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Akutsu Y, Fujiwara T, Suzuki R, Nishigaya Y, Yamazaki T. Juglone, a plant-derived 1,4-naphthoquinone, binds to hydroxylamine oxidoreductase and inhibits the electron transfer to cytochrome c554. Appl Environ Microbiol 2023; 89:e0129123. [PMID: 38009977 PMCID: PMC10734522 DOI: 10.1128/aem.01291-23] [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: 08/10/2023] [Accepted: 09/20/2023] [Indexed: 11/29/2023] Open
Abstract
IMPORTANCE Nitrification, the microbial conversion of ammonia to nitrate via nitrite, plays a pivotal role in the global nitrogen cycle. However, the excessive use of ammonium-based fertilizers in agriculture has disrupted this cycle, leading to groundwater pollution and greenhouse gas emissions. In this study, we have demonstrated the inhibitory effects of plant-derived juglone and related 1,4-naphthoquinones on the nitrification process in Nitrosomonas europaea. Notably, the inhibition mechanism is elucidated in which 1,4-naphthoquinones interact with hydroxylamine oxidoreductase, disrupting the electron transfer to cytochrome c554, a physiological electron acceptor. These findings support the notion that phytochemicals can impede nitrification by interfering with the essential electron transfer process in ammonia oxidation. The findings presented in this article offer valuable insights for the development of strategies aimed at the management of nitrification, reduction of fertilizer utilization, and mitigation of greenhouse gas emissions.
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Affiliation(s)
- Yukie Akutsu
- Research Center for Advanced Analysis, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan
| | - Takaaki Fujiwara
- Research Center for Advanced Analysis, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan
| | - Rintaro Suzuki
- Research Center for Advanced Analysis, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan
| | | | - Toshimasa Yamazaki
- Research Center for Advanced Analysis, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan
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2
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Ferousi C, Schmitz RA, Maalcke WJ, Lindhoud S, Versantvoort W, Jetten MSM, Reimann J, Kartal B. Characterization of a nitrite-reducing octaheme hydroxylamine oxidoreductase that lacks the tyrosine cross-link. J Biol Chem 2021; 296:100476. [PMID: 33652023 PMCID: PMC8042395 DOI: 10.1016/j.jbc.2021.100476] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/18/2021] [Accepted: 02/24/2021] [Indexed: 02/06/2023] Open
Abstract
The hydroxylamine oxidoreductase (HAO) family consists of octaheme proteins that harbor seven bis-His ligated electron-transferring hemes and one 5-coordinate catalytic heme with His axial ligation. Oxidative HAOs have a homotrimeric configuration with the monomers covalently attached to each other via a unique double cross-link between a Tyr residue and the catalytic heme moiety of an adjacent subunit. This cross-linked active site heme, termed the P460 cofactor, has been hypothesized to modulate enzyme reactivity toward oxidative catalysis. Conversely, the absence of this cross-link is predicted to favor reductive catalysis. However, this prediction has not been directly tested. In this study, an HAO homolog that lacks the heme-Tyr cross-link (HAOr) was purified to homogeneity from the nitrite-dependent anaerobic ammonium-oxidizing (anammox) bacterium Kuenenia stuttgartiensis, and its catalytic and spectroscopic properties were assessed. We show that HAOr reduced nitrite to nitric oxide and also reduced nitric oxide and hydroxylamine as nonphysiological substrates. In contrast, HAOr was not able to oxidize hydroxylamine or hydrazine supporting the notion that cross-link-deficient HAO enzymes are reductases. Compared with oxidative HAOs, we found that HAOr harbors an active site heme with a higher (at least 80 mV) midpoint potential and a much lower degree of porphyrin ruffling. Based on the physiology of anammox bacteria and our results, we propose that HAOr reduces nitrite to nitric oxide in vivo, providing anammox bacteria with NO, which they use to activate ammonium in the absence of oxygen.
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Affiliation(s)
- Christina Ferousi
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
| | - Rob A Schmitz
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
| | - Wouter J Maalcke
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
| | - Simon Lindhoud
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
| | - Wouter Versantvoort
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
| | - Joachim Reimann
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Nijmegen, The Netherlands
| | - Boran Kartal
- Microbial Physiology Group, Max Planck Institute for Marine Microbiology, Bremen, Germany.
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3
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Abstract
Ammonia-oxidizing bacteria (AOB) convert ammonia (NH3) to nitrite (NO2-) as their primary metabolism and thus provide a blueprint for the use of NH3 as a chemical fuel. The first energy-producing step involves the homotrimeric enzyme hydroxylamine oxidoreductase (HAO), which was originally reported to oxidize hydroxylamine (NH2OH) to NO2-. HAO uses the heme P460 cofactor as the site of catalysis. This heme is supported by seven other c hemes in each monomer that mediate electron transfer. Heme P460 cofactors are c-heme-based cofactors that have atypical protein cross-links between the peptide backbone and the porphyrin macrocycle. This cofactor has been observed in both the HAO and cytochrome (cyt) P460 protein families. However, there are differences; specifically, HAO uses a single tyrosine residue to form two covalent attachments to the macrocycle whereas cyt P460 uses a lysine residue to form one. In Nitrosomonas europaea, which expresses both HAO and cyt P460, these enzymes achieve the oxidation of NH2OH and were both originally reported to produce NO2-. Each can inspire means to effect controlled release of chemical energy.Spectroscopically studying the P460 cofactors of HAO is complicated by the 21 non-P460 heme cofactors, which obscure the active site. However, monoheme cyt P460 is more approachable biochemically and spectroscopically. Thus, we have used cyt P460 to study biological NH2OH oxidation. Under aerobic conditions substoichiometric production of NO2- was observed along with production of nitrous oxide (N2O). Under anaerobic conditions, however, N2O was the exclusive product of NH2OH oxidation. We have advanced our understanding of the mechanism of this enzyme and have showed that a key intermediate is a ferric nitrosyl that can dissociate the bound nitric oxide (NO) molecule and react with O2, thus producing NO2- abiotically. Because N2O was the true product of one P460 cofactor-containing enzyme, this prompted us to reinvestigate whether NO2- is enzymatically generated from HAO catalysis. Like cyt P460, we showed that HAO does not produce NO2- enzymatically, but unlike cyt P460, its final product is NO, establishing it as an intermediate of nitrification. More broadly, NO can be recognized as a molecule common to the primary metabolisms of all organisms involved in nitrogen "defixation".Delving deeper into cyt P460 yielded insights broadly applicable to controlled biochemical redox processes. Studies of an inactive cyt P460 from Nitrosomonas sp. AL212 showed that this enzyme was unable to oxidize NH2OH because it lacked a glutamate residue in its secondary coordination sphere that was present in the active N. europaea cyt P460 variant. Restoring the Glu residue imbued activity, revealing that a second-sphere base is Nature's key to controlled oxidation of NH2OH. A key lesson of bioinorganic chemistry is reinforced: the polypeptide matrix is an essential part of dictating function. Our work also exposed some key functional contributions of noncanonical heme-protein cross-links. The heme-Lys cross-link of cyt P460 enforces the relative position of the cofactor and second-sphere residues. Moreover, the cross-link prevents the dissociation of the axial histidine residue, which stops catalysis, emphasizing the importance of this unique post-translational modification.
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Affiliation(s)
- Rachael E. Coleman
- Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Kyle M. Lancaster
- Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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4
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Adams HR, Krewson C, Vardanega JE, Fujii S, Moreno-Chicano T, Moreno T, Chicano, Sambongi Y, Svistunenko D, Paps J, Andrew CR, Hough MA. One fold, two functions: cytochrome P460 and cytochrome c'-β from the methanotroph Methylococcus capsulatus (Bath). Chem Sci 2019; 10:3031-3041. [PMID: 30996884 PMCID: PMC6427953 DOI: 10.1039/c8sc05210g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 01/20/2019] [Indexed: 11/21/2022] Open
Abstract
Nature is adept at utilising highly similar protein folds to carry out very different functions, yet the mechanisms by which this functional divergence occurs remain poorly characterised. In certain methanotrophic bacteria, two homologous pentacoordinate c-type heme proteins have been identified: a cytochrome P460 (cyt P460) and a cytochrome c'-β (cyt cp-β). Cytochromes P460 are able to convert hydroxylamine to nitrous oxide (N2O), a potent greenhouse gas. This reactivity is similar to that of hydroxylamine oxidoreductase (HAO), which is a key enzyme in nitrifying and methanotrophic bacteria. Cyt P460 and HAO both have unusual protein-heme cross-links, formed by a Tyr residue in HAO and a Lys in cyt P460. In contrast, cyts cp-β (the only known cytochromes c' with a β-sheet fold) lack this crosslink and appears to be optimized for binding non-polar molecules (including NO and CO) without enzymatic conversion. Our bioinformatics analysis supports the proposal that cyt cp-β may have evolved from cyt P460 via a gene duplication event. Using high-resolution X-ray crystallography, UV-visible absorption, electron paramagnetic resonance (EPR) and resonance Raman spectroscopy, we have characterized the overall protein folding and active site structures of cyt cp-β and cyt P460 from the obligate methanotroph, Methylococcus capsulatus (Bath). These proteins display a similar β-sheet protein fold, together with a pattern of changes to the heme pocket regions and localised tertiary structure that have converted a hydroxylamine oxidizing enzyme into a gas-binding protein. Structural comparisons provide insights relevant to enzyme redesign for synthetic enzymology and engineering of gas sensor proteins. We also show the widespread occurrence of cyts cp-β and characterise their phylogeny.
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Affiliation(s)
- Hannah R Adams
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
| | - Callie Krewson
- Department of Chemistry and Biochemistry , Eastern Oregon University , La Grande , Oregon 97850 , USA .
| | - Jenny E Vardanega
- Department of Chemistry and Biochemistry , Eastern Oregon University , La Grande , Oregon 97850 , USA .
| | - Sotaro Fujii
- Graduate School of Biosphere Science , Hiroshima University , Kagamiyama 1-4-4, Higashi-Hiroshima , Hiroshima , 739-8528 , Japan
| | | | - Tadeo Moreno
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
| | - Chicano
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
| | - Yoshihiro Sambongi
- Graduate School of Biosphere Science , Hiroshima University , Kagamiyama 1-4-4, Higashi-Hiroshima , Hiroshima , 739-8528 , Japan
| | - Dimitri Svistunenko
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
| | - Jordi Paps
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
| | - Colin R Andrew
- Department of Chemistry and Biochemistry , Eastern Oregon University , La Grande , Oregon 97850 , USA .
| | - Michael A Hough
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
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Yang Y, Lin E, Huang S. Heterotrophic nitrogen removal in Bacillus sp. K5: involvement of a novel hydroxylamine oxidase. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2017; 76:3461-3467. [PMID: 29236024 DOI: 10.2166/wst.2017.510] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
An aerobic denitrifying bacterium isolated from a bio-trickling filter treating NOx, Bacillus sp. K5, is able to convert ammonium to nitrite, in which hydroxylamine oxidase (HAO) plays a critical role. In the present study, the performance for simultaneous nitrification and denitrification was investigated with batch experiments and an HAO was purified by an anion-exchange and gel-filtration chromatography from strain K5. The purified HAO's molecular mass was determined by SDS-PAGE and its activity by measuring the change in the concentration of ferricyanide, the electron acceptor. Results showed that as much as 87.8 mg L-1 ammonium-N was removed without nitrite accumulation within 24 hours in the sodium citrate medium at C/N of 15. The HAO isolated from the strain K5 was approximately 71 KDa. With hydroxylamine (NH2OH) as a substrate and potassium ferricyanide as an electron acceptor, the enzyme was capable of oxidizing NH2OH to nitrite in vitro when the pH varied from 7 to 9 and temperature ranged from 25 °C to 40 °C. This is the first time that an HAO has been purified from the Bacillus genus, and the findings revealed that it is distinctive in its molecular mass and enzyme properties.
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Affiliation(s)
- Yunlong Yang
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ershu Lin
- College of Life Science, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shaobin Huang
- The Key Laboratory of Environmental Protection and Eco-Remediation of Guangdong Regular Higher Education Institutions, Guangzhou 510006, China and School of Environment and Energy, South China University of Technology, Guangzhou 510006, China E-mail:
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6
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Nishigaya Y, Fujimoto Z, Yamazaki T. Optimized inhibition assays reveal different inhibitory responses of hydroxylamine oxidoreductases from beta- and gamma-proteobacterial ammonium-oxidizing bacteria. Biochem Biophys Res Commun 2016; 476:127-33. [DOI: 10.1016/j.bbrc.2016.05.041] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 05/08/2016] [Indexed: 10/21/2022]
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7
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Maalcke WJ, Dietl A, Marritt SJ, Butt JN, Jetten MSM, Keltjens JT, Barends TRM, Kartal B. Structural basis of biological NO generation by octaheme oxidoreductases. J Biol Chem 2013; 289:1228-42. [PMID: 24302732 DOI: 10.1074/jbc.m113.525147] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Nitric oxide is an important molecule in all domains of life with significant biological functions in both pro- and eukaryotes. Anaerobic ammonium-oxidizing (anammox) bacteria that contribute substantially to the release of fixed nitrogen into the atmosphere use the oxidizing power of NO to activate inert ammonium into hydrazine (N2H4). Here, we describe an enzyme from the anammox bacterium Kuenenia stuttgartiensis that uses a novel pathway to make NO from hydroxylamine. This new enzyme is related to octaheme hydroxylamine oxidoreductase, a key protein in aerobic ammonium-oxidizing bacteria. By a multiphasic approach including the determination of the crystal structure of the K. stuttgartiensis enzyme at 1.8 Å resolution and refinement and reassessment of the hydroxylamine oxidoreductase structure from Nitrosomonas europaea, both in the presence and absence of their substrates, we propose a model for NO formation by the K. stuttgartiensis enzyme. Our results expand the understanding of the functions that the widespread family of octaheme proteins have.
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Affiliation(s)
- Wouter J Maalcke
- From the Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, 6525AJ Nijmegen, The Netherlands
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8
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Cedervall P, Hooper AB, Wilmot CM. Structural Studies of Hydroxylamine Oxidoreductase Reveal a Unique Heme Cofactor and a Previously Unidentified Interaction Partner. Biochemistry 2013; 52:6211-8. [DOI: 10.1021/bi400960w] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Peder Cedervall
- Department
of Biochemistry,
Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Alan B. Hooper
- Department
of Biochemistry,
Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Carrie M. Wilmot
- Department
of Biochemistry,
Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
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