val(631) align with previously identified positional determinants of S-LOX isoforms. Multiple site-directed mutagenesis studies on Phe(390) and Ala(455) did not induce specific alterations in the reaction specificity, but yielded enzyme species with reduced specific activities and stereo random product patterns. Mutation of Gly(441) to Ala, which caused drastic alterations in the reaction specificity of other LOX isoforms, failed to induce major alterations in the positional specificity of mouse (12R)-LOX, but markedly modified the enantioselectivity of the enzyme. When Val(631), which aligns with the positional determinant Ile(593) of rabbit 15-LOX, was mutated to a less space-filling residue (Ala or Gly), we obtained an enzyme species with augmented catalytic activity and specifically altered reaction characteristics (major formation of chiral (11R)-hydroxyeicosatetraenoic acid methyl ester). The importance of Val(631) for the stereo control of murine (12R)-LOX was confirmed with other substrates such as methyl linoleate and 20-hydroxyeicosatetraenoic acid methyl ester. These data identify Val(631) as the major sequence determinant for the specificity of murine (12R)-LOX. Furthermore, we conclude that substrate fatty acids may adopt different catalytically productive arrangements at the active site of murine (12R)-LOX and that each of these arrangements may lead to the formation of chiral oxygenation products.
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Affiliation(s)
- Sunitha Meruvu
- University Medicine Berlin Charité, Monbijoustrasse 2, 10117 Berlin, Germany
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Schneider C, Boeglin WE, Brash AR. Human cyclo-oxygenase-1 and an alternative splice variant: contrasts in expression of mRNA, protein and catalytic activities. Biochem J 2005; 385:57-64. [PMID: 15361066 PMCID: PMC1134673 DOI: 10.1042/bj20041115] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The two COX (cyclo-oxygenase) isoenzymes COX-1 and -2 catalyse the initial step in the conversion of arachidonic acid into PG (prostaglandin) hormones. The identification of an mRNA transcript encoding a splice variant of human COX-1 was reported more than a decade ago [Diaz, Reginato and Jimenez (1992) J. Biol. Chem. 267, 10816-10822], yet catalytic activity and tissue expression of the corresponding spliced protein remained uncharacterized. The splice variant lacks amino acids 396-432, corresponding to the last 37 amino acids of exon 9 of the gene encoding COX-1. These amino acids form a loop at one side of the peroxidase active site of the protein. We expressed the full-length and spliced COX-1 cDNAs in COS-7 and Sf9 insect cells, and determined the PG-forming activity using incubations with radiolabelled arachidonic acid and HPLC analyses. When expressed in either system, abundant PG formation was observed with the full-length COX-1, whereas the spliced protein did not form any detectable product. Peroxidase activity was readily detected in microsomes prepared from COS-7 cells transfected with COX-1 but not with the splice variant. In reverse transcriptase-PCR experiments, we detected the mRNA for the alternatively spliced and full-length COX-1 in human brain, tonsil and colon tissue, yet we were unable to detect expression of the spliced protein in the same tissues using immunoprecipitation and Western-blot analyses. We conclude that, whereas the mRNA transcript for the spliced COX-1 is present in various human tissues, the corresponding protein is either not formed or subject to rapid proteolytic degradation.
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Affiliation(s)
- Claus Schneider
- Department of Pharmacology, Vanderbilt University School of Medicine, 23rd Ave. at Pierce, Nashville, TN 37232-6602, USA.
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Kitaguchi H, Ohkubo K, Ogo S, Fukuzumi S. Direct ESR Detection of Pentadienyl Radicals and Peroxyl Radicals in Lipid Peroxidation: Mechanistic Insight into Regioselective Oxygenation in Lipoxygenases. J Am Chem Soc 2005; 127:6605-9. [PMID: 15869281 DOI: 10.1021/ja044345j] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Well-resolved ESR spectra of free pentadienyl radicals have been observed under photoirradiation of di-tert-butylperoxide (Bu(t)OOBu(t)) and polyunsaturated fatty acids in the absence of O(2), allowing us to determine the hfc values. The hfc values of linoleyl radical indicate that the spin density is the largest at the C-11 position. The linoleyl radical is readily trapped by O(2) to produce the peroxyl radical (11-HPO.) in which O(2) is added mainly at the C-11 position of the pentadienyl radical as indicated by the comparison of the ESR spectra of peroxyl radicals derived from linoleic acid and [11,11-(2)H(2)]linoleic acid. The peroxyl radical (13-HPO.), which is initially formed by the hydrogen abstraction from 13-(S)-hydroperoxy-9(Z),11(E)-octadecadienoic acid (13-HPOD) by Bu(t)O., is found to isomerize to 11-HPO. via removal of O(2) from 13-HPO. and addition of O(2) to linoleyl radical to produce 11-HPO. . This finding supports an idea of O(2) entering via a specific protein channel, which determines the stereo- and regiochemistry of the biradical combination between O(2) and linoleyl radical in lipoxygenases.
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Affiliation(s)
- Hironori Kitaguchi
- Department of Material and Life Science, Graduate School of Engineering, Osaka University, SORST, Japan Science and Technology Agency (JST), Suita, Osaka 565-0871, Japan
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Hübke H, Garbe LA, Tressl R. Characterization and quantification of free and esterified 9- and 13-hydroxyoctadecadienoic acids (HODE) in barley, germinating barley, and finished malt. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:1556-1562. [PMID: 15740040 DOI: 10.1021/jf048490s] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The analysis of (R)-9- and (S)-9-hydroxy-10E,12Z-octadecadienoic acid as well as (R)-13- and (S)-13-hydroxy-9Z,11E-octadecadienoic acid (HODE) as free acids, esterified in triacylglycerols (storage lipids), and esterified in polar lipids (phospholipids, glycolipids, etc.) in barley, germinating barley, and finished malt was performed using [13-(18)O(1)]-(S)-13-HODE isotope dilution assays with GC-MS and straight- and chiral-phase HPLC. 9- and 13- HODE occur approximately racemically in barley, indicating an autoxidation. The enantiomeric excesses increase to 78% S for free 9-HODE and to 58% S for free 13-HODE in germinating barley as a result of lipoxygenase-2 (LOX-2) catalysis, but free HODEs are at low concentration. More than 90% of HODEs in barley and malt are esterified. In the storage lipids of green malt 53 mg/kg 9-HODE and 147 mg/kg 13-HODE were detected. This ratio of 30:70 reflects the regioselectivity of the LOX-2 enzyme in malt. In the polar lipids 45 mg/kg 9-HODE and 44 mg/kg 13-HODE were characterized. The latter indicate a hitherto unknown 9-lipoxygenase activity with polar lipids as substrates. During kilning the contents of most HODEs decreased significantly due to chemical and enzymatic degradation, whereas polar-esterified (R)-13-HODE increased (43%) in the finished malt.
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Affiliation(s)
- Holger Hübke
- Institut für Biotechnologie, Molekularanalytik, Technische Universität Berlin, Seestrasse 13, D-13353 Berlin, Germany
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Senger T, Wichard T, Kunze S, Göbel C, Lerchl J, Pohnert G, Feussner I. A multifunctional lipoxygenase with fatty acid hydroperoxide cleaving activity from the moss Physcomitrella patens. J Biol Chem 2004; 280:7588-96. [PMID: 15611050 DOI: 10.1074/jbc.m411738200] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A complex mixture of fatty acid-derived aldehydes, ketones, and alcohols is released upon wounding of the moss Physcomitrella patens. To investigate the formation of these oxylipins at the molecular level we isolated a lipoxygenase from P. patens, which was identified in an EST library by sequence homology to lipoxygenases from plants. Sequence analysis of the cDNA showed that it exhibits a domain structure similar to that of type2 lipoxygenases from plants, harboring an N-terminal import signal for chloroplasts. The recombinant protein was identified as arachidonate 12-lipoxygenase and linoleate 13-lipoxygenase with a preference for arachidonic acid and eicosapentaenoic acid. In contrast to any other lipoxygenase cloned so far, this enzyme exhibited in addition an unusual high hydroperoxidase and also a fatty acid chain-cleaving lyase activity. Because of these unique features the pronounced formation of (2Z)-octen-1-ol, 1-octen-3-ol, the dienal (5Z,8Z,10E)-12-oxo-dodecatrienoic acid and 12-keto eicosatetraenoic acid was observed when arachidonic acid was administered as substrate. 12-Hydroperoxy eicosatetraenoic acid was found to be only a minor product. Moreover, the P. patens LOX has a relaxed substrate tolerance accepting C(18)-C(22) fatty acids giving rise to even more LOX-derived products. In contrast to other lipoxygenases a highly diverse product spectrum is formed by a single enzyme accounting for most of the observed oxylipins produced by the moss. This single enzyme might, in a fast and effective way, be involved in the formation of signal and/or defense molecules thus contributing to the broad resistance of mosses against pathogens.
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Affiliation(s)
- Toralf Senger
- Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Corrensstr. 3, D-06466 Gatersleben, Germany
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Coffa G, Brash AR. A single active site residue directs oxygenation stereospecificity in lipoxygenases: stereocontrol is linked to the position of oxygenation. Proc Natl Acad Sci U S A 2004; 101:15579-84. [PMID: 15496467 PMCID: PMC524819 DOI: 10.1073/pnas.0406727101] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lipoxygenases are a class of dioxygenases that form hydroperoxy fatty acids with distinct positional and stereo configurations. Several amino acid residues influencing regiospecificity have been identified, whereas the basis of stereocontrol is not understood. We have now identified a single residue in the lipoxygenase catalytic domain that is important for stereocontrol; it is conserved as an Ala in S lipoxygenases and a Gly in R lipoxygenases. Our results with mutation of the conserved Ala to Gly in two S lipoxygenases (mouse 8S-LOX and human 15-LOX-2) and the corresponding Gly-Ala substitution in two R lipoxygenases (human 12R-LOX and coral 8R-LOX) reveal that the basis for R or S stereo-control also involves a switch in the position of oxygenation on the substrate. After the initial hydrogen abstraction, antarafacial oxygenation at one end or the other of the activated pair of double bonds (pentadiene) gives, for example, 8S or 12R product. The Ala residue promotes oxygenation on the reactive pentadiene at the end deep in the substrate binding pocket and S stereochemistry of the product hydroperoxide, and a Gly residue promotes oxygenation at the proximal end of the reactive pentadiene resulting in R stereochemistry. A model of lipoxygenase reaction specificity is proposed in which product regiochemistry and stereochemistry are determined by fixed relationships between substrate orientation, hydrogen abstraction, and the Gly or Ala residue we have identified.
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Affiliation(s)
- Gianguido Coffa
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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Valmsen K, Boeglin WE, Järving I, Schneider C, Varvas K, Brash AR, Samel N. Structural and functional comparison of 15S- and 15R-specific cyclooxygenases from the coral Plexaura homomalla. ACTA ACUST UNITED AC 2004; 271:3533-8. [PMID: 15317588 DOI: 10.1111/j.0014-2956.2004.04289.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It has been known for 30 years that the gorgonian coral Plexaura homomalla contains either 15S- or 15R-configuration prostaglandins (PGs), depending on its location in the Caribbean. Recently we showed that the 15R-PGs in the R-variety of P. homomalla are formed by a unique cyclooxygenase (COX) with 15R oxygenation specificity [Valmsen, K., Järving, I., Boeglin, W.E., Varvas, K., Koljak, R., Pehk, T., Brash, A.R. & Samel, N. (2001) Proc. Natl. Acad. Sci. USA98, 7700]. Here we describe the cloning and characterization of a closely related COX protein (97% amino acid sequence identity) from the S-variety of P. homomalla. Functional expression of the S-variant COX cDNA in Sf9 insect cells followed by incubation with exogenous arachidonic acid resulted in formation of PG products with > 98% 15S-configuration. Mutational analysis was performed on a suggested active site determinant of C-15 oxygenation specificity, position 349 (Val in all S-specific COX, Ile in 15R-COX). The 15S-COX Val349 to Ile mutant formed 35% 15R-PGs, while the reverse mutation in the 15R-COX (Ile349Val) led to formation of 70% 15S-products. This establishes position 349 as an important determinant of the product stereochemistry at C-15. Our characterization of the enzyme variants demonstrates that very minor sequence divergence accounts for the content of epimeric PGs in the two variants of P. homomalla and that the differences do not arise by isomerization of the products.
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Affiliation(s)
- Karin Valmsen
- Department of Chemistry, Tallinn University of Technology, Estonia
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Abstract
The reactivity of O(2) with soybean lipoxygenase-1 (SLO) has been examined using a range of kinetic probes. We are able to rule out diffusional encounter of O(2) with protein, an outer-sphere electron transfer to O(2), and proton transfer as rate-limiting steps in k(cat)/K(M)(O(2)) for wild-type enzyme (WT SLO); this restricts the rate-limiting step to either the combination of O(2) with L(*) or a subsequent conformational change. In the Ile(553) --> Phe mutant, which constricts the putative O(2) binding channel [Knapp et al. (2001) J. Am. Chem. Soc. 123, 2931-2932], k(cat)/K(M)(O(2)) decreases by over a factor of 20; yet, this mutant appears to have the same rate-limiting step as WT SLO. It is argued that the slow step on k(cat)/K(M)(O(2)) is the combination of O(2) with L(*), with proximal protein effects determining the rate of reaction. The available data for SLO support the view that enzymes can affect O(2) reactivity without a direct involvement of metal cofactors. The primary role of the Fe(3+) cofactor is to generate an enzyme-bound radical, while the protein is concluded to control the stereo- and regiochemistry of O(2) encounter with this radical.
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Affiliation(s)
- Michael J Knapp
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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Kuhn H, Walther M, Kuban RJ. Mammalian arachidonate 15-lipoxygenases structure, function, and biological implications. Prostaglandins Other Lipid Mediat 2002; 68-69:263-90. [PMID: 12432923 DOI: 10.1016/s0090-6980(02)00035-7] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Lipoxygenases (LOXs) constitute a heterogeneous family of lipid peroxidizing enzymes capable of oxygenating polyunsaturated fatty acids to their corresponding hydroperoxy derivatives. In mammals, LOXs are classified with respect to their positional specificity of arachidonic acid oxygenation into 5-, 8-, 12-, and 15-LOXs. Arachidonate 15-LOXs may be sub-classified into a reticulocyte-type (type-1) and an epidermis-type (type-2) enzyme. Since the leukocyte-type 12-LOXs are very similar to the reticulocyte-type 15-LOXs, these enzymes are designated 12/15-LOXs. Several LOX isoforms, in particular the reticulocyte-type 15-LOX and the human 5-LOX, are well characterized with respect to their structural and functional properties On the other hand, the biological role of most LOX-isozymes including the reticulocyte-type 15-LOC is far from clear. This review is intended to summarize the recent developments in 15-LOX research with particular emphasis to molecular enzymology and regulation of gene expression. In addition, the major hypotheses on the physiological and patho-physiological roles of 15-LOXs will be discussed briefly.
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Affiliation(s)
- Hartmut Kuhn
- Institute of Biochemistry, University Clinics Charité, Humboldt University, Berlin, Germany.
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44
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Schneider C, Brash AR. Lipoxygenase-catalyzed formation of R-configuration hydroperoxides. Prostaglandins Other Lipid Mediat 2002; 68-69:291-301. [PMID: 12432924 DOI: 10.1016/s0090-6980(02)00041-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Prototypical lipoxygenases (LOXs) of animals and plants synthesize hydroperoxy fatty acids of the S stereoconfiguration, yet enzymes forming R-configuration products are found in both the animal and plant kingdoms. R-LOX are widespread in aquatic invertebrates, in some of which their R-HETE products have a defined role in reproductive function. A 12R-LOX has been found recently in humans and mice. The human 12R-LOX product, 12R-HETE, appears to be involved in the pathophysiology of psoriasis and other proliferative skin diseases; a role in normal skin development is implied from the spatial and temporal expression patterns of the 12R-LOX in the mouse embryo. In plants, there are few reports of R-LOX activity and in higher plants this is limited to enzymes that catalyze a significant degree of non-specific oxygenation. There are no obvious amino acid sequence motifs characterizing R-LOXs; and in the phylogenetic tree of the LOX superfamily, the R-LOXs do not group into a specific branch of genes. The mechanistic basis of stereocontrol over the oxygenation reaction performed by LOXs may relate to a changed binding orientation of the fatty acid substrate or to the direction of attack by molecular oxygen. A potentially relevant precedent for switching of R- and S-oxygenation specificity was described recently in studies of prostaglandin C-15 oxygenation during cycloxygenase catalysis; single amino acid changes can invert the oxygenation stereospecificity at C-15. In this case, the evidence suggests that R/S switching can occur with the substrate binding in the normal conformation.
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Affiliation(s)
- Claus Schneider
- Division of Clinical Pharmacology, Vanderbilt University Medical School, Nashville, TN 37232-6602, USA
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Kühn H, Borchert A. Regulation of enzymatic lipid peroxidation: the interplay of peroxidizing and peroxide reducing enzymes. Free Radic Biol Med 2002; 33:154-72. [PMID: 12106812 DOI: 10.1016/s0891-5849(02)00855-9] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
For a long time lipid peroxidation has only been considered a deleterious process leading to disruption of biomembranes and thus, to cellular dysfunction. However, when restricted to a certain cellular compartment and tightly regulated, lipid peroxidation may have beneficial effects. Early on during evolution of living organisms special lipid peroxidizing enzymes, called lipoxygenases, appeared and they have been conserved during phylogenesis of plants and animals. In fact, a diverse family of lipoxygenase isoforms has evolved starting from a putative ancient precursor. As with other enzymes, lipoxygenases are regulated on various levels of gene expression and there are endogenous antagonists controlling their cellular activity. Among the currently known mammalian lipoxygenase isoforms only 12/15-lipoxygenases are capable of directly oxygenating ester lipids even when they are bound to membranes and lipoproteins. Thus, these enzymes represent the pro-oxidative part in the cellular metabolism of complex hydroperoxy ester lipids. Its metabolic counterplayer, representing the antioxidative part, appears to be the phospholipid hydroperoxide glutathione peroxidase. This enzyme is unique among glutathione peroxidases because of its capability of reducing ester lipid hydroperoxides. Thus, 12/15-lipoxygenase and phospholipid hydroperoxide glutathione peroxidase constitute a pair of antagonizing enzymes in the metabolism of hydroperoxy ester lipids, and a balanced regulation of the two proteins appears to be of major cell physiological importance. This review is aimed at summarizing the recent developments in the enzymology and molecular biology of 12/15-lipoxygenase and phospholipid hydroperoxide glutathione peroxidase, with emphasis on cytokine-dependent regulation and their regulatory interplay.
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Affiliation(s)
- Hartmut Kühn
- Institute of Biochemistry, University Clinics Charité, Humboldt University, Berlin, Germany.
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Valmsen K, Järving I, Boeglin WE, Varvas K, Koljak R, Pehk T, Brash AR, Samel N. The origin of 15R-prostaglandins in the Caribbean coral Plexaura homomalla: molecular cloning and expression of a novel cyclooxygenase. Proc Natl Acad Sci U S A 2001; 98:7700-5. [PMID: 11427702 PMCID: PMC35405 DOI: 10.1073/pnas.131022398] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2001] [Indexed: 11/18/2022] Open
Abstract
The highest concentrations of prostaglandins in nature are found in the Caribbean gorgonian Plexaura homomalla. Depending on its geographical location, this coral contains prostaglandins with typical mammalian stereochemistry (15S-hydroxy) or the unusual 15R-prostaglandins. Their metabolic origin has remained the subject of mechanistic speculations for three decades. Here, we report the structure of a type of cyclooxygenase (COX) that catalyzes transformation of arachidonic acid into 15R-prostaglandins. Using a homology-based reverse transcriptase--PCR strategy, we cloned a cDNA corresponding to a COX protein from the R variety of P. homomalla. The deduced peptide sequence shows 80% identity with the 15S-specific coral COX from the Arctic soft coral Gersemia fruticosa and approximately 50% identity to mammalian COX-1 and COX-2. The predicted tertiary structure shows high homology with mammalian COX isozymes having all of the characteristic structural units and the amino acid residues important in catalysis. Some structural differences are apparent around the peroxidase active site, in the membrane-binding domain, and in the pattern of glycosylation. When expressed in Sf9 cells, the P. homomalla enzyme forms a 15R-prostaglandin endoperoxide together with 11R-hydroxyeicosatetraenoic acid and 15R-hydroxyeicosatetraenoic acid as by-products. The endoperoxide gives rise to 15R-prostaglandins and 12R-hydroxyheptadecatrienoic acid, identified by comparison to authentic standards. Evaluation of the structural differences of this 15R-COX isozyme should provide new insights into the substrate binding and stereospecificity of the dioxygenation reaction of arachidonic acid in the cyclooxygenase active site.
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Affiliation(s)
- K Valmsen
- Department of Bioorganic Chemistry, Institute of Chemistry at Tallinn Technical University, Akadeemia tee 15, Tallinn 12618, Estonia
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Tijet N, Schneider C, Muller BL, Brash AR. Biogenesis of volatile aldehydes from fatty acid hydroperoxides: molecular cloning of a hydroperoxide lyase (CYP74C) with specificity for both the 9- and 13-hydroperoxides of linoleic and linolenic acids. Arch Biochem Biophys 2001; 386:281-9. [PMID: 11368353 DOI: 10.1006/abbi.2000.2218] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A novel member of the plant cytochrome P450 CYP74 family of fatty acid hydroperoxide metabolizing enzymes has been cloned from melon fruit (Cucumis melo). The cDNA is comprised of 1,446 nucleotides encoding a protein of 481 amino acids. The homology at the amino acid level to other members of the CYP74 family is 35-50%, the closest relatives being allene oxide synthases. The cDNA was expressed in Escherichia coli, and the corresponding protein was purified by affinity column chromatography. The native enzyme showed a main Soret band at 418 nm, indicative of a low spin ferric cytochrome P450, and a 447-nm peak appeared in the CO-difference spectrum. Using [U-14C]radiolabeled substrate, HPLC, UV, and GC-MS, the products of conversion of 9S-hydroperoxy-linoleic acid were identified as 9-oxo-nonanic acid and 3Z-nonenal. Kinetic analysis of this hydroperoxide lyase showed the highest rate of reaction with 9-hydroperoxy-linolenic acid followed by 9-hydroperoxy-linoleic acid and then the corresponding 13-hydroperoxides. Overall, the newly characterized cytochrome P450 enzyme is a fatty acid hydroperoxide lyase with a preference, but not absolute specificity for the 9-positional hydroperoxides of linoleic and linolenic acids.
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Affiliation(s)
- N Tijet
- Department of Pharmacology, Vanderbilt University Medical School, Nashville, Tennessee 37232, USA
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Siebert M, Krieg P, Lehmann WD, Marks F, Fürstenberger G. Enzymic characterization of epidermis-derived 12-lipoxygenase isoenzymes. Biochem J 2001; 355:97-104. [PMID: 11256953 PMCID: PMC1221716 DOI: 10.1042/0264-6021:3550097] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Substrate selectivity and other enzymic characteristics of two epidermis-derived lipoxygenases (LOXs), the epidermis-type (e) (12S)-LOX and (12R)-LOX, were compared with those of the platelet-type (p) (12S)-LOX. In contrast with p(12S)-LOX, e(12S)-LOX and (12R)-LOX exhibited no or very low reactivity towards the customary substrates linoleic acid and arachidonic acid but metabolized the corresponding fatty acid methyl esters, which, in contrast, were not accepted as substrates by p(12S)-LOX. Other esters of arachidonic acid and linoleic acid, including propan-2-yl and cholesterol esters, 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphocholine, 1-palmitoyl-2-linoleyl-sn-glycero-3-phosphoethanolamine, and ceramide 1 carrying an omega-linoleic acid ester, were not metabolized by these three LOX isoenzymes. Among various polyunsaturated fatty acids the isomeric eicosatrienoic acids were found to be oxygenated by e(12S)-LOX but not by (12R)-LOX. 4,7,10,13,16,19-Docosahexaenoic acid as a substrate was restricted to p(12S)-LOX. Variations in the pH and the Ca(2+) content of the incubation medium affected the catalytic potential only slightly. Whereas (12R)-LOX activity increased in the presence of Ca(2+) and with an acidic pH, Ca(2+) had no effect on p(12S)-LOX and e(12S)-LOX; an acidic pH decreased the catalytic activity of the latter two. However, the catalytic activity of the epidermis-type isoenzymes, but not of p(12S)-LOX, was found to be markedly increased in the presence of DMSO. Under these conditions, e(12S)-LOX and (12R)-LOX oxygenated 4,7,10,13,16,19-docosahexaenoic acid to 14-hydroxy-4,7,10,12,16,19-docosahexaenoic acid and 13-hydroxy-4,7,10,14,16,19-docosahexaenoic acid respectively. In addition, (9R)-hydroxyoctadeca-10,12-dienoic acid methyl ester was generated from linoleic acid methyl ester by (12R)-LOX. Independently of the substrate, the catalytic activity of e(12S)-LOX and (12R)-LOX was always at most 2% of that of p(12S)-LOX with arachidonic acid as substrate.
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Affiliation(s)
- M Siebert
- Research Program on Tumor Cell Regulation (B0500), Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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Abstract
Tumor cell proliferation and metastasis proceed via a network of interdependent molecular events with a vast array of molecular players and signal transduction mechanisms differing in various types of human tumors. In the sequence of events necessary for carcinogenesis, arachidonate metabolites have been documented to play a significant role at several steps. Arachidonate metabolism in human cells occurs via several enzymatic pathways, including enzymes such as cyclo-oxygenases and lipoxygenases. This review pays particular attention to one member of the lipoxygenase family of enzymes, namely 12-lipoxygenase, since an arachidonate metabolite generated via 12-lipoxygenase action, 12(S)-HETE, has been shown to elicit various prometastatic effects of tumor cells in vivo and in vitro. We focus especially on mechanisms of activation and modulation of 12-lipoxygenase expression in human tumor cells, since various tumor cells express 12-lipoxygenase or are responsive to metabolites derived from 12-lipoxygenase action, thus offering a potential for successful therapeutic intervention against such tumors.
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Affiliation(s)
- Wolfgang Hagmann
- Deutsches Krebsforschungszentrum, Division of Tumor Biochemistry, Heidelberg, Germany
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Abstract
The positional specificity of arachidonic acid oxygenation is currently the decisive parameter for classification of mammalian lipoxygenases but, unfortunately, the structural reasons for lipoxygenase specificity are not well understood. Although there are no direct structural data on lipoxygenase/substrate interaction, experiments with modified fatty acid substrates and mutagenesis studies suggest that for 12- and 15-lipoxygenases, arachidonic acid slides into the substrate-binding pocket with its methyl end ahead. For arachidonate 5- and/or 8-lipoxygenation two alternative models for the enzyme/substrate interaction have been developed: 1) The orientation-determined model and 2) the space-determined model. This review explores the experimental data available on the mechanistic reasons for lipoxygenase specificity and concludes that each of the above-mentioned hypotheses may be valid for arachidonate 5-lipoxygenation under certain circumstances.
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Affiliation(s)
- H Kuhn
- Institute of Biochemistry, University Clinics Charite, Humboldt University, Hessische Str. 3-4, 10 115., Berlin, F.R, Germany.
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