1
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Barreiro DS, Oliveira RN, Pauleta SR. Bacterial peroxidases – Multivalent enzymes that enable the use of hydrogen peroxide for microaerobic and anaerobic proliferation. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2023.215114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2023]
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2
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Spring S, Rohde M, Bunk B, Spröer C, Will SE, Neumann-Schaal M. New insights into the energy metabolism and taxonomy of Deferribacteres revealed by the characterization of a new isolate from a hypersaline microbial mat. Environ Microbiol 2022; 24:2543-2575. [PMID: 35415868 DOI: 10.1111/1462-2920.15999] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 04/04/2022] [Indexed: 12/13/2022]
Abstract
Strain L21-Ace-BEST , isolated from a lithifying cyanobacterial mat, could be assigned to a novel species and genus within the Deferribacteres. It is an important model organism for the study of anaerobic acetate degradation under hypersaline conditions. The metabolism of strain L21-Ace-BEST was characterized by biochemical studies, comparative genome analyses, and the evaluation of gene expression patterns. The central metabolic pathway is the citric acid cycle, which is mainly controlled by the enzyme succinyl-CoA:acetate-CoA transferase. The potential use of a reversed oxidative citric acid cycle to fix CO2 has been revealed through genome analysis. However, no autotrophic growth was detected in this strain, whereas sulfide and H2 can be used mixotrophically. Preferred electron acceptors for the anaerobic oxidation of acetate are nitrate, fumarate and DMSO, while oxygen can be utilized only under microoxic conditions. Aerotolerant growth by fermentation was observed at higher oxygen concentrations. The redox cycling of sulfur/sulfide enables the generation of reducing power for the assimilation of acetate during growth and could prevent the over-reduction of cells in stationary phase. Extracellular electron transfer appears to be an essential component of the respiratory metabolism in this clade of Deferribacteres and may be involved in the reduction of nitrite to ammonium. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Stefan Spring
- Department Microorganisms, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Manfred Rohde
- Central Facility for Microscopy, Helmholtz Centre for Infection Research, HZI, Braunschweig, Germany
| | - Boyke Bunk
- Department Bioinformatics, Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Cathrin Spröer
- Department Bioinformatics, Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Sabine Eva Will
- Research Group Metabolomics, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Meina Neumann-Schaal
- Research Group Metabolomics, Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
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3
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Lennartz F, Jeoung JH, Ruenger S, Dobbek H, Weiss MS. Determining the oxidation state of elements by X-ray crystallography. ACTA CRYSTALLOGRAPHICA SECTION D STRUCTURAL BIOLOGY 2022; 78:238-247. [PMID: 35102889 PMCID: PMC8805299 DOI: 10.1107/s2059798321013048] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/08/2021] [Indexed: 11/10/2022]
Abstract
Protein-mediated redox reactions play a critical role in many biological processes and often occur at centres that contain metal ions as cofactors. In order to understand the exact mechanisms behind these reactions it is important to not only characterize the three-dimensional structures of these proteins and their cofactors, but also to identify the oxidation states of the cofactors involved and to correlate this knowledge with structural information. The only suitable approach for this based on crystallographic measurements is spatially resolved anomalous dispersion (SpReAD) refinement, a method that has been used previously to determine the redox states of metals in iron–sulfur cluster-containing proteins. In this article, the feasibility of this approach for small, non-iron–sulfur redox centres is demonstrated by employing SpReAD analysis to characterize Sulfolobus tokodaii sulerythrin, a ruberythrin-like protein that contains a binuclear metal centre. Differences in oxidation states between the individual iron ions of the binuclear metal centre are revealed in sulerythrin crystals treated with H2O2. Furthermore, data collection at high X-ray doses leads to photoreduction of this metal centre, showing that careful control of the total absorbed dose is a prerequisite for successfully determining the oxidation state through SpReAD analysis.
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4
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Neira G, Vergara E, Cortez D, Holmes DS. A Large-Scale Multiple Genome Comparison of Acidophilic Archaea (pH ≤ 5.0) Extends Our Understanding of Oxidative Stress Responses in Polyextreme Environments. Antioxidants (Basel) 2021; 11:antiox11010059. [PMID: 35052563 PMCID: PMC8773360 DOI: 10.3390/antiox11010059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/19/2021] [Accepted: 12/23/2021] [Indexed: 11/16/2022] Open
Abstract
Acidophilic archaea thrive in anaerobic and aerobic low pH environments (pH < 5) rich in dissolved heavy metals that exacerbate stress caused by the production of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), hydroxyl radical (OH) and superoxide (O2−). ROS react with lipids, proteins and nucleic acids causing oxidative stress and damage that can lead to cell death. Herein, genes and mechanisms potentially involved in ROS mitigation are predicted in over 200 genomes of acidophilic archaea with sequenced genomes. These organisms are often be subjected to simultaneous multiple stresses such as high temperature, high salinity, low pH and high heavy metal loads. Some of the topics addressed include: (1) the phylogenomic distribution of these genes and what this can tell us about the evolution of these mechanisms in acidophilic archaea; (2) key differences in genes and mechanisms used by acidophilic versus non-acidophilic archaea and between acidophilic archaea and acidophilic bacteria and (3) how comparative genomic analysis predicts novel genes or pathways involved in oxidative stress responses in archaea and likely horizontal gene transfer (HGT) events.
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Affiliation(s)
- Gonzalo Neira
- Center for Bioinformatics and Genome Biology, Fundación Ciencia & Vida, Santiago 7780272, Chile; (G.N.); (E.V.); (D.C.)
| | - Eva Vergara
- Center for Bioinformatics and Genome Biology, Fundación Ciencia & Vida, Santiago 7780272, Chile; (G.N.); (E.V.); (D.C.)
| | - Diego Cortez
- Center for Bioinformatics and Genome Biology, Fundación Ciencia & Vida, Santiago 7780272, Chile; (G.N.); (E.V.); (D.C.)
| | - David S. Holmes
- Center for Bioinformatics and Genome Biology, Fundación Ciencia & Vida, Santiago 7780272, Chile; (G.N.); (E.V.); (D.C.)
- Facultad de Medicina y Ciencias, Universidad San Sebastián, Santiago 8420524, Chile
- Correspondence:
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5
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Caldas Nogueira ML, Pastore AJ, Davidson VL. Diversity of structures and functions of oxo-bridged non-heme diiron proteins. Arch Biochem Biophys 2021; 705:108917. [PMID: 33991497 PMCID: PMC8165033 DOI: 10.1016/j.abb.2021.108917] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 02/07/2023]
Abstract
Oxo-bridged diiron proteins are a distinct class of non-heme iron proteins. Their active sites are composed of two irons that are coordinated by amino acid side chains, and a bridging oxygen that interacts with each iron. These proteins are members of the ferritin superfamily and share the structural feature of a four α-helix bundle that provides the residues that coordinate the irons. The different proteins also display a wide range of structures and functions. A prototype of this family is hemerythrin, which functions as an oxygen transporter. Several other hemerythrin-like proteins have been described with a diversity of functions including oxygen and iron sensing, and catalytic activities. Rubrerythrins react with hydrogen peroxide and rubrerythrin-like proteins possess a rubredoxin domain, in addition to the oxo-bridged diiron center. Other redox enzymes with oxo-bridged irons include flavodiiron proteins that act as O2 or NO reductases, ribonucleotide reductase and methane monooxygenase. Ferritins have an oxo-bridged diiron in the ferroxidase center of the protein, which plays a role in the iron storage function of these proteins. There are also bacterial ferritins that exhibit catalytic activities. The structures and functions of this broad class of oxo-bridged diiron proteins are described and compared in this review.
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Affiliation(s)
- Maria Luiza Caldas Nogueira
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, 32827, United States
| | - Anthony J Pastore
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, 32827, United States
| | - Victor L Davidson
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, 32827, United States.
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6
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Piergentili C, Ross J, He D, Gallagher KJ, Stanley WA, Adam L, Mackay CL, Baslé A, Waldron KJ, Clarke DJ, Marles-Wright J. Dissecting the structural and functional roles of a putative metal entry site in encapsulated ferritins. J Biol Chem 2020; 295:15511-15526. [PMID: 32878987 DOI: 10.1074/jbc.ra120.014502] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 08/24/2020] [Indexed: 11/06/2022] Open
Abstract
Encapsulated ferritins belong to the universally distributed ferritin superfamily, whose members function as iron detoxification and storage systems. Encapsulated ferritins have a distinct annular structure and must associate with an encapsulin nanocage to form a competent iron store that is capable of holding significantly more iron than classical ferritins. The catalytic mechanism of iron oxidation in the ferritin family is still an open question because of the differences in organization of the ferroxidase catalytic site and neighboring secondary metal-binding sites. We have previously identified a putative metal-binding site on the inner surface of the Rhodospirillum rubrum encapsulated ferritin at the interface between the two-helix subunits and proximal to the ferroxidase center. Here we present a comprehensive structural and functional study to investigate the functional relevance of this putative iron-entry site by means of enzymatic assays, MS, and X-ray crystallography. We show that catalysis occurs in the ferroxidase center and suggest a dual role for the secondary site, which both serves to attract metal ions to the ferroxidase center and acts as a flow-restricting valve to limit the activity of the ferroxidase center. Moreover, confinement of encapsulated ferritins within the encapsulin nanocage, although enhancing the ability of the encapsulated ferritin to undergo catalysis, does not influence the function of the secondary site. Our study demonstrates a novel molecular mechanism by which substrate flux to the ferroxidase center is controlled, potentially to ensure that iron oxidation is productively coupled to mineralization.
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Affiliation(s)
- Cecilia Piergentili
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jennifer Ross
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, Scotland
| | - Didi He
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, The University of Edinburgh, Edinburgh, Scotland
| | - Kelly J Gallagher
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, Scotland
| | - Will A Stanley
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Laurène Adam
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - C Logan Mackay
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, Scotland
| | - Arnaud Baslé
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Kevin J Waldron
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David J Clarke
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, Scotland.
| | - Jon Marles-Wright
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom.
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7
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Pedone E, Fiorentino G, Bartolucci S, Limauro D. Enzymatic Antioxidant Signatures in Hyperthermophilic Archaea. Antioxidants (Basel) 2020; 9:antiox9080703. [PMID: 32756530 PMCID: PMC7465337 DOI: 10.3390/antiox9080703] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 07/28/2020] [Accepted: 07/31/2020] [Indexed: 12/17/2022] Open
Abstract
To fight reactive oxygen species (ROS) produced by both the metabolism and strongly oxidative habitats, hyperthermophilic archaea are equipped with an array of antioxidant enzymes whose role is to protect the biological macromolecules from oxidative damage. The most common ROS, such as superoxide radical (O2-.) and hydrogen peroxide (H2O2), are scavenged by superoxide dismutase, peroxiredoxins, and catalase. These enzymes, together with thioredoxin, protein disulfide oxidoreductase, and thioredoxin reductase, which are involved in redox homeostasis, represent the core of the antioxidant system. In this review, we offer a panorama of progression of knowledge on the antioxidative system in aerobic or microaerobic (hyper)thermophilic archaea and possible industrial applications of these enzymes.
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Affiliation(s)
- Emilia Pedone
- Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, 80134 Napoli, Italy;
| | - Gabriella Fiorentino
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso universitario Monte S. Angelo, Via Cinthia, 80126 Napoli, Italy; (G.F.); (S.B.)
| | - Simonetta Bartolucci
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso universitario Monte S. Angelo, Via Cinthia, 80126 Napoli, Italy; (G.F.); (S.B.)
| | - Danila Limauro
- Dipartimento di Biologia, Università degli Studi di Napoli Federico II, Complesso universitario Monte S. Angelo, Via Cinthia, 80126 Napoli, Italy; (G.F.); (S.B.)
- Correspondence:
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8
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Young L, Rosell-Hidalgo A, Inaoka DK, Xu F, Albury M, May B, Kita K, Moore AL. Kinetic and structural characterisation of the ubiquinol-binding site and oxygen reduction by the trypanosomal alternative oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148247. [PMID: 32565080 DOI: 10.1016/j.bbabio.2020.148247] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 06/08/2020] [Accepted: 06/12/2020] [Indexed: 12/15/2022]
Abstract
The alternative oxidase (AOX) is a monotopic di‑iron carboxylate protein which acts as a terminal respiratory chain oxidase in a variety of plants, fungi and protists. Of particular importance is the finding that both emerging infectious diseases caused by human and plant fungal pathogens, the majority of which are multi-drug resistant, appear to be dependent upon AOX activity for survival. Since AOX is absent in mammalian cells, AOX is considered a viable therapeutic target for the design of specific fungicidal and anti-parasitic drugs. In this work, we have mutated conserved residues within the hydrophobic channel (R96, D100, R118, L122, L212, E215 and T219), which crystallography has indicated leads to the active site. Our data shows that all mutations result in a drastic reduction in Vmax and catalytic efficiency whilst some also affected the Km for quinol and oxygen. The extent to which mutation effects inhibitor sensitivity was also investigated, with mutation of R118 and T219 leading to a complete loss of inhibitor potency. However, only a slight reduction in IC50 values was observed when R96 was mutated, implying that this residue is less important in inhibitor binding. In silico modelling has been used to provide insight into the reason for such changes, which we suggest is due to disruptions in the proton transfer network, resulting in a reduction in overall reaction kinetics. We discuss our results in terms of the structural features of the ubiquinol binding site and consider the implications of such findings on the nature of the catalytic cycle. SIGNIFICANCE: The alternative oxidase is a ubiquinol oxidoreductase enzyme that catalyses the oxidation of ubiquinol and the reduction of oxygen to water. It is widely distributed amongst the plant, fungal and parasitic kingdoms and plays a central role in metabolism through facilitating the turnover of the TCA cycle whilst reducing ROS production.
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Affiliation(s)
- Luke Young
- Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United Kingdom.
| | - Alicia Rosell-Hidalgo
- Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United Kingdom
| | - Daniel Ken Inaoka
- Department of Molecular Infection Dynamics, Shinogi Global Infectious Diseases Division, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki 852-8523, Japan; School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki 852-8523, Japan
| | - Fei Xu
- Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United Kingdom
| | - Mary Albury
- Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United Kingdom
| | - Benjamin May
- Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United Kingdom
| | - Kiyoshi Kita
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki 852-8523, Japan
| | - Anthony L Moore
- Biochemistry and Biomedicine, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United Kingdom
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9
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Theoretical study of the mechanism of the manganese catalase KatB. J Biol Inorg Chem 2018; 24:103-115. [DOI: 10.1007/s00775-018-1631-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 11/14/2018] [Indexed: 11/30/2022]
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10
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Chemistry at the protein-mineral interface in L-ferritin assists the assembly of a functional (μ 3-oxo)Tris[(μ 2-peroxo)] triiron(III) cluster. Proc Natl Acad Sci U S A 2017; 114:2580-2585. [PMID: 28202724 DOI: 10.1073/pnas.1614302114] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
X-ray structures of homopolymeric L-ferritin obtained by freezing protein crystals at increasing exposure times to a ferrous solution showed the progressive formation of a triiron cluster on the inner cage surface of each subunit. After 60 min exposure, a fully assembled (μ3-oxo)Tris[(μ2-peroxo)(μ2-glutamato-κO:κO')](glutamato-κO)(diaquo)triiron(III) anionic cluster appears in human L-ferritin. Glu60, Glu61, and Glu64 provide the anchoring of the cluster to the protein cage. Glu57 shuttles incoming iron ions toward the cluster. We observed a similar metallocluster in horse spleen L-ferritin, indicating that it represents a common feature of mammalian L-ferritins. The structures suggest a mechanism for iron mineral formation at the protein interface. The functional significance of the observed patch of carboxylate side chains and resulting metallocluster for biomineralization emerges from the lower iron oxidation rate measured in the E60AE61AE64A variant of human L-ferritin, leading to the proposal that the observed metallocluster corresponds to the suggested, but yet unobserved, nucleation site of L-ferritin.
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11
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Cardenas JP, Quatrini R, Holmes DS. Aerobic Lineage of the Oxidative Stress Response Protein Rubrerythrin Emerged in an Ancient Microaerobic, (Hyper)Thermophilic Environment. Front Microbiol 2016; 7:1822. [PMID: 27917155 PMCID: PMC5114695 DOI: 10.3389/fmicb.2016.01822] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 10/31/2016] [Indexed: 11/27/2022] Open
Abstract
Rubrerythrins (RBRs) are non-heme di-iron proteins belonging to the ferritin-like superfamily. They are involved in oxidative stress defense as peroxide scavengers in a wide range of organisms. The vast majority of RBRs, including classical forms of this protein, contain a C-terminal rubredoxin-like domain involved in electron transport that is used during catalysis in anaerobic conditions. Rubredoxin is an ancient and large protein family of short length (<100 residues) that contains a Fe-S center involved in electron transfer. However, functional forms of the enzyme lacking the rubredoxin-like domain have been reported (e.g., sulerythrin and ferriperoxin). In this study, phylogenomic evidence is presented that suggests that a complete lineage of rubrerythrins, lacking the rubredoxin-like domain, arose in an ancient microaerobic and (hyper)thermophilic environments in the ancestors of the Archaea Thermoproteales and Sulfolobales. This lineage (termed the “aerobic-type” lineage) subsequently evolved to become adapted to environments with progressively lower temperatures and higher oxygen concentrations via the acquisition of two co-localized genes, termed DUF3501 and RFO, encoding a conserved protein of unknown function and a predicted Fe-S oxidoreductase, respectively. Proposed Horizontal Gene Transfer events from these archaeal ancestors to Bacteria expanded the opportunities for further evolution of this RBR including adaption to lower temperatures. The second lineage (termed the cyanobacterial lineage) is proposed to have evolved in cyanobacterial ancestors, maybe in direct response to the production of oxygen via oxygenic photosynthesis during the Great Oxygen Event (GOE). It is hypothesized that both lineages of RBR emerged in a largely anaerobic world with “whiffs” of oxygen and that their subsequent independent evolutionary trajectories allowed microorganisms to transition from this anaerobic world to an aerobic one.
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Affiliation(s)
- Juan P Cardenas
- Center for Bioinformatics and Genome Biology, Fundacion Ciencia & VidaSantiago, Chile; Facultad de Ciencias Biologicas, Universidad Andres BelloSantiago, Chile
| | - Raquel Quatrini
- Laboratory of Microbial Ecophysiology, Fundación Ciencia & Vida Santiago, Chile
| | - David S Holmes
- Center for Bioinformatics and Genome Biology, Fundacion Ciencia & VidaSantiago, Chile; Facultad de Ciencias Biologicas, Universidad Andres BelloSantiago, Chile
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12
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Kim S, Lee JH, Seok JH, Park YH, Jung SW, Cho AE, Lee C, Chung MS, Kim KH. Structural Basis of Novel Iron-Uptake Route and Reaction Intermediates in Ferritins from Gram-Negative Bacteria. J Mol Biol 2016; 428:5007-5018. [PMID: 27777002 DOI: 10.1016/j.jmb.2016.10.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 10/17/2016] [Accepted: 10/18/2016] [Indexed: 10/20/2022]
Abstract
Iron and oxygen chemistry is mediated by iron proteins for many biological functions. Carboxylate-bridged diiron enzymes including ferritin have the common mechanism of oxygen activation via peroxodiferric intermediates. However, the route for iron uptake and the structural identification of intermediates still remain incomplete. The 4-fold symmetry channel of Helicobacter pylori ferritin was previously proposed as the iron-uptake route in eubacteria, but the amino acid residues at the 4-fold channel are not highly conserved. Here, we show evidence for a short path for iron uptake from His93 on the surface to the ferroxidase center in H. pylori ferritin and Escherichia coli ferritin. The amino acid residues along this path are highly conserved in Gram-negative bacteria and some archaea, and the mutants containing S20A and H93L showed significantly decreased iron oxidation. Surprisingly, the E. coli ferritin S20A crystal structure showed oxygen binding and side-on, symmetric μ-η2:η2 peroxodiferric and oxodiferric intermediates. The results provide the structural basis for understanding the chemical nature of intermediates in iron oxidation in bacteria and some of archaea.
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Affiliation(s)
- Sella Kim
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea
| | - Ji-Hye Lee
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea
| | - Jong Hyeon Seok
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea
| | - Yi-Ho Park
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea
| | - Sang Won Jung
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea
| | - Art E Cho
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea
| | - Cheolju Lee
- Functional Proteomics Center, Korea Institute of Science and Technology, Seoul 136-791, Korea
| | - Mi Sook Chung
- Department of Food and Nutrition, Duksung Women's University, Seoul 132-714, Korea
| | - Kyung Hyun Kim
- Department of Biotechnology & Bioinformatics, Korea University, Sejong 339-700, Korea.
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13
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14
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Zanello P. The competition between chemistry and biology in assembling iron–sulfur derivatives. Molecular structures and electrochemistry. Part I. {Fe(SγCys)4} proteins. Coord Chem Rev 2013. [DOI: 10.1016/j.ccr.2013.02.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Sato Y, Kameya M, Fushinobu S, Wakagi T, Arai H, Ishii M, Igarashi Y. A novel enzymatic system against oxidative stress in the thermophilic hydrogen-oxidizing bacterium Hydrogenobacter thermophilus. PLoS One 2012; 7:e34825. [PMID: 22485188 PMCID: PMC3317640 DOI: 10.1371/journal.pone.0034825] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 03/06/2012] [Indexed: 11/19/2022] Open
Abstract
Rubrerythrin (Rbr) is a non-heme iron protein composed of two distinctive domains and functions as a peroxidase in anaerobic organisms. A novel Rbr-like protein, ferriperoxin (Fpx), was identified in Hydrogenobacter thermophilus and was found not to possess the rubredoxin-like domain that is present in typical Rbrs. Although this protein is widely distributed among aerobic organisms, its function remains unknown. In this study, Fpx exhibited ferredoxin:NADPH oxidoreductase (FNR)-dependent peroxidase activity and reduced both hydrogen peroxide (H(2)O(2)) and organic hydroperoxide in the presence of NADPH and FNR as electron donors. The calculated K(m) and V(max) values of Fpx for organic hydroperoxides were comparable to that for H(2)O(2), demonstrating a multiple reactivity of Fpx towards hydroperoxides. An fpx gene disruptant was unable to grow under aerobic conditions, whereas its growth profiles were comparable to those of the wild-type strain under anaerobic and microaerobic conditions, clearly indicating the indispensability of Fpx as an antioxidant of H. thermophilus in aerobic environments. Structural analysis suggested that domain-swapping occurs in Fpx, and this domain-swapped structure is well conserved among thermophiles, implying the importance of structural stability of domain-swapped conformation for thermal environments. In addition, Fpx was located on a deep branch of the phylogenetic tree of Rbr and Rbr-like proteins. This finding, taken together with the wide distribution of Fpx among Bacteria and Archaea, suggests that Fpx is an ancestral type of Rbr homolog that functions as an essential antioxidant and may be part of an ancestral peroxide-detoxification system.
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Affiliation(s)
- Yuya Sato
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Masafumi Kameya
- Biotechnology Research Center and Department of Biotechnology, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Shinya Fushinobu
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Takayoshi Wakagi
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hiroyuki Arai
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Masaharu Ishii
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- * E-mail:
| | - Yasuo Igarashi
- Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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Cooley RB, Arp DJ, Karplus PA. Symerythrin structures at atomic resolution and the origins of rubrerythrins and the ferritin-like superfamily. J Mol Biol 2011; 413:177-94. [PMID: 21872605 DOI: 10.1016/j.jmb.2011.08.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 08/08/2011] [Accepted: 08/09/2011] [Indexed: 11/25/2022]
Abstract
Rubrerythrins are diiron-containing peroxidases that belong to the ferritin-like superfamily (FLSF). Here, we describe the structures of symerythrin, a novel rubrerythrin variant from the oxygenic phototroph Cyanophora paradoxa, at 1.20-1.40 Å resolution in three different states: diferric, azide-bound diferric and chemically reduced. The symerythrin metallocenter has a unique eighth ligating residue compared to rubrerythrin-an additional glutamate inserted into helix A of the four-helix bundle that resides on a π-helical segment. Otherwise, the diferric metallocenter structure is highly similar to that of characterized rubrerythrins. Azide binds the diferric center in a μ-1,1 orientation similar to how peroxide binds to diferric rubrerythrin. The structure of the diferrous metallocenter shows heterogeneity that we ascribe to the acidic pH of the crystals. In what we consider the neutral pH conformation, reduction causes a 2.0-Å shift in Fe1 and the toggling of a Glu to a His ligand, as seen with rubrerythrins. The function of symerythrin remains unknown, but preliminary tests showing oxidase and peroxidase activities and the similarities of its metallocenter to other rubrerythrins suggest similar functionalities between the two despite the additional ligating glutamate in symerythrin. Of particular interest is the high internal symmetry of symerythrin, which supports the notion that its core four-helix bundle was formed by the gene duplication and fusion of a two-helix peptide. Sequence comparisons with another family in the FLSF that also has notable internal symmetry provide compelling evidence that, contrary to previous assumptions, there have been multiple gene fusion events that have generated the single-chain FLSF fold.
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Affiliation(s)
- Richard B Cooley
- Department of Biochemistry and Biophysics, 2011 Ag and Life Sciences Building, Oregon State University, Corvallis, OR 97331, USA
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