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Sun X, LaVoie M, Lefebvre PA, Gallaher SD, Glaesener AG, Strenkert D, Mehta R, Merchant SS, Silflow CD. Mutation of negative regulatory gene CEHC1 encoding an FBXO3 protein results in normoxic expression of HYDA genes in Chlamydomonas reinhardtii. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.22.586359. [PMID: 38586028 PMCID: PMC10996464 DOI: 10.1101/2024.03.22.586359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Oxygen is known to prevent hydrogen production in Chlamydomonas, both by inhibiting the hydrogenase enzyme and by preventing the accumulation of HYDA-encoding transcripts. We developed a screen for mutants showing constitutive accumulation of HYDA1 transcripts in the presence of oxygen. A reporter gene required for ciliary motility, placed under the control of the HYDA1 promoter, conferred motility only in hypoxic conditions. By selecting for mutants able to swim even in the presence of oxygen we obtained strains that express the reporter gene constitutively. One mutant identified a gene encoding an F-box only protein 3 (FBXO3), known to participate in ubiquitylation and proteasomal degradation pathways in other eukaryotes. Transcriptome profiles revealed that the mutation, termed cehc1-1 , leads to constitutive expression of HYDA1 and other genes regulated by hypoxia, and of many genes known to be targets of CRR1, a transcription factor in the nutritional copper signaling pathway. CRR1 was required for the constitutive expression of the HYDA1 reporter gene in cehc1-1 mutants. The CRR1 protein, which is normally degraded in Cu-supplemented cells, was stabilized in cehc1-1 cells, supporting the conclusion that CEHC1 acts to facilitate the degradation of CRR1. Our results reveal a novel negative regulator in the CRR1 pathway and possibly other pathways leading to complex metabolic changes associated with response to hypoxia.
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Egas RA, Kurth JM, Boeren S, Sousa DZ, Welte CU, Sánchez-Andrea I. A novel mechanism for dissimilatory nitrate reduction to ammonium in Acididesulfobacillus acetoxydans. mSystems 2024; 9:e0096723. [PMID: 38323850 PMCID: PMC10949509 DOI: 10.1128/msystems.00967-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 12/25/2023] [Indexed: 02/08/2024] Open
Abstract
The biological route of nitrate reduction has important implications for the bioavailability of nitrogen within ecosystems. Nitrate reduction via nitrite, either to ammonium (ammonification) or to nitrous oxide or dinitrogen (denitrification), determines whether nitrogen is retained within the system or lost as a gas. The acidophilic sulfate-reducing bacterium (aSRB) Acididesulfobacillus acetoxydans can perform dissimilatory nitrate reduction to ammonium (DNRA). While encoding a Nar-type nitrate reductase, A. acetoxydans lacks recognized nitrite reductase genes. In this study, A. acetoxydans was cultivated under conditions conducive to DNRA. During cultivations, we monitored the production of potential nitrogen intermediates (nitrate, nitrite, nitric oxide, hydroxylamine, and ammonium). Resting cell experiments were performed with nitrate, nitrite, and hydroxylamine to confirm their reduction to ammonium, and formed intermediates were tracked. To identify the enzymes involved in DNRA, comparative transcriptomics and proteomics were performed with A. acetoxydans growing under nitrate- and sulfate-reducing conditions. Nitrite is likely reduced to ammonia by the previously undescribed nitrite reductase activity of the NADH-linked sulfite reductase AsrABC, or by a putatively ferredoxin-dependent homolog of the nitrite reductase NirA (DEACI_1836), or both. We identified enzymes and intermediates not previously associated with DNRA and nitrosative stress in aSRB. This increases our knowledge about the metabolism of this type of bacteria and helps the interpretation of (meta)genome data from various ecosystems on their DNRA potential and the nitrogen cycle.IMPORTANCENitrogen is crucial to any ecosystem, and its bioavailability depends on microbial nitrogen-transforming reactions. Over the recent years, various new nitrogen-transforming reactions and pathways have been identified, expanding our view on the nitrogen cycle and metabolic versatility. In this study, we elucidate a novel mechanism employed by Acididesulfobacillus acetoxydans, an acidophilic sulfate-reducing bacterium, to reduce nitrate to ammonium. This finding underscores the diverse physiological nature of dissimilatory reduction to ammonium (DNRA). A. acetoxydans was isolated from acid mine drainage, an extremely acidic environment where nitrogen metabolism is poorly studied. Our findings will contribute to understanding DNRA potential and variations in extremely acidic environments.
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Affiliation(s)
- Reinier A. Egas
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Julia M. Kurth
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
- Microcosm Earth Centre, Philipps-Universität Marburg & Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Sjef Boeren
- Laboratory of Biochemistry, Wageningen University & Research, Wageningen, The Netherlands
| | - Diana Z. Sousa
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
- Centre for Living Technologies, Alliance TU/e, WUR, UU, UMC Utrecht, Utrecht, The Netherlands
| | - Cornelia U. Welte
- Department of Microbiology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, The Netherlands
| | - Irene Sánchez-Andrea
- Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands
- Department of Environmental Sciences for Sustainability, IE University, Segovia, Spain
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Fujishiro T, Takaoka K. Class III hybrid cluster protein homodimeric architecture shows evolutionary relationship with Ni, Fe-carbon monoxide dehydrogenases. Nat Commun 2023; 14:5609. [PMID: 37709776 PMCID: PMC10502027 DOI: 10.1038/s41467-023-41289-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 08/30/2023] [Indexed: 09/16/2023] Open
Abstract
Hybrid cluster proteins (HCPs) are Fe-S-O cluster-containing metalloenzymes in three distinct classes (class I and II: monomer, III: homodimer), all of which structurally related to homodimeric Ni, Fe-carbon monoxide dehydrogenases (CODHs). Here we show X-ray crystal structure of class III HCP from Methanothermobacter marburgensis (Mm HCP), demonstrating its homodimeric architecture structurally resembles those of CODHs. Also, despite the different architectures of class III and I/II HCPs, [4Fe-4S] and hybrid clusters are found in equivalent positions in all HCPs. Structural comparison of Mm HCP and CODHs unveils some distinct features such as the environments of their homodimeric interfaces and the active site metalloclusters. Furthermore, structural analysis of Mm HCP C67Y and characterization of several Mm HCP variants with a Cys67 mutation reveal the significance of Cys67 in protein structure, metallocluster binding and hydroxylamine reductase activity. Structure-based bioinformatics analysis of HCPs and CODHs provides insights into the structural evolution of the HCP/CODH superfamily.
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Affiliation(s)
- Takashi Fujishiro
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Shimo-Okubo 255, Sakura-ku, Saitama, 338-8570, Japan.
| | - Kyosei Takaoka
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Shimo-Okubo 255, Sakura-ku, Saitama, 338-8570, Japan
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Lemaire ON, Belhamri M, Wagner T. Structural and biochemical elucidation of class I hybrid cluster protein natively extracted from a marine methanogenic archaeon. Front Microbiol 2023; 14:1179204. [PMID: 37250035 PMCID: PMC10210160 DOI: 10.3389/fmicb.2023.1179204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 04/03/2023] [Indexed: 05/31/2023] Open
Abstract
Whilst widespread in the microbial world, the hybrid cluster protein (HCP) has been paradoxically a long-time riddle for microbiologists. During three decades, numerous studies on a few model organisms unravelled its structure and dissected its metal-containing catalyst, but the physiological function of the enzyme remained elusive. Recent studies on bacteria point towards a nitric oxide reductase activity involved in resistance during nitrate and nitrite reduction as well as host infection. In this study, we isolated and characterised a naturally highly produced HCP class I from a marine methanogenic archaeon grown on ammonia. The crystal structures of the enzyme in a reduced and partially oxidised state, obtained at a resolution of 1.45 and 1.36-Å, respectively, offered a precise picture of the archaeal enzyme intimacy. There are striking similarities with the well-studied enzymes from Desulfovibrio species regarding sequence, kinetic parameters, structure, catalyst conformations, and internal channelling systems. The close phylogenetic relationship between the enzymes from Methanococcales and many Bacteria corroborates this similarity. Indeed, Methanococcales HCPs are closer to these bacterial homologues than to any other archaeal enzymes. The relatively high constitutive production of HCP in M. thermolithotrophicus, in the absence of a notable nitric oxide source, questions the physiological function of the enzyme in these ancient anaerobes.
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Jeoung JH, Fesseler J, Domnik L, Klemke F, Sinnreich M, Teutloff C, Dobbek H. A Morphing [4Fe-3S-nO]-Cluster within a Carbon Monoxide Dehydrogenase Scaffold. Angew Chem Int Ed Engl 2022; 61:e202117000. [PMID: 35133707 PMCID: PMC9311411 DOI: 10.1002/anie.202117000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Indexed: 11/12/2022]
Abstract
Ni,Fe‐containing carbon monoxide dehydrogenases (CODHs) catalyze the reversible reduction of CO2 to CO. Several anaerobic microorganisms encode multiple CODHs in their genome, of which some, despite being annotated as CODHs, lack a cysteine of the canonical binding motif for the active site Ni,Fe‐cluster. Here, we report on the structure and reactivity of such a deviant enzyme, termed CooS‐VCh. Its structure reveals the typical CODH scaffold, but contains an iron‐sulfur‐oxo hybrid‐cluster. Although closely related to true CODHs, CooS‐VCh catalyzes neither CO oxidation, nor CO2 reduction. The active site of CooS‐VCh undergoes a redox‐dependent restructuring between a reduced [4Fe‐3S]‐cluster and an oxidized [4Fe‐2S‐S*‐2O‐2(H2O)]‐cluster. Hydroxylamine, a slow‐turnover substrate of CooS‐VCh, oxidizes the hybrid‐cluster in two structurally distinct steps. Overall, minor changes in CODHs are sufficient to accommodate a Fe/S/O‐cluster in place of the Ni,Fe‐heterocubane‐cluster of CODHs.
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Affiliation(s)
- Jae-Hun Jeoung
- Humboldt-Universität zu Berlin, Institut für Biologie, Unter den Linden 6, 10099, Berlin, Germany
| | - Jochen Fesseler
- Humboldt-Universität zu Berlin, Institut für Biologie, Unter den Linden 6, 10099, Berlin, Germany
| | - Lilith Domnik
- Humboldt-Universität zu Berlin, Institut für Biologie, Unter den Linden 6, 10099, Berlin, Germany
| | - Friederike Klemke
- Humboldt-Universität zu Berlin, Institut für Biologie, Unter den Linden 6, 10099, Berlin, Germany
| | - Malte Sinnreich
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195, Berlin, Germany
| | - Christian Teutloff
- Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195, Berlin, Germany
| | - Holger Dobbek
- Humboldt-Universität zu Berlin, Institut für Biologie, Unter den Linden 6, 10099, Berlin, Germany
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Jeoung J, Fesseler J, Domnik L, Klemke F, Sinnreich M, Teutloff C, Dobbek H. Ein sich umstrukturierender [4Fe‐3S‐nO]‐Cluster in einem Kohlenmonoxid‐Dehydrogenase‐Gerüst. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202117000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jae‐Hun Jeoung
- Humboldt-Universität zu Berlin Institut für Biologie Unter den Linden 6 10099 Berlin Deutschland
| | - Jochen Fesseler
- Humboldt-Universität zu Berlin Institut für Biologie Unter den Linden 6 10099 Berlin Deutschland
| | - Lilith Domnik
- Humboldt-Universität zu Berlin Institut für Biologie Unter den Linden 6 10099 Berlin Deutschland
| | - Friederike Klemke
- Humboldt-Universität zu Berlin Institut für Biologie Unter den Linden 6 10099 Berlin Deutschland
| | - Malte Sinnreich
- Freie Universität Berlin, Fachbereich Physik Arnimallee 14 14195 Berlin Deutschland
| | - Christian Teutloff
- Freie Universität Berlin, Fachbereich Physik Arnimallee 14 14195 Berlin Deutschland
| | - Holger Dobbek
- Humboldt-Universität zu Berlin Institut für Biologie Unter den Linden 6 10099 Berlin Deutschland
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Fujishiro T, Ooi M, Takaoka K. Crystal structure of Escherichia coli class II hybrid cluster protein, HCP, reveals a [4Fe-4S] cluster at the N-terminal protrusion. FEBS J 2021; 288:6752-6768. [PMID: 34101368 DOI: 10.1111/febs.16062] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 05/06/2021] [Accepted: 06/07/2021] [Indexed: 01/26/2023]
Abstract
Hybrid cluster protein (HCP) is a unique Fe-S-O-type metallocluster-containing enzyme present in many anaerobic organisms and is categorized into three distinct classes (I, II, and III). The class II HCP uniquely utilizes hybrid cluster protein reductase (HCR), unlike the other classes of HCPs. To gain structural insights into the electron transfer system between the class II HCP and HCR, we elucidated the X-ray crystal structure of Escherichia coli HCP (Ec HCP), representing the first report of a class II HCP structure. Surprisingly, Ec HCP was found to harbor a [4Fe-4S] cluster rather than a [2Fe-2S] cluster at the N-terminal Cys-rich region, similar to class I HCPs. It was also found that the Cys-rich motif forms a unique protrusion and that the surrounding charge distributions on the surface of class II Ec HCP are distinct from those of class I HCPs. The functional significance of the Cys-rich region was investigated using an Ec HCP variant (chimeric HCP) containing a class I HCP Cys-rich motif from Desulfovibrio desulfuricans. The biochemical analyses showed that the chimeric HCP lacks the hybrid cluster and the electron-accepting function from HCR despite the formation of the chimeric HCP-HCR complex. Furthermore, HCP-HCR molecular docking analysis suggested that the protrusion area serves as an HCR-binding region. Therefore, the protrusion of the unique Cys-rich motif and the surrounding area of class II HCP are likely important for maturation of Ec HCP and orienting HCR onto the surface of HCP to facilitate electron transfer in the HCP-HCR complex.
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Affiliation(s)
- Takashi Fujishiro
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Miho Ooi
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Kyosei Takaoka
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
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Cole JA. Anaerobic bacterial response to nitric oxide stress: Widespread misconceptions and physiologically relevant responses. Mol Microbiol 2021; 116:29-40. [PMID: 33706420 DOI: 10.1111/mmi.14713] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 03/04/2021] [Accepted: 03/09/2021] [Indexed: 11/27/2022]
Abstract
How anaerobic bacteria protect themselves against nitric oxide-induced stress is controversial, not least because far higher levels of stress were used in the experiments on which most of the literature is based than bacteria experience in their natural environments. This results in chemical damage to enzymes that inactivates their physiological function. This review illustrates how transcription control mechanisms reveal physiological roles of the encoded gene products. Evidence that the hybrid cluster protein, Hcp, is a major high affinity NO reductase in anaerobic bacteria is reviewed: if so, its trans-nitrosation activity is a nonspecific secondary consequence of chemical inactivation. Whether the flavorubredoxin, NorV, is equally effective at such low [NO] is unknown. YtfE is proposed to be an enzyme rather than a source of iron for the repair of iron-sulfur proteins damaged by nitrosative stress. Any reaction catalyzed by YtfE needs to be revealed. The concentration of NO that accumulates in the cytoplasm of anaerobic bacteria is unknown, but indirect evidence indicates that it is in the pM to low nM range. Also unknown are the functions of the NO-inducible cytoplasmic proteins YgbA, YeaR, or YoaG. Experiments to resolve some of these questions are proposed.
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Affiliation(s)
- J A Cole
- School of Biosciences and Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
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Reed CJ, Lam QN, Mirts EN, Lu Y. Molecular understanding of heteronuclear active sites in heme-copper oxidases, nitric oxide reductases, and sulfite reductases through biomimetic modelling. Chem Soc Rev 2021; 50:2486-2539. [PMID: 33475096 PMCID: PMC7920998 DOI: 10.1039/d0cs01297a] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Heme-copper oxidases (HCO), nitric oxide reductases (NOR), and sulfite reductases (SiR) catalyze the multi-electron and multi-proton reductions of O2, NO, and SO32-, respectively. Each of these reactions is important to drive cellular energy production through respiratory metabolism and HCO, NOR, and SiR evolved to contain heteronuclear active sites containing heme/copper, heme/nonheme iron, and heme-[4Fe-4S] centers, respectively. The complexity of the structures and reactions of these native enzymes, along with their large sizes and/or membrane associations, make it challenging to fully understand the crucial structural features responsible for the catalytic properties of these active sites. In this review, we summarize progress that has been made to better understand these heteronuclear metalloenzymes at the molecular level though study of the native enzymes along with insights gained from biomimetic models comprising either small molecules or proteins. Further understanding the reaction selectivity of these enzymes is discussed through comparisons of their similar heteronuclear active sites, and we offer outlook for further investigations.
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Affiliation(s)
- Christopher J Reed
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urban, IL 61801, USA.
| | - Quan N Lam
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urban, IL 61801, USA
| | - Evan N Mirts
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urban, IL 61801, USA. and Department of Biochemistry, University of Illinois at Urbana-Champaign, Urban, IL 61801, USA and Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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