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Gonzalez L, Chau-Duy Tam Vo S, Faivre B, Pierrel F, Fontecave M, Hamdane D, Lombard M. Activation of Coq6p, a FAD Monooxygenase Involved in Coenzyme Q Biosynthesis, by Adrenodoxin Reductase/Ferredoxin. Chembiochem 2024; 25:e202300738. [PMID: 38141230 DOI: 10.1002/cbic.202300738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/22/2023] [Accepted: 12/23/2023] [Indexed: 12/25/2023]
Abstract
Adrenodoxin reductase (AdxR) plays a pivotal role in electron transfer, shuttling electrons between NADPH and iron/sulfur adrenodoxin proteins in mitochondria. This electron transport system is essential for P450 enzymes involved in various endogenous biomolecules biosynthesis. Here, we present an in-depth examination of the kinetics governing the reduction of human AdxR by NADH or NADPH. Our results highlight the efficiency of human AdxR when utilizing NADPH as a flavin reducing agent. Nevertheless, akin to related flavoenzymes such as cytochrome P450 reductase, we observe that low NADPH concentrations hinder flavin reduction due to intricate equilibrium reactions between the enzyme and its substrate/product. Remarkably, the presence of MgCl2 suppresses this complex kinetic behavior by decreasing NADPH binding to oxidized AdxR, effectively transforming AdxR into a classical Michaelis-Menten enzyme. We propose that the addition of MgCl2 may be adapted for studying the reductive half-reactions of other flavoenzymes with NADPH. Furthermore, in vitro experiments provide evidence that the reduction of the yeast flavin monooxygenase Coq6p relies on an electron transfer chain comprising NADPH-AdxR-Yah1p-Coq6p, where Yah1p shuttles electrons between AdxR and Coq6p. This discovery explains the previous in vivo observation that Yah1p and the AdxR homolog, Arh1p, are required for the biosynthesis of coenzyme Q in yeast.
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Affiliation(s)
- Lucie Gonzalez
- Laboratoire de Chimie des Processus Biologiques, Collège de France, Sorbonne Université, CNRS UMR8229, PSL Research University, Sorbonne Université, 11 place Marcelin Berthelot, 75 005, Paris, France
| | - Samuel Chau-Duy Tam Vo
- Laboratoire de Chimie des Processus Biologiques, Collège de France, Sorbonne Université, CNRS UMR8229, PSL Research University, Sorbonne Université, 11 place Marcelin Berthelot, 75 005, Paris, France
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Bruno Faivre
- Laboratoire de Chimie des Processus Biologiques, Collège de France, Sorbonne Université, CNRS UMR8229, PSL Research University, Sorbonne Université, 11 place Marcelin Berthelot, 75 005, Paris, France
| | - Fabien Pierrel
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000, Grenoble, France
| | - Marc Fontecave
- Laboratoire de Chimie des Processus Biologiques, Collège de France, Sorbonne Université, CNRS UMR8229, PSL Research University, Sorbonne Université, 11 place Marcelin Berthelot, 75 005, Paris, France
| | - Djemel Hamdane
- Laboratoire de Chimie des Processus Biologiques, Collège de France, Sorbonne Université, CNRS UMR8229, PSL Research University, Sorbonne Université, 11 place Marcelin Berthelot, 75 005, Paris, France
- Institut de Biologie Paris-Seine, Biology of Aging and Adaptation, UMR 8256, Sorbonne Université, 7 quai Saint-Bernard, 75 252, Paris, France
| | - Murielle Lombard
- Laboratoire de Chimie des Processus Biologiques, Collège de France, Sorbonne Université, CNRS UMR8229, PSL Research University, Sorbonne Université, 11 place Marcelin Berthelot, 75 005, Paris, France
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Wang S, Jain A, Novales NA, Nashner AN, Tran F, Clarke CF. Predicting and Understanding the Pathology of Single Nucleotide Variants in Human COQ Genes. Antioxidants (Basel) 2022; 11:antiox11122308. [PMID: 36552517 PMCID: PMC9774615 DOI: 10.3390/antiox11122308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/11/2022] [Accepted: 11/14/2022] [Indexed: 11/23/2022] Open
Abstract
Coenzyme Q (CoQ) is a vital lipid that functions as an electron carrier in the mitochondrial electron transport chain and as a membrane-soluble antioxidant. Deficiencies in CoQ lead to metabolic diseases with a wide range of clinical manifestations. There are currently few treatments that can slow or stop disease progression. Primary CoQ10 deficiency can arise from mutations in any of the COQ genes responsible for CoQ biosynthesis. While many mutations in these genes have been identified, the clinical significance of most of them remains unclear. Here we analyzed the structural and functional impact of 429 human missense single nucleotide variants (SNVs) that give rise to amino acid substitutions in the conserved and functional regions of human genes encoding a high molecular weight complex known as the CoQ synthome (or Complex Q), consisting of the COQ3-COQ7 and COQ9 gene products. Using structures of COQ polypeptides, close homologs, and AlphaFold models, we identified 115 SNVs that are potentially pathogenic. Further biochemical characterizations in model organisms such as Saccharomyces cerevisiae are required to validate the pathogenicity of the identified SNVs. Collectively, our results will provide a resource for clinicians during patient diagnosis and guide therapeutic efforts toward combating primary CoQ10 deficiency.
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Manicki M, Aydin H, Abriata LA, Overmyer KA, Guerra RM, Coon JJ, Dal Peraro M, Frost A, Pagliarini DJ. Structure and functionality of a multimeric human COQ7:COQ9 complex. Mol Cell 2022; 82:4307-4323.e10. [PMID: 36306796 PMCID: PMC10058641 DOI: 10.1016/j.molcel.2022.10.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 07/01/2022] [Accepted: 10/04/2022] [Indexed: 11/18/2022]
Abstract
Coenzyme Q (CoQ) is a redox-active lipid essential for core metabolic pathways and antioxidant defense. CoQ is synthesized upon the mitochondrial inner membrane by an ill-defined "complex Q" metabolon. Here, we present structure-function analyses of a lipid-, substrate-, and NADH-bound complex comprising two complex Q subunits: the hydroxylase COQ7 and the lipid-binding protein COQ9. We reveal that COQ7 adopts a ferritin-like fold with a hydrophobic channel whose substrate-binding capacity is enhanced by COQ9. Using molecular dynamics, we further show that two COQ7:COQ9 heterodimers form a curved tetramer that deforms the membrane, potentially opening a pathway for the CoQ intermediates to translocate from the bilayer to the proteins' lipid-binding sites. Two such tetramers assemble into a soluble octamer with a pseudo-bilayer of lipids captured within. Together, these observations indicate that COQ7 and COQ9 cooperate to access hydrophobic precursors within the membrane and coordinate subsequent synthesis steps toward producing CoQ.
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Affiliation(s)
- Mateusz Manicki
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Morgridge Institute for Research, Madison, WI 53715, USA
| | - Halil Aydin
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80309, USA
| | - Luciano A Abriata
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Protein Production and Structure Core Facility, School of Life Sciences, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Katherine A Overmyer
- Morgridge Institute for Research, Madison, WI 53715, USA; National Center for Quantitative Biology of Complex Systems, Madison, WI 53562, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53562, USA
| | - Rachel M Guerra
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Morgridge Institute for Research, Madison, WI 53715, USA
| | - Joshua J Coon
- Morgridge Institute for Research, Madison, WI 53715, USA; National Center for Quantitative Biology of Complex Systems, Madison, WI 53562, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53562, USA; Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53506, USA
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Adam Frost
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA; Chan Zuckerberg Biohub and Altos Labs Bay Area Institute of Science, San Francisco, CA, USA.
| | - David J Pagliarini
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Morgridge Institute for Research, Madison, WI 53715, USA; Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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Self-sacrificial tyrosine cleavage by an Fe:Mn oxygenase for the biosynthesis of para-aminobenzoate in Chlamydia trachomatis. Proc Natl Acad Sci U S A 2022; 119:e2210908119. [PMID: 36122239 PMCID: PMC9522330 DOI: 10.1073/pnas.2210908119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chlamydia protein associating with death domains (CADD) is involved in the biosynthesis of para-aminobenzoate (pABA), an essential component of the folate cofactor that is required for the survival and proliferation of the human pathogen Chlamydia trachomatis. The pathway used by Chlamydiae for pABA synthesis differs from the canonical multi-enzyme pathway used by most bacteria that relies on chorismate as a metabolic precursor. Rather, recent work showed pABA formation by CADD derives from l-tyrosine. As a member of the emerging superfamily of heme oxygenase-like diiron oxidases (HDOs), CADD was proposed to use a diiron cofactor for catalysis. However, we report maximal pABA formation by CADD occurs upon the addition of both iron and manganese, which implicates a heterobimetallic Fe:Mn cluster is the catalytically active form. Isotopic labeling experiments and proteomics studies show that CADD generates pABA from a protein-derived tyrosine (Tyr27), a residue that is ∼14 Å from the dimetal site. We propose that this self-sacrificial reaction occurs through O2 activation by a probable Fe:Mn cluster through a radical relay mechanism that connects to the "substrate" Tyr, followed by amination and direct oxygen insertion. These results provide the molecular basis for pABA formation in C. trachomatis, which will inform the design of novel therapeutics.
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Wang Y, Hekimi S. The CoQ biosynthetic di-iron carboxylate hydroxylase COQ7 is inhibited by in vivo metalation with manganese but remains functional by metalation with cobalt. MICROPUBLICATION BIOLOGY 2022; 2022:10.17912/micropub.biology.000635. [PMID: 36176269 PMCID: PMC9513594 DOI: 10.17912/micropub.biology.000635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/30/2022] [Accepted: 09/12/2022] [Indexed: 11/28/2022]
Abstract
Coenzyme Q (CoQ; ubiquinone) is an obligate component of the mitochondrial electron transport chain. COQ7 is a mitochondrial hydroxylase that is required for CoQ biosynthesis. COQ7 belongs to di-iron carboxylate enzymes, a rare type of enzyme that carries out a wide range of reactions. We found that manganese exposure of mouse cells leads to decreased COQ7 activity, but that pre-treatment with cobalt interferes with the inhibition by manganese. Our findings suggest that cobalt has greater affinity for the active site of COQ7 than both iron and manganese and that replacement of iron by cobalt at the active site preserves catalytic activity.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec, Canada
,
Correspondence to: Siegfried Hekimi (
)
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Latimer S, Keene SA, Stutts LR, Berger A, Bernert AC, Soubeyrand E, Wright J, Clarke CF, Block AK, Colquhoun TA, Elowsky C, Christensen A, Wilson MA, Basset GJ. A dedicated flavin-dependent monooxygenase catalyzes the hydroxylation of demethoxyubiquinone into ubiquinone (coenzyme Q) in Arabidopsis. J Biol Chem 2021; 297:101283. [PMID: 34626646 PMCID: PMC8559556 DOI: 10.1016/j.jbc.2021.101283] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/30/2021] [Accepted: 10/04/2021] [Indexed: 01/08/2023] Open
Abstract
Ubiquinone (Coenzyme Q) is a vital respiratory cofactor and liposoluble antioxidant. In plants, it is not known how the C-6 hydroxylation of demethoxyubiquinone, the penultimate step in ubiquinone biosynthesis, is catalyzed. The combination of cross-species gene network modeling along with mining of embryo-defective mutant databases of Arabidopsis thaliana identified the embryo lethal locus EMB2421 (At1g24340) as a top candidate for the missing plant demethoxyubiquinone hydroxylase. In marked contrast with prototypical eukaryotic demethoxyubiquinone hydroxylases, the catalytic mechanism of which depends on a carboxylate-bridged di-iron domain, At1g24340 is homologous to FAD-dependent oxidoreductases that instead use NAD(P)H as an electron donor. Complementation assays in Saccharomyces cerevisiae and Escherichia coli demonstrated that At1g24340 encodes a functional demethoxyubiquinone hydroxylase and that the enzyme displays strict specificity for the C-6 position of the benzoquinone ring. Laser-scanning confocal microscopy also showed that GFP-tagged At1g24340 is targeted to mitochondria. Silencing of At1g24340 resulted in 40 to 74% decrease in ubiquinone content and de novo ubiquinone biosynthesis. Consistent with the role of At1g24340 as a benzenoid ring modification enzyme, this metabolic blockage could not be bypassed by supplementation with 4-hydroxybenzoate, the immediate precursor of ubiquinone's ring. Unlike in yeast, in Arabidopsis overexpression of demethoxyubiquinone hydroxylase did not boost ubiquinone content. Phylogenetic reconstructions indicated that plant demethoxyubiquinone hydroxylase is most closely related to prokaryotic monooxygenases that act on halogenated aromatics and likely descends from an event of horizontal gene transfer between a green alga and a bacterium.
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Affiliation(s)
- Scott Latimer
- Department of Horticultural Sciences, University of Florida, Gainesville, Florida, USA.
| | - Shea A Keene
- Department of Environmental Horticulture, Plant Innovation Center, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, USA
| | - Lauren R Stutts
- Department of Horticultural Sciences, University of Florida, Gainesville, Florida, USA
| | - Antoine Berger
- Department of Horticultural Sciences, University of Florida, Gainesville, Florida, USA
| | - Ann C Bernert
- Department of Horticultural Sciences, University of Florida, Gainesville, Florida, USA
| | - Eric Soubeyrand
- Department of Horticultural Sciences, University of Florida, Gainesville, Florida, USA
| | - Janet Wright
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Catherine F Clarke
- Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California, Los Angeles, California, USA
| | - Anna K Block
- Center for Medical, Agricultural and Veterinary Entomology, Chemistry Research Unit, ARS, USDA, Gainesville, Florida, USA
| | - Thomas A Colquhoun
- Department of Environmental Horticulture, Plant Innovation Center, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida, USA
| | - Christian Elowsky
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Alan Christensen
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Mark A Wilson
- Department of Biochemistry and Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Gilles J Basset
- Department of Horticultural Sciences, University of Florida, Gainesville, Florida, USA.
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7
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Chen GE, Adams NBP, Jackson PJ, Dickman MJ, Hunter CN. How the O 2-dependent Mg-protoporphyrin monomethyl ester cyclase forms the fifth ring of chlorophylls. NATURE PLANTS 2021; 7:365-375. [PMID: 33731920 PMCID: PMC7610348 DOI: 10.1038/s41477-021-00876-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 02/08/2021] [Indexed: 05/19/2023]
Abstract
Mg-protoporphyrin IX monomethyl ester (MgPME) cyclase catalyses the formation of the isocyclic ring, producing protochlorophyllide a and contributing substantially to the absorption properties of chlorophylls and bacteriochlorophylls. The O2-dependent cyclase is found in both oxygenic phototrophs and some purple bacteria. We overproduced the simplest form of the cyclase, AcsF, from Rubrivivax gelatinosus, in Escherichia coli. In biochemical assays the di-iron cluster within AcsF is reduced by ferredoxin furnished by NADPH and ferredoxin:NADP+ reductase, or by direct coupling to Photosystem I photochemistry, linking cyclase to the photosynthetic electron transport chain. Kinetic analyses yielded a turnover number of 0.9 min-1, a Michaelis-Menten constant of 7.0 µM for MgPME and a dissociation constant for MgPME of 0.16 µM. Mass spectrometry identified 131-hydroxy-MgPME and 131-keto-MgPME as cyclase reaction intermediates, revealing the steps that form the isocyclic ring and completing the work originated by Sam Granick in 1950.
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Affiliation(s)
- Guangyu E Chen
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK.
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
| | - Nathan B P Adams
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
| | - Philip J Jackson
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
| | - Mark J Dickman
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
| | - C Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK.
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Tsuganezawa K, Sekimata K, Nakagawa Y, Utata R, Nakamura K, Ogawa N, Koyama H, Shirouzu M, Fukami T, Kita K, Tanaka A. Identification of small molecule inhibitors of human COQ7. Bioorg Med Chem 2019; 28:115182. [PMID: 31753803 DOI: 10.1016/j.bmc.2019.115182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 12/29/2022]
Abstract
Given that the associated clinical manifestations of ubiquinone (UQ, or coenzyme Q) deficiency diseases are highly heterogeneous and complicated, effective new research tools for UQ homeostasis studies are awaited. We set out to develop human COQ7 inhibitors that interfere with UQ synthesis. Systematic structure-activity relationship development starting from a screening hit compound led to the identification of highly potent COQ7 inhibitors that did not disturb physiological cell growth of human normal culture cells. These new COQ7 inhibitors may serve as useful tools for studying the balance between UQ supplementation pathways: de novo UQ synthesis and extracellular UQ uptake.
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Affiliation(s)
- Keiko Tsuganezawa
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan; RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Katsuhiko Sekimata
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yukari Nakagawa
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan; RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Rei Utata
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Kana Nakamura
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan; RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Naoko Ogawa
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan; RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Hiroo Koyama
- RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Mikako Shirouzu
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan; RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Takehiro Fukami
- RIKEN Program for Drug Discovery and Medical Technology Platforms, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Kiyoshi Kita
- School of Tropical Medicine and Global Health, Nagasaki University, 1-12-4, Sakamoto, Nagasaki 852-8523, Japan
| | - Akiko Tanaka
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan; RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan.
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9
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Ubiquinone Biosynthesis over the Entire O 2 Range: Characterization of a Conserved O 2-Independent Pathway. mBio 2019; 10:mBio.01319-19. [PMID: 31289180 PMCID: PMC6747719 DOI: 10.1128/mbio.01319-19] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In order to colonize environments with large O2 gradients or fluctuating O2 levels, bacteria have developed metabolic responses that remain incompletely understood. Such adaptations have been recently linked to antibiotic resistance, virulence, and the capacity to develop in complex ecosystems like the microbiota. Here, we identify a novel pathway for the biosynthesis of ubiquinone, a molecule with a key role in cellular bioenergetics. We link three uncharacterized genes of Escherichia coli to this pathway and show that the pathway functions independently from O2. In contrast, the long-described pathway for ubiquinone biosynthesis requires O2 as a substrate. In fact, we find that many proteobacteria are equipped with the O2-dependent and O2-independent pathways, supporting that they are able to synthesize ubiquinone over the entire O2 range. Overall, we propose that the novel O2-independent pathway is part of the metabolic plasticity developed by proteobacteria to face various environmental O2 levels. Most bacteria can generate ATP by respiratory metabolism, in which electrons are shuttled from reduced substrates to terminal electron acceptors, via quinone molecules like ubiquinone. Dioxygen (O2) is the terminal electron acceptor of aerobic respiration and serves as a co-substrate in the biosynthesis of ubiquinone. Here, we characterize a novel, O2-independent pathway for the biosynthesis of ubiquinone. This pathway relies on three proteins, UbiT (YhbT), UbiU (YhbU), and UbiV (YhbV). UbiT contains an SCP2 lipid-binding domain and is likely an accessory factor of the biosynthetic pathway, while UbiU and UbiV (UbiU-UbiV) are involved in hydroxylation reactions and represent a novel class of O2-independent hydroxylases. We demonstrate that UbiU-UbiV form a heterodimer, wherein each protein binds a 4Fe-4S cluster via conserved cysteines that are essential for activity. The UbiT, -U, and -V proteins are found in alpha-, beta-, and gammaproteobacterial clades, including several human pathogens, supporting the widespread distribution of a previously unrecognized capacity to synthesize ubiquinone in the absence of O2. Together, the O2-dependent and O2-independent ubiquinone biosynthesis pathways contribute to optimizing bacterial metabolism over the entire O2 range.
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10
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An Isoprene Lipid-Binding Protein Promotes Eukaryotic Coenzyme Q Biosynthesis. Mol Cell 2019; 73:763-774.e10. [PMID: 30661980 DOI: 10.1016/j.molcel.2018.11.033] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 10/16/2018] [Accepted: 11/27/2018] [Indexed: 02/06/2023]
Abstract
The biosynthesis of coenzyme Q presents a paradigm for how cells surmount hydrophobic barriers in lipid biology. In eukaryotes, CoQ precursors-among nature's most hydrophobic molecules-must somehow be presented to a series of enzymes peripherally associated with the mitochondrial inner membrane. Here, we reveal that this process relies on custom lipid-binding properties of COQ9. We show that COQ9 repurposes the bacterial TetR fold to bind aromatic isoprenes with high specificity, including CoQ intermediates that likely reside entirely within the bilayer. We reveal a process by which COQ9 associates with cardiolipin-rich membranes and warps the membrane surface to access this cargo. Finally, we identify a molecular interface between COQ9 and the hydroxylase COQ7, motivating a model whereby COQ9 presents intermediates directly to CoQ enzymes. Overall, our results provide a mechanism for how a lipid-binding protein might access, select, and deliver specific cargo from a membrane to promote biosynthesis.
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11
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Stefely JA, Pagliarini DJ. Biochemistry of Mitochondrial Coenzyme Q Biosynthesis. Trends Biochem Sci 2017; 42:824-843. [PMID: 28927698 DOI: 10.1016/j.tibs.2017.06.008] [Citation(s) in RCA: 194] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 06/14/2017] [Accepted: 06/22/2017] [Indexed: 11/16/2022]
Abstract
Coenzyme Q (CoQ, ubiquinone) is a redox-active lipid produced across all domains of life that functions in electron transport and oxidative phosphorylation and whose deficiency causes human diseases. Yet, CoQ biosynthesis has not been fully defined in any organism. Several proteins with unclear molecular functions facilitate CoQ biosynthesis through unknown means, and multiple steps in the pathway are catalyzed by currently unidentified enzymes. Here we highlight recent progress toward filling these knowledge gaps through both traditional biochemistry and cutting-edge 'omics' approaches. To help fill the remaining gaps, we present questions framed by the recently discovered CoQ biosynthetic complex and by putative biophysical barriers. Mapping CoQ biosynthesis, metabolism, and transport pathways has great potential to enhance treatment of numerous human diseases.
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Affiliation(s)
- Jonathan A Stefely
- Morgridge Institute for Research, Madison, WI, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA; School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - David J Pagliarini
- Morgridge Institute for Research, Madison, WI, USA; Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA.
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12
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CLD1 Reverses the Ubiquinone Insufficiency of Mutant cat5/coq7 in a Saccharomyces cerevisiae Model System. PLoS One 2016; 11:e0162165. [PMID: 27603010 PMCID: PMC5014327 DOI: 10.1371/journal.pone.0162165] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/16/2016] [Indexed: 11/23/2022] Open
Abstract
Ubiquinone (Qn) functions as a mobile electron carrier in mitochondria. In humans, Q biosynthetic pathway mutations lead to Q10 deficiency, a life threatening disorder. We have used a Saccharomyces cerevisiae model of Q6 deficiency to screen for new modulators of ubiquinone biosynthesis. We generated several hypomorphic alleles of coq7/cat5 (clk-1 in Caenorhabditis elegans) encoding the penultimate enzyme in Q biosynthesis which converts 5-demethoxy Q6 (DMQ6) to 5-demethyl Q6, and screened for genes that, when overexpressed, suppressed their inability to grow on non-fermentable ethanol—implying recovery of lost mitochondrial function. Through this approach we identified Cardiolipin-specific Deacylase 1 (CLD1), a gene encoding a phospholipase A2 required for cardiolipin acyl remodeling. Interestingly, not all coq7 mutants were suppressed by Cld1p overexpression, and molecular modeling of the mutant Coq7p proteins that were suppressed showed they all contained disruptions in a hydrophobic α-helix that is predicted to mediate membrane-binding. CLD1 overexpression in the suppressible coq7 mutants restored the ratio of DMQ6 to Q6 toward wild type levels, suggesting recovery of lost Coq7p function. Identification of a spontaneous Cld1p loss-of-function mutation illustrated that Cld1p activity was required for coq7 suppression. This observation was further supported by HPLC-ESI-MS/MS profiling of monolysocardiolipin, the product of Cld1p. In summary, our results present a novel example of a lipid remodeling enzyme reversing a mitochondrial ubiquinone insufficiency by facilitating recovery of hypomorphic enzymatic function.
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Evolution of Ubiquinone Biosynthesis: Multiple Proteobacterial Enzymes with Various Regioselectivities To Catalyze Three Contiguous Aromatic Hydroxylation Reactions. mSystems 2016; 1:mSystems00091-16. [PMID: 27822549 PMCID: PMC5069965 DOI: 10.1128/msystems.00091-16] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 08/05/2016] [Indexed: 11/27/2022] Open
Abstract
UQ, a key molecule for cellular bioenergetics that is conserved from proteobacteria to humans, appeared in an ancestral proteobacterium more than 2 billion years ago. UQ biosynthesis has been studied only in a few model organisms, and thus, the diversity of UQ biosynthesis pathways is largely unknown. In the work reported here, we conducted a phylogenomic analysis of hydroxylases involved in UQ biosynthesis. Our results support the existence of at least two UQ hydroxylases in the proteobacterial ancestor, and yet, we show that their number varies from one to four in extant proteobacterial species. Our biochemical experiments demonstrated that bacteria containing only one or two UQ hydroxylases have developed generalist enzymes that are able to catalyze several steps of UQ biosynthesis. Our study documents a rare case where evolution favored the broadening of an enzyme’s regioselectivity, which resulted in gene loss in several proteobacterial species with small genomes. The ubiquitous ATP synthase uses an electrochemical gradient to synthesize cellular energy in the form of ATP. The production of this electrochemical gradient relies on liposoluble proton carriers like ubiquinone (UQ), which is used in the respiratory chains of eukaryotes and proteobacteria. The biosynthesis of UQ requires three hydroxylation reactions on contiguous positions of an aromatic ring. In Escherichia coli, each of three UQ flavin monooxygenases (FMOs), called UbiF, UbiH, and UbiI, modifies a single position of the aromatic ring. This pattern of three hydroxylation reactions/three proteins has been accepted as a paradigm in UQ biology. Using a phylogenetic analysis, we found that UbiF, UbiH, and UbiI are detected only in a small fraction of proteobacteria, and we identified two new types of UQ FMOs: UbiM, which is distributed in members of the alpha, beta, and gamma classes of proteobacteria, and UbiL, which is restricted to members of the alphaproteobacteria. Remarkably, the ubiL and ubiM genes were found in genomes with fewer than three UQ hydroxylase-encoding genes. We demonstrated, using biochemical approaches, that UbiL from Rhodospirillum rubrum and UbiM from Neisseria meningitidis hydroxylate, respectively, two and three positions of the aromatic ring during UQ biosynthesis. We conclude that bacteria have evolved a large repertoire of hydroxylase combinations for UQ biosynthesis, including pathways with either three specialist enzymes or pathways with one or two generalist enzymes of broader regioselectivity. The emergence of the latter is potentially related to genome reduction events. IMPORTANCE UQ, a key molecule for cellular bioenergetics that is conserved from proteobacteria to humans, appeared in an ancestral proteobacterium more than 2 billion years ago. UQ biosynthesis has been studied only in a few model organisms, and thus, the diversity of UQ biosynthesis pathways is largely unknown. In the work reported here, we conducted a phylogenomic analysis of hydroxylases involved in UQ biosynthesis. Our results support the existence of at least two UQ hydroxylases in the proteobacterial ancestor, and yet, we show that their number varies from one to four in extant proteobacterial species. Our biochemical experiments demonstrated that bacteria containing only one or two UQ hydroxylases have developed generalist enzymes that are able to catalyze several steps of UQ biosynthesis. Our study documents a rare case where evolution favored the broadening of an enzyme’s regioselectivity, which resulted in gene loss in several proteobacterial species with small genomes.
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Ozeir M, Pelosi L, Ismail A, Mellot-Draznieks C, Fontecave M, Pierrel F. Coq6 is responsible for the C4-deamination reaction in coenzyme Q biosynthesis in Saccharomyces cerevisiae. J Biol Chem 2015; 290:24140-51. [PMID: 26260787 DOI: 10.1074/jbc.m115.675744] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Indexed: 11/06/2022] Open
Abstract
The yeast Saccharomyces cerevisiae is able to use para-aminobenzoic acid (pABA) in addition to 4-hydroxybenzoic acid as a precursor of coenzyme Q, a redox lipid essential to the function of the mitochondrial respiratory chain. The biosynthesis of coenzyme Q from pABA requires a deamination reaction at position C4 of the benzene ring to substitute the amino group with an hydroxyl group. We show here that the FAD-dependent monooxygenase Coq6, which is known to hydroxylate position C5, also deaminates position C4 in a reaction implicating molecular oxygen, as demonstrated with labeling experiments. We identify mutations in Coq6 that abrogate the C4-deamination activity, whereas preserving the C5-hydroxylation activity. Several results support that the deletion of Coq9 impacts Coq6, thus explaining the C4-deamination defect observed in Δcoq9 cells. The vast majority of flavin monooxygenases catalyze hydroxylation reactions on a single position of their substrate. Coq6 is thus a rare example of a flavin monooxygenase that is able to act on two different carbon atoms of its C4-aminated substrate, allowing its deamination and ultimately its conversion into coenzyme Q by the other proteins constituting the coenzyme Q biosynthetic pathway.
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Affiliation(s)
- Mohammad Ozeir
- From the University of Grenoble Alpes, LCBM, UMR5249, F-38000 Grenoble, France
| | - Ludovic Pelosi
- the University of Grenoble Alpes, LAPM, F-38000 Grenoble, France, the CNRS, LAPM, F-38000 Grenoble, France
| | - Alexandre Ismail
- the Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, UPMC, Collège de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France, and the Sup'Biotech, IONIS Education Group, 66 rue Guy-Moquet, F-94800 Villejuif, France
| | - Caroline Mellot-Draznieks
- the Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, UPMC, Collège de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France, and
| | - Marc Fontecave
- the Laboratoire de Chimie des Processus Biologiques, UMR 8229 CNRS, UPMC, Collège de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France, and
| | - Fabien Pierrel
- the University of Grenoble Alpes, LAPM, F-38000 Grenoble, France, the CNRS, LAPM, F-38000 Grenoble, France,
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15
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Freyer C, Stranneheim H, Naess K, Mourier A, Felser A, Maffezzini C, Lesko N, Bruhn H, Engvall M, Wibom R, Barbaro M, Hinze Y, Magnusson M, Andeer R, Zetterström RH, von Döbeln U, Wredenberg A, Wedell A. Rescue of primary ubiquinone deficiency due to a novel COQ7 defect using 2,4-dihydroxybensoic acid. J Med Genet 2015; 52:779-83. [PMID: 26084283 PMCID: PMC4680133 DOI: 10.1136/jmedgenet-2015-102986] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/26/2015] [Indexed: 11/24/2022]
Abstract
Background Coenzyme Q is an essential mitochondrial electron carrier, redox cofactor and a potent antioxidant in the majority of cellular membranes. Coenzyme Q deficiency has been associated with a range of metabolic diseases, as well as with some drug treatments and ageing. Methods We used whole exome sequencing (WES) to investigate patients with inherited metabolic diseases and applied a novel ultra-pressure liquid chromatography—mass spectrometry approach to measure coenzyme Q in patient samples. Results We identified a homozygous missense mutation in the COQ7 gene in a patient with complex mitochondrial deficiency, resulting in severely reduced coenzyme Q levels We demonstrate that the coenzyme Q analogue 2,4-dihydroxybensoic acid (2,4DHB) was able to specifically bypass the COQ7 deficiency, increase cellular coenzyme Q levels and rescue the biochemical defect in patient fibroblasts. Conclusion We report the first patient with primary coenzyme Q deficiency due to a homozygous COQ7 mutation and a potentially beneficial treatment using 2,4DHB.
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Affiliation(s)
- Christoph Freyer
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Henrik Stranneheim
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Karin Naess
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Arnaud Mourier
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Andrea Felser
- Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Camilla Maffezzini
- Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Nicole Lesko
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Helene Bruhn
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Martin Engvall
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Rolf Wibom
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Michela Barbaro
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Yvonne Hinze
- Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Måns Magnusson
- Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Robin Andeer
- Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
| | - Rolf H Zetterström
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Ulrika von Döbeln
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Anna Wredenberg
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Anna Wedell
- Centre for Inherited Metabolic Diseases, Karolinska University Hospital, Stockholm, Sweden Max Planck Institute Biology of Ageing - Karolinska Institutet Laboratory, Division of Metabolic Diseases, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden Department of Molecular Medicine and Surgery, Science for Life Laboratory, Karolinska Institutet, Stockholm, Sweden
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Yeast Coq9 controls deamination of coenzyme Q intermediates that derive from para-aminobenzoic acid. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:1227-39. [PMID: 26008578 DOI: 10.1016/j.bbalip.2015.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 03/20/2015] [Accepted: 05/14/2015] [Indexed: 11/20/2022]
Abstract
Coq9 is a polypeptide subunit in a mitochondrial multi-subunit complex, termed the CoQ-synthome, required for biosynthesis of coenzyme Q (ubiquinone or Q). Deletion of COQ9 results in dissociation of the CoQ-synthome, but over-expression of Coq8 putative kinase stabilizes the CoQ-synthome in the coq9 null mutant and leads to the accumulation of two nitrogen-containing Q intermediates, imino-demethoxy-Q6 (IDMQ6) and 3-hexaprenyl-4-aminophenol (4-AP) when para-aminobenzoic acid (pABA) is provided as a ring precursor. To investigate whether Coq9 is responsible for deamination steps in Q biosynthesis, we utilized the yeast coq5-5 point mutant. The yeast coq5-5 point mutant is defective in the C-methyltransferase step of Q biosynthesis but retains normal steady-state levels of the Coq5 polypeptide. Here, we show that when high amounts of 13C6-pABA are provided, the coq5-5 mutant accumulates both 13C6-imino-demethyl-demethoxy-Q6 (13C6-IDDMQ6) and 13C6-demethyl-demethoxy-Q6 (13C6-DDMQ6). Deletion of COQ9 in the yeast coq5-5 mutant along with Coq8 over-expression and 13C6- pABA labeling leads to the absence of 13C6-DDMQ6, and the nitrogen-containing intermediates 13C6-4-AP and 13C6-IDDMQ6 persist. We describe a coq9 temperature-sensitive mutant and show that at the non-permissive temperature, steady-state polypeptide levels of Coq9-ts19 increased, while Coq4, Coq5, Coq6, and Coq7 decreased. The coq9-ts19 mutant had decreased Q6 content and increased levels of nitrogen-containing intermediates. These findings identify Coq9 as a multi-functional protein that is required for the function of Coq6 and Coq7 hydroxylases, for removal of the nitrogen substituent from pABA-derived Q intermediates, and is an essential component of the CoQ synthome.
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Mitochondrial COQ9 is a lipid-binding protein that associates with COQ7 to enable coenzyme Q biosynthesis. Proc Natl Acad Sci U S A 2014; 111:E4697-705. [PMID: 25339443 DOI: 10.1073/pnas.1413128111] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Coenzyme Q (CoQ) is an isoprenylated quinone that is essential for cellular respiration and is synthesized in mitochondria by the combined action of at least nine proteins (COQ1-9). Although most COQ proteins are known to catalyze modifications to CoQ precursors, the biochemical role of COQ9 remains unclear. Here, we report that a disease-related COQ9 mutation leads to extensive disruption of the CoQ protein biosynthetic complex in a mouse model, and that COQ9 specifically interacts with COQ7 through a series of conserved residues. Toward understanding how COQ9 can perform these functions, we solved the crystal structure of Homo sapiens COQ9 at 2.4 Å. Unexpectedly, our structure reveals that COQ9 has structural homology to the TFR family of bacterial transcriptional regulators, but that it adopts an atypical TFR dimer orientation and is not predicted to bind DNA. Our structure also reveals a lipid-binding site, and mass spectrometry-based analyses of purified COQ9 demonstrate that it associates with multiple lipid species, including CoQ itself. The conserved COQ9 residues necessary for its interaction with COQ7 comprise a surface patch around the lipid-binding site, suggesting that COQ9 might serve to present its bound lipid to COQ7. Collectively, our data define COQ9 as the first, to our knowledge, mammalian TFR structural homolog and suggest that its lipid-binding capacity and association with COQ7 are key features for enabling CoQ biosynthesis.
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18
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Acheson JF, Bailey LJ, Elsen NL, Fox BG. Structural basis for biomolecular recognition in overlapping binding sites in a diiron enzyme system. Nat Commun 2014; 5:5009. [PMID: 25248368 PMCID: PMC4200526 DOI: 10.1038/ncomms6009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 08/18/2014] [Indexed: 12/23/2022] Open
Abstract
Productive biomolecular recognition requires exquisite control of affinity and specificity. Accordingly, nature has devised many strategies to achieve proper binding interactions. Bacterial multicomponent monooxygenases provide a fascinating example, where a diiron hydroxylase must reversibly interact with both ferredoxin and catalytic effector in order to achieve electron transfer and O2 activation during catalysis. Because these two accessory proteins have distinct structures, and because the hydroxylase-effector complex covers the entire surface closest to the hydroxylase diiron centre, how ferredoxin binds to the hydroxylase has been unclear. Here we present high-resolution structures of toluene 4-monooxygenase hydroxylase complexed with its electron transfer ferredoxin and compare them with the hydroxylase-effector structure. These structures reveal that ferredoxin or effector protein binding produce different arrangements of conserved residues and customized interfaces on the hydroxylase in order to achieve different aspects of catalysis.
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Affiliation(s)
- Justin F Acheson
- Department of Biochemistry, University of Wisconsin, Biochemistry Addition, 433 Babcock Drive, Madison, Wisconsin 53706, USA
| | - Lucas J Bailey
- Department of Biochemistry, University of Wisconsin, Biochemistry Addition, 433 Babcock Drive, Madison, Wisconsin 53706, USA
| | - Nathaniel L Elsen
- Department of Biochemistry, University of Wisconsin, Biochemistry Addition, 433 Babcock Drive, Madison, Wisconsin 53706, USA
| | - Brian G Fox
- Department of Biochemistry, University of Wisconsin, Biochemistry Addition, 433 Babcock Drive, Madison, Wisconsin 53706, USA
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19
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Wang W, Iacob RE, Luoh RP, Engen JR, Lippard SJ. Electron transfer control in soluble methane monooxygenase. J Am Chem Soc 2014; 136:9754-62. [PMID: 24937475 PMCID: PMC4105053 DOI: 10.1021/ja504688z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
![]()
The
hydroxylation or epoxidation of hydrocarbons by bacterial multicomponent
monooxygenases (BMMs) requires the interplay of three or four protein
components. How component protein interactions control catalysis,
however, is not well understood. In particular, the binding sites
of the reductase components on the surface of their cognate hydroxylases
and the role(s) that the regulatory proteins play during intermolecular
electron transfer leading to the hydroxylase reduction have been enigmatic.
Here we determine the reductase binding site on the hydroxylase of
a BMM enzyme, soluble methane monooxygenase (sMMO) from Methylococcus
capsulatus (Bath). We present evidence that the ferredoxin
domain of the reductase binds to the canyon region of the hydroxylase,
previously determined to be the regulatory protein binding site as
well. The latter thus inhibits reductase binding to the hydroxylase
and, consequently, intermolecular electron transfer from the reductase
to the hydroxylase diiron active site. The binding competition between
the regulatory protein and the reductase may serve as a control mechanism
for regulating electron transfer, and other BMM enzymes are likely
to adopt the same mechanism.
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Affiliation(s)
- Weixue Wang
- Departments of †Chemistry and §Biological Engineering, Massachusetts Institute of Technology , Cambridge, Massachusetts 02139, United States
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20
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Lu TT, Lee SJ, Apfel UP, Lippard SJ. Aging-associated enzyme human clock-1: substrate-mediated reduction of the diiron center for 5-demethoxyubiquinone hydroxylation. Biochemistry 2013; 52:2236-44. [PMID: 23445365 DOI: 10.1021/bi301674p] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The mitochondrial membrane-bound enzyme Clock-1 (CLK-1) extends the average longevity of mice and Caenorhabditis elegans, as demonstrated for Δclk-1 constructs for both organisms. Such an apparent impact on aging and the presence of a carboxylate-bridged diiron center in the enzyme inspired this work. We expressed a soluble human CLK-1 (hCLK-1) fusion protein with an N-terminal immunoglobulin binding domain of protein G (GB1). Inclusion of the solubility tag allowed for thorough characterization of the carboxylate-bridged diiron active site of the resulting GB1-hCLK-1 by spectroscopic and kinetic methods. Both UV-visible and Mössbauer experiments provide unambiguous evidence that GB1-hCLK-1 functions as a 5-demethoxyubiquinone-hydroxylase, utilizing its carboxylate-bridged diiron center. The binding of DMQn (n = 0 or 2) to GB1-hCLK-1 mediates reduction of the diiron center by nicotinamide adenine dinucleotide (NADH) and initiates O2 activation for subsequent DMQ hydroxylation. Deployment of DMQ to mediate reduction of the diiron center in GB1-hCLK-1 improves substrate specificity and diminishes consumption of NADH that is uncoupled from substrate oxidation. Both Vmax and kcat/KM for DMQ hydroxylation increase when DMQ0 is replaced by DMQ2 as the substrate, which demonstrates that an isoprenoid side chain enhances enzymatic hydroxylation and improves catalytic efficiency.
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Affiliation(s)
- Tsai-Te Lu
- Department of Chemistry, Massachusetts Institute of Technology , Cambridge, MA 02139, USA
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21
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Moore AL, Shiba T, Young L, Harada S, Kita K, Ito K. Unraveling the heater: new insights into the structure of the alternative oxidase. ANNUAL REVIEW OF PLANT BIOLOGY 2013; 64:637-63. [PMID: 23638828 DOI: 10.1146/annurev-arplant-042811-105432] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The alternative oxidase is a membrane-bound ubiquinol oxidase found in the majority of plants as well as many fungi and protists, including pathogenic organisms such as Trypanosoma brucei. It catalyzes a cyanide- and antimycin-A-resistant oxidation of ubiquinol and the reduction of oxygen to water, short-circuiting the mitochondrial electron-transport chain prior to proton translocation by complexes III and IV, thereby dramatically reducing ATP formation. In plants, it plays a key role in cellular metabolism, thermogenesis, and energy homeostasis and is generally considered to be a major stress-induced protein. We describe recent advances in our understanding of this protein's structure following the recent successful crystallization of the alternative oxidase from T. brucei. We focus on the nature of the active site and ubiquinol-binding channels and propose a mechanism for the reduction of oxygen to water based on these structural insights. We also consider the regulation of activity at the posttranslational and retrograde levels and highlight challenges for future research.
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Affiliation(s)
- Anthony L Moore
- Biochemistry and Molecular Biology, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom.
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22
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Abstract
Ubiquinone (UQ), also known as coenzyme Q (CoQ), is a redox-active lipid present in all cellular membranes where it functions in a variety of cellular processes. The best known functions of UQ are to act as a mobile electron carrier in the mitochondrial respiratory chain and to serve as a lipid soluble antioxidant in cellular membranes. All eukaryotic cells synthesize their own UQ. Most of the current knowledge on the UQ biosynthetic pathway was obtained by studying Escherichia coli and Saccharomyces cerevisiae UQ-deficient mutants. The orthologues of all the genes known from yeast studies to be involved in UQ biosynthesis have subsequently been found in higher organisms. Animal mutants with different genetic defects in UQ biosynthesis display very different phenotypes, despite the fact that in all these mutants the same biosynthetic pathway is affected. This review summarizes the present knowledge of the eukaryotic biosynthesis of UQ, with focus on the biosynthetic genes identified in animals, including Caenorhabditis elegans, rodents, and humans. Moreover, we review the phenotypes of mutants in these genes and discuss the functional consequences of UQ deficiency in general.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montréal, Quebec, Canada
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23
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Gomez F, Saiki R, Chin R, Srinivasan C, Clarke CF. Restoring de novo coenzyme Q biosynthesis in Caenorhabditis elegans coq-3 mutants yields profound rescue compared to exogenous coenzyme Q supplementation. Gene 2012; 506:106-16. [PMID: 22735617 DOI: 10.1016/j.gene.2012.06.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 05/16/2012] [Accepted: 06/15/2012] [Indexed: 12/24/2022]
Abstract
Coenzyme Q (ubiquinone or Q) is an essential lipid component of the mitochondrial electron transport chain. In Caenorhabditis elegans Q biosynthesis involves at least nine steps, including the hydroxylation of the hydroquinone ring by CLK-1 and two O-methylation steps mediated by COQ-3. We characterize two C. elegans coq-3 deletion mutants, and show that while each has defects in Q synthesis, their phenotypes are distinct. First generation homozygous coq-3(ok506) mutants are fertile when fed the standard lab diet of Q-replete OP50 Escherichia coli, but their second generation homozygous progeny does not reproduce. In contrast, the coq-3(qm188) deletion mutant remains sterile when fed Q-replete OP50. Quantitative PCR analyses suggest that the longer qm188 deletion may alter expression of the flanking nuo-3 and gdi-1 genes, located 5' and 3', respectively of coq-3 within an operon. We surmise that variable expression of nuo-3, a subunit of complex I, or of gdi-1, a guanine nucleotide dissociation inhibitor, may act in combination with defects in Q biosynthesis to produce a more severe phenotype. The phenotypes of both coq-3 mutants are more drastic as compared to the C. elegans clk-1 mutants. When fed OP50, clk-1 mutants reproduce for many generations, but show reduced fertility, slow behaviors, and enhanced life span. The coq-3 and clk-1 mutants all show arrested development and are sterile when fed the Q-deficient E. coli strain GD1 (harboring a mutation in the ubiG gene). However, unlike clk-1 mutant worms, neither coq-3 mutant strain responded to dietary supplementation with purified exogenous Q(10). Here we show that the Q(9) content can be determined in lipid extracts from just 200 individual worms, enabling the determination of Q content in the coq-3 mutants unable to reproduce. An extra-chromosomal array expressing wild-type C. elegans coq-3 rescued fertility of both coq-3 mutants and partially restored steady-state levels of COQ-3 polypeptide and Q(9) content, indicating that primary defect in both is limited to coq-3. The limited response of the coq-3 mutants to dietary supplementation with Q provides a powerful model to probe the effectiveness of exogenous Q supplementation as compared to restoration of de novo Q biosynthesis.
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Affiliation(s)
- Fernando Gomez
- Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA.
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Bailey LJ, Acheson JF, McCoy JG, Elsen NL, Phillips GN, Fox BG. Crystallographic analysis of active site contributions to regiospecificity in the diiron enzyme toluene 4-monooxygenase. Biochemistry 2012; 51:1101-13. [PMID: 22264099 DOI: 10.1021/bi2018333] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Crystal structures of toluene 4-monooxygenase hydroxylase in complex with reaction products and effector protein reveal active site interactions leading to regiospecificity. Complexes with phenolic products yield an asymmetric μ-phenoxo-bridged diiron center and a shift of diiron ligand E231 into a hydrogen bonding position with conserved T201. In contrast, complexes with inhibitors p-NH(2)-benzoate and p-Br-benzoate showed a μ-1,1 coordination of carboxylate oxygen between the iron atoms and only a partial shift in the position of E231. Among active site residues, F176 trapped the aromatic ring of products against a surface of the active site cavity formed by G103, E104 and A107, while F196 positioned the aromatic ring against this surface via a π-stacking interaction. The proximity of G103 and F176 to the para substituent of the substrate aromatic ring and the structure of G103L T4moHD suggest how changes in regiospecificity arise from mutations at G103. Although effector protein binding produced significant shifts in the positions of residues along the outer portion of the active site (T201, N202, and Q228) and in some iron ligands (E231 and E197), surprisingly minor shifts (<1 Å) were produced in F176, F196, and other interior residues of the active site. Likewise, products bound to the diiron center in either the presence or absence of effector protein did not significantly shift the position of the interior residues, suggesting that positioning of the cognate substrates will not be strongly influenced by effector protein binding. Thus, changes in product distributions in the absence of the effector protein are proposed to arise from differences in rates of chemical steps of the reaction relative to motion of substrates within the active site channel of the uncomplexed, less efficient enzyme, while structural changes in diiron ligand geometry associated with cycling between diferrous and diferric states are discussed for their potential contribution to product release.
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Affiliation(s)
- Lucas J Bailey
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706-1544, United States
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Do LH, Lippard SJ. Evolution of strategies to prepare synthetic mimics of carboxylate-bridged diiron protein active sites. J Inorg Biochem 2011; 105:1774-85. [PMID: 22113107 PMCID: PMC3232320 DOI: 10.1016/j.jinorgbio.2011.08.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 08/08/2011] [Accepted: 08/11/2011] [Indexed: 10/17/2022]
Abstract
We present a comprehensive review of research conducted in our laboratory in pursuit of the long-term goal of reproducing the structures and reactivity of carboxylate-bridged diiron centers used in biology to activate dioxygen for the conversion of hydrocarbons to alcohols and related products. This article describes the evolution of strategies devised to achieve these goals and illustrates the challenges in getting there. Particular emphasis is placed on controlling the geometry and coordination environment of the diiron core, preventing formation of polynuclear iron clusters, maintaining the structural integrity of model complexes during reactions with dioxygen, and tuning the ligand framework to stabilize desired oxygenated diiron species. Studies of the various model systems have improved our understanding of the electronic and physical characteristics of carboxylate-bridged diiron units and their reactivity toward molecular oxygen and organic moieties. The principles and lessons that have emerged from these investigations will guide future efforts to develop more sophisticated diiron protein model complexes.
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Affiliation(s)
- Loi H. Do
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139. U.S.A
| | - Stephen J. Lippard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139. U.S.A
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Ozeir M, Mühlenhoff U, Webert H, Lill R, Fontecave M, Pierrel F. Coenzyme Q Biosynthesis: Coq6 Is Required for the C5-Hydroxylation Reaction and Substrate Analogs Rescue Coq6 Deficiency. ACTA ACUST UNITED AC 2011; 18:1134-42. [DOI: 10.1016/j.chembiol.2011.07.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 06/27/2011] [Accepted: 07/06/2011] [Indexed: 10/17/2022]
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Do LH, Lippard SJ. Toward functional carboxylate-bridged diiron protein mimics: achieving structural stability and conformational flexibility using a macrocylic ligand framework. J Am Chem Soc 2011; 133:10568-81. [PMID: 21682286 PMCID: PMC3149837 DOI: 10.1021/ja2021312] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A dinucleating macrocycle, H(2)PIM, containing phenoxylimine metal-binding units has been prepared. Reaction of H(2)PIM with [Fe(2)(Mes)(4)] (Mes = 2,4,6-trimethylphenyl) and sterically hindered carboxylic acids, Ph(3)CCO(2)H or Ar(Tol)CO(2)H (2,6-bis(p-tolyl)benzoic acid), afforded complexes [Fe(2)(PIM)(Ph(3)CCO(2))(2)] (1) and [Fe(2)(PIM)(Ar(Tol)CO(2))(2)] (2), respectively. X-ray diffraction studies revealed that these diiron(II) complexes closely mimic the active site structures of the hydroxylase components of bacterial multicomponent monooxygenases (BMMs), particularly the syn disposition of the nitrogen donor atoms and the bridging μ-η(1)η(2) and μ-η(1)η(1) modes of the carboxylate ligands at the diiron(II) centers. Cyclic voltammograms of 1 and 2 displayed quasi-reversible redox couples at +16 and +108 mV vs ferrocene/ferrocenium, respectively. Treatment of 2 with silver perchlorate afforded a silver(I)/iron(III) heterodimetallic complex, [Fe(2)(μ-OH)(2)(ClO(4))(2)(PIM)(Ar(Tol)CO(2))Ag] (3), which was structurally and spectroscopically characterized. Complexes 1 and 2 both react rapidly with dioxygen. Oxygenation of 1 afforded a (μ-hydroxo)diiron(III) complex [Fe(2)(μ-OH)(PIM)(Ph(3)CCO(2))(3)] (4), a hexa(μ-hydroxo)tetrairon(III) complex [Fe(4)(μ-OH)(6)(PIM)(2)(Ph(3)CCO(2))(2)] (5), and an unidentified iron(III) species. Oxygenation of 2 exclusively formed di(carboxylato)diiron(III) compounds, a testimony to the role of the macrocylic ligand in preserving the dinuclear iron center under oxidizing conditions. X-ray crystallographic and (57)Fe Mössbauer spectroscopic investigations indicated that 2 reacts with dioxygen to give a mixture of (μ-oxo)diiron(III) [Fe(2)(μ-O)(PIM)(Ar(Tol)CO(2))(2)] (6) and di(μ-hydroxo)diiron(III) [Fe(2)(μ-OH)(2)(PIM)(Ar(Tol)CO(2))(2)] (7) units in the same crystal lattice. Compounds 6 and 7 spontaneously convert to a tetrairon(III) complex, [Fe(4)(μ-OH)(6)(PIM)(2)(Ar(Tol)CO(2))(2)] (8), when treated with excess H(2)O.
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Affiliation(s)
- Loi H. Do
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Stephen J. Lippard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139
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Song WJ, Lippard SJ. Mechanistic studies of reactions of peroxodiiron(III) intermediates in T201 variants of toluene/o-xylene monooxygenase hydroxylase. Biochemistry 2011; 50:5391-9. [PMID: 21595439 PMCID: PMC3116272 DOI: 10.1021/bi200340f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Site-directed mutagenesis studies of a strictly conserved T201 residue in the active site of toluene/o-xylene monooxygenase hydroxylase (ToMOH) revealed that a single mutation can facilitate kinetic isolation of two distinctive peroxodiiron(III) species, designated T201(peroxo) and ToMOH(peroxo), during dioxygen activation. Previously, we characterized both oxygenated intermediates by UV-vis and Mössbauer spectroscopy, proposed structures from DFT and QM/MM computational studies, and elucidated chemical steps involved in dioxygen activation through the kinetic studies of T201(peroxo) formation. In this study, we investigate the kinetics of T201(peroxo) decay to explore the reaction mechanism of the oxygenated intermediates following O(2) activation. The decay rates of T201(peroxo) were monitored in the absence and presence of external (phenol) or internal (tryptophan residue in an I100W variant) substrates under pre-steady-state conditions. Three possible reaction models for the formation and decay of T201(peroxo) were evaluated, and the results demonstrate that this species is on the pathway of arene oxidation and appears to be in equilibrium with ToMOH(peroxo).
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Affiliation(s)
- Woon Ju Song
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Stephen J. Lippard
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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Krebs C, Bollinger JM, Booker SJ. Cyanobacterial alkane biosynthesis further expands the catalytic repertoire of the ferritin-like 'di-iron-carboxylate' proteins. Curr Opin Chem Biol 2011; 15:291-303. [PMID: 21440485 PMCID: PMC3113506 DOI: 10.1016/j.cbpa.2011.02.019] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 02/01/2011] [Accepted: 02/21/2011] [Indexed: 01/19/2023]
Abstract
Enzymes that activate dioxygen at carboxylate-bridged non-heme diiron clusters residing within ferritin-like, four-helix-bundle protein architectures have crucial roles in, among other processes, the global carbon cycle (e.g. soluble methane monooxygenase), fatty acid biosynthesis [plant fatty acyl-acyl carrier protein (ACP) desaturases], DNA biosynthesis [the R2 or β2 subunits of class Ia ribonucleotide reductases (RNRs)], and cellular iron trafficking (ferritins). Classic studies on class Ia RNRs showed long ago how this obligatorily oxidative di-iron/O2 chemistry can be used to activate an enzyme for even a reduction reaction, and more recent investigations of class Ib and Ic RNRs, coupled with earlier studies on dimanganese catalases, have shown that members of this protein family can also incorporate either one or two Mn ions and use them in place of iron for redox catalysis. These two strategies--oxidative activation for non-oxidative reactions and use of alternative metal ions--expand the catalytic repertoire of the family, probably to include activities that remain to be discovered. Indeed, a recent study has suggested that fatty aldehyde decarbonylases (ADs) from cyanobacteria, purported to catalyze a redox-neutral cleavage of a Cn aldehyde to the Cn-1 alkane (or alkene) and CO, also belong to this enzyme family and are most similar in structure to two other members with heterodinuclear (Mn-Fe) cofactors. Here, we first briefly review both the chemical principles underlying the O2-dependent oxidative chemistry of the 'classical' di-iron-carboxylate proteins and the two aforementioned strategies that have expanded their functional range, and then consider what metal ion(s) and what chemical mechanism(s) might be employed by the newly discovered cyanobacterial ADs.
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Affiliation(s)
- Carsten Krebs
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University, 332 Chemistry Building, University Park, PA, 16802, USA
| | - J. Martin Bollinger
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University, 336 Chemistry Building, University Park, PA, 16802, USA
| | - Squire J. Booker
- Department of Chemistry and Department of Biochemistry and Molecular Biology, Penn State University, 302 Chemistry Building, University Park, PA, 16802, USA
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