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Molecules (Basel, Switzerland) Apr 2020Abundant in nature, carotenoids are a class of fat-soluble pigments with a polyene tetraterpenoid structure. They possess antioxidant properties and their consumption...
Abundant in nature, carotenoids are a class of fat-soluble pigments with a polyene tetraterpenoid structure. They possess antioxidant properties and their consumption leads to certain health benefits in humans. Carotenoid cleavage oxygenases (CCOs) are a superfamily of enzymes which oxidatively cleave carotenoids and they are present in all kingdoms of life. Complexity of CCO evolution is high. For example, in this study we serendipitously found a new family of eukaryotic CCOs, the apocarotenoid oxygenase-like (ACOL) family. This family has several members in animal genomes and lacks the animal-specific amino acid motif PDPCK. This motif is likely to be associated with palmitoylation of some animal CCOs. We recently demonstrated that two mammalian members of the carotenoid oxygenase family retinal pigment epithelial-specific 65 kDa protein (RPE65) and beta-carotene oxygenase 2 (BCO2) are palmitoylated proteins. Here we used the acyl-resin-assisted capture (acyl-RAC) method to demonstrate protein palmitoylation and immunochemistry to localize mouse BCO2 (mBCO2) in COS7 cell line in the absence and presence of its substrate β-carotene. We demonstrate that mBCO2 palmitoylation depends on the evolutionarily conserved motif PDPCK and that metazoan family members lacking the motif (Lancelet beta-carotene oxygenase-like protein (BCOL) and Acropora ACOL) are not palmitoylated. Additionally, we observed that the palmitoylation status of mBCO2 and its membrane association depend on the presence of its substrate β-carotene. Based on our results we conclude that most metazoan carotenoid oxygenases retain the evolutionarily conserved palmitoylation PDPCK motif to target proteins to internal membranes depending on substrate status. Exceptions are in the secreted BCOL subfamily and the strictly cytosolic ancient ACOL subfamily of carotenoid oxygenases.
Topics: Animals; Carotenoids; Dioxygenases; Fatty Acids, Monounsaturated; Fluorescent Antibody Technique; Humans; Mice; Multigene Family; Mutation; Oxygenases; Phylogeny; Protein Transport; Substrate Specificity
PubMed: 32331396
DOI: 10.3390/molecules25081942 -
Journal of Medicinal Chemistry Dec 2021MINA53 is a JmjC domain 2-oxoglutarate-dependent oxygenase that catalyzes ribosomal hydroxylation and is a target of the oncogenic transcription factor -MYC. Despite its...
MINA53 is a JmjC domain 2-oxoglutarate-dependent oxygenase that catalyzes ribosomal hydroxylation and is a target of the oncogenic transcription factor -MYC. Despite its anticancer target potential, no small-molecule MINA53 inhibitors are reported. Using ribosomal substrate fragments, we developed mass spectrometry assays for MINA53 and the related oxygenase NO66. These assays enabled the identification of 2-(aryl)alkylthio-3,4-dihydro-4-oxoypyrimidine-5-carboxylic acids as potent MINA53 inhibitors, with selectivity over NO66 and other JmjC oxygenases. Crystallographic studies with the JmjC demethylase KDM5B revealed active site binding but without direct metal chelation; however, molecular modeling investigations indicated that the inhibitors bind to MINA53 by directly interacting with the iron cofactor. The MINA53 inhibitors manifest evidence for target engagement and selectivity for MINA53 over KDM4-6. The MINA53 inhibitors show antiproliferative activity with solid cancer lines and sensitize cancer cells to conventional chemotherapy, suggesting that further work investigating their potential in combination therapies is warranted.
Topics: Cell Line, Tumor; Cell Proliferation; Crystallization; Dioxygenases; Enzyme Inhibitors; Histone Demethylases; Humans; Models, Molecular; Nuclear Proteins; Protein Conformation; Ribosomes; Substrate Specificity
PubMed: 34843649
DOI: 10.1021/acs.jmedchem.1c00605 -
Cells Sep 2021Heme oxygenases (HOs) act on heme degradation to produce carbon monoxide (CO), free iron, ferritin, and biliverdin. Upregulation of cellular HO-1 levels is signature of... (Review)
Review
Heme oxygenases (HOs) act on heme degradation to produce carbon monoxide (CO), free iron, ferritin, and biliverdin. Upregulation of cellular HO-1 levels is signature of oxidative stress for its downstream effects particularly under pro-oxidative status. Subcellular traffics of HO-1 to different organelles constitute a network of interactions compromising a variety of effectors such as pro-oxidants, ROS, mitochondrial enzymes, and nucleic transcription factors. Some of the compartmentalized HO-1 have been demonstrated as functioning in the progression of cancer. Emerging data show the multiple roles of HO-1 in tumorigenesis from pathogenesis to the progression to malignancy, metastasis, and even resistance to therapy. However, the role of HO-1 in tumorigenesis has not been systematically addressed. This review describes the crosstalk between HO-1 and oxidative stress, and following redox regulation in the tumorigenesis. HO-1-regulated signaling pathways are also summarized. This review aims to integrate basic information and current progress of HO-1 in cancer research in order to enhance the understandings and facilitate following studies.
Topics: Animals; Heme Oxygenase-1; Humans; Neoplasms; Oxidation-Reduction; Oxidative Stress; Signal Transduction
PubMed: 34572050
DOI: 10.3390/cells10092401 -
Pharmacology & Therapeutics Mar 2022Obesity-mediated metabolic syndrome remains the leading cause of death worldwide. Among many potential targets for pharmacological intervention, a promising strategy... (Review)
Review
Obesity-mediated metabolic syndrome remains the leading cause of death worldwide. Among many potential targets for pharmacological intervention, a promising strategy involves the heme oxygenase (HO) system, specifically its inducible form, HO-1. This review collects and updates much of the current knowledge relevant to pharmacology and clinical medicine concerning HO-1 in metabolic diseases and its effect on lipid metabolism. HO-1 has pleotropic effects that collectively reduce inflammation, while increasing vasodilation and insulin and leptin sensitivity. Recent reports indicate that HO-1 with its antioxidants via the effect of bilirubin increases formation of biologically active lipid metabolites such as epoxyeicosatrienoic acid (EET), omega-3 and other polyunsaturated fatty acids (PUFAs). Similarly, HO-1and bilirubin are potential therapeutic targets in the treatment of fat-induced liver diseases. HO-1-mediated upregulation of EET is capable not only of reversing endothelial dysfunction and hypertension, but also of reversing cardiac remodeling, a hallmark of the metabolic syndrome. This process involves browning of white fat tissue (i.e. formation of healthy adipocytes) and reduced lipotoxicity, which otherwise will be toxic to the heart. More importantly, this review examines the activity of EET in biological systems and a series of pathways that explain its mechanism of action and discusses how these might be exploited for potential therapeutic use. We also discuss the link between cardiac ectopic fat deposition and cardiac function in humans, which is similar to that described in obese mice and is regulated by HO-1-EET-PGC1α signaling, a potent negative regulator of the inflammatory adipokine NOV.
Topics: Animals; Eicosanoids; Heme; Heme Oxygenase (Decyclizing); Heme Oxygenase-1; Humans; Hypertension; Mice; Obesity
PubMed: 34499923
DOI: 10.1016/j.pharmthera.2021.107975 -
Natural Product Reports Jul 2018Covering: up to 2017 The participation of non-heme dinuclear iron cluster-containing monooxygenases in natural product biosynthetic pathways has been recognized only... (Review)
Review
Covering: up to 2017 The participation of non-heme dinuclear iron cluster-containing monooxygenases in natural product biosynthetic pathways has been recognized only recently. At present, two families have been discovered. The archetypal member of the first family, CmlA, catalyzes β-hydroxylation of l-p-aminophenylalanine (l-PAPA) covalently linked to the nonribosomal peptide synthetase (NRPS) CmlP, thereby effecting the first step in the biosynthesis of chloramphenicol by Streptomyces venezuelae. CmlA houses the diiron cluster in a metallo-β-lactamase protein fold instead of the 4-helix bundle fold of nearly every other diiron monooxygenase. CmlA couples O2 activation and substrate hydroxylation via a structural change caused by formation of the l-PAPA-loaded CmlP:CmlA complex. The other new diiron family is typified by two enzymes, AurF and CmlI, which catalyze conversion of aryl-amine substrates to aryl-nitro products with incorporation of oxygen from O2. AurF from Streptomyces thioluteus catalyzes the formation of p-nitrobenzoate from p-aminobenzoate as a precursor to the biostatic compound aureothin, whereas CmlI from S. venezuelae catalyzes the ultimate aryl-amine to aryl-nitro step in chloramphenicol biosynthesis. Both enzymes stabilize a novel type of peroxo-intermediate as the reactive species. The rare 6-electron N-oxygenation reactions of CmlI and AurF involve two progressively oxidized pathway intermediates. The enzymes optimize efficiency by utilizing one of the reaction pathway intermediates as an in situ reductant for the diiron cluster, while simultaneously generating the next pathway intermediate. For CmlI, this reduction allows mid-pathway regeneration of the peroxo intermediate required to complete the biosynthesis. CmlI ensures specificity by carrying out the multistep aryl-amine oxygenation without dissociating intermediate products.
Topics: Bacterial Proteins; Biological Products; Biosynthetic Pathways; Chloramphenicol; Crystallography, X-Ray; Kinetics; Mixed Function Oxygenases; Oxygen; Oxygenases; Peptide Synthases; Protein Conformation
PubMed: 29552683
DOI: 10.1039/C7NP00061H -
Chemical Society Reviews Sep 2016Many efforts are being made in the design and engineering of metalloenzymes with catalytic properties fulfilling the needs of practical applications. Progress in this... (Review)
Review
Many efforts are being made in the design and engineering of metalloenzymes with catalytic properties fulfilling the needs of practical applications. Progress in this field has recently been accelerated by advances in computational, molecular and structural biology. This review article focuses on the recent examples of oxygen-activating metalloenzymes, developed through the strategies of de novo design, miniaturization processes and protein redesign. Considerable progress in these diverse design approaches has produced many metal-containing biocatalysts able to adopt the functions of native enzymes or even novel functions beyond those found in Nature.
Topics: Enzyme Activation; Metalloproteins; Oxygen; Oxygenases; Protein Engineering
PubMed: 27341693
DOI: 10.1039/c5cs00923e -
Nature Feb 2015The most powerful oxidant found in nature is compound Q, an enzymatic intermediate that oxidizes methane. New spectroscopic data have resolved the long-running...
The most powerful oxidant found in nature is compound Q, an enzymatic intermediate that oxidizes methane. New spectroscopic data have resolved the long-running controversy about Q’s chemical structure.
Topics: Iron Compounds; Methane; Methanol; Oxygenases
PubMed: 25607367
DOI: 10.1038/nature14199 -
Metal Ions in Life Sciences 2015Methane monooxygenases (MMOs) catalyze the conversion of methane to methanol as the first committed step in the assimilation of this hydrocarbon into biomass and energy... (Review)
Review
Methane monooxygenases (MMOs) catalyze the conversion of methane to methanol as the first committed step in the assimilation of this hydrocarbon into biomass and energy by methanotrophs, thus playing a significant role in the biogeochemistry of this potent greenhouse gas. Two distinct enzymes, a copper-dependent membrane protein, particulate methane monooxygenase (pMMO), and an iron-dependent cytosolic protein, soluble methane monooxygenase (sMMO), carry out this transformation using large protein scaffolds that help to facilitate the timely transport of hydrocarbon, O₂, proton, and electron substrates to buried dimetallic active sites. For both enzymes, reaction of the reduced metal centers with O₂leads to intermediates that activate the relatively inert C-H bonds of hydrocarbons to yield oxidized products. Among synthetic and biological catalysts, MMOs are unique because they are the only ones known to hydroxylate methane at ambient temperatures. As a need for new industrial catalysts and green chemical transformations increases, understanding how the different MMO metal centers efficiently accomplish this challenging chemistry has become the focus of intense study. This chapter examines current understanding of the sMMO and pMMO protein structures, their methods for substrate channeling, and mechanisms for the dimetallic activation of O₂and C-H bonds.
Topics: Bacteria; Bacterial Proteins; Biological Transport, Active; Catalytic Domain; Cell Membrane; Copper; Iron; Membrane Proteins; Oxygenases
PubMed: 25707469
DOI: 10.1007/978-3-319-12415-5_6 -
International Journal of Molecular... Dec 2020The heme oxygenase (HO) system involves three isoforms of this enzyme, HO-1, HO-2, and HO-3. The three of them display the same catalytic activity, oxidating the heme... (Review)
Review
The heme oxygenase (HO) system involves three isoforms of this enzyme, HO-1, HO-2, and HO-3. The three of them display the same catalytic activity, oxidating the heme group to produce biliverdin, ferrous iron, and carbon monoxide (CO). HO-1 is the isoform most widely studied in proinflammatory diseases because treatments that overexpress this enzyme promote the generation of anti-inflammatory products. However, neonatal jaundice (hyperbilirubinemia) derived from HO overexpression led to the development of inhibitors, such as those based on metaloproto- and meso-porphyrins inhibitors with competitive activity. Further, non-competitive inhibitors have also been identified, such as synthetic and natural imidazole-dioxolane-based, small synthetic molecules, inhibitors of the enzyme regulation pathway, and genetic engineering using iRNA or CRISPR cas9. Despite most of the applications of the HO inhibitors being related to metabolic diseases, the beneficial effects of these molecules in immune-mediated diseases have also emerged. Different medical implications, including cancer, Alzheimer´s disease, and infections, are discussed in this article and as to how the selective inhibition of HO isoforms may contribute to the treatment of these ailments.
Topics: Alzheimer Disease; Animals; Dioxolanes; Enzyme Inhibitors; Heme Oxygenase (Decyclizing); Heme Oxygenase-1; Humans; Imidazoles; Neoplasms
PubMed: 33396647
DOI: 10.3390/ijms22010294 -
Current Opinion in Chemical Biology Apr 2016Non-heme iron-dependent oxygenases catalyse the incorporation of O2 into a wide range of biological molecules and use diverse strategies to activate their substrates.... (Review)
Review
Non-heme iron-dependent oxygenases catalyse the incorporation of O2 into a wide range of biological molecules and use diverse strategies to activate their substrates. Recent kinetic studies, including in crystallo, have provided experimental support for some of the intermediates used by different subclasses of this enzyme family. Plant non-heme iron-dependent oxygenases have diverse and important biological roles, including in growth signalling, stress responses and secondary metabolism. Recently identified roles include in strigolactone biosynthesis, O-demethylation in morphine biosynthesis and regulating the stability of hypoxia-responsive transcription factors. We discuss current structural and mechanistic understanding of plant non-heme iron oxygenases, and how their chemical/genetic manipulation could have agricultural benefit, for example, for improved yield, stress tolerance or herbicide development.
Topics: Catalysis; Heme; Methylation; Oxygenases; Plant Physiological Phenomena
PubMed: 27015291
DOI: 10.1016/j.cbpa.2016.02.017