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Erba F, Mei G, Minicozzi V, Sabatucci A, Di Venere A, Maccarrone M. Conformational Dynamics of Lipoxygenases and Their Interaction with Biological Membranes. Int J Mol Sci 2024; 25:2241. [PMID: 38396917 PMCID: PMC10889196 DOI: 10.3390/ijms25042241] [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: 12/29/2023] [Revised: 02/06/2024] [Accepted: 02/09/2024] [Indexed: 02/25/2024] Open
Abstract
Lipoxygenases (LOXs) are a family of enzymes that includes different fatty acid oxygenases with a common tridimensional structure. The main functions of LOXs are the production of signaling compounds and the structural modifications of biological membranes. These features of LOXs, their widespread presence in all living organisms, and their involvement in human diseases have attracted the attention of the scientific community over the last decades, leading to several studies mainly focused on understanding their catalytic mechanism and designing effective inhibitors. The aim of this review is to discuss the state-of-the-art of a different, much less explored aspect of LOXs, that is, their interaction with lipid bilayers. To this end, the general architecture of six relevant LOXs (namely human 5-, 12-, and 15-LOX, rabbit 12/15-LOX, coral 8-LOX, and soybean 15-LOX), with different specificity towards the fatty acid substrates, is analyzed through the available crystallographic models. Then, their putative interface with a model membrane is examined in the frame of the conformational flexibility of LOXs, that is due to their peculiar tertiary structure. Finally, the possible future developments that emerge from the available data are discussed.
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Affiliation(s)
- Fulvio Erba
- Department of Clinical Science and Translational Medicine, Tor Vergata University of Rome, Via Montpellier 1, 00133 Rome, Italy;
| | - Giampiero Mei
- Department of Experimental Medicine, Tor Vergata University of Rome, Via Montpellier 1, 00133 Rome, Italy;
| | - Velia Minicozzi
- Department of Physics and INFN, Tor Vergata University of Rome, Via Della Ricerca Scientifica 1, 00133 Rome, Italy;
| | - Annalaura Sabatucci
- Department of Biosciences and Technology for Food Agriculture and Environment, University of Teramo, Via Renato Balzarini 1, 64100 Teramo, Italy;
| | - Almerinda Di Venere
- Department of Experimental Medicine, Tor Vergata University of Rome, Via Montpellier 1, 00133 Rome, Italy;
| | - Mauro Maccarrone
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, Via Vetoio, Coppito, 67100 L’Aquila, Italy
- European Center for Brain Research (CERC), Santa Lucia Foundation IRCCS, 00143 Rome, Italy
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2
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Elsayed S, Abdelkhalek AS, Rezq S, Abu Kull ME, Romero DG, Kothayer H. Magic shotgun approach to anti-inflammatory pharmacotherapy: Synthesis of novel thienopyrimidine monomers/heterodimer as dual COX-2 and 15-LOX inhibitors endowed with potent antioxidant activity. Eur J Med Chem 2023; 260:115724. [PMID: 37611534 PMCID: PMC10528942 DOI: 10.1016/j.ejmech.2023.115724] [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: 06/11/2023] [Revised: 08/12/2023] [Accepted: 08/13/2023] [Indexed: 08/25/2023]
Abstract
Emerging evidence points to the intertwining framework of inflammation and oxidative stress in various ailments. We speculate on the potential impact of the magic shotgun approach in these ailments as an attempt to mitigate the drawbacks of current NSAIDs. Hence, we rationally designed and synthesized new tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidine monomers/heterodimer as dual selective COX-2/15-LOX inhibitors with potent antioxidant activity. The synthesized compounds were challenged with diverse in vitro biological assays. Regarding the monomeric series, compound 5k exerted the highest COX-2 inhibitory activity (IC50 = 0.068 μM, SI = 160.441), while compound 5i showed the highest 15-LOX inhibitory activity (IC50 = 1.97 μM). Surpassing the most active monomeric members, the heterodimer 11 stemmed as the most potent and selective one in the whole study (COX-2 IC50 = 0.065 μM, SI = 173.846, 15-LOX IC50 = 1.86 μM). Heterodimer design was inspired by the cross-talk between the partner monomers of the COX-2 isoform. Moreover, some of our synthesized compounds could significantly reverse the LPS-enhanced production of ROS and proinflammatory cytokines (IL-6, TNF-α, and NO) in RAW 264.7 macrophages. Again, the heterodimer showed the strongest suppressor activity against ROS (IC50 = 18.79 μM) and IL-6 (IC50 = 4.15 μM) production outperforming the two references, celecoxib and diclofenac. Regarding NO suppressor activity, compound 5j (IC50 = 18.62 μM) surpassed the two references. Only compound 5a significantly suppressed TNF-α production (IC50 = 19.68 μM). Finally, molecular modeling simulated the possible binding scenarios of our synthesized thienopyrimidines within the active sites of COX-2 and 15-LOX. These findings suggest that those novel thienopyrimidines are promising leads showing pharmacodynamics synergy against the selected targets.
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Affiliation(s)
- Sara Elsayed
- Medicinal Chemistry Department, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Ahmed S Abdelkhalek
- Medicinal Chemistry Department, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Samar Rezq
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zagazig University, Zagazig, Egypt; Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, MS, USA; Mississippi Center of Excellence in Perinatal Research, University of Mississippi Medical Center, Jackson, MS, USA; Women's Health Research Center, University of Mississippi Medical Center, Jackson, MS, USA; Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA
| | - Mansour E Abu Kull
- Medicinal Chemistry Department, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt
| | - Damian G Romero
- Department of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, MS, USA; Mississippi Center of Excellence in Perinatal Research, University of Mississippi Medical Center, Jackson, MS, USA; Women's Health Research Center, University of Mississippi Medical Center, Jackson, MS, USA; Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA
| | - Hend Kothayer
- Medicinal Chemistry Department, Faculty of Pharmacy, Zagazig University, Zagazig, 44519, Egypt.
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Mobbs JI, Black KA, Tran M, Burger WAC, Venugopal H, Holman TR, Holinstat M, Thal DM, Glukhova A. Cryo-EM structures of human arachidonate 12S-lipoxygenase bound to endogenous and exogenous inhibitors. Blood 2023; 142:1233-1242. [PMID: 37506345 PMCID: PMC10579047 DOI: 10.1182/blood.2023020441] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 07/05/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023] Open
Abstract
Human 12-lipoxygenase (12-LOX) is a key enzyme involved in platelet activation, and the regulation of its activity has been targeted for the treatment of heparin-induced thrombocytopenia. Despite the clinical importance of 12-LOX, the exact mechanisms by which it affects platelet activation are not fully understood, and the lack of structural information has limited drug discovery efforts. In this study, we used single-particle cryo-electron microscopy to determine high-resolution structures (1.7-2.8 Å) of human 12-LOX. Our results showed that 12-LOX can exist in multiple oligomeric states, from monomer to hexamer, which may affect its catalytic activity and membrane association. We also identified different conformations within the 12-LOX dimer, which likely represent different time points in its catalytic cycle. Furthermore, we identified small molecules bound to 12-LOX. The active site of the 12-LOX tetramer was occupied by an endogenous 12-LOX inhibitor, a long-chain acyl coenzyme A. In addition, we found that the 12-LOX hexamer can simultaneously bind to arachidonic acid and ML355, a selective 12-LOX inhibitor that has passed a phase 1 clinical trial for the treatment of heparin-induced thrombocytopenia and received a fast-track designation by the Food and Drug Administration. Overall, our findings provide novel insights into the assembly of 12-LOX oligomers, their catalytic mechanism, and small molecule binding, paving the way for further drug development targeting the 12-LOX enzyme.
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Affiliation(s)
- Jesse I. Mobbs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Katrina A. Black
- Structural Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
- Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne, VIC, Australia
| | - Michelle Tran
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA
| | - Wessel A. C. Burger
- ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- Structural Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
- Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne, VIC, Australia
| | - Hariprasad Venugopal
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, VIC, Australia
| | - Theodore R. Holman
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, CA
| | - Michael Holinstat
- Department of Pharmacology, University of Michigan, Ann Arbor, MI
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - David M. Thal
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Alisa Glukhova
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- ARC Centre for Cryo-Electron Microscopy of Membrane Proteins, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- Structural Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
- Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne, VIC, Australia
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4
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Guevara L, Gouge M, Ohler A, Hill SG, Patel S, Offenbacher AR. Effect of solvent viscosity on the activation barrier of hydrogen tunneling in the lipoxygenase reaction. Arch Biochem Biophys 2023; 747:109740. [PMID: 37678425 DOI: 10.1016/j.abb.2023.109740] [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: 07/15/2023] [Revised: 08/22/2023] [Accepted: 09/05/2023] [Indexed: 09/09/2023]
Abstract
Hydrogen tunneling in enzyme reactions has played an important role in linking protein thermal motions to the chemical steps of catalysis. Lipoxygenases (LOXs) have served as model systems for such reactions, showcasing deep hydrogen tunneling mechanisms associated with enzymatic C-H bond cleavage from polyunsaturated fatty acids. Here, we examined the effect of solvent viscosity on the protein thermal motions associated with LOX catalysis using trehalose and glucose as viscogens. Kinetic analysis of the reaction of the paradigm plant orthologue, soybean lipoxygenase (SLO), with linoleic acid revealed no effect on the first-order rate constants, kcat, or activation energy, Ea. Further studies of SLO active site mutants displaying varying Eas, which have been used to probe catalytically relevant motions, likewise provided no evidence for viscogen-dependent motions. Kinetic analyses were extended to a representative fungal LOX from M. oryzae, MoLOX, and a human LOX, 15-LOX-2. While MoLOX behaved similarly to SLO, we show that viscogens inhibit 15-LOX-2 activity. The latter implicates viscogen sensitive, conformational motions in animal LOX reactions. The data provide insight into the role of water hydration layers in facilitating hydrogen (quantum) tunneling in LOX.
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Affiliation(s)
- Luis Guevara
- Department of Chemistry, East Carolina University, Greenville, NC, 27858, USA
| | - Melissa Gouge
- Department of Chemistry and Biochemistry, Ohio Northern University, Ada, OH, 45810, USA
| | - Amanda Ohler
- Department of Chemistry, East Carolina University, Greenville, NC, 27858, USA
| | - S Gage Hill
- Department of Chemistry, East Carolina University, Greenville, NC, 27858, USA
| | - Soham Patel
- Department of Chemistry, East Carolina University, Greenville, NC, 27858, USA
| | - Adam R Offenbacher
- Department of Chemistry, East Carolina University, Greenville, NC, 27858, USA.
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5
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Zhuravlev A, Cruz A, Aksenov V, Golovanov A, Lluch JM, Kuhn H, González-Lafont À, Ivanov I. Different Structures-Similar Effect: Do Substituted 5-(4-Methoxyphenyl)-1 H-indoles and 5-(4-Methoxyphenyl)-1 H-imidazoles Represent a Common Pharmacophore for Substrate Selective Inhibition of Linoleate Oxygenase Activity of ALOX15? Molecules 2023; 28:5418. [PMID: 37513289 PMCID: PMC10383952 DOI: 10.3390/molecules28145418] [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: 05/21/2023] [Revised: 07/04/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
Mammalian 15-lipoxygenases (ALOX15) are lipid peroxidizing enzymes that exhibit variable functionality in different cancer and inflammation models. The pathophysiological role of linoleic acid- and arachidonic acid-derived ALOX15 metabolites rendered this enzyme a target for pharmacological research. Several indole and imidazole derivatives inhibit the catalytic activity of rabbit ALOX15 in a substrate-specific manner, but the molecular basis for this allosteric inhibition remains unclear. Here, we attempt to define a common pharmacophore, which is critical for this allosteric inhibition. We found that substituted imidazoles induce weaker inhibitory effects when compared with the indole derivatives. In silico docking studies and molecular dynamics simulations using a dimeric allosteric enzyme model, in which the inhibitor occupies the substrate-binding pocket of one monomer, whereas the substrate fatty acid is bound at the catalytic center of another monomer within the ALOX15 dimer, indicated that chemical modification of the core pharmacophore alters the enzyme-inhibitor interactions, inducing a reduced inhibitory potency. In our dimeric ALOX15 model, the structural differences induced by inhibitor binding are translated to the hydrophobic dimerization cluster and affect the structures of enzyme-substrate complexes. These data are of particular importance since substrate-specific inhibition may contribute to elucidation of the putative roles of ALOX15 metabolites derived from different polyunsaturated fatty acids in mammalian pathophysiology.
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Affiliation(s)
- Alexander Zhuravlev
- Lomonosov Institute of Fine Chemical Technologies, MIREA-Russian Technological University, Vernadskogo pr. 86, 119571 Moscow, Russia
| | - Alejandro Cruz
- Departament de Química, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Vladislav Aksenov
- Lomonosov Institute of Fine Chemical Technologies, MIREA-Russian Technological University, Vernadskogo pr. 86, 119571 Moscow, Russia
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Miklihio-Maklaja Str., 16/10c4, 117997 Moscow, Russia
| | - Alexey Golovanov
- Lomonosov Institute of Fine Chemical Technologies, MIREA-Russian Technological University, Vernadskogo pr. 86, 119571 Moscow, Russia
| | - José M Lluch
- Departament de Química, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Hartmut Kuhn
- Department of Biochemistry, Charite-University Medicine Berlin, Corporate Member of Free University Berlin and Humboldt University Berlin, Charitéplatz 1, D-10117 Berlin, Germany
| | - Àngels González-Lafont
- Departament de Química, Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, Bellaterra, 08193 Barcelona, Spain
| | - Igor Ivanov
- Lomonosov Institute of Fine Chemical Technologies, MIREA-Russian Technological University, Vernadskogo pr. 86, 119571 Moscow, Russia
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Benatzy Y, Palmer MA, Brüne B. Arachidonate 15-lipoxygenase type B: Regulation, function, and its role in pathophysiology. Front Pharmacol 2022; 13:1042420. [PMID: 36438817 PMCID: PMC9682198 DOI: 10.3389/fphar.2022.1042420] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/26/2022] [Indexed: 10/30/2023] Open
Abstract
As a lipoxygenase (LOX), arachidonate 15-lipoxygenase type B (ALOX15B) peroxidizes polyenoic fatty acids (PUFAs) including arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and linoleic acid (LA) to their corresponding fatty acid hydroperoxides. Distinctive to ALOX15B, fatty acid oxygenation occurs with positional specificity, catalyzed by the non-heme iron containing active site, and in addition to free PUFAs, membrane-esterified fatty acids serve as substrates for ALOX15B. Like other LOX enzymes, ALOX15B is linked to the formation of specialized pro-resolving lipid mediators (SPMs), and altered expression is apparent in various inflammatory diseases such as asthma, psoriasis, and atherosclerosis. In primary human macrophages, ALOX15B expression is associated with cellular cholesterol homeostasis and is induced by hypoxia. Like in inflammation, the role of ALOX15B in cancer is inconclusive. In prostate and breast carcinomas, ALOX15B is attributed a tumor-suppressive role, whereas in colorectal cancer, ALOX15B expression is associated with a poorer prognosis. As the biological function of ALOX15B remains an open question, this review aims to provide a comprehensive overview of the current state of research related to ALOX15B.
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Affiliation(s)
- Yvonne Benatzy
- Faculty of Medicine, Institute of Biochemistry I, Goethe University Frankfurt, Frankfurt, Germany
| | - Megan A. Palmer
- Faculty of Medicine, Institute of Biochemistry I, Goethe University Frankfurt, Frankfurt, Germany
| | - Bernhard Brüne
- Faculty of Medicine, Institute of Biochemistry I, Goethe University Frankfurt, Frankfurt, Germany
- Frankfurt Cancer Institute, Goethe University Frankfurt, Frankfurt, Germany
- German Cancer Consortium (DKTK), Partner Site Frankfurt, Frankfurt, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Frankfurt, Germany
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7
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Golovanov A, Zhuravlev A, Cruz A, Aksenov V, Shafiullina R, Kakularam KR, Lluch JM, Kuhn H, González-Lafont À, Ivanov I. N-Substituted 5-(1H-Indol-2-yl)-2-methoxyanilines Are Allosteric Inhibitors of the Linoleate Oxygenase Activity of Selected Mammalian ALOX15 Orthologs: Mechanism of Action. J Med Chem 2022; 65:1979-1995. [DOI: 10.1021/acs.jmedchem.1c01563] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Alexey Golovanov
- Lomonosov Institute of Fine Chemical Technologies, MIREA─Russian Technological University, Vernadskogo Pr. 86, 119571 Moscow, Russia
| | - Alexander Zhuravlev
- Lomonosov Institute of Fine Chemical Technologies, MIREA─Russian Technological University, Vernadskogo Pr. 86, 119571 Moscow, Russia
| | - Alejandro Cruz
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Vladislav Aksenov
- Lomonosov Institute of Fine Chemical Technologies, MIREA─Russian Technological University, Vernadskogo Pr. 86, 119571 Moscow, Russia
| | - Rania Shafiullina
- Lomonosov Institute of Fine Chemical Technologies, MIREA─Russian Technological University, Vernadskogo Pr. 86, 119571 Moscow, Russia
| | - Kumar R. Kakularam
- Department of Biochemistry, Charite─University Medicine Berlin, Corporate Member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Charitéplatz 1, D-10117 Berlin, Germany
| | - José M. Lluch
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Hartmut Kuhn
- Department of Biochemistry, Charite─University Medicine Berlin, Corporate Member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Charitéplatz 1, D-10117 Berlin, Germany
| | - Àngels González-Lafont
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Igor Ivanov
- Lomonosov Institute of Fine Chemical Technologies, MIREA─Russian Technological University, Vernadskogo Pr. 86, 119571 Moscow, Russia
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Roberts DE, Benton AM, Fabian-Bayola C, Spuches AM, Offenbacher AR. Thermodynamic and biophysical study of fatty acid effector binding to soybean lipoxygenase: implications for allostery driven by helix α2 dynamics. FEBS Lett 2022; 596:350-359. [PMID: 34997975 DOI: 10.1002/1873-3468.14275] [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: 09/23/2021] [Revised: 12/09/2021] [Accepted: 12/20/2021] [Indexed: 11/10/2022]
Abstract
Previous comparative kinetic isotope effects have inferred an allosteric site for fatty acids and their derivatives that modulates substrate selectivity in 15-lipoxygenases. Hydrogen-deuterium exchange also previously revealed regionally defined enhanced protein flexibility, centred at helix α2 - a gate to the substrate entrance. Direct evidence for allosteric binding and a complete understanding of its mechanism remains elusive. In this study, we examine the binding thermodynamics of the fatty acid mimic, oleyl sulfate (OS), with the monomeric model plant 15-LOX, soybean lipoxygenase (SLO), using isothermal titration calorimetry. Dynamic light scattering and differential scanning calorimetry rule out OS-induced oligomerization or structural changes. These data provide evidence that the fatty acid allosteric regulation of SLO is controlled by the dynamics of helix α2.
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Affiliation(s)
| | - Amy M Benton
- Department of Chemistry, East Carolina University, Greenville, NC, USA
| | | | - Anne M Spuches
- Department of Chemistry, East Carolina University, Greenville, NC, USA
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9
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Zhuravlev A, Golovanov A, Toporkov V, Kuhn H, Ivanov I. Functionalized Homologues and Positional Isomers of Rabbit 15-Lipoxygenase RS75091 Inhibitor. Med Chem 2021; 18:406-416. [PMID: 34097594 DOI: 10.2174/1573406417666210604112009] [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: 11/05/2020] [Revised: 03/12/2021] [Accepted: 04/05/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND RS75091 is a cinnamic acid derivative that has been used for the crystallization of the rabbit ALOX15-inhibitor complex. The atomic coordinates of the resolved ALOX15-inhibitor complex were later used to define the binding sites of other mammalian lipoxygenase orthologs, for which no direct structural data with ligand has been reported so far. INTRODUCTION The putative binding pocket of the human ALOX5 was reconstructed on the basis of its structural alignment with rabbit ALOX15-RS75091 inhibitor. However, considering the possible conformational changes the enzyme may undergo in solution, it remains unclear whether the existing models adequately mirror the architecture of the ALOX5 active site. METHODS In this study, we prepared a series of RS75091 derivatives using a Sonogashira coupling reaction of regioisomeric bromocinnamates with protected acetylenic alcohols and tested their inhibitory properties on rabbit ALOX15. RESULTS A bulky pentafluorophenyl moiety linked to either ortho- or metha-ethynylcinnamates via aliphatic spacer does not significantly impair the inhibitory properties of RS75091. CONCLUSION Hydroxylated 2- and 3-alkynylcinnamates may be suitable candidates for incorporation of an aromatic linker group like tetrafluorophenylazides for photoaffinity labeling assays.
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Affiliation(s)
- Alexander Zhuravlev
- Lomonosov Institute of Fine Chemical Technologies, MIREA - Russian Technological University, Vernadskogo pr. 86, 119571 Moscow. Russian Federation
| | - Alexey Golovanov
- Lomonosov Institute of Fine Chemical Technologies, MIREA - Russian Technological University, Vernadskogo pr. 86, 119571 Moscow. Russian Federation
| | - Valery Toporkov
- Lomonosov Institute of Fine Chemical Technologies, MIREA - Russian Technological University, Vernadskogo pr. 86, 119571 Moscow. Russian Federation
| | - Hartmut Kuhn
- Institute of Biochemistry, Charite - University Medicine Berlin, Corporate member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Charitéplatz 1, D-10117 Berlin. Germany
| | - Igor Ivanov
- Lomonosov Institute of Fine Chemical Technologies, MIREA - Russian Technological University, Vernadskogo pr. 86, 119571 Moscow. Russian Federation
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10
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Ivanov I, Cruz A, Zhuravlev A, Di Venere A, Nicolai E, Stehling S, Lluch JM, González-Lafont À, Kuhn H. Conformational Heterogeneity and Cooperative Effects of Mammalian ALOX15. Int J Mol Sci 2021; 22:ijms22063285. [PMID: 33807076 PMCID: PMC8004969 DOI: 10.3390/ijms22063285] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/16/2021] [Accepted: 03/19/2021] [Indexed: 12/19/2022] Open
Abstract
Arachidonic acid lipoxygenases (ALOXs) have been suggested to function as monomeric enzymes, but more recent data on rabbit ALOX15 indicated that there is a dynamic monomer-dimer equilibrium in aqueous solution. In the presence of an active site ligand (the ALOX15 inhibitor RS7) rabbit ALOX15 was crystalized as heterodimer and the X-ray coordinates of the two monomers within the dimer exhibit subtle structural differences. Using native polyacrylamide electrophoresis, we here observed that highly purified and predominantly monomeric rabbit ALOX15 and human ALOX15B are present in two conformers with distinct electrophoretic mobilities. In silico docking studies, molecular dynamics simulations, site directed mutagenesis experiments and kinetic measurements suggested that in aqueous solutions the two enzymes exhibit motional flexibility, which may impact the enzymatic properties.
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Affiliation(s)
- Igor Ivanov
- Lomonosov Institute of Fine Chemical Technologies, MIREA—Russian Technological University, Vernadskogo pr. 86, 119571 Moscow, Russia; (I.I.); (A.Z.)
| | - Alejandro Cruz
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain; (A.C.); (J.M.L.); (À.G.-L.)
| | - Alexander Zhuravlev
- Lomonosov Institute of Fine Chemical Technologies, MIREA—Russian Technological University, Vernadskogo pr. 86, 119571 Moscow, Russia; (I.I.); (A.Z.)
| | - Almerinda Di Venere
- Department of Experimental Medicine, University of Tor Vergata, Via Montpellier 1, 00133 Rome, Italy; (A.D.V.); (E.N.)
| | - Eleonora Nicolai
- Department of Experimental Medicine, University of Tor Vergata, Via Montpellier 1, 00133 Rome, Italy; (A.D.V.); (E.N.)
| | - Sabine Stehling
- Institute of Biochemistry, Charite—University Medicine Berlin, Corporate member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Charitéplatz 1, D-10117 Berlin, Germany;
| | - José M. Lluch
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain; (A.C.); (J.M.L.); (À.G.-L.)
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Àngels González-Lafont
- Departament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain; (A.C.); (J.M.L.); (À.G.-L.)
- Institut de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Hartmut Kuhn
- Institute of Biochemistry, Charite—University Medicine Berlin, Corporate member of Free University Berlin, Humboldt University Berlin and Berlin Institute of Health, Charitéplatz 1, D-10117 Berlin, Germany;
- Correspondence: ; Tel.: +49-30-450-528040
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11
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Tsai WC, Aleem AM, Whittington C, Cortopassi WA, Kalyanaraman C, Baroz A, Iavarone AT, Skrzypczak-Jankun E, Jacobson MP, Offenbacher AR, Holman T. Mutagenesis, Hydrogen-Deuterium Exchange, and Molecular Docking Investigations Establish the Dimeric Interface of Human Platelet-Type 12-Lipoxygenase. Biochemistry 2021; 60:802-812. [PMID: 33635645 DOI: 10.1021/acs.biochem.1c00053] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
It was previously shown that human platelet 12S-lipoxygenase (h12-LOX) exists as a dimer; however, the specific structure is unknown. In this study, we create a model of the dimer through a combination of computational methods, experimental mutagenesis, and hydrogen-deuterium exchange (HDX) investigations. Initially, Leu183 and Leu187 were replaced by negatively charged glutamate residues and neighboring aromatic residues were replaced with alanine residues (F174A/W176A/L183E/L187E/Y191A). This quintuple mutant disrupted both the hydrophobic and π-π interactions, generating an h12-LOX monomer. To refine the determinants for dimer formation further, the L183E/L187E mutant was generated and the equilibrium shifted mostly toward the monomer. We then submitted the predicted monomeric structure to protein-protein docking to create a model of the dimeric complex. A total of nine of the top 10 most energetically favorable docking conformations predict a TOP-to-TOP dimeric arrangement of h12-LOX, with the α-helices containing a Leu-rich region (L172, L183, L187, and L194), corroborating our experimental results showing the importance of these hydrophobic interactions for dimerization. This model was supported by HDX investigations that demonstrated the stabilization of four, non-overlapping peptides within helix α2 of the TOP subdomain for wt-h12-LOX, consistent with the dimer interface. Most importantly, our data reveal that the dimer and monomer of h12-LOX have distinct biochemical properties, suggesting that the structural changes due to dimerization have allosteric effects on active site catalysis and inhibitor binding.
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Affiliation(s)
- Wan-Chen Tsai
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Ansari Mukhtar Aleem
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Chris Whittington
- Department of Chemistry, East Carolina University, Greenville, North Carolina 27858, United States
| | - Wilian A Cortopassi
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, San Francisco, California 94143, United States
| | - Chakrapani Kalyanaraman
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, San Francisco, California 94143, United States
| | - Angel Baroz
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Anthony T Iavarone
- QB3/Chemistry Mass Spectrometry Facility, University of California, Berkeley, Berkeley, California 94720, United States
| | - Ewa Skrzypczak-Jankun
- Department of Urology, University of Toledo, Health Science Campus, Toledo, Ohio 43614, United States
| | - Matthew P Jacobson
- Department of Pharmaceutical Chemistry, School of Pharmacy, University of California, San Francisco, San Francisco, California 94143, United States
| | - Adam R Offenbacher
- Department of Chemistry, East Carolina University, Greenville, North Carolina 27858, United States
| | - Theodore Holman
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
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12
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Kutzner L, Goloshchapova K, Rund KM, Jübermann M, Blum M, Rothe M, Kirsch SF, Schunck WH, Kühn H, Schebb NH. Human lipoxygenase isoforms form complex patterns of double and triple oxygenated compounds from eicosapentaenoic acid. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158806. [PMID: 32841762 DOI: 10.1016/j.bbalip.2020.158806] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 07/27/2020] [Accepted: 08/17/2020] [Indexed: 02/07/2023]
Abstract
Lipoxygenases (ALOX) are lipid peroxidizing enzymes that catalyze the biosynthesis of pro- and anti-inflammatory lipid mediators and have been implicated in (patho-)physiological processes. In humans, six functional ALOX isoforms exist and their arachidonic acid oxygenation products have been characterized. Products include leukotrienes and lipoxins which are involved in the regulation of inflammation and resolution. Oxygenation of n3-polyunsaturated fatty acids gives rise to specialized pro-resolving mediators, e.g. resolvins. However, the catalytic activity of different ALOX isoforms can lead to a multitude of potentially bioactive products. Here, we characterized the patterns of oxygenation products formed by human recombinant ALOX5, ALOX15, ALOX15B and ALOX12 from eicosapentaenoic acid (EPA) and its 18-hydroxy derivative 18-HEPE with particular emphasis on double and triple oxygenation products. ALOX15 and ALOX5 formed a complex mixture of various double oxygenation products from EPA, which include 5,15-diHEPE and various 8,15-diHEPE isomers. Their biosynthetic mechanisms were explored using heavy oxygen isotopes (H218O, 18O2 gas) and three catalytic activities contributed to product formation: i) fatty acid oxygenase activity, ii) leukotriene synthase activity, iii) lipohydroperoxidase activity. For ALOX15B and ALOX12 more specific product patterns were identified, which was also the case when these enzymes reacted in concert with ALOX5. Several double oxygenated compounds were formed from 18-HEPE by ALOX5, ALOX15B and ALOX12 including previously identified resolvins (RvE2, RvE3), while formation of triple oxygenation products, e.g. 5,17,18-triHEPE, required ALOX5. Taken together our data show that EPA can be converted by human ALOX isoforms to a large number of secondary oxygenation products, which might exhibit bioactivity.
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Affiliation(s)
- Laura Kutzner
- Chair of Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaussstr. 20, 42119 Wuppertal, Germany
| | - Kateryna Goloshchapova
- Institute of Biochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Charitéplatz 1, CCO-Building, Virchowweg 6, 10117 Berlin, Germany
| | - Katharina M Rund
- Chair of Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaussstr. 20, 42119 Wuppertal, Germany
| | - Martin Jübermann
- Chair of Organic Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaussstr. 20, 42119 Wuppertal, Germany
| | - Maximilian Blum
- Max Delbrueck Center for Molecular Medicine, Robert-Roessle-Str. 10, 13125 Berlin, Germany
| | - Michael Rothe
- Lipidomix GmbH, Robert-Roessle-Str. 10, 13125 Berlin, Germany
| | - Stefan F Kirsch
- Chair of Organic Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaussstr. 20, 42119 Wuppertal, Germany
| | - Wolf-Hagen Schunck
- Max Delbrueck Center for Molecular Medicine, Robert-Roessle-Str. 10, 13125 Berlin, Germany
| | - Hartmut Kühn
- Institute of Biochemistry, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Charitéplatz 1, CCO-Building, Virchowweg 6, 10117 Berlin, Germany
| | - Nils Helge Schebb
- Chair of Food Chemistry, Faculty of Mathematics and Natural Sciences, University of Wuppertal, Gaussstr. 20, 42119 Wuppertal, Germany.
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13
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A role of Gln596 in fine-tuning mammalian ALOX15 specificity, protein stability and allosteric properties. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158680. [PMID: 32151768 DOI: 10.1016/j.bbalip.2020.158680] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 02/12/2020] [Accepted: 03/04/2020] [Indexed: 12/31/2022]
Abstract
His596 of human ALOX12 has been suggested to interact with the COO--group of arachidonic acid during ALOX catalysis. In mammalian ALOX15 orthologs Gln596 occupies this position and this amino acid exchange might contribute to the functional differences between the two ALOX-isoforms. To explore the role of Gln596 for ALOX15 functionality we mutated this amino acid to different residues in rabbit and human ALOX15 and investigated the impact of these mutations on structural, catalytic and allosteric enzyme properties. To shed light on the molecular basis of the observed functional alterations we performed in silico substrate docking studies and molecular dynamics simulations and also explored the impact of Gln596 exchange on the protein structure. The combined theoretical and experimental data suggest that Gln596 may not directly interact with the COO--group of arachidonic acid. In contrast, mutations at Gln596 destabilize the secondary and tertiary structure of ALOX15 orthologs, which may be related to a disturbance of the electrostatic interaction network with other amino acids in the immediate surrounding. Moreover, our MD-simulations suggest that the geometry of the dimer interface depends on the structure of substrate bound inside the substrate-binding pocket and that Gln596Ala exchange impairs the allosteric properties of the enzyme. Taken together, these data indicate the structural and functional importance of Gln596 for ALOX15 catalysis.
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14
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Hajeyah AA, Griffiths WJ, Wang Y, Finch AJ, O’Donnell VB. The Biosynthesis of Enzymatically Oxidized Lipids. Front Endocrinol (Lausanne) 2020; 11:591819. [PMID: 33329396 PMCID: PMC7711093 DOI: 10.3389/fendo.2020.591819] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/26/2020] [Indexed: 12/14/2022] Open
Abstract
Enzymatically oxidized lipids are a specific group of biomolecules that function as key signaling mediators and hormones, regulating various cellular and physiological processes from metabolism and cell death to inflammation and the immune response. They are broadly categorized as either polyunsaturated fatty acid (PUFA) containing (free acid oxygenated PUFA "oxylipins", endocannabinoids, oxidized phospholipids) or cholesterol derivatives (oxysterols, steroid hormones, and bile acids). Their biosynthesis is accomplished by families of enzymes that include lipoxygenases (LOX), cyclooxygenases (COX), cytochrome P450s (CYP), and aldo-keto reductases (AKR). In contrast, non-enzymatically oxidized lipids are produced by uncontrolled oxidation and are broadly considered to be harmful. Here, we provide an overview of the biochemistry and enzymology of LOXs, COXs, CYPs, and AKRs in humans. Next, we present biosynthetic pathways for oxylipins, oxidized phospholipids, oxysterols, bile acids and steroid hormones. Last, we address gaps in knowledge and suggest directions for future work.
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Affiliation(s)
- Ali A. Hajeyah
- Systems Immunity Research Institute and Division of Infection and Immunity, Cardiff University, Cardiff, United Kingdom
- *Correspondence: Ali A. Hajeyah,
| | - William J. Griffiths
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
| | - Yuqin Wang
- Institute of Life Science, Swansea University Medical School, Swansea, United Kingdom
| | - Andrew J. Finch
- Centre for Tumour Biology, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Valerie B. O’Donnell
- Systems Immunity Research Institute and Division of Infection and Immunity, Cardiff University, Cardiff, United Kingdom
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15
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Gly188Arg substitution eliminates substrate inhibition in arachidonate 11R-lipoxygenase. Biochem Biophys Res Commun 2019; 519:81-85. [PMID: 31477267 DOI: 10.1016/j.bbrc.2019.08.132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 08/23/2019] [Indexed: 11/21/2022]
Abstract
Lipoxygenases (LOXs) are dioxygenases that catalyze the oxygenation of polyunsaturated fatty acids to hydroperoxyl derivates. These products are precursors for different lipid mediators which are associated with pathogenesis of various diseases such as asthma, atherosclerosis and cancer. Several LOXs suffer from substrate inhibition, a potential regulatory mechanism, yet it is unclear what is the cause of this phenomenon. One such enzyme is the coral 11R-LOX which displays a significant decrease in turnover rate at arachidonic acid concentrations above 30 μM. In this report, site-directed mutagenesis and inhibition assays were employed to shed light on the mechanism of substrate inhibition in 11R-LOX. We found that introduction of a positive charge to the active site entrance with Gly188Arg substitution completely eliminates the slow-down at higher substrate concentrations. Inhibition of 11R-LOX by its catalysis product, 11(R)-hydroperoxyeicosatetraenoic acid, suggests an uncompetitive mechanism. We reason that substrate inhibition in 11R-LOX is due to additional fatty acid binding by the enzyme:substrate complex at an allosteric site situated in the very vicinity of the active site entrance.
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16
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Meng H, Dai Z, Zhang W, Liu Y, Lai L. Molecular mechanism of 15-lipoxygenase allosteric activation and inhibition. Phys Chem Chem Phys 2018; 20:14785-14795. [PMID: 29780994 DOI: 10.1039/c7cp08586a] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Human reticulocyte 15-lipoxygenase (15-LOX) plays an important role in inflammation resolution and is also involved in many cancer-related processes. Both an activator and an inhibitor will serve as research tools for understanding the biological functions of 15-LOX and provide opportunities for drug discovery. In a previous study, both allosteric activators and inhibitors of 15-LOX were discovered through a virtual screening based computational approach. However, why molecules binding to the same site causes different effects remains to be disclosed. In the present study, we used previously reported activator and inhibitor molecules as probes to elucidate the mechanism of allosteric regulation of 15-LOX. We measured the influences of the allosteric activator and inhibitor on the enzymatic reaction rate and found that the activator increases 15-LOX activity by preventing substrate inhibition instead of increasing the turnover number. The inhibitor can also prevent substrate inhibition but decreases the turnover number at the same time, resulting in inhibition. Molecular dynamics simulations were conducted to help explain the underlying mechanism of allostery. Both the activator and inhibitor were demonstrated to be able to prevent 15-LOX from transforming into potentially inactive conformations. Compared to the activator, the inhibitor molecule restrains the motions of residues around the substrate binding site and reduces the flexibility of 15-LOX. These results explained the different effects between the activator and the inhibitor and shed light on how to effectively design novel activator molecules.
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Affiliation(s)
- Hu Meng
- BNLMS, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, A518 Chemistry Building, 202 Chengfu Road, Beijing 100871, China.
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17
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Yu S, Kent B, Jafta CJ, Petzold A, Radulescu A, Schuchardt M, Tölle M, van der Giet M, Zidek W, Ballauff M. Stability of human serum albumin structure upon toxin uptake explored by small angle neutron scattering. POLYMER 2018. [DOI: 10.1016/j.polymer.2018.02.060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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18
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Eek P, Põldemaa K, Kasvandik S, Järving I, Samel N. A PDZ-like domain mediates the dimerization of 11 R -lipoxygenase. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1121-1128. [DOI: 10.1016/j.bbalip.2017.07.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 07/04/2017] [Accepted: 07/26/2017] [Indexed: 01/18/2023]
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19
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Mittal M, Hasan M, Balagunaseelan N, Fauland A, Wheelock C, Rådmark O, Haeggström JZ, Rinaldo-Matthis A. Investigation of calcium-dependent activity and conformational dynamics of zebra fish 12-lipoxygenase. Biochim Biophys Acta Gen Subj 2017; 1861:2099-2111. [DOI: 10.1016/j.bbagen.2017.05.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 05/12/2017] [Accepted: 05/17/2017] [Indexed: 11/26/2022]
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20
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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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21
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Lara-Gonzalez S, Estrella P, Portillo C, Cruces ME, Jimenez-Sandoval P, Fattori J, Migliorini-Figueira AC, Lopez-Hidalgo M, Diaz-Quezada C, Lopez-Castillo M, Trasviña-Arenas CH, Sanchez-Sandoval E, Gómez-Puyou A, Ortega-Lopez J, Arroyo R, Benítez-Cardoza CG, Brieba LG. Substrate-Induced Dimerization of Engineered Monomeric Variants of Triosephosphate Isomerase from Trichomonas vaginalis. PLoS One 2015; 10:e0141747. [PMID: 26618356 PMCID: PMC4664265 DOI: 10.1371/journal.pone.0141747] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 10/11/2015] [Indexed: 11/29/2022] Open
Abstract
The dimeric nature of triosephosphate isomerases (TIMs) is maintained by an extensive surface area interface of more than 1600 Å2. TIMs from Trichomonas vaginalis (TvTIM) are held in their dimeric state by two mechanisms: a ball and socket interaction of residue 45 of one subunit that fits into the hydrophobic pocket of the complementary subunit and by swapping of loop 3 between subunits. TvTIMs differ from other TIMs in their unfolding energetics. In TvTIMs the energy necessary to unfold a monomer is greater than the energy necessary to dissociate the dimer. Herein we found that the character of residue I45 controls the dimer-monomer equilibrium in TvTIMs. Unfolding experiments employing monomeric and dimeric mutants led us to conclude that dimeric TvTIMs unfold following a four state model denaturation process whereas monomeric TvTIMs follow a three state model. In contrast to other monomeric TIMs, monomeric variants of TvTIM1 are stable and unexpectedly one of them (I45A) is only 29-fold less active than wild-type TvTIM1. The high enzymatic activity of monomeric TvTIMs contrast with the marginal catalytic activity of diverse monomeric TIMs variants. The stability of the monomeric variants of TvTIM1 and the use of cross-linking and analytical ultracentrifugation experiments permit us to understand the differences between the catalytic activities of TvTIMs and other marginally active monomeric TIMs. As TvTIMs do not unfold upon dimer dissociation, herein we found that the high enzymatic activity of monomeric TvTIM variants is explained by the formation of catalytic dimeric competent species assisted by substrate binding.
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Affiliation(s)
- Samuel Lara-Gonzalez
- IPICYT, División de Biología Molecular, Camino a la Presa San José 2055, CP 78216, San Luis Potosí, San Luis Potosí, México
| | - Priscilla Estrella
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36500, Irapuato, Guanajuato, México
| | - Carmen Portillo
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36500, Irapuato, Guanajuato, México
| | - María E. Cruces
- Laboratorio de Investigación Bioquímica, Programa Institucional en Biomedicina Molecular ENMyH-IPN, Guillermo Massieu Helguera No. 239, La Escalera Ticoman, 07320, D.F, Mexico
| | - Pedro Jimenez-Sandoval
- Laboratorio de Investigación Bioquímica, Programa Institucional en Biomedicina Molecular ENMyH-IPN, Guillermo Massieu Helguera No. 239, La Escalera Ticoman, 07320, D.F, Mexico
| | - Juliana Fattori
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais Campinas SP, Brazil
| | - Ana C. Migliorini-Figueira
- Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais Campinas SP, Brazil
| | - Marisol Lopez-Hidalgo
- Laboratorio de Investigación Bioquímica, Programa Institucional en Biomedicina Molecular ENMyH-IPN, Guillermo Massieu Helguera No. 239, La Escalera Ticoman, 07320, D.F, Mexico
| | - Corina Diaz-Quezada
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36500, Irapuato, Guanajuato, México
| | - Margarita Lopez-Castillo
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36500, Irapuato, Guanajuato, México
| | - Carlos H. Trasviña-Arenas
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36500, Irapuato, Guanajuato, México
| | - Eugenia Sanchez-Sandoval
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36500, Irapuato, Guanajuato, México
| | - Armando Gómez-Puyou
- Departamento de Bioquímica y Biología Estructural, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, México
| | - Jaime Ortega-Lopez
- Departamento de Biotecnología y Bioingeniería, Centro de Investigación y de Estudios Avanzados del IPN, Col. San Pedro Zacatenco, Av. IPN, 2508, C.P. 07360, D.F., México
| | - Rossana Arroyo
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Col. San Pedro Zacatenco, Av. IPN, 2508, C.P. 07360, D.F., México
| | - Claudia G. Benítez-Cardoza
- Laboratorio de Investigación Bioquímica, Programa Institucional en Biomedicina Molecular ENMyH-IPN, Guillermo Massieu Helguera No. 239, La Escalera Ticoman, 07320, D.F, Mexico
- * E-mail: (LGB); (CGB)
| | - Luis G. Brieba
- Laboratorio Nacional de Genómica para la Biodiversidad, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, CP 36500, Irapuato, Guanajuato, México
- * E-mail: (LGB); (CGB)
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22
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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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23
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Kuhn H, Banthiya S, van Leyen K. Mammalian lipoxygenases and their biological relevance. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:308-30. [PMID: 25316652 DOI: 10.1016/j.bbalip.2014.10.002] [Citation(s) in RCA: 409] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 09/30/2014] [Accepted: 10/03/2014] [Indexed: 02/07/2023]
Abstract
Lipoxygenases (LOXs) form a heterogeneous class of lipid peroxidizing enzymes, which have been implicated not only in cell proliferation and differentiation but also in the pathogenesis of various diseases with major public health relevance. As other fatty acid dioxygenases LOXs oxidize polyunsaturated fatty acids to their corresponding hydroperoxy derivatives, which are further transformed to bioactive lipid mediators (eicosanoids and related substances). On the other hand, lipoxygenases are key players in the regulation of the cellular redox homeostasis, which is an important element in gene expression regulation. Although the first mammalian lipoxygenases were discovered 40 years ago and although the enzymes have been well characterized with respect to their structural and functional properties the biological roles of the different lipoxygenase isoforms are not completely understood. This review is aimed at summarizing the current knowledge on the physiological roles of different mammalian LOX-isoforms and their patho-physiological function in inflammatory, metabolic, hyperproliferative, neurodegenerative and infectious disorders. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".
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Affiliation(s)
- Hartmut Kuhn
- Institute of Biochemistry, University Medicine Berlin - Charite, Chariteplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany.
| | - Swathi Banthiya
- Institute of Biochemistry, University Medicine Berlin - Charite, Chariteplatz 1, CCO-Building, Virchowweg 6, D-10117 Berlin, Germany
| | - Klaus van Leyen
- Neuroprotection Research Laboratory, Department of Radiology, Massachusetts Genrel Hospital and Harvard Medical School, Charlestown, MA, USA
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Tuukkanen AT, Svergun DI. Weak protein-ligand interactions studied by small-angle X-ray scattering. FEBS J 2014; 281:1974-87. [PMID: 24588935 DOI: 10.1111/febs.12772] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 01/22/2014] [Accepted: 02/28/2014] [Indexed: 12/20/2022]
Abstract
Small-angle X-ray scattering (SAXS) is a powerful technique for studying weak interactions between proteins and their ligands (other proteins, DNA/RNA or small molecules) in solution. SAXS provides knowledge about the equilibrium state, the stoichiometry of binding and association-dissociation processes. The measurements are conducted in a solution environment that allows easy monitoring of modifications in protein-ligand association state upon environmental changes. Model-free parameters such as the molecular mass of a system and the radius of gyration can be obtained directly from the SAXS data and give indications about the association state. SAXS is also widely employed to build models of biological assemblies at a resolution of approximately 10-20 Å. Low-resolution shapes can be generated ab initio, although more detailed and biologically interpretable information can be obtained by hybrid modelling. In the latter approach, composite structures of protein-ligand complexes are constructed using atomic models of individual molecules. These may be predicted homology models or experimental structures from X-ray crystallography or NMR. This review focuses on using SAXS data to model structures of protein-ligand complexes and to study their dynamics. The combination of SAXS with other methods such as size exclusion chromatography and dynamic light scattering is discussed.
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Horn T, Reddy Kakularam K, Anton M, Richter C, Reddanna P, Kuhn H. Functional characterization of genetic enzyme variations in human lipoxygenases. Redox Biol 2013; 1:566-77. [PMID: 24282679 PMCID: PMC3840004 DOI: 10.1016/j.redox.2013.11.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 11/01/2013] [Indexed: 01/09/2023] Open
Abstract
Mammalian lipoxygenases play a role in normal cell development and differentiation but they have also been implicated in the pathogenesis of cardiovascular, hyperproliferative and neurodegenerative diseases. As lipid peroxidizing enzymes they are involved in the regulation of cellular redox homeostasis since they produce lipid hydroperoxides, which serve as an efficient source for free radicals. There are various epidemiological correlation studies relating naturally occurring variations in the six human lipoxygenase genes (SNPs or rare mutations) to the frequency for various diseases in these individuals, but for most of the described variations no functional data are available. Employing a combined bioinformatical and enzymological strategy, which included structural modeling and experimental site-directed mutagenesis, we systematically explored the structural and functional consequences of non-synonymous genetic variations in four different human lipoxygenase genes (ALOX5, ALOX12, ALOX15, and ALOX15B) that have been identified in the human 1000 genome project. Due to a lack of a functional expression system we resigned to analyze the functionality of genetic variations in the hALOX12B and hALOXE3 gene. We found that most of the frequent non-synonymous coding SNPs are located at the enzyme surface and hardly alter the enzyme functionality. In contrast, genetic variations which affect functional important amino acid residues or lead to truncated enzyme variations (nonsense mutations) are usually rare with a global allele frequency<0.1%. This data suggest that there appears to be an evolutionary pressure on the coding regions of the lipoxygenase genes preventing the accumulation of loss-of-function variations in the human population. Non-synonymous coding variations in human lipoxygenases are mostly rare with a global allele frequency <1%. Common ALOX SNPs are mainly localized on the enzyme surface and hardly effect the enzyme functionality. hALOX15B Ala416Asp is a newly discovered loss-of-function mutation in the hALOX gene family while inactivity seems to be caused by severe structural alterations. Our data indicate that there is evolutionary pressure on these redox enzymes preventing the accumulation of loss-of-function variations in the human population. 1000 Genome database is a useful tool to analyze the distribution and functionality of variations in genes of interest.
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Key Words
- 12-H(p)ETE, (5Z,8Z,10E,14Z)-12-hydroperoxyeicosa-5,8,10,14-tetraenoic acid
- 15-H(p)ETE, (5Z,8Z,11Z,13E)-15-hydroperoxyeicosa-5,8,11,13-tetraenoic acid
- 5-H(p)ETE, (6E,8Z,11Z,14Z)-5-hydroperoxyeicosa-6,8,11,14-tetraenoic acid
- 8-H(p)ETE, (5Z,9E,11Z,14Z)-8-hydroperoxyeicosa-5,9,11,14-tetraenoic acid
- ALOX, arachidonate lipoxygenase
- Eicosanoids
- Gene polymorphism
- H(p)ETE, hydroperoxyeicosatetraenoic acid
- HETE, hydroxyeicosatetraenoic acid
- IPTG, Isopropyl-β-D-thiogalactopyranosid
- LOXs, lipoxygenases
- LTA4, 4-[(2S,3S)-3-[(1E,3E,5Z,8Z)-tetradeca-1,3,5,8-tetraen-1-yl]oxiran-2-yl]butanoic acid
- LTB4, 5(S),12(R)-dihydroxy-6,8,10,14-(Z,E,E,Z)-eicosatetraenoic acid
- LTC4, (5S,6R,7E,9E,11Z,14Z)-6-{[(2R)-2-[(4S)-4-amino-4-carboxybutanamido]-2-[(carboxymethyl) carbamoyl]ethyl]sulfanyl}-5-hydroxyeicosa-7,9,11,14-tetraenoic acid
- Leukotrienes
- Lipoxygenases
- SNP
- UTR, untranslated region
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Affiliation(s)
- Thomas Horn
- Institute of Biochemistry, University Medicine Berlin-Charité, Charitéplatz 1, D-10117 Berlin, Germany
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Joshi N, Hoobler EK, Perry S, Diaz G, Fox B, Holman TR. Kinetic and structural investigations into the allosteric and pH effect on the substrate specificity of human epithelial 15-lipoxygenase-2. Biochemistry 2013; 52:8026-35. [PMID: 24171444 DOI: 10.1021/bi4010649] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lipoxygenases, important enzymes in inflammation, can regulate their substrate specificity by allosteric interactions with their own hydroperoxide products. In this work, addition of both 13-(S)-hydroxy-(9Z,11E)-octadecadienoic acid [13-(S)-HODE] and 13-(S)-hydroperoxy-(6Z,9Z,11E)-octadecatrienoic acid to human epithelial 15-lipoxygenase-2 (15-LOX-2) increases the kcat/KM substrate specificity ratio of arachidonic acid (AA) and γ-linolenic acid (GLA) by 4-fold. 13-(S)-HODE achieves this change by activating kcat/KM(AA) but inhibiting kcat/KM(GLA), which indicates that the allosteric structural changes at the active site discriminate between the length and unsaturation differences of AA and GLA to achieve opposite kinetic effects. The substrate specificity ratio is further increased, 11-fold in total, with an increase in pH, suggesting mechanistic differences between the pH and allosteric effects. Interestingly, the loss of the PLAT domain affects substrate specificity but does not eliminate the allosteric properties of 15-LOX-2, indicating that the allosteric site is located in the catalytic domain. However, the removal of the PLAT domain does change the magnitude of the allosteric effect. These data suggest that the PLAT domain moderates the communication pathway between the allosteric and catalytic sites, thus affecting substrate specificity. These results are discussed in the context of protein dimerization and other structural changes.
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Affiliation(s)
- Netra Joshi
- Department of Chemistry and Biochemistry, University of California , Santa Cruz, California 95064, United States
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Small-molecule modulation of neurotrophin receptors: a strategy for the treatment of neurological disease. Nat Rev Drug Discov 2013; 12:507-25. [PMID: 23977697 DOI: 10.1038/nrd4024] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Neurotrophins and their receptors modulate multiple signalling pathways to regulate neuronal survival and to maintain axonal and dendritic networks and synaptic plasticity. Neurotrophins have potential for the treatment of neurological diseases. However, their therapeutic application has been limited owing to their poor plasma stability, restricted nervous system penetration and, importantly, the pleiotropic actions that derive from their concomitant binding to multiple receptors. One strategy to overcome these limitations is to target individual neurotrophin receptors — such as tropomyosin receptor kinase A (TRKA), TRKB, TRKC, the p75 neurotrophin receptor or sortilin — with small-molecule ligands. Such small molecules might also modulate various aspects of these signalling pathways in ways that are distinct from the programmes triggered by native neurotrophins. By departing from conventional neurotrophin signalling, these ligands might provide novel therapeutic options for a broad range of neurological indications.
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Di Venere A, Nicolai E, Ivanov I, Dainese E, Adel S, Angelucci BC, Kuhn H, Maccarrone M, Mei G. Probing conformational changes in lipoxygenases upon membrane binding: fine-tuning by the active site inhibitor ETYA. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:1-10. [PMID: 24012824 DOI: 10.1016/j.bbalip.2013.08.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 07/29/2013] [Accepted: 08/14/2013] [Indexed: 11/27/2022]
Abstract
Lipoxygenases (LOXs) are lipid-peroxidizing enzymes that are involved in the metabolism of polyunsaturated fatty acids. Their biological activity includes a membrane binding process whose molecular details are not completely understood. The mechanism of enzyme-membrane interactions is thought to involve conformational changes at the level of the protein tertiary structure, and the extent of such alterations depends on the degree of structural flexibility of the different LOX isoforms. In this study, we have tested the resilience properties of a plant and a mammalian LOX, by using high pressure fluorescence measurements at different temperatures. The binding of LOXs to the lipid bilayer has been characterized using both large and giant unilamellar vesicles and electron transfer particles (inner mitochondrial membranes) as model membranes. The data indicate that the degree of LOXs' flexibility is strictly dependent on the two distinct N- and C-terminal domains that characterize the 3D structure of these enzymes. Furthermore, they demonstrate that increasing the rigidity of protein scaffolding by the presence of an active site ligand impairs the membrane binding ability of LOXs. These findings provide evidence that the amphitropic nature of LOXs is finely tuned by the interaction of the substrate with the residues of the active site, suggesting new strategies for the design of enzyme inhibitors.
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Affiliation(s)
- Almerinda Di Venere
- Department of Experimental Medicine and Surgery, Tor Vergata University of Rome, Via Montpellier 1, 00133 Rome, Italy
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29
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Di Venere A, Horn T, Stehling S, Mei G, Masgrau L, González-Lafont A, Kühn H, Ivanov I. Role of Arg403 for thermostability and catalytic activity of rabbit 12/15-lipoxygenase. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1079-88. [PMID: 23438511 DOI: 10.1016/j.bbalip.2013.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 01/10/2013] [Accepted: 02/13/2013] [Indexed: 11/30/2022]
Abstract
12/15-Lipoxygenases (12/15-LOX) have been implicated in inflammatory and hyperproliferative diseases but the numerous aspects of structural biology of these enzymes are far from clear. Early mutagenesis data and structural modeling of enzyme-substrate complexes suggested that Arg403, which is localized at the entrance of the putative substrate binding pocket, might interact with the fatty acid carboxylic group. On the other hand, side-chain of Arg403 is a part of an ionic network with the residues of α2-helix, which undergoes pronounced conformation changes upon inhibitor binding. To explore the role of Arg403 for catalysis in more detail we exchanged positively charged Arg403 to neutral Leu and quantified structural and functional consequences of the alteration at the site of mutation using fluorometric techniques. We found that a loss of electrostatic interaction between Arg403 and negatively charged amino acid residues of α2-helix has only minor impact on protein folding, but partially destabilized the tertiary structure of the enzyme. We hypothesize that interaction of Arg403 with the substrate's carboxylate might be involved in a complex mechanism triggering conformational changes of the α2-helix, which are required for formation of the catalytically competent dimer r12/15-LOX complex at pre-catalytic stages.
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Affiliation(s)
- Almerinda Di Venere
- Department of Experimental Medicine and Surgery, University of Tor Vergata, Rome, Italy
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Hofheinz K, Kakularam KR, Adel S, Anton M, Polymarasetty A, Reddanna P, Kuhn H, Horn T. Conversion of pro-inflammatory murine Alox5 into an anti-inflammatory 15S-lipoxygenating enzyme by multiple mutations of sequence determinants. Arch Biochem Biophys 2013; 530:40-7. [DOI: 10.1016/j.abb.2012.11.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 11/23/2012] [Accepted: 11/29/2012] [Indexed: 12/19/2022]
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