1
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Deng Y, Carnevale V, Ditchfield R, Pletneva EV. Applications of the Newly Developed Force-Field Parameters Uncover a Dynamic Nature of Ω-Loop C in the Lys-Ligated Alkaline Form of Cytochrome c. J Phys Chem B 2024. [PMID: 38864552 DOI: 10.1021/acs.jpcb.4c00625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Lys-ligated cytochromes make up an emerging family of heme proteins. Density functional theory calculations on the amine/imidazole-ligated c-type ferric heme were employed to develop force-field parameters for molecular dynamics (MD) simulations of structural and dynamic features of these proteins. The new force-field parameters were applied to the alkaline form of yeast iso-1 cytochrome c to rationalize discrepancies resulting from distinct experimental conditions in prior structural studies and to provide insights into the mechanisms of the alkaline transition. Our simulations have revealed the dynamic nature of Ω-loop C in the Lys-ligated protein and its unfolding in the Lys-ligated conformer having this loop in the same position as in the native Met-ligated protein. The proximity of Tyr67 or Tyr74 to the Lys ligand of ferric heme iron suggests a possible mechanism of the backward alkaline transition where a proton donor Tyr assists in Lys dissociation. The developed force-field parameters will be useful in structural and dynamic characterization of other native or engineered Lys-ligated heme proteins.
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Affiliation(s)
- Yunling Deng
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Vincenzo Carnevale
- Institute for Genomics and Evolutionary Medicine, Institute for Computational Molecular Science, and Department of Biology, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Robert Ditchfield
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Ekaterina V Pletneva
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
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2
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Bradley JM, Bugg Z, Sackey A, Andrews SC, Wilson MT, Svistunenko DA, Moore GR, Le Brun NE. The Ferroxidase Centre of Escherichia coli Bacterioferritin Plays a Key Role in the Reductive Mobilisation of the Mineral Iron Core. Angew Chem Int Ed Engl 2024; 63:e202401379. [PMID: 38407997 DOI: 10.1002/anie.202401379] [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: 01/19/2024] [Revised: 02/22/2024] [Accepted: 02/22/2024] [Indexed: 02/28/2024]
Abstract
Ferritins are multimeric cage-forming proteins that play a crucial role in cellular iron homeostasis. All H-chain-type ferritins harbour a diiron site, the ferroxidase centre, at the centre of a 4 α-helical bundle, but bacterioferritins are unique in also binding 12 hemes per 24 meric assembly. The ferroxidase centre is known to be required for the rapid oxidation of Fe2+ during deposition of an immobilised ferric mineral core within the protein's hollow interior. In contrast, the heme of bacterioferritin is required for the efficient reduction of the mineral core during iron release, but has little effect on the rate of either oxidation or mineralisation of iron. Thus, the current view is that these two cofactors function in iron uptake and release, respectively, with no functional overlap. However, rapid electron transfer between the heme and ferroxidase centre of bacterioferritin from Escherichia coli was recently demonstrated, suggesting that the two cofactors may be functionally connected. Here we report absorbance and (magnetic) circular dichroism spectroscopies, together with in vitro assays of iron-release kinetics, which demonstrate that the ferroxidase centre plays an important role in the reductive mobilisation of the bacterioferritin mineral core, which is dependent on the heme-ferroxidase centre electron transfer pathway.
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Affiliation(s)
- Justin M Bradley
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Zinnia Bugg
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Aaren Sackey
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Simon C Andrews
- School of Biological Sciences, University of Reading, Whiteknights, Reading, RG6 6AS, UK
| | - Michael T Wilson
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Dimitri A Svistunenko
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Geoffrey R Moore
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Nick E Le Brun
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
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3
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Han S, Li Y, Gao H. Generation and Physiology of Hydrogen Sulfide and Reactive Sulfur Species in Bacteria. Antioxidants (Basel) 2022; 11:antiox11122487. [PMID: 36552695 PMCID: PMC9774590 DOI: 10.3390/antiox11122487] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
Sulfur is not only one of the most abundant elements on the Earth, but it is also essential to all living organisms. As life likely began and evolved in a hydrogen sulfide (H2S)-rich environment, sulfur metabolism represents an early form of energy generation via various reactions in prokaryotes and has driven the sulfur biogeochemical cycle since. It has long been known that H2S is toxic to cells at high concentrations, but now this gaseous molecule, at the physiological level, is recognized as a signaling molecule and a regulator of critical biological processes. Recently, many metabolites of H2S, collectively called reactive sulfur species (RSS), have been gradually appreciated as having similar or divergent regulatory roles compared with H2S in living organisms, especially mammals. In prokaryotes, even in bacteria, investigations into generation and physiology of RSS remain preliminary and an understanding of the relevant biological processes is still in its infancy. Despite this, recent and exciting advances in the fields are many. Here, we discuss abiotic and biotic generation of H2S/RSS, sulfur-transforming enzymes and their functioning mechanisms, and their physiological roles as well as the sensing and regulation of H2S/RSS.
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4
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Jenner LP, Crack JC, Kurth JM, Soldánová Z, Brandt L, Sokol KP, Reisner E, Bradley JM, Dahl C, Cheesman MR, Butt JN. Reaction of Thiosulfate Dehydrogenase with a Substrate Mimic Induces Dissociation of the Cysteine Heme Ligand Giving Insights into the Mechanism of Oxidative Catalysis. J Am Chem Soc 2022; 144:18296-18304. [PMID: 36173876 PMCID: PMC9562282 DOI: 10.1021/jacs.2c06062] [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] [Indexed: 11/29/2022]
Abstract
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Thiosulfate dehydrogenases are bacterial cytochromes
that contribute
to the oxidation of inorganic sulfur. The active sites of these enzymes
contain low-spin c-type heme with Cys–/His axial ligation. However, the reduction potentials of these hemes
are several hundred mV more negative than that of the thiosulfate/tetrathionate
couple (Em, +198 mV), making it difficult
to rationalize the thiosulfate oxidizing capability. Here, we describe
the reaction of Campylobacter jejuni thiosulfate dehydrogenase (TsdA) with sulfite, an analogue of thiosulfate.
The reaction leads to stoichiometric conversion of the active site
Cys to cysteinyl sulfonate (Cα-CH2-S-SO3–) such that the protein exists in a form
closely resembling a proposed intermediate in the pathway for thiosulfate
oxidation that carries a cysteinyl thiosulfate (Cα-CH2-S-SSO3–). The active
site heme in the stable sulfonated protein displays an Em approximately 200 mV more positive than the Cys–/His-ligated state. This can explain the thiosulfate
oxidizing activity of the enzyme and allows us to propose a catalytic
mechanism for thiosulfate oxidation. Substrate-driven release of the
Cys heme ligand allows that side chain to provide the site of substrate
binding and redox transformation; the neighboring heme then simply
provides a site for electron relay to an appropriate partner. This
chemistry is distinct from that displayed by the Cys-ligated hemes
found in gas-sensing hemoproteins and in enzymes such as the cytochromes
P450. Thus, a further class of thiolate-ligated hemes is proposed,
as exemplified by the TsdA centers that have evolved to catalyze the
controlled redox transformations of inorganic oxo anions of sulfur.
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Affiliation(s)
- Leon P Jenner
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, NorwichNR4 7TJ, United Kingdom
| | - Jason C Crack
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, NorwichNR4 7TJ, United Kingdom
| | - Julia M Kurth
- Institut für Mikrobiologie & Biotechnologie, Friedrich Wilhelms Universität Bonn, D-53115Bonn, Germany
| | - Zuzana Soldánová
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, NorwichNR4 7TJ, United Kingdom
| | - Linda Brandt
- Institut für Mikrobiologie & Biotechnologie, Friedrich Wilhelms Universität Bonn, D-53115Bonn, Germany
| | - Katarzyna P Sokol
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, CambridgeCB2 1EW, United Kingdom
| | - Erwin Reisner
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, CambridgeCB2 1EW, United Kingdom
| | - Justin M Bradley
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, NorwichNR4 7TJ, United Kingdom
| | - Christiane Dahl
- Institut für Mikrobiologie & Biotechnologie, Friedrich Wilhelms Universität Bonn, D-53115Bonn, Germany
| | - Myles R Cheesman
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, NorwichNR4 7TJ, United Kingdom
| | - Julea N Butt
- Centre for Molecular and Structural Biochemistry, School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, NorwichNR4 7TJ, United Kingdom
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5
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Teixeira LR, Fernandes TM, Silva MA, Morgado L, Salgueiro CA. Characterization of a Novel Cytochrome Involved in
Geobacter sulfurreducens’
Electron Harvesting Pathways. Chemistry 2022; 28:e202202333. [DOI: 10.1002/chem.202202333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Indexed: 11/12/2022]
Affiliation(s)
- Liliana R. Teixeira
- Associate Laboratory i4HB-Institute for Health and Bioeconomy NOVA School of Science and Technology NOVA University Lisbon 2819-516 Caparica Portugal
- UCIBIO – Applied Molecular Biosciences Unit, Chemistry Department NOVA School of Science and Technology NOVA University Lisbon 2829-516 Caparica Portugal
| | - Tomás M. Fernandes
- Associate Laboratory i4HB-Institute for Health and Bioeconomy NOVA School of Science and Technology NOVA University Lisbon 2819-516 Caparica Portugal
- UCIBIO – Applied Molecular Biosciences Unit, Chemistry Department NOVA School of Science and Technology NOVA University Lisbon 2829-516 Caparica Portugal
| | - Marta A. Silva
- Associate Laboratory i4HB-Institute for Health and Bioeconomy NOVA School of Science and Technology NOVA University Lisbon 2819-516 Caparica Portugal
- UCIBIO – Applied Molecular Biosciences Unit, Chemistry Department NOVA School of Science and Technology NOVA University Lisbon 2829-516 Caparica Portugal
| | - Leonor Morgado
- Associate Laboratory i4HB-Institute for Health and Bioeconomy NOVA School of Science and Technology NOVA University Lisbon 2819-516 Caparica Portugal
- UCIBIO – Applied Molecular Biosciences Unit, Chemistry Department NOVA School of Science and Technology NOVA University Lisbon 2829-516 Caparica Portugal
| | - Carlos A. Salgueiro
- Associate Laboratory i4HB-Institute for Health and Bioeconomy NOVA School of Science and Technology NOVA University Lisbon 2819-516 Caparica Portugal
- UCIBIO – Applied Molecular Biosciences Unit, Chemistry Department NOVA School of Science and Technology NOVA University Lisbon 2829-516 Caparica Portugal
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6
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Du R, Gao D, Wang Y, Liu L, Cheng J, Liu J, Zhang XH, Yu M. Heterotrophic Sulfur Oxidation of Halomonas titanicae SOB56 and Its Habitat Adaptation to the Hydrothermal Environment. Front Microbiol 2022; 13:888833. [PMID: 35774465 PMCID: PMC9237845 DOI: 10.3389/fmicb.2022.888833] [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: 03/03/2022] [Accepted: 05/24/2022] [Indexed: 11/23/2022] Open
Abstract
Halomonas bacteria are ubiquitous in global marine environments, however, their sulfur-oxidizing abilities and survival adaptations in hydrothermal environments are not well understood. In this study, we characterized the sulfur oxidation ability and metabolic mechanisms of Halomonas titanicae SOB56, which was isolated from the sediment of the Tangyin hydrothermal field in the Southern Okinawa Trough. Physiological characterizations showed that it is a heterotrophic sulfur-oxidizing bacterium that can oxidize thiosulfate to tetrathionate, with the Na2S2O3 degradation reaching 94.86%. Two potential thiosulfate dehydrogenase-related genes, tsdA and tsdB, were identified as encoding key catalytic enzymes, and their expression levels in strain SOB56 were significantly upregulated. Nine of fifteen examined Halomonas genomes possess TsdA- and TsdB-homologous proteins, whose amino acid sequences have two typical Cys-X2-Cys-His heme-binding regions. Moreover, the thiosulfate oxidation process in H. titanicae SOB56 might be regulated by quorum sensing, and autoinducer-2 synthesis protein LuxS was identified in its genome. Regarding the mechanisms underlying adaptation to hydrothermal environment, strain SOB56 was capable of forming biofilms and producing EPS. In addition, genes related to complete flagellum assembly system, various signal transduction histidine kinases, heavy metal transporters, anaerobic respiration, and variable osmotic stress regulation were also identified. Our results shed light on the potential functions of heterotrophic Halomonas bacteria in hydrothermal sulfur cycle and revealed possible adaptations for living at deep-sea hydrothermal fields by H. titanicae SOB56.
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Affiliation(s)
- Rui Du
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Di Gao
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Yiting Wang
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Lijun Liu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Jingguang Cheng
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
| | - Jiwen Liu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Xiao-Hua Zhang
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
| | - Min Yu
- College of Marine Life Sciences, and Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, China
- Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China
- *Correspondence: Min Yu,
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7
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Crack JC, Balasiny BK, Bennett SP, Rolfe MD, Froes A, MacMillan F, Green J, Cole JA, Le Brun NE. The Di-Iron Protein YtfE Is a Nitric Oxide-Generating Nitrite Reductase Involved in the Management of Nitrosative Stress. J Am Chem Soc 2022; 144:7129-7145. [PMID: 35416044 PMCID: PMC9052748 DOI: 10.1021/jacs.1c12407] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
![]()
Previously characterized
nitrite reductases fall into three classes:
siroheme-containing enzymes (NirBD), cytochrome c hemoproteins (NrfA and NirS), and copper-containing enzymes (NirK).
We show here that the di-iron protein YtfE represents a physiologically
relevant new class of nitrite reductases. Several functions have been
previously proposed for YtfE, including donating iron for the repair
of iron–sulfur clusters that have been damaged by nitrosative
stress, releasing nitric oxide (NO) from nitrosylated iron, and reducing
NO to nitrous oxide (N2O). Here, in vivo reporter assays confirmed that Escherichia coli YtfE increased cytoplasmic NO production from nitrite. Spectroscopic
and mass spectrometric investigations revealed that the di-iron site
of YtfE exists in a mixture of forms, including nitrosylated and nitrite-bound,
when isolated from nitrite-supplemented, but not nitrate-supplemented,
cultures. Addition of nitrite to di-ferrous YtfE resulted in nitrosylated
YtfE and the release of NO. Kinetics of nitrite reduction were dependent
on the nature of the reductant; the lowest Km, measured for the di-ferrous form, was ∼90 μM,
well within the intracellular nitrite concentration range. The vicinal
di-cysteine motif, located in the N-terminal domain of YtfE, was shown
to function in the delivery of electrons to the di-iron center. Notably,
YtfE exhibited very low NO reductase activity and was only able to
act as an iron donor for reconstitution of apo-ferredoxin under conditions
that damaged its di-iron center. Thus, YtfE is a high-affinity, low-capacity
nitrite reductase that we propose functions to relieve nitrosative
stress by acting in combination with the co-regulated NO-consuming
enzymes Hmp and Hcp.
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Affiliation(s)
- Jason C Crack
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Basema K Balasiny
- Institute of Microbiology and Infection and School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Sophie P Bennett
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Matthew D Rolfe
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Afonso Froes
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Fraser MacMillan
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Jeffrey Green
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Jeffrey A Cole
- Institute of Microbiology and Infection and School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Nick E Le Brun
- Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
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8
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Zhong F, Alden SL, Hughes RP, Pletneva EV. Comparing Properties of Common Bioinorganic Ligands with Switchable Variants of Cytochrome c. Inorg Chem 2021; 61:1207-1227. [PMID: 34699724 DOI: 10.1021/acs.inorgchem.1c02322] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ligand substitution at the metal center is common in catalysis and signal transduction of metalloproteins. Understanding the effects of particular ligands, as well as the polypeptide surrounding, is critical for uncovering mechanisms of these biological processes and exploiting them in the design of bioinspired catalysts and molecular devices. A series of switchable K79G/M80X/F82C (X = Met, His, or Lys) variants of cytochrome (cyt) c was employed to directly compare the stability of differently ligated proteins and activation barriers for Met, His, and Lys replacement at the ferric heme iron. Studies of these variants and their nonswitchable counterparts K79G/M80X have revealed stability trends Met < Lys < His and Lys < His < Met for the protein FeIII-X and FeII-X species, respectively. The differences in the hydrogen-bonding interactions in folded proteins and in solvation of unbound X in the unfolded proteins explain these trends. Calculations of free energy of ligand dissociation in small heme model complexes reveal that the ease of the FeIII-X bond breaking increases in the series amine < imidazole < thioether, mirroring trends in hardness of these ligands. Experimental rate constants for X dissociation in differently ligated cyt c variants are consistent with this sequence, but the differences between Met and His dissociation rates are attenuated because the former process is limited by the heme crevice opening. Analyses of activation parameters and comparisons to those for the Lys-to-Met ligand switch in the alkaline transition suggest that ligand dissociation is entropically driven in all the variants and accompanied by Lys protonation at neutral pH. The described thiolate redox-linked switches have offered a wealth of new information about interactions of different protein-derived ligands with the heme iron in cyt c model proteins, and we anticipate that the strategy of employing these switches could benefit studies of other redox metalloproteins and model complexes.
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Affiliation(s)
- Fangfang Zhong
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Stephanie L Alden
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Russell P Hughes
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
| | - Ekaterina V Pletneva
- Department of Chemistry, Dartmouth College, Hanover, New Hampshire 03755, United States
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9
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Yu Q, Sun W, Gao H. Thiosulfate oxidation in sulfur-reducing Shewanella oneidensis and its unexpected influences on the cytochrome c content. Environ Microbiol 2021; 23:7056-7072. [PMID: 34664382 DOI: 10.1111/1462-2920.15807] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/04/2021] [Accepted: 10/07/2021] [Indexed: 12/13/2022]
Abstract
Thiosulfate, an important form of sulfur compounds, can serve as both electron donor and acceptor in various microorganisms. In Shewanella oneidensis, a bacterium renowned for respiratory versatility, thiosulfate reduction has long been recognized but whether it can catalyse thiosulfate oxidation remains elusive. In this study, we discovered that S. oneidensis is capable of thiosulfate oxidation, a process specifically catalysed by two periplasmic cytochrome c (cyt c) proteins, TsdA and TsdB, which act as the catalytic subunit and the electron transfer subunit respectively. In the presence of oxygen, oxidation of thiosulfate has priority over reduction. Intriguingly, thiosulfate oxidation negatively regulates the cyt c content in S. oneidensis cells, largely by reducing intracellular levels of cAMP, which as the cofactor modulates activity of global regulator Crp required for transcription of many cyt c genes. This unexpected finding provides an additional dimension to interplays between the respiration regulator and the respiratory pathways in S. oneidensis. Moreover, the data presented here identified S. oneidensis as the first bacterium known to date owning both functional thiosulfate reductase and dehydrogenase, and importantly, genomics analyses suggested that the number of bacterial species possessing this feature is rather limited.
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Affiliation(s)
- Qingzi Yu
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
| | - Weining Sun
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
| | - Haichun Gao
- Institute of Microbiology and College of Life Sciences, Zhejiang University, Zhejiang, Hangzhou, 310058, China
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10
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Wu B, Liu F, Fang W, Yang T, Chen GH, He Z, Wang S. Microbial sulfur metabolism and environmental implications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 778:146085. [PMID: 33714092 DOI: 10.1016/j.scitotenv.2021.146085] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/19/2021] [Accepted: 02/20/2021] [Indexed: 06/12/2023]
Abstract
Sulfur as a macroelement plays an important role in biochemistry in both natural environments and engineering biosystems, which can be further linked to other important element cycles, e.g. carbon, nitrogen and iron. Consequently, the sulfur cycling primarily mediated by sulfur compounds oxidizing microorganisms and sulfur compounds reducing microorganisms has enormous environmental implications, particularly in wastewater treatment and pollution bioremediation. In this review, to connect the knowledge in microbial sulfur metabolism to environmental applications, we first comprehensively review recent advances in understanding microbial sulfur metabolisms at molecular-, cellular- and ecosystem-levels, together with their energetics. We then discuss the environmental implications to fight against soil and water pollution, with four foci: (1) acid mine drainage, (2) water blackening and odorization in urban rivers, (3) SANI® and DS-EBPR processes for sewage treatment, and (4) bioremediation of persistent organic pollutants. In addition, major challenges and further developments toward elucidation of microbial sulfur metabolisms and their environmental applications are identified and discussed.
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Affiliation(s)
- Bo Wu
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou 510006, China
| | - Feifei Liu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, State Key Laboratory of Applied Microbiology Southern China, Guangzhou 510070, China
| | - Wenwen Fang
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou 510006, China
| | - Tony Yang
- Swift Current Research and Development Centre, Agriculture and Agri-Food Canada, Swift Current, SK S9H 3X2, Canada
| | - Guang-Hao Chen
- Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Zhili He
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou 510006, China
| | - Shanquan Wang
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou 510006, China.
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11
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Márquez I, Olloqui-Sariego JL, Molero M, Andreu R, Roldán E, Calvente JJ. Active Role of the Buffer in the Proton-Coupled Electron Transfer of Immobilized Iron Porphyrins. Inorg Chem 2021; 60:42-54. [PMID: 32568550 DOI: 10.1021/acs.inorgchem.0c01091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Evaluation of the proton-coupled electron transfer thermodynamics of immobilized hemin is challenging due to the disparity of its electrochemical titration curves reported in the literature. Deviations from the one-electron, one-proton transfer at circumneutral pHs have been commonly ascribed to either the formation of dimeric species or the ionization of a second iron-bound water molecule. Herein, however, we report on non-idealities in the more acidic region, whose onset and extent vary with the nature and concentration of the commonly used phosphate and acetate buffers. It is shown that these deviations originate in the ligand-exchange binding between the oxidized aquo-hemin complex and the anionic components of the buffer, so that they are restricted to the pH interval where these forms coexist. A stepwise approach was developed to quantify unambiguously the apparent and intrinsic binding equilibrium constants. The apparent binding equilibrium constant exhibits a peak-shaped pH dependence, whose maximum is located at approximately the midpoint between the pKa of the iron-bound water and the first pKa of the buffer, and its magnitude is greater for the phosphate than for the acetate buffer. But strikingly, the opposite trend was found for the magnitude of the intrinsic binding equilibrium constants determined from the apparent ones, due to the different relative locations of the phosphoric and acetic pKa values with respect to that of the oxidized aquo-hemin. To probe the role of the heme propionic residues, a similar study was carried out with a propionic-free iron porphyrin containing eight ethyl residues. These substituents decrease the acidity of the iron-bound water, strengthen the iron(III)-acetate binding, weaken the iron(III)-dihydrogen phosphate binding, and enable the binding between iron(III) and monohydrogen phosphate, which was hampered in hemin by the presence of the negatively charged propionate residues. Overall, this work provides a more complete speciation of immobilized iron porphyrins under acidic conditions than previously considered, showing the substitutional lability of the aqua ligand in the oxidized state of the iron center and the reluctance of its hydroxyl counterpart to anion exchange. Knowledge of these redox- and pH-dependent bindings with the buffer components is crucial for a rigorous quantification of the proton-coupled electron transfer and the electrocatalytic activity of iron porphyrins.
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Affiliation(s)
- Inmaculada Márquez
- Departamento de Quı́mica Fı́sica, Universidad de Sevilla, C/Profesor Garcı́a Conzález, 1, 41012 Sevilla, Spain
| | - José Luis Olloqui-Sariego
- Departamento de Quı́mica Fı́sica, Universidad de Sevilla, C/Profesor Garcı́a Conzález, 1, 41012 Sevilla, Spain
| | - Miguel Molero
- Departamento de Quı́mica Fı́sica, Universidad de Sevilla, C/Profesor Garcı́a Conzález, 1, 41012 Sevilla, Spain
| | - Rafael Andreu
- Departamento de Quı́mica Fı́sica, Universidad de Sevilla, C/Profesor Garcı́a Conzález, 1, 41012 Sevilla, Spain
| | - Emilio Roldán
- Departamento de Quı́mica Fı́sica, Universidad de Sevilla, C/Profesor Garcı́a Conzález, 1, 41012 Sevilla, Spain
| | - Juan José Calvente
- Departamento de Quı́mica Fı́sica, Universidad de Sevilla, C/Profesor Garcı́a Conzález, 1, 41012 Sevilla, Spain
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12
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Li DB, Edwards MJ, Blake AW, Newton-Payne SE, Piper SEH, Jenner LP, Sokol KP, Reisner E, Van Wonderen JH, Clarke TA, Butt JN. His/Met heme ligation in the PioA outer membrane cytochrome enabling light-driven extracellular electron transfer by Rhodopseudomonas palustris TIE-1. NANOTECHNOLOGY 2020; 31:354002. [PMID: 32403091 DOI: 10.1088/1361-6528/ab92c7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A growing number of bacterial species are known to move electrons across their cell envelopes. Naturally this occurs in support of energy conservation and carbon-fixation. For biotechnology it allows electron exchange between bacteria and electrodes in microbial fuel cells and during microbial electrosynthesis. In this context Rhodopseudomonas palustris TIE-1 is of much interest. These bacteria respond to light by taking electrons from their external environment, including electrodes, to drive CO2-fixation. The PioA cytochrome, that spans the bacterial outer membrane, is essential for this electron transfer and yet little is known about its structure and electron transfer properties. Here we reveal the ten c-type hemes of PioA are redox active across the window +250 to -400 mV versus Standard Hydrogen Electrode and that the hemes with most positive reduction potentials have His/Met and His/H2O ligation. These chemical and redox properties distinguish PioA from the more widely studied family of MtrA outer membrane decaheme cytochromes with ten His/His ligated hemes. We predict a structure for PioA in which the hemes form a chain spanning the longest dimension of the protein, from Heme 1 to Heme 10. Hemes 2, 3 and 7 are identified as those most likely to have His/Met and/or His/H2O ligation. Sequence analysis suggests His/Met ligation of Heme 2 and/or 7 is a defining feature of decaheme PioA homologs from over 30 different bacterial genera. His/Met ligation of Heme 3 appears to be less common and primarily associated with PioA homologs from purple non-sulphur bacteria belonging to the alphaproteobacteria class.
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Affiliation(s)
- Dao-Bo Li
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom. Present address: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China and State Key Laboratory of Applied Microbiology Southern China, Guangzhou, People's Republic of China
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13
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Pfanzagl V, Beale JH, Michlits H, Schmidt D, Gabler T, Obinger C, Djinović-Carugo K, Hofbauer S. X-ray-induced photoreduction of heme metal centers rapidly induces active-site perturbations in a protein-independent manner. J Biol Chem 2020; 295:13488-13501. [PMID: 32723869 DOI: 10.1074/jbc.ra120.014087] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/24/2020] [Indexed: 12/31/2022] Open
Abstract
Since the advent of protein crystallography, atomic-level macromolecular structures have provided a basis to understand biological function. Enzymologists use detailed structural insights on ligand coordination, interatomic distances, and positioning of catalytic amino acids to rationalize the underlying electronic reaction mechanisms. Often the proteins in question catalyze redox reactions using metal cofactors that are explicitly intertwined with their function. In these cases, the exact nature of the coordination sphere and the oxidation state of the metal is of utmost importance. Unfortunately, the redox-active nature of metal cofactors makes them especially susceptible to photoreduction, meaning that information obtained by photoreducing X-ray sources about the environment of the cofactor is the least trustworthy part of the structure. In this work we directly compare the kinetics of photoreduction of six different heme protein crystal species by X-ray radiation. We show that a dose of ∼40 kilograys already yields 50% ferrous iron in a heme protein crystal. We also demonstrate that the kinetics of photoreduction are completely independent from variables unique to the different samples tested. The photoreduction-induced structural rearrangements around the metal cofactors have to be considered when biochemical data of ferric proteins are rationalized by constraints derived from crystal structures of reduced enzymes.
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Affiliation(s)
- Vera Pfanzagl
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria.
| | | | - Hanna Michlits
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Daniel Schmidt
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Thomas Gabler
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Christian Obinger
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria
| | - Kristina Djinović-Carugo
- Department of Structural and Computational Biology, Max Perutz Labs, University of Vienna, Vienna, Austria; Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia
| | - Stefan Hofbauer
- Department of Chemistry, Institute of Biochemistry, BOKU-University of Natural Resources and Life Sciences, Vienna, Austria.
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14
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Rameez MJ, Pyne P, Mandal S, Chatterjee S, Alam M, Bhattacharya S, Mondal N, Sarkar J, Ghosh W. Two pathways for thiosulfate oxidation in the alphaproteobacterial chemolithotroph Paracoccus thiocyanatus SST. Microbiol Res 2019; 230:126345. [PMID: 31585234 DOI: 10.1016/j.micres.2019.126345] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 09/08/2019] [Accepted: 09/21/2019] [Indexed: 02/02/2023]
Abstract
Chemolithotrophic bacteria oxidize various sulfur species for energy and electrons, thereby operationalizing biogeochemical sulfur cycles in nature. The best-studied pathway of bacterial sulfur-chemolithotrophy involves direct oxidation of thiosulfate (S2O32-) to sulfate (SO42-) without any free intermediate. This pathway mediated by SoxXAYZBCD is apparently the exclusive mechanism of thiosulfate oxidation in facultatively chemolithotrophic alphaproteobacteria. Here we explore the molecular mechanisms of sulfur oxidation in the thiosulfate- and tetrathionate(S4O62-)-oxidizing alphaproteobacterium Paracoccus thiocyanatus SST, and compare them with the prototypical Sox process of Paracoccus pantotrophus. Our results reveal a unique case where an alphaproteobacterium has Sox as its secondary pathway of thiosulfate oxidation converting ∼10% of the thiosulfate supplied, whilst ∼90% of the substrate is oxidized via a pathway that produces tetrathionate as an intermediate. Sulfur oxidation kinetics of a deletion mutant showed that thiosulfate-to-tetrathionate conversion, in SST, is catalyzed by a thiosulfate dehydrogenase (TsdA) homolog that has far-higher substrate-affinity than the Sox system of this bacterium, which in turn is also less efficient than the P. pantotrophus Sox. Deletion of soxB abolished sulfate-formation from thiosulfate/tetrathionate, while thiosulfate-to-tetrathionate conversion remained unperturbed. Physiological studies revealed the involvement of glutathione in SST tetrathionate oxidation. However, zero impact of the insertional mutation of a thiol dehydrotransferase (thdT) homolog, together with the absence of sulfite as an intermediate, indicated that SST tetrathionate oxidation is mechanistically novel, and distinct from its betaproteobacterial counterpart mediated by glutathione, ThdT, SoxBCD and sulfite:acceptor oxidoreductase. The present findings highlight extensive functional diversification of sulfur-oxidizing enzymes across phylogenetically close, as well as distant, bacteria.
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Affiliation(s)
- Moidu Jameela Rameez
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Prosenjit Pyne
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Subhrangshu Mandal
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Sumit Chatterjee
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Masrure Alam
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | | | - Nibendu Mondal
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Jagannath Sarkar
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India
| | - Wriddhiman Ghosh
- Department of Microbiology, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India.
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15
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Shimizu T, Lengalova A, Martínek V, Martínková M. Heme: emergent roles of heme in signal transduction, functional regulation and as catalytic centres. Chem Soc Rev 2019; 48:5624-5657. [DOI: 10.1039/c9cs00268e] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Molecular mechanisms of unprecedented functions of exchangeable/labile heme and heme proteins including transcription, DNA binding, protein kinase activity, K+ channel functions, cis–trans isomerization, N–N bond formation, and other functions are described.
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Affiliation(s)
- Toru Shimizu
- Department of Biochemistry
- Faculty of Science
- Charles University
- Prague 2
- Czech Republic
| | - Alzbeta Lengalova
- Department of Biochemistry
- Faculty of Science
- Charles University
- Prague 2
- Czech Republic
| | - Václav Martínek
- Department of Biochemistry
- Faculty of Science
- Charles University
- Prague 2
- Czech Republic
| | - Markéta Martínková
- Department of Biochemistry
- Faculty of Science
- Charles University
- Prague 2
- Czech Republic
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