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Zhang H, Cheng Y, Qiu L, Zeng W, Hu T, Yang J, Wang J, Wang H, Gong W, Liang H. In situ electron generation through Fe/C supported sludge coupled with a counter-diffusion biofilm for electron-deficient wastewater treatment: Binding properties and catalytic competition mechanism of nitrate reductase. WATER RESEARCH 2024; 257:121688. [PMID: 38723349 DOI: 10.1016/j.watres.2024.121688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/15/2024] [Accepted: 04/27/2024] [Indexed: 05/29/2024]
Abstract
A membrane-aerated biofilm-coupled Fe/C supported sludge system (MABR-Fe/C) was constructed to achieve in situ electron production for NO3--N reduction enhancement in different Fe/C loadings (10 g and 200 g). The anoxic environment formed in the MABR-Fe/C promoted a continual Fe2+release of Fe/C in 120 d operation (average Fe2+concentrations is 1.18 and 2.95 mg/L in MABR-Fe/C10 and MABR-Fe/C200, respectively). Metagenomics results suggested that the electrons generated from ongoing Fe2+ oxidation were transferred via the Quinone pool to EC 1.7.5.1 rather than EC 1.9.6.1 to complete the process of NO3--N reduction to NO2--N in Acidovorax, Ottowia, and Polaromonas. In the absence of organic matter, the NO3--N removal in MABR-Fe/C10 and MABR-Fe/C200 increased by 11.99 and 12.52 mg/L, respectively, compared to that in MABR. In the further NO2--N reduction, even if the minimum binding free energy (MBFE) was low, NO2--N in Acidovorax and Dechloromonas preferentially bind the Gln-residues for dissimilatory nitrate reduction (DNR) in the presence of Fe/C. Increasing Fe/C loading (MABR-Fe/C200) caused the formation of different residue binding sites, further enhancing the already dominant DNR. When DNR in MABR-Fe/C200 intensified, the TN in the effluent increased by 3.75 mg/L although the effluent NO3--N concentration was lower than that in MABR-Fe/C10. This study demonstrated a new MABR-Fe/C system for in situ electron generation to enhance biological nitrogen removal and analyzed the NO3--N reduction pathway and metabolic mechanism, thus providing new ideas for nitrogen removal in electron-deficient wastewater.
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Affiliation(s)
- Han Zhang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Yufei Cheng
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Linhong Qiu
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Weichen Zeng
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Tianyi Hu
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Jiaxuan Yang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Jinlong Wang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Hesong Wang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China
| | - Weijia Gong
- School of Engineering, Northeast Agricultural University, 600 Changjiang Street, Xiangfang District, Harbin, 150030, PR China
| | - Heng Liang
- State Key Laboratory of Urban Water Resource and Environment (SKLUWRE), Harbin Institute of Technology, 73 Huanghe Road, Nangang District, Harbin, 150090, PR China.
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2
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Liang H, Jia Y, Khanal SK, Huang D, Sun L, Lu H. Electrochemical-coupled sulfur-driven autotrophic denitrification for nitrogen removal from raw landfill leachate: Evaluation of performance and mechanisms. WATER RESEARCH 2024; 256:121592. [PMID: 38626614 DOI: 10.1016/j.watres.2024.121592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 04/03/2024] [Accepted: 04/08/2024] [Indexed: 04/18/2024]
Abstract
The cost-effective and environment-friendly sulfur-driven autotrophic denitrification (SdAD) process has drawn significant attention for advanced nitrogen removal from low carbon-to-nitrogen (C/N) ratio wastewater in recent years. However, achieving efficient nitrogen removal and maintaining system stability of SdAD process in treating low C/N landfill leachate treatment have been a major challenge. In this study, a novel electrochemical-coupled sulfur-driven autotrophic denitrification (ESdAD) system was developed and compared with SdAD system through a long-term continuous study. Superior nitrogen removal performance (removal efficiency of 89.1 ± 2.5 %) was achieved in ESdAD system compared to SdAD process when treating raw landfill leachate (influent total nitrogen (TN) concentration of 241.7 ± 36.3 mg-N/L), and the effluent TN concentration of ESdAD bioreactor was as low as 24.8 ± 5.1 mg-N/L, which meets the discharge standard of China (< 40 mg N/L). Moreover, less sulfate production rate (1.3 ± 0.2 mg SO42--S/mgNOx--N vs 1.7 ± 0.2 mg SO42--S/mgNOx--N) and excellent pH modulation (pH of 6.9 ± 0.2 vs 5.8 ± 0.4) were also achieved in the ESdAD system compared to SdAD system. The improvement of ESdAD system performance was contributed to coexistence and interaction of heterotrophic bacteria (e.g., Rhodanobacter, Thermomonas, etc.), sulfur autotrophic bacteria (e.g., Thiobacillus, Sulfurimonas, Ignavibacterium etc.) and hydrogen autotrophic bacteria (e.g., Thauera, Comamonas, etc.) under current stimulation. In addition, microbial nitrogen metabolic activity, including functional enzyme (e.g., Nar and Nir) activities and electron transfer capacity of extracellular polymeric substances (EPS) and cytochrome c (Cyt-C), were also enhanced during current stimulation, which facilitated the nitrogen removal and maintained system stability. These findings suggested that ESdAD is an effective and eco-friendly process for advanced nitrogen removal for low C/N wastewater.
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Affiliation(s)
- Huiyu Liang
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-Sen University), Guangzhou, PR China
| | - Yanyan Jia
- School of Ecology, Sun Yat-Sen University, Shenzhen, PR China
| | - Samir Kumar Khanal
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, USA
| | - Dongqi Huang
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-Sen University), Guangzhou, PR China
| | - Lianpeng Sun
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-Sen University), Guangzhou, PR China
| | - Hui Lu
- School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, PR China; Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-Sen University), Guangzhou, PR China.
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3
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Roger M, Leone P, Blackburn NJ, Horrell S, Chicano TM, Biaso F, Giudici-Orticoni MT, Abriata LA, Hura GL, Hough MA, Sciara G, Ilbert M. Beyond the coupled distortion model: structural analysis of the single domain cupredoxin AcoP, a green mononuclear copper centre with original features. Dalton Trans 2024; 53:1794-1808. [PMID: 38170898 PMCID: PMC10804444 DOI: 10.1039/d3dt03372d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 11/30/2023] [Indexed: 01/05/2024]
Abstract
Cupredoxins are widely occurring copper-binding proteins with a typical Greek-key beta barrel fold. They are generally described as electron carriers that rely on a T1 copper centre coordinated by four ligands provided by the folded polypeptide. The discovery of novel cupredoxins demonstrates the high diversity of this family, with variations in terms of copper-binding ligands, copper centre geometry, redox potential, as well as biological function. AcoP is a periplasmic cupredoxin belonging to the iron respiratory chain of the acidophilic bacterium Acidithiobacillus ferrooxidans. AcoP presents original features, including high resistance to acidic pH and a constrained green-type copper centre of high redox potential. To understand the unique properties of AcoP, we undertook structural and biophysical characterization of wild-type AcoP and of two Cu-ligand mutants (H166A and M171A). The crystallographic structures, including native reduced AcoP at 1.65 Å resolution, unveil a typical cupredoxin fold. The presence of extended loops, never observed in previously characterized cupredoxins, might account for the interaction of AcoP with physiological partners. The Cu-ligand distances, determined by both X-ray diffraction and EXAFS, show that the AcoP metal centre seems to present both T1 and T1.5 features, in turn suggesting that AcoP might not fit well to the coupled distortion model. The crystal structures of two AcoP mutants confirm that the active centre of AcoP is highly constrained. Comparative analysis with other cupredoxins of known structures, suggests that in AcoP the second coordination sphere might be an important determinant of active centre rigidity due to the presence of an extensive hydrogen bond network. Finally, we show that other cupredoxins do not perfectly follow the coupled distortion model as well, raising the suspicion that further alternative models to describe copper centre geometries need to be developed, while the importance of rack-induced contributions should not be underestimated.
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Affiliation(s)
- Magali Roger
- CNRS, Aix-Marseille University, Bioenergetic and Protein Engineering Laboratory, BIP UMR 7281, Mediterranean Institute of Microbiology, 13009 Marseille, France.
| | - Philippe Leone
- CNRS, Aix-Marseille University, Laboratoire d'Ingénierie des Systèmes Macromoléculaires, LISM UMR7255, 13009 Marseille, France
| | - Ninian J Blackburn
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Sam Horrell
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Tadeo Moreno Chicano
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK
| | - Frédéric Biaso
- CNRS, Aix-Marseille University, Bioenergetic and Protein Engineering Laboratory, BIP UMR 7281, Mediterranean Institute of Microbiology, 13009 Marseille, France.
| | - Marie-Thérèse Giudici-Orticoni
- CNRS, Aix-Marseille University, Bioenergetic and Protein Engineering Laboratory, BIP UMR 7281, Mediterranean Institute of Microbiology, 13009 Marseille, France.
| | - Luciano A Abriata
- Laboratory for Biomolecular Modeling and Protein Purification and Structure Core Facility, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Greg L Hura
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Lab, Berkeley, CA, USA
| | - Michael A Hough
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK
- Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Giuliano Sciara
- CNRS, Aix-Marseille University, Bioenergetic and Protein Engineering Laboratory, BIP UMR 7281, Mediterranean Institute of Microbiology, 13009 Marseille, France.
- Aix Marseille Univ, INRAE, BBF UMR1163, Biodiversité et Biotechnologie Fongiques, 13288 Marseille, France
| | - Marianne Ilbert
- CNRS, Aix-Marseille University, Bioenergetic and Protein Engineering Laboratory, BIP UMR 7281, Mediterranean Institute of Microbiology, 13009 Marseille, France.
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4
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Chang J, Peng P, Farhan Ul-Haque M, Hira A, DiSpirito AA, Semrau JD. Inhibition of nitrous oxide reduction in forest soil microcosms by different forms of methanobactin. Environ Microbiol 2023; 25:2338-2350. [PMID: 37395163 DOI: 10.1111/1462-2920.16456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 06/14/2023] [Indexed: 07/04/2023]
Abstract
Copper plays a critical role in controlling greenhouse gas emissions as it is a key component of the particulate methane monooxygenase and nitrous oxide reductase. Some methanotrophs excrete methanobactin (MB) that has an extremely high copper affinity. As a result, MB may limit the ability of other microbes to gather copper, thereby decreasing their activity as well as impacting microbial community composition. Here, we show using forest soil microcosms that multiple forms of MB; MB from Methylosinus trichosporium OB3b (MB-OB3b) and MB from Methylocystis sp. strain SB2 (MB-SB2) increased nitrous oxide (N2 O) production as well caused significant shifts in microbial community composition. Such effects, however, were mediated by the amount of copper in the soils, with low-copper soil microcosms showing the strongest response to MB. Furthermore, MB-SB2 had a stronger effect, likely due to its higher affinity for copper. The presence of either form of MB also inhibited nitrite reduction and generally increased the presence of genes encoding for the iron-containing nitrite reductase (nirS) over the copper-dependent nitrite reductase (nirK). These data indicate the methanotrophic-mediated production of MB can significantly impact multiple steps of denitrification, as well as have broad effects on microbial community composition of forest soils.
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Affiliation(s)
- Jin Chang
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Peng Peng
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Abid Hira
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore, Pakistan
| | - Alan A DiSpirito
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, Iowa, USA
| | - Jeremy D Semrau
- Department of Civil and Environmental Engineering, University of Michigan, Ann Arbor, Michigan, USA
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5
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Sato W, Ishimori K. Regulation of electron transfer in the terminal step of the respiratory chain. Biochem Soc Trans 2023; 51:1611-1619. [PMID: 37409479 DOI: 10.1042/bst20221449] [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: 04/27/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/07/2023]
Abstract
In mitochondria, electrons are transferred along a series of enzymes and electron carriers that are referred to as the respiratory chain, leading to the synthesis of cellular ATP. The series of the interprotein electron transfer (ET) reactions is terminated by the reduction in molecular oxygen at Complex IV, cytochrome c oxidase (CcO) that is coupled with the proton pumping from the matrix to the inner membrane space. Unlike the ET reactions from Complex I to Complex III, the ET reaction to CcO, mediated by cytochrome c (Cyt c), is quite specific in that it is irreversible with suppressed electron leakage, which characterizes the ET reactions in the respiratory chain and is thought to play a key role in the regulation of mitochondrial respiration. In this review, we summarize the recent findings regarding the molecular mechanism of the ET reaction from Cyt c to CcO in terms of specific interaction between two proteins, a molecular breakwater, and the effects of the conformational fluctuation on the ET reaction, conformational gating. Both of these are essential factors, not only in the ET reaction from Cyt c to CcO, but also in the interprotein ET reactions in general. We also discuss the significance of a supercomplex in the terminal ET reaction, which provides information on the regulatory factors of the ET reactions that are specific to the mitochondrial respiratory chain.
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Affiliation(s)
- Wataru Sato
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Ako, Hyogo 678-1297, Japan
| | - Koichiro Ishimori
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan
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6
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Li X, Zou H. A molecular dynamics and quantum mechanical investigation of intermolecular interaction and electron-transfer mechanism between copper-containing nitrite reductase and redox partner pseudoazurin. Phys Chem Chem Phys 2023; 25:7783-7793. [PMID: 36857651 DOI: 10.1039/d2cp05534a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Much of biological electron transfer occurs between proteins. These molecular processes usually involve molecular recognition and intermolecular electron transfer (inter-ET). The inter-ET reaction between copper-containing nitrite reductase (CuNiR) and partner protein pseudoazurin (PAz) is the first step in denitrification, which is affected by intermolecular association. However, the transient interaction between CuNiR and PAz and the indistinct inter-ET pathway pose challenges for people to understand the biological functions of the CuNiR-PAz complex. Thus, molecular dynamics simulation and quantum mechanical calculation were used to investigate the question in this study. The interaction of the interface residues was determined through hydrogen bonds, root-mean-square deviation, root-mean-square fluctuation, the dynamics cross-correlation matrix, and molecular mechanics Poisson-Boltzmann surface area of molecular dynamics simulations. The interactions among the residues Glu89, Gly200, Asp205, Asn91, Glu204, Thr92, and Met141 on CuNiR and the residues Lys109, Ala15, Lys10, Asn9, Ile110, Met84, and Met16 on PAz are responsible for the stabilization of the complex. The binding free energy is up to -25.33 kcal mol-1. We compared the wild-type and mutant (M84A) interfacial optimized complex models at the CAM-B3LYP level with Grimme dispersion corrections (GD3) to confirm Met84 as a relay station for promoting the inter-ET. Additionally, to test whether Met84 may combine with the adjacent Met141 to form a special two-center, three-electron (S∴S)+ structure to promote the inter-ET, QM/MM was further performed to discuss the possibility of generating an electron stepping stone. Our study will promote a deep understanding of the stable protein-protein interaction, and the identified inter-residue interaction will be theoretical guidance for enhancing the catalytic activity of CuNiR in denitrification.
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Affiliation(s)
- Xin Li
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, China.
| | - Hang Zou
- School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China.
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7
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Peng L, Qiu H, Li S, Xu Y, Liang C, Wang N, Liu Y, Ni BJ. The mitigation effect of free ammonia and free nitrous acid on nitrous oxide production from the full-nitrification and partial-nitritation systems. BIORESOURCE TECHNOLOGY 2023; 372:128564. [PMID: 36592867 DOI: 10.1016/j.biortech.2022.128564] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/27/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
The potentials of using endogenous free ammonia (FA) and free nitrous acid (FNA) as nitrous oxide (N2O) mitigators were investigated in treatment of both mainstream and sidestream wastewater. Although the N2O emission factor of a sidestream partial-nitritation (PN) reactor (averaged 1.70 % ± 0.39 %, n = 30) was about 2.4 times higher than a mainstream full-nitrification (FN) reactor (averaged 0.72 % ± 0.24 %, n = 30) (P < 0.01), one-hour exposure of PN sludge to 1.5 mg HNO2-N/L FNA could virtually abolish N2O emission. As for FN sludge, both 45 mg NH3-N/L FA and 0.015 mg HNO2-N/L FNA successfully mitigated N2O production at varying dissolved oxygen (DO) levels (50 % vs 61 %), while 1.5 mg HNO2-N/L FNA not only reduced more N2O (92 %) but also altered the N2O dependency on DO. Both FNA and FA sludge treatment were effective N2O mitigation strategies with FNA toward the end of carbon neutrality and FA being more economically appealing (2 % cost saving).
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Affiliation(s)
- Lai Peng
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; Shenzhen Research Institute of Wuhan University of Technology, Shenzhen 518000, Guangdong, China
| | - Huiling Qiu
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; Shenzhen Research Institute of Wuhan University of Technology, Shenzhen 518000, Guangdong, China
| | - Shengjun Li
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China; Shenzhen Research Institute of Wuhan University of Technology, Shenzhen 518000, Guangdong, China.
| | - Yifeng Xu
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Chuanzhou Liang
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Ning Wang
- Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan 430070, China
| | - Yiwen Liu
- University of Technology Sydney, Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, Sydney, NSW 2007, Australia
| | - Bing-Jie Ni
- University of Technology Sydney, Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, Sydney, NSW 2007, Australia
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8
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Li YQ, Zhao BH, Chen XT, Zhang YQ, Yang HS. Co-existence effect of copper oxide nanoparticles and ciprofloxacin on simultaneous nitrification, endogenous denitrification, and phosphorus removal by aerobic granular sludge. CHEMOSPHERE 2023; 312:137254. [PMID: 36395892 DOI: 10.1016/j.chemosphere.2022.137254] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/25/2022] [Accepted: 11/14/2022] [Indexed: 06/16/2023]
Abstract
Nanoparticles and antibiotics are toxic to humans and ecosystems, and they inevitably coexist in the wastewater treatment plants. Hence, the co-existence effects and stress mechanism of copper (II) oxide nanoparticles (CuO NPs) and ciprofloxacin (CIP) on simultaneous nitrification, endogenous denitrification and phosphorus removal (SNEDPR) by aerobic granular sludge (AGS) were investigated here. The co-existence stress of 5 mg/L CuO NPs and 5 mg/L CIP resulted in the synergistic inhibitory effect on nutrient removal. Transformation inhibition mechanisms of carbon (C), nitrogen (N) and phosphorus (P) with CuO NPs and CIP addition were time-dependent. Furthermore, the long-term stress mainly inhibited PO43--P removal by inhibiting phosphorus release process, while short-term stress mainly inhibited phosphorus uptake process. The synergistic inhibitory effect of CuO NPs and CIP may be due to the changes of physicochemical characteristics under the co-existence of CuO NPs and CIP. This further altered the sludge characteristics, microbial community structure and functional metabolic pathways under the long-term stress. Resistance genes analysis exhibited that the co-existence stress of CuO NPs and CIP induced the amplification of qnrA (2.38 folds), qnrB (4.70 folds) and intI1 (3.41 folds) compared with the control group.
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Affiliation(s)
- Yu-Qi Li
- Department of Municipal Engineering, Beijing University of Technology, Beijing, 100124, PR China
| | - Bai-Hang Zhao
- Department of Municipal Engineering, Beijing University of Technology, Beijing, 100124, PR China.
| | - Xiao-Tang Chen
- Department of Municipal Engineering, Beijing University of Technology, Beijing, 100124, PR China
| | - Yu-Qing Zhang
- Department of Municipal Engineering, Beijing University of Technology, Beijing, 100124, PR China
| | - Hai-Shan Yang
- Department of Municipal Engineering, Beijing University of Technology, Beijing, 100124, PR China
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9
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Eady RR, Samar Hasnain S. New horizons in structure-function studies of copper nitrite reductase. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214463] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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10
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Chang YL, Chen HY, Chen SH, Kao CL, Chiang MY, Hsu SCN. An investigation on catalytic nitrite reduction reaction by bioinspired Cu II complexes. Dalton Trans 2022; 51:7715-7722. [PMID: 35522169 DOI: 10.1039/d1dt04102a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Catalytic nitrite reductions by CuII complexes containing anionic Me2Tp, neutral Me2Tpm, or neutral iPrTIC ligands in the presence of L-ascorbic acid, which served as an electron donor and proton source, were investigated. The results showed that auxiliary ligands are important for copper-mediated catalytic nitrite reduction. Furthermore, the electronic effects of the ligand govern the nitrite reduction efficiency, which should be considered at two control points: one is the susceptibility of the LCuI-nitrite species to protonation and the other is the susceptibility of LCuII to reduction giving LCuI. In addition, an external strong acid leads to the production of nitrous acid, which may suggest that the reactivity of nitrous acid toward the LCuI species is a third control point.
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Affiliation(s)
- Yu-Lun Chang
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shi-Chuan 1st Rd., San-Ming District, Kaohsiung 807, Taiwan.
| | - Hsing-Yin Chen
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shi-Chuan 1st Rd., San-Ming District, Kaohsiung 807, Taiwan.
| | - Si-Hong Chen
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shi-Chuan 1st Rd., San-Ming District, Kaohsiung 807, Taiwan.
| | - Chai-Lin Kao
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shi-Chuan 1st Rd., San-Ming District, Kaohsiung 807, Taiwan.
| | - Michael Y Chiang
- Department of Chemistry, National Sun Yat-Sen University No. 70, Lienhai Rd., Kaohsiung 804, Taiwan
| | - Sodio C N Hsu
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shi-Chuan 1st Rd., San-Ming District, Kaohsiung 807, Taiwan. .,Department of Chemistry, National Sun Yat-Sen University No. 70, Lienhai Rd., Kaohsiung 804, Taiwan.,Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
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11
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Schröder GC, Meilleur F. Metalloprotein catalysis: structural and mechanistic insights into oxidoreductases from neutron protein crystallography. Acta Crystallogr D Struct Biol 2021; 77:1251-1269. [PMID: 34605429 PMCID: PMC8489226 DOI: 10.1107/s2059798321009025] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 08/31/2021] [Indexed: 11/11/2022] Open
Abstract
Metalloproteins catalyze a range of reactions, with enhanced chemical functionality due to their metal cofactor. The reaction mechanisms of metalloproteins have been experimentally characterized by spectroscopy, macromolecular crystallography and cryo-electron microscopy. An important caveat in structural studies of metalloproteins remains the artefacts that can be introduced by radiation damage. Photoreduction, radiolysis and ionization deriving from the electromagnetic beam used to probe the structure complicate structural and mechanistic interpretation. Neutron protein diffraction remains the only structural probe that leaves protein samples devoid of radiation damage, even when data are collected at room temperature. Additionally, neutron protein crystallography provides information on the positions of light atoms such as hydrogen and deuterium, allowing the characterization of protonation states and hydrogen-bonding networks. Neutron protein crystallography has further been used in conjunction with experimental and computational techniques to gain insight into the structures and reaction mechanisms of several transition-state metal oxidoreductases with iron, copper and manganese cofactors. Here, the contribution of neutron protein crystallography towards elucidating the reaction mechanism of metalloproteins is reviewed.
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Affiliation(s)
- Gabriela C. Schröder
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Flora Meilleur
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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12
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Qin X, Chen X. Remote Water-Mediated Proton Transfer Triggers Inter-Cu Electron Transfer: Nitrite Reduction Activation in Copper-Containing Nitrite Reductase. Chembiochem 2021; 22:1405-1414. [PMID: 33295048 DOI: 10.1002/cbic.202000644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 12/07/2020] [Indexed: 11/05/2022]
Abstract
The copper-containing nitrite reductase (CuNiR) catalyzes the biological conversion of nitrite to nitric oxide; key long-range electron/proton transfers are involved in the catalysis. However, the details of the electron-/proton-transfer mechanism are still unknown. In particular, the driving force of the electron transfer from the type-1 copper (T1Cu) site to the type-2 copper (T2Cu) site is ambiguous. Here, we explored the two possible proton-transfer channels, the high-pH proton channel and the primary proton channel, by using two-layered ONIOM calculations. Our calculation results reveal that the driving force for electron transfer from T1Cu to T2Cu comes from a remote water-mediated triple-proton-coupled electron-transfer mechanism. In the high-pH proton channel, the water-mediated triple-proton transfer occurs from Glu113 to an intermediate water molecule, whereas in the primary channel, the transfer is from Lys128 to His260. Subsequently, the two channels employ another two or three distinct proton-transfer steps to deliver the proton to the nitrite substrate at the T2Cu site. These findings explain the detailed proton-/electron-transfer mechanisms of copper-containing nitrite reductase and could extend our understanding of the diverse proton-coupled electron-transfer mechanisms in complicated proteins.
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Affiliation(s)
- Xin Qin
- Chongqing Key Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Chongqing University, 55 University City South Road, Shapingba District, Chongqing, 401331, P. R. China.,National-Municipal Joint Engineering Laboratory for Chemical Process Intensification and Reaction, Chongqing University, Chongqing, 401331, P. R. China
| | - Xiaohua Chen
- Chongqing Key Laboratory of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Chongqing University, 55 University City South Road, Shapingba District, Chongqing, 401331, P. R. China.,National-Municipal Joint Engineering Laboratory for Chemical Process Intensification and Reaction, Chongqing University, Chongqing, 401331, P. R. China
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13
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Cristaldi JC, Ferroni FM, Duré AB, Ramírez CS, Dalosto SD, Rizzi AC, González PJ, Rivas MG, Brondino CD. Heterologous production and functional characterization of Bradyrhizobium japonicum copper-containing nitrite reductase and its physiological redox partner cytochrome c550. Metallomics 2020; 12:2084-2097. [PMID: 33226040 DOI: 10.1039/d0mt00177e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two domain copper-nitrite reductases (NirK) contain two types of copper centers, one electron transfer (ET) center of type 1 (T1) and a catalytic site of type 2 (T2). NirK activity is pH-dependent, which has been suggested to be produced by structural modifications at high pH of some catalytically relevant residues. To characterize the pH-dependent kinetics of NirK and the relevance of T1 covalency in intraprotein ET, we studied the biochemical, electrochemical, and spectroscopic properties complemented with QM/MM calculations of Bradyrhizobium japonicum NirK (BjNirK) and of its electron donor cytochrome c550 (BjCycA). BjNirK presents absorption spectra determined mainly by a S(Cys)3pπ → Cu2+ ligand-to-metal charge-transfer (LMCT) transition. The enzyme shows low activity likely due to the higher flexibility of a protein loop associated with BjNirK/BjCycA interaction. Nitrite is reduced at high pH in a T1-decoupled way without T1 → T2 ET in which proton delivery for nitrite reduction at T2 is maintained. Our results are analyzed in comparison with previous results found by us in Sinorhizobium meliloti NirK, whose main UV-vis absorption features are determined by S(Cys)3pσ/π → Cu2+ LMCT transitions.
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Affiliation(s)
- Julio C Cristaldi
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral and CONICET, S3000ZAA Santa Fe, Argentina.
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14
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Osmotic pressure effects identify dehydration upon cytochrome c-cytochrome c oxidase complex formation contributing to a specific electron pathway formation. Biochem J 2020; 477:1565-1578. [PMID: 32250438 DOI: 10.1042/bcj20200023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/27/2020] [Accepted: 04/06/2020] [Indexed: 01/18/2023]
Abstract
In the electron transfer (ET) reaction from cytochrome c (Cyt c) to cytochrome c oxidase (CcO), we determined the number and sites of the hydration water released from the protein surface upon the formation of the ET complex by evaluating the osmotic pressure dependence of kinetics for the ET from Cyt c to CcO. We identified that ∼20 water molecules were dehydrated in complex formation under turnover conditions, and systematic Cyt c mutations in the interaction site for CcO revealed that nearly half of the released hydration water during the complexation were located around Ile81, one of the hydrophobic amino acid residues near the exposed heme periphery of Cyt c. Such a dehydration dominantly compensates for the entropy decrease due to the association of Cyt c with CcO, resulting in the entropy-driven ET reaction. The energetic analysis of the interprotein interactions in the ET complex predicted by the docking simulation suggested the formation of hydrophobic interaction sites surrounding the exposed heme periphery of Cyt c in the Cyt c-CcO interface (a 'molecular breakwater'). Such sites would contribute to the formation of the hydrophobic ET pathway from Cyt c to CcO by blocking water access from the bulk water phase.
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15
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Hedison TM, Shanmugam M, Heyes DJ, Edge R, Scrutton NS. Active Intermediates in Copper Nitrite Reductase Reactions Probed by a Cryotrapping-Electron Paramagnetic Resonance Approach. Angew Chem Int Ed Engl 2020; 59:13936-13940. [PMID: 32352195 PMCID: PMC7497095 DOI: 10.1002/anie.202005052] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Indexed: 11/25/2022]
Abstract
Redox active metalloenzymes catalyse a range of biochemical processes essential for life. However, due to their complex reaction mechanisms, and often, their poor optical signals, detailed mechanistic understandings of them are limited. Here, we develop a cryoreduction approach coupled to electron paramagnetic resonance measurements to study electron transfer between the copper centers in the copper nitrite reductase (CuNiR) family of enzymes. Unlike alternative methods used to study electron transfer reactions, the cryoreduction approach presented here allows observation of the redox state of both metal centers, a direct read-out of electron transfer, determines the presence of the substrate/product in the active site and shows the importance of protein motion in inter-copper electron transfer catalyzed by CuNiRs. Cryoreduction-EPR is broadly applicable for the study of electron transfer in other redox enzymes and paves the way to explore transient states in multiple redox-center containing proteins (homo and hetero metal ions).
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Affiliation(s)
- Tobias M. Hedison
- Manchester Institute of Biotechnology and School of ChemistryUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
- BBSRC and EPSRC funded Future Biomanfacturing Research HubManchester Institute of Biotechnology and School of ChemistryUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
| | - Muralidharan Shanmugam
- Manchester Institute of Biotechnology and School of ChemistryUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
| | - Derren J. Heyes
- Manchester Institute of Biotechnology and School of ChemistryUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
| | - Ruth Edge
- Dalton Cumbrian FacilityThe University of ManchesterCumbriaUK
| | - Nigel S. Scrutton
- Manchester Institute of Biotechnology and School of ChemistryUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
- BBSRC and EPSRC funded Future Biomanfacturing Research HubManchester Institute of Biotechnology and School of ChemistryUniversity of ManchesterPrincess StreetManchesterM1 7DNUK
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16
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Hedison TM, Shanmugam M, Heyes DJ, Edge R, Scrutton NS. Active Intermediates in Copper Nitrite Reductase Reactions Probed by a Cryotrapping‐Electron Paramagnetic Resonance Approach. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202005052] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Tobias M. Hedison
- Manchester Institute of Biotechnology and School of Chemistry University of Manchester Princess Street Manchester M1 7DN UK
- BBSRC and EPSRC funded Future Biomanfacturing Research Hub Manchester Institute of Biotechnology and School of Chemistry University of Manchester Princess Street Manchester M1 7DN UK
| | - Muralidharan Shanmugam
- Manchester Institute of Biotechnology and School of Chemistry University of Manchester Princess Street Manchester M1 7DN UK
| | - Derren J. Heyes
- Manchester Institute of Biotechnology and School of Chemistry University of Manchester Princess Street Manchester M1 7DN UK
| | - Ruth Edge
- Dalton Cumbrian Facility The University of Manchester Cumbria UK
| | - Nigel S. Scrutton
- Manchester Institute of Biotechnology and School of Chemistry University of Manchester Princess Street Manchester M1 7DN UK
- BBSRC and EPSRC funded Future Biomanfacturing Research Hub Manchester Institute of Biotechnology and School of Chemistry University of Manchester Princess Street Manchester M1 7DN UK
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17
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Hira D, Matsumura M, Kitamura R, Furukawa K, Fujii T. Unique hexameric structure of copper-containing nitrite reductase of an anammox bacterium KSU-1. Biochem Biophys Res Commun 2020; 526:654-660. [DOI: 10.1016/j.bbrc.2020.03.144] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 03/25/2020] [Indexed: 10/24/2022]
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18
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Sasaki D, Watanabe TF, Eady RR, Garratt RC, Antonyuk SV, Hasnain SS. Structures of substrate- and product-bound forms of a multi-domain copper nitrite reductase shed light on the role of domain tethering in protein complexes. IUCRJ 2020; 7:557-565. [PMID: 32431838 PMCID: PMC7201279 DOI: 10.1107/s2052252520005230] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 04/14/2020] [Indexed: 06/11/2023]
Abstract
Copper-containing nitrite reductases (CuNiRs) are found in all three kingdoms of life and play a major role in the denitrification branch of the global nitro-gen cycle where nitrate is used in place of di-oxy-gen as an electron acceptor in respiratory energy metabolism. Several C- and N-terminal redox domain tethered CuNiRs have been identified and structurally characterized during the last decade. Our understanding of the role of tethered domains in these new classes of three-domain CuNiRs, where an extra cytochrome or cupredoxin domain is tethered to the catalytic two-domain CuNiRs, has remained limited. This is further compounded by a complete lack of substrate-bound structures for these tethered CuNiRs. There is still no substrate-bound structure for any of the as-isolated wild-type tethered enzymes. Here, structures of nitrite and product-bound states from a nitrite-soaked crystal of the N-terminal cupredoxin-tethered enzyme from the Hyphomicrobium denitrificans strain 1NES1 (Hd 1NES1NiR) are provided. These, together with the as-isolated structure of the same species, provide clear evidence for the role of the N-terminal peptide bearing the conserved His27 in water-mediated anchoring of the substrate at the catalytic T2Cu site. Our data indicate a more complex role of tethering than the intuitive advantage for a partner-protein electron-transfer complex by narrowing the conformational search in such a combined system.
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Affiliation(s)
- Daisuke Sasaki
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Tatiana F. Watanabe
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
- The São Carlos Institute of Physics, University of São Paulo, São Carlos 13563-120, Brazil
| | - Robert R. Eady
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Richard C. Garratt
- The São Carlos Institute of Physics, University of São Paulo, São Carlos 13563-120, Brazil
| | - Svetlana V. Antonyuk
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - S. Samar Hasnain
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
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19
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Sasaki D, Watanabe TF, Eady RR, Garratt RC, Antonyuk SV, Hasnain SS. Reverse protein engineering of a novel 4-domain copper nitrite reductase reveals functional regulation by protein-protein interaction. FEBS J 2020; 288:262-280. [PMID: 32255260 DOI: 10.1111/febs.15324] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 03/16/2020] [Accepted: 04/01/2020] [Indexed: 01/03/2023]
Abstract
Cu-containing nitrite reductases that convert NO2 - to NO are critical enzymes in nitrogen-based energy metabolism. Among organisms in the order Rhizobiales, we have identified two copies of nirK, one encoding a new class of 4-domain CuNiR that has both cytochrome and cupredoxin domains fused at the N terminus and the other, a classical 2-domain CuNiR (Br2D NiR). We report the first enzymatic studies of a novel 4-domain CuNiR from Bradyrhizobium sp. ORS 375 (BrNiR), its genetically engineered 3- and 2-domain variants, and Br2D NiR revealing up to ~ 500-fold difference in catalytic efficiency in comparison with classical 2-domain CuNiRs. Contrary to the expectation that tethering would enhance electron delivery by restricting the conformational search by having a self-contained donor-acceptor system, we demonstrate that 4-domain BrNiR utilizes N-terminal tethering for downregulating enzymatic activity instead. Both Br2D NiR and an engineered 2-domain variant of BrNiR (Δ(Cytc-Cup) BrNiR) have 3 to 5% NiR activity compared to the well-characterized 2-domain CuNiRs from Alcaligenes xylosoxidans (AxNiR) and Achromobacter cycloclastes (AcNiR). Structural comparison of Δ(Cytc-Cup) BrNiR and Br2D NiR with classical 2-domain AxNiR and AcNiR reveals structural differences of the proton transfer pathway that could be responsible for the lowering of activity. Our study provides insights into unique structural and functional characteristics of naturally occurring 4-domain CuNiR and its engineered 3- and 2-domain variants. The reverse protein engineering approach utilized here has shed light onto the broader question of the evolution of transient encounter complexes and tethered electron transfer complexes. ENZYME: Copper-containing nitrite reductase (CuNiR) (EC 1.7.2.1). DATABASE: The atomic coordinate and structure factor of Δ(Cytc-Cup) BrNiR and Br2D NiR have been deposited in the Protein Data Bank (http://www.rcsb.org/) under the accession code 6THE and 6THF, respectively.
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Affiliation(s)
- Daisuke Sasaki
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
| | - Tatiana F Watanabe
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK.,The São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Robert R Eady
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
| | - Richard C Garratt
- The São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Svetlana V Antonyuk
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
| | - S Samar Hasnain
- Molecular Biophysics Group, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, UK
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20
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High-resolution neutron crystallography visualizes an OH-bound resting state of a copper-containing nitrite reductase. Proc Natl Acad Sci U S A 2020; 117:4071-4077. [PMID: 32041886 PMCID: PMC7049163 DOI: 10.1073/pnas.1918125117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
X-ray crystallography often fails to determine the positions of hydrogen atoms, which play crucial roles in enzymatic reactions. Despite many X-ray crystallographic studies, the reaction mechanism of copper-containing nitrite reductases (CuNIRs), which reduce nitrite using two protons, has been controversial. The high-resolution neutron structure of a CuNIR reveals the protonation states of catalytic residues and key water molecules, thus providing insights into the catalytic mechanism. The catalytic Cu is shown to be coordinated by a hydroxide ion and not water. Furthermore, the hydrogen-deuterium exchange ratio suggests that intramolecular electron transfer is involved in a hydrogen-bond jump. These observations are consistent with previous computational chemistry; therefore, our study forms a bridge between the structural biology and quantum chemistry of CuNIRs. Copper-containing nitrite reductases (CuNIRs) transform nitrite to gaseous nitric oxide, which is a key process in the global nitrogen cycle. The catalytic mechanism has been extensively studied to ultimately achieve rational control of this important geobiochemical reaction. However, accumulated structural biology data show discrepancies with spectroscopic and computational studies; hence, the reaction mechanism is still controversial. In particular, the details of the proton transfer involved in it are largely unknown. This situation arises from the failure of determining positions of hydrogen atoms and protons, which play essential roles at the catalytic site of CuNIRs, even with atomic resolution X-ray crystallography. Here, we determined the 1.50 Å resolution neutron structure of a CuNIR from Geobacillus thermodenitrificans (trimer molecular mass of ∼106 kDa) in its resting state at low pH. Our neutron structure reveals the protonation states of catalytic residues (deprotonated aspartate and protonated histidine), thus providing insights into the catalytic mechanism. We found that a hydroxide ion can exist as a ligand to the catalytic Cu atom in the resting state even at a low pH. This OH-bound Cu site is unexpected from previously given X-ray structures but consistent with a reaction intermediate suggested by computational chemistry. Furthermore, the hydrogen-deuterium exchange ratio in our neutron structure suggests that the intramolecular electron transfer pathway has a hydrogen-bond jump, which is proposed by quantum chemistry. Our study can seamlessly link the structural biology to the computational chemistry of CuNIRs, boosting our understanding of the enzymes at the atomic and electronic levels.
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21
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Rajta A, Bhatia R, Setia H, Pathania P. Role of heterotrophic aerobic denitrifying bacteria in nitrate removal from wastewater. J Appl Microbiol 2019; 128:1261-1278. [PMID: 31587489 DOI: 10.1111/jam.14476] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 09/30/2019] [Accepted: 10/01/2019] [Indexed: 11/27/2022]
Abstract
With the increase in industrial and agricultural activities, a large amount of nitrogenous compounds are released into the environment, leading to nitrate pollution. The perilous effects of nitrate present in the environment pose a major threat to human and animal health. Bioremediation provides a cost-effective and environmental friendly method to deal with this problem. The process of aerobic denitrification can reduce nitrate compounds to harmless dinitrogen gas. This review provides a brief view of the exhaustive role played by aerobic denitrifiers for tackling nitrate pollution under different ecological niches and their dependency on various environmental parameters. It also provides an understanding of the enzymes involved in aerobic denitrification. The role of aerobic denitrification to solve the issues faced by the conventional method (aerobic nitrification-anaerobic denitrification) in treating nitrogen-polluted wastewaters is elaborated.
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Affiliation(s)
- A Rajta
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, India
| | - R Bhatia
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, India
| | - H Setia
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, India
| | - P Pathania
- Department of Biotechnology, University Institute of Engineering and Technology, Panjab University, Chandigarh, India
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22
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Abstract
Utilization of electron transfer methods for description of quantum transport is popular due to simplicity of the formulation and its ability to account for basic physics of electron exchange between the system and baths. At the same time, the necessity to go beyond simple golden rule-type expressions for rates was indicated in the literature and ad hoc formulations were proposed. Similarly, kinetic schemes for quantum transport beyond the usual second-order Lindblad/Redfield considerations were discussed. Here we utilize recently introduced the nonequilibrium Hubbard Green's function diagrammatic technique to analyze the construction of rates in open systems. We show that previous considerations for rates of second and fourth order can be obtained as a particular case of zero- and second-order Green's function diagrammatic series with bare diagrams. We discuss limitations of previous considerations, stress advantages of the Hubbard Green's function approach in constructing the rates, and indicate that standard dressing of the diagrams is a natural way to account for additional baths/degrees of freedom in the formulation of generalized expressions for the rates.
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Affiliation(s)
- Nicolas Bergmann
- Department of Chemistry , Technical University of Munich , D-85748 Garching , Germany
| | - Michael Galperin
- Department of Chemistry & Biochemistry , University of California San Diego , La Jolla , California 92093 , United States
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23
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Hedison T, Shenoy RT, Iorgu AI, Heyes DJ, Fisher K, Wright GSA, Hay S, Eady RR, Antonyuk SV, Hasnain SS, Scrutton NS. Unexpected Roles of a Tether Harboring a Tyrosine Gatekeeper Residue in Modular Nitrite Reductase Catalysis. ACS Catal 2019; 9:6087-6099. [PMID: 32051772 PMCID: PMC7007197 DOI: 10.1021/acscatal.9b01266] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/19/2019] [Indexed: 01/26/2023]
Abstract
It is generally assumed that tethering enhances rates of electron harvesting and delivery to active sites in multidomain enzymes by proximity and sampling mechanisms. Here, we explore this idea in a tethered 3-domain, trimeric copper-containing nitrite reductase. By reverse engineering, we find that tethering does not enhance the rate of electron delivery from its pendant cytochrome c to the catalytic copper-containing core. Using a linker that harbors a gatekeeper tyrosine in a nitrite access channel, the tethered haem domain enables catalysis by other mechanisms. Tethering communicates the redox state of the haem to the distant T2Cu center that helps initiate substrate binding for catalysis. It also tunes copper reduction potentials, suppresses reductive enzyme inactivation, enhances enzyme affinity for substrate, and promotes intercopper electron transfer. Tethering has multiple unanticipated beneficial roles, the combination of which fine-tunes function beyond simplistic mechanisms expected from proximity and restrictive sampling models.
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Affiliation(s)
- Tobias
M. Hedison
- Manchester
Institute of Biotechnology and School of Chemistry, Faculty of Science
and Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Rajesh T. Shenoy
- Molecular
Biophysics Group, Institute of Integrative Biology, Faculty of Health
and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Andreea I. Iorgu
- Manchester
Institute of Biotechnology and School of Chemistry, Faculty of Science
and Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Derren J. Heyes
- Manchester
Institute of Biotechnology and School of Chemistry, Faculty of Science
and Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Karl Fisher
- Manchester
Institute of Biotechnology and School of Chemistry, Faculty of Science
and Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Gareth S. A. Wright
- Molecular
Biophysics Group, Institute of Integrative Biology, Faculty of Health
and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Sam Hay
- Manchester
Institute of Biotechnology and School of Chemistry, Faculty of Science
and Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Robert R. Eady
- Molecular
Biophysics Group, Institute of Integrative Biology, Faculty of Health
and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Svetlana V. Antonyuk
- Molecular
Biophysics Group, Institute of Integrative Biology, Faculty of Health
and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - S. Samar Hasnain
- Molecular
Biophysics Group, Institute of Integrative Biology, Faculty of Health
and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Nigel S. Scrutton
- Manchester
Institute of Biotechnology and School of Chemistry, Faculty of Science
and Engineering, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
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24
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Halsted TP, Yamashita K, Gopalasingam CC, Shenoy RT, Hirata K, Ago H, Ueno G, Blakeley MP, Eady RR, Antonyuk SV, Yamamoto M, Hasnain SS. Catalytically important damage-free structures of a copper nitrite reductase obtained by femtosecond X-ray laser and room-temperature neutron crystallography. IUCRJ 2019; 6:761-772. [PMID: 31316819 PMCID: PMC6608623 DOI: 10.1107/s2052252519008285] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 06/12/2019] [Indexed: 05/31/2023]
Abstract
Copper-containing nitrite reductases (CuNiRs) that convert NO2 - to NO via a CuCAT-His-Cys-CuET proton-coupled redox system are of central importance in nitrogen-based energy metabolism. These metalloenzymes, like all redox enzymes, are very susceptible to radiation damage from the intense synchrotron-radiation X-rays that are used to obtain structures at high resolution. Understanding the chemistry that underpins the enzyme mechanisms in these systems requires resolutions of better than 2 Å. Here, for the first time, the damage-free structure of the resting state of one of the most studied CuNiRs was obtained by combining X-ray free-electron laser (XFEL) and neutron crystallography. This represents the first direct comparison of neutron and XFEL structural data for any protein. In addition, damage-free structures of the reduced and nitrite-bound forms have been obtained to high resolution from cryogenically maintained crystals by XFEL crystallography. It is demonstrated that AspCAT and HisCAT are deprotonated in the resting state of CuNiRs at pH values close to the optimum for activity. A bridging neutral water (D2O) is positioned with one deuteron directed towards AspCAT Oδ1 and one towards HisCAT N∊2. The catalytic T2Cu-ligated water (W1) can clearly be modelled as a neutral D2O molecule as opposed to D3O+ or OD-, which have previously been suggested as possible alternatives. The bridging water restricts the movement of the unprotonated AspCAT and is too distant to form a hydrogen bond to the O atom of the bound nitrite that interacts with AspCAT. Upon the binding of NO2 - a proton is transferred from the bridging water to the Oδ2 atom of AspCAT, prompting electron transfer from T1Cu to T2Cu and reducing the catalytic redox centre. This triggers the transfer of a proton from AspCAT to the bound nitrite, enabling the reaction to proceed.
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Affiliation(s)
- Thomas P. Halsted
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, England
| | - Keitaro Yamashita
- SR Life Science Instrumentation Unit, RIKEN SPring-8 Centre, Sayo 679-5148, Japan
| | - Chai C. Gopalasingam
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, England
| | - Rajesh T. Shenoy
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, England
| | - Kunio Hirata
- SR Life Science Instrumentation Unit, RIKEN SPring-8 Centre, Sayo 679-5148, Japan
| | - Hideo Ago
- SR Life Science Instrumentation Unit, RIKEN SPring-8 Centre, Sayo 679-5148, Japan
| | - Go Ueno
- SR Life Science Instrumentation Unit, RIKEN SPring-8 Centre, Sayo 679-5148, Japan
| | - Matthew P. Blakeley
- Large-Scale Structures Group, Institut Laue–Langevin, 71 Avenue des Martyrs, 38000 Grenoble, France
| | - Robert R. Eady
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, England
| | - Svetlana V. Antonyuk
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, England
| | - Masaki Yamamoto
- SR Life Science Instrumentation Unit, RIKEN SPring-8 Centre, Sayo 679-5148, Japan
| | - S. Samar Hasnain
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, England
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25
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Opperman DJ, Murgida DH, Dalosto SD, Brondino CD, Ferroni FM. A three-domain copper-nitrite reductase with a unique sensing loop. IUCRJ 2019; 6:248-258. [PMID: 30867922 PMCID: PMC6400189 DOI: 10.1107/s2052252519000241] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/06/2019] [Indexed: 06/09/2023]
Abstract
Dissimilatory nitrite reductases are key enzymes in the denitrification pathway, reducing nitrite and leading to the production of gaseous products (NO, N2O and N2). The reaction is catalysed either by a Cu-containing nitrite reductase (NirK) or by a cytochrome cd 1 nitrite reductase (NirS), as the simultaneous presence of the two enzymes has never been detected in the same microorganism. The thermophilic bacterium Thermus scotoductus SA-01 is an exception to this rule, harbouring both genes within a denitrification cluster, which encodes for an atypical NirK. The crystal structure of TsNirK has been determined at 1.63 Å resolution. TsNirK is a homotrimer with subunits of 451 residues that contain three copper atoms each. The N-terminal region possesses a type 2 Cu (T2Cu) and a type 1 Cu (T1CuN) while the C-terminus contains an extra type 1 Cu (T1CuC) bound within a cupredoxin motif. T1CuN shows an unusual Cu atom coordination (His2-Cys-Gln) compared with T1Cu observed in NirKs reported so far (His2-Cys-Met). T1CuC is buried at ∼5 Å from the molecular surface and located ∼14.1 Å away from T1CuN; T1CuN and T2Cu are ∼12.6 Å apart. All these distances are compatible with an electron-transfer process T1CuC → T1CuN → T2Cu. T1CuN and T2Cu are connected by a typical Cys-His bridge and an unexpected sensing loop which harbours a SerCAT residue close to T2Cu, suggesting an alternative nitrite-reduction mechanism in these enzymes. Biophysicochemical and functional features of TsNirK are discussed on the basis of X-ray crystallography, electron paramagnetic resonance, resonance Raman and kinetic experiments.
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Affiliation(s)
- Diederik Johannes Opperman
- Department of Biotechnology, University of the Free State, 205 Nelson Mandela Drive, Bloemfontein, Free State 9300, South Africa
| | - Daniel Horacio Murgida
- Departamento de Química Inorgánica, Analítica y Química Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2 piso 1, Buenos Aires, Buenos Aires C1428EHA, Argentina
| | - Sergio Daniel Dalosto
- Instituto de Física del Litoral, CONICET-UNL, Güemes 3450, Santa Fe, Santa Fe S3000ZAA, Argentina
| | - Carlos Dante Brondino
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral (UNL), CONICET, Ciudad Universitaria, Paraje El Pozo, Santa Fe, Santa Fe S3000ZAA, Argentina
| | - Felix Martín Ferroni
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral (UNL), CONICET, Ciudad Universitaria, Paraje El Pozo, Santa Fe, Santa Fe S3000ZAA, Argentina
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26
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Kobayashi S, Hira D, Yoshida K, Toyofuku M, Shida Y, Ogasawara W, Yamaguchi T, Araki N, Oshiki M. Nitric Oxide Production from Nitrite Reduction and Hydroxylamine Oxidation by Copper-containing Dissimilatory Nitrite Reductase (NirK) from the Aerobic Ammonia-oxidizing Archaeon, Nitrososphaera viennensis. Microbes Environ 2018; 33:428-434. [PMID: 30318500 PMCID: PMC6308003 DOI: 10.1264/jsme2.me18058] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Aerobic ammonia-oxidizing archaea (AOA) play a crucial role in the global nitrogen cycle by oxidizing ammonia to nitrite, and nitric oxide (NO) is a key intermediate in AOA for sustaining aerobic ammonia oxidation activity. We herein heterologously expressed the NO-forming, copper-containing, dissimilatory nitrite reductase (NirK) from Nitrososphaera viennensis and investigated its enzymatic properties. The recombinant protein catalyzed the reduction of 15NO2− to 15NO, the oxidation of hydroxylamine (15NH2OH) to 15NO, and the production of 14–15N2O from 15NH2OH and 14NO2−. To the best of our knowledge, the present study is the first to document the enzymatic properties of AOA NirK.
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Affiliation(s)
- Shun Kobayashi
- Department of Civil Engineering, National Institute of Technology, Nagaoka College
| | - Daisuke Hira
- Department of Applied Life Science, Faculty of Biotechnology and Life Science, Sojo University
| | - Keitaro Yoshida
- Graduate School of Life and Environmental Sciences, University of Tsukuba
| | - Masanori Toyofuku
- Graduate School of Life and Environmental Sciences, University of Tsukuba
| | - Yosuke Shida
- Department of Bioengineering, Nagaoka University of Technology
| | | | - Takashi Yamaguchi
- Department of Science of Technology Innovation, Nagaoka University of Technology
| | - Nobuo Araki
- Department of Civil Engineering, National Institute of Technology, Nagaoka College
| | - Mamoru Oshiki
- Department of Civil Engineering, National Institute of Technology, Nagaoka College
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27
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Chuang WJ, Narwane M, Chen HY, Kao CL, Huang B, Hsu KM, Wang YM, Hsu SCN. Nitric oxide-release study of a bio-inspired copper(i)-nitrito complex under chemical and biological conditions. Dalton Trans 2018; 47:13151-13157. [PMID: 30175363 DOI: 10.1039/c8dt02281j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The selective and efficient nitrite reduction process is ubiquitous in biological systems. To understand copper-mediated nitrite reduction, we developed a bio-inspired model system to investigate the mechanism of copper-containing nitrite reductase. A well-characterized copper(i)-nitrate complex with amino functionalized 2-(diphenylphosphino)aniline ligands, [(Ph2PC6H4(o-NH2))2Cu(ONO)], demonstrated the aniline protonation will cause NO release in an acidic environment. To further understand NO releasing ability, we also performed pH-dependency experiments and confocal imaging to release NO under physiological buffer conditions. According to titration and spectroscopic studies on the protonation reaction of complex [(Ph2PC6H4(o-NH2))2Cu(ONO)], we proposed a mechanistic pathway for proton transfer and NO release. Furthermore, DFT calculations predicted that the release of NO takes place via aniline in both organic and aqueous media. These results highlight the importance of the proton-rich microenvironment around the copper(i)-nitrite core to induce nitrate reduction in a chemical and biological environment.
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Affiliation(s)
- Wan-Jung Chuang
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Manmath Narwane
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Hsing-Yin Chen
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
| | - Chai-Lin Kao
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan. and Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
| | - Bin Huang
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Kuang-Mei Hsu
- Department of Biological Science and Technology, Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu 300, Taiwan.
| | - Yun-Ming Wang
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung 807, Taiwan and Department of Biological Science and Technology, Institute of Molecular Medicine and Bioengineering, National Chiao Tung University, Hsinchu 300, Taiwan.
| | - Sodio C N Hsu
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan. and Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
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28
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Fukuda Y, Matsusaki T, Tse KM, Mizohata E, Murphy MEP, Inoue T. Crystallographic study of dioxygen chemistry in a copper-containing nitrite reductase from Geobacillus thermodenitrificans. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2018; 74:769-777. [PMID: 30082512 DOI: 10.1107/s2059798318010082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Accepted: 07/12/2018] [Indexed: 11/10/2022]
Abstract
Copper-containing nitrite reductases (CuNIRs) are multifunctional enzymes that catalyse the one-electron reduction of nitrite (NO2-) to nitric oxide (NO) and the two-electron reduction of dioxygen (O2) to hydrogen peroxide (H2O2). In contrast to the mechanism of nitrite reduction, that of dioxygen reduction is poorly understood. Here, results from anaerobic synchrotron-radiation crystallography (SRX) and aerobic in-house radiation crystallography (iHRX) with a CuNIR from the thermophile Geobacillus thermodenitrificans (GtNIR) support the hypothesis that the dioxygen present in an aerobically manipulated crystal can bind to the catalytic type 2 copper (T2Cu) site of GtNIR during SRX experiments. The anaerobic SRX structure showed a dual conformation of one water molecule as an axial ligand in the T2Cu site, while previous aerobic SRX GtNIR structures were refined as diatomic molecule-bound states. Moreover, an SRX structure of the C135A mutant of GtNIR with peroxide bound to the T2Cu atom was determined. The peroxide molecule was mainly observed in a side-on binding manner, with a possible minor end-on conformation. The structures provide insights into dioxygen chemistry in CuNIRs and hence help to unmask the other face of CuNIRs.
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Affiliation(s)
- Yohta Fukuda
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Takuro Matsusaki
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Ka Man Tse
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Eiichi Mizohata
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Michael E P Murphy
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Tsuyoshi Inoue
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
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29
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Dong J, Sasaki D, Eady RR, Antonyuk SV, Hasnain SS. Identification of a tyrosine switch in copper-haem nitrite reductases. IUCRJ 2018; 5:510-518. [PMID: 30002851 PMCID: PMC6038957 DOI: 10.1107/s2052252518008242] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 06/04/2018] [Indexed: 06/08/2023]
Abstract
There are few cases where tyrosine has been shown to be involved in catalysis or the control of catalysis despite its ability to carry out chemistry at much higher potentials (1 V versus NHE). Here, it is shown that a tyrosine that blocks the hydrophobic substrate-entry channel in copper-haem nitrite reductases can be activated like a switch by the treatment of crystals of Ralstonia pickettii nitrite reductase (RpNiR) with nitric oxide (NO) (-0.8 ± 0.2 V). Treatment with NO results in an opening of the channel originating from the rotation of Tyr323 away from AspCAT97. Remarkably, the structure of a catalytic copper-deficient enzyme also shows Tyr323 in the closed position despite the absence of type 2 copper (T2Cu), clearly demonstrating that the status of Tyr323 is not controlled by T2Cu or its redox chemistry. It is also shown that the activation by NO is not through binding to haem. It is proposed that activation of the Tyr323 switch is controlled by NO through proton abstraction from tyrosine and the formation of HNO. The insight gained here for the use of tyrosine as a switch in catalysis has wider implications for catalysis in biology.
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Affiliation(s)
- Jianshu Dong
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZX, England
| | - Daisuke Sasaki
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZX, England
| | - Robert R. Eady
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZX, England
| | - Svetlana V. Antonyuk
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZX, England
| | - S. Samar Hasnain
- Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZX, England
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30
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Chang YL, Lin YF, Chuang WJ, Kao CL, Narwane M, Chen HY, Chiang MY, Hsu SCN. Structure and nitrite reduction reactivity study of bio-inspired copper(i)-nitro complexes in steric and electronic considerations of tridentate nitrogen ligands. Dalton Trans 2018; 47:5335-5341. [PMID: 29589010 DOI: 10.1039/c7dt03843g] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Two copper(i)-nitro complexes [Tpm3-tBuCu(NO2)] (1) and [(Ph3P)2N][Tp3-tBuCu(NO2)] (2), containing steric bulky neutral tris(3-tert-butylpyrazolyl)methane and anionic hydrotris(3-tert-butylpyrazolyl)borate ligands, have been synthesized and characterized. Complex 2 adopts a unique κ2-binding mode of Tp3-tBu around the copper(i)-nitro environment in the solid state and shows a four-coordinated tetrahedral geometry surrounded by a nitro and three pz3-tBu groups in solution. Both complexes 1 and 2 allow for the stoichiometric reduction of NO2- to NO with H+ addition. The results of this effort show that increasing steric bulk and electron donation properties on the nitrogen ancillary ligand will improve the nitrite reduction ability of the copper(i)-nitro model complexes.
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Affiliation(s)
- Yu-Lun Chang
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
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31
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Hira D, Kitamura R, Nakamura T, Yamagata Y, Furukawa K, Fujii T. Anammox Organism KSU-1 Expresses a Novel His/DOPA Ligated Cytochrome c. J Mol Biol 2018; 430:1189-1200. [DOI: 10.1016/j.jmb.2018.02.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 02/18/2018] [Accepted: 02/20/2018] [Indexed: 10/18/2022]
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32
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Zheng X, Wang J, Chen Y, Wei Y. Comprehensive analysis of transcriptional and proteomic profiling reveals silver nanoparticles-induced toxicity to bacterial denitrification. JOURNAL OF HAZARDOUS MATERIALS 2018; 344:291-298. [PMID: 29055833 DOI: 10.1016/j.jhazmat.2017.10.028] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 10/13/2017] [Accepted: 10/14/2017] [Indexed: 05/12/2023]
Abstract
Although the toxicity of silver nanoparticles (Ag NPs or nanosilver) to model bacteria has been reported, the effects of Ag NPs on microbial denitrification under anoxic conditions and the mechanism of Ag NPs induced-toxicity to denitrification remain unclear. In this study, the effects of Ag NPs on Paracoccus denitrificans under anoxic conditions were investigated, and the mechanism was explored by analyzing the transcriptional and proteomic responses of bacteria to Ag NPs. The presence of 5mg/L Ag NPs led to excessive nitrate accumulation (232.5 versus 5.3mg/L) and increased nitrous oxide emission. Transcriptional analysis indicated that Ag NPs restrained the expression of key genes related to denitrification. Specifically, the genes involved in denitrifying catalytic reduction and electron transfer were significantly down-regulated. Moreover, the expression of the genes responsible for polyhydroxybutyrate synthesis was enhanced, which was adverse to denitrification. Proteomic profiling revealed that the syntheses of the proteins involved in catalytic process, electron transfer, and metabolic process were inhibited by Ag NPs. The activities of nitrate reductase and nitrite reductase in the presence of 5mg/L Ag NPs were only 42% and 61% of those in the control, respectively, indicating the inhibition of denitrifying enzymes. These results improve understanding of the inhibitory mechanism of Ag NPs toward bacterial denitrification.
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Affiliation(s)
- Xiong Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Juan Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
| | - Yuanyuan Wei
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
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33
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Li S, Cooke RA, Huang X, Christianson L, Bhattarai R. Evaluation of fly ash pellets for phosphorus removal in a laboratory scale denitrifying bioreactor. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 207:269-275. [PMID: 29179116 DOI: 10.1016/j.jenvman.2017.11.040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 10/24/2017] [Accepted: 11/15/2017] [Indexed: 06/07/2023]
Abstract
Nitrate and orthophosphate from agricultural activities contribute significantly to nutrient loading in surface water bodies around the world. This study evaluated the efficacy of woodchips and fly ash pellets in tandem to remove nitrate and orthophosphate from simulated agricultural runoff in flow-through tests. The fly ash pellets had previously been developed specifically for orthophosphate removal for this type of application, and the sorption bench testing showed a good promise for flow-through testing. The lab-scale horizontal-flow bioreactor used in this study consisted of an upstream column filled with woodchips followed by a downstream column filled with fly ash pellets (3 and 1 m lengths, respectively; both 0.15 m diameter). Using influent concentrations of 12 mg/L nitrate and 5 mg/L orthophosphate, the woodchip bioreactor section was able to remove 49-85% of the nitrate concentration at three hydraulic retention times ranging from 0.67 to 4.0 h. The nitrate removal rate for woodchips ranged from 40 to 49 g N/m3/d. Higher hydraulic retention times (i.e., smaller flow rates) corresponded with greater nitrate load reduction. The fly ash pellets showed relatively stable removal efficiency of 68-75% across all retention times. Total orthophosphate adsorption by the pellets was 0.059-0.114 mg P/g which was far less than the saturated capacity (1.69 mg/g; based on previous work). The fly ash pellets also removed some nitrate and the woodchips also removed some orthophosphate, but these reductions were not significant. Overall, woodchip denitrification followed by fly ash pellet P-sorption can be an effective treatment technology for nitrate and phosphate removal in subsurface drainage.
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Affiliation(s)
- Shiyang Li
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana Champaign, 1304 W Pennsylvania Ave #338, Urbana IL 61801, USA
| | - Richard A Cooke
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana Champaign, 1304 W Pennsylvania Ave #338, Urbana IL 61801, USA
| | - Xiangfeng Huang
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Tongji University, Shanghai 200092, PR China
| | - Laura Christianson
- Department of Crop Sciences, University of Illinois at Urbana Champaign, AW-101 Turner Hall, 1102 South Goodwin Avenue, Urbana, IL, 61801, USA
| | - Rabin Bhattarai
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana Champaign, 1304 W Pennsylvania Ave #338, Urbana IL 61801, USA.
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34
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Lintuluoto M, Lintuluoto JM. Intra-electron transfer induced by protonation in copper-containing nitrite reductase. Metallomics 2018. [DOI: 10.1039/c7mt00323d] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Electron transfer between two Cu sites in the enzyme induced by protonation of remote catalytic residues.
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Affiliation(s)
- Masami Lintuluoto
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University
- Kyoto 606-8522
- Japan
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35
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Cloning, purification and characterization of novel Cu-containing nitrite reductase from the Bacillus firmus GY-49. World J Microbiol Biotechnol 2017; 34:10. [DOI: 10.1007/s11274-017-2383-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 11/22/2017] [Indexed: 11/27/2022]
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36
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Qin X, Deng L, Hu C, Li L, Chen X. Copper-Containing Nitrite Reductase Employing Proton-Coupled Spin-Exchanged Electron-Transfer and Multiproton Synchronized Transfer to Reduce Nitrite. Chemistry 2017; 23:14900-14910. [DOI: 10.1002/chem.201703221] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Xin Qin
- National-Municipal Joint Engineering Laboratory for Chemical; Process Intensification and Reaction; School of Chemistry and Chemical Engineering; Chongqing University; Chongqing 401331 P.R. China
| | - Li Deng
- National-Municipal Joint Engineering Laboratory for Chemical; Process Intensification and Reaction; School of Chemistry and Chemical Engineering; Chongqing University; Chongqing 401331 P.R. China
| | - Caihong Hu
- National-Municipal Joint Engineering Laboratory for Chemical; Process Intensification and Reaction; School of Chemistry and Chemical Engineering; Chongqing University; Chongqing 401331 P.R. China
| | - Li Li
- National-Municipal Joint Engineering Laboratory for Chemical; Process Intensification and Reaction; School of Chemistry and Chemical Engineering; Chongqing University; Chongqing 401331 P.R. China
| | - Xiaohua Chen
- National-Municipal Joint Engineering Laboratory for Chemical; Process Intensification and Reaction; School of Chemistry and Chemical Engineering; Chongqing University; Chongqing 401331 P.R. China
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37
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Zheng XY, Lu D, Chen W, Gao YJ, Zhou G, Zhang Y, Zhou X, Jin MQ. Response of Aerobic Granular Sludge to the Long-Term Presence of CuO NPs in A/O/A SBRs: Nitrogen and Phosphorus Removal, Enzymatic Activity, and the Microbial Community. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:10503-10510. [PMID: 28832135 DOI: 10.1021/acs.est.7b02768] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The increasing use of cupric oxide nanoparticles (CuO NPs) has raised concerns about their potential environmental toxicity. Aerobic granular sludge (AGS) is a special form of microbial aggregates. In this study, the removal efficiencies of nitrogen and phosphorus, enzyme activities and microbial community of AGS under long-term exposure to CuO NPs (at concentrations of 5, 20, 50 mg/L) in aerobic/oxic/anoxic (A/O/A) sequencing batch reactors (SBRs) were investigated. The results showed the chronic toxicity caused by different concentrations of CuO NPs (5, 20, 50 mg/L) resulted in increases in the production of ROS of 110.37%, 178.64%, and 188.93% and in the release of lactate dehydrogenase (LDH) of 108.33%, 297.05%, 335.94%, respectively, compared to the control. Besides, CuO NPs decreased the activities of polyphosphate kinase (PPK) and exophosphatase (PPX), leading to lower phosphorus removal efficiency. However, the NH4+-N removal rates remained stable, and the removal efficiencies of TN increased due to the synthesis of nitrite and nitrous oxide (N2O) reductases. In addition, CuO NPs at concentrations of 0, 5, 20 mg/L increased the secretion of protein (PN) to 90, 91, 105 mg/gVSS, respectively, which could alleviate the toxicity of CuO NPs. High-throughput sequencing showed that CuO NPs increased the abundance of nitrogen-removal bacteria and reduced the abundance of phosphorus-removal bacteria, which is consistent with the results of pollutant removal upon long-term exposure to CuO NPs.
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Affiliation(s)
- Xiao-Ying Zheng
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University , Nanjing 210098, PR China
- College of Environment, Hohai University , Nanjing 210098, PR China
| | - Dan Lu
- College of Environment, Hohai University , Nanjing 210098, PR China
| | - Wei Chen
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University , Nanjing 210098, PR China
- College of Environment, Hohai University , Nanjing 210098, PR China
| | - Ya-Jie Gao
- College of Environment, Hohai University , Nanjing 210098, PR China
| | - Gan Zhou
- College of Environment, Hohai University , Nanjing 210098, PR China
| | - Yuan Zhang
- College of Environment, Hohai University , Nanjing 210098, PR China
| | - Xiang Zhou
- College of Environment, Hohai University , Nanjing 210098, PR China
| | - Meng-Qi Jin
- College of Environment, Hohai University , Nanjing 210098, PR China
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38
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Dynamics of nitric oxide controlled by protein complex in bacterial system. Proc Natl Acad Sci U S A 2017; 114:9888-9893. [PMID: 28847930 DOI: 10.1073/pnas.1621301114] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nitric oxide (NO) plays diverse and significant roles in biological processes despite its cytotoxicity, raising the question of how biological systems control the action of NO to minimize its cytotoxicity in cells. As a great example of such a system, we found a possibility that NO-generating nitrite reductase (NiR) forms a complex with NO-decomposing membrane-integrated NO reductase (NOR) to efficiently capture NO immediately after its production by NiR in anaerobic nitrate respiration called denitrification. The 3.2-Å resolution structure of the complex of one NiR functional homodimer and two NOR molecules provides an idea of how these enzymes interact in cells, while the structure may not reflect the one in cells due to the membrane topology. Subsequent all-atom molecular dynamics (MD) simulations of the enzyme complex model in a membrane and structure-guided mutagenesis suggested that a few interenzyme salt bridges and coulombic interactions of NiR with the membrane could stabilize the complex of one NiR homodimer and one NOR molecule and contribute to rapid NO decomposition in cells. The MD trajectories of the NO diffusion in the NiR:NOR complex with the membrane showed that, as a plausible NO transfer mechanism, NO released from NiR rapidly migrates into the membrane, then binds to NOR. These results help us understand the mechanism of the cellular control of the action of cytotoxic NO.
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Lintuluoto M, Yamada C, Lintuluoto JM. QM/MM Calculation of the Enzyme Catalytic Cycle Mechanism for Copper- and Zinc-Containing Superoxide Dismutase. J Phys Chem B 2017; 121:7235-7246. [DOI: 10.1021/acs.jpcb.7b03589] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Masami Lintuluoto
- Graduate
School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamohanki-cho, Sakyo, Kyoto 606-8522, Japan
| | - Chiaki Yamada
- Graduate
School of Life and Environmental Sciences, Kyoto Prefectural University, Shimogamohanki-cho, Sakyo, Kyoto 606-8522, Japan
| | - Juha M. Lintuluoto
- Graduate
School of Engineering, Kyoto University, Katsura Campus, Nishikyo-ku, Kyoto 615-8530, Japan
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Horrell S, Kekilli D, Strange RW, Hough MA. Recent structural insights into the function of copper nitrite reductases. Metallomics 2017; 9:1470-1482. [DOI: 10.1039/c7mt00146k] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Copper nitrite reductases (CuNiRs) catalyse the reduction of nitrite to nitric oxide as part of the denitrification pathway. In this review, we describe insights into CuNiR function from structural studies.
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Affiliation(s)
- Sam Horrell
- School of Biological Sciences
- University of Essex
- Colchester
- UK
| | - Demet Kekilli
- School of Biological Sciences
- University of Essex
- Colchester
- UK
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Shimada S, Shinzawa-Itoh K, Baba J, Aoe S, Shimada A, Yamashita E, Kang J, Tateno M, Yoshikawa S, Tsukihara T. Complex structure of cytochrome c-cytochrome c oxidase reveals a novel protein-protein interaction mode. EMBO J 2016; 36:291-300. [PMID: 27979921 PMCID: PMC5286356 DOI: 10.15252/embj.201695021] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 10/21/2016] [Accepted: 11/16/2016] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial cytochrome c oxidase (CcO) transfers electrons from cytochrome c (Cyt.c) to O2 to generate H2O, a process coupled to proton pumping. To elucidate the mechanism of electron transfer, we determined the structure of the mammalian Cyt.c–CcO complex at 2.0‐Å resolution and identified an electron transfer pathway from Cyt.c to CcO. The specific interaction between Cyt.c and CcO is stabilized by a few electrostatic interactions between side chains within a small contact surface area. Between the two proteins are three water layers with a long inter‐molecular span, one of which lies between the other two layers without significant direct interaction with either protein. Cyt.c undergoes large structural fluctuations, using the interacting regions with CcO as a fulcrum. These features of the protein–protein interaction at the docking interface represent the first known example of a new class of protein–protein interaction, which we term “soft and specific”. This interaction is likely to contribute to the rapid association/dissociation of the Cyt.c–CcO complex, which facilitates the sequential supply of four electrons for the O2 reduction reaction.
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Affiliation(s)
- Satoru Shimada
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Kyoko Shinzawa-Itoh
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Junpei Baba
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Shimpei Aoe
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Atsuhiro Shimada
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Eiki Yamashita
- Institute for Protein Research, Osaka University, Suita, Osaka, Japan
| | - Jiyoung Kang
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Masaru Tateno
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Shinya Yoshikawa
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan
| | - Tomitake Tsukihara
- Picobiology Institute, Graduate School of Life Science, University of Hyogo, Akoh, Hyogo, Japan .,Institute for Protein Research, Osaka University, Suita, Osaka, Japan.,JST, CREST, Kawaguchi, Saitama, Japan
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Su Y, Chen Y, Zheng X, Wan R, Huang H, Li M, Wu L. Using sludge fermentation liquid to reduce the inhibitory effect of copper oxide nanoparticles on municipal wastewater biological nutrient removal. WATER RESEARCH 2016; 99:216-224. [PMID: 27161888 DOI: 10.1016/j.watres.2016.04.066] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/19/2016] [Accepted: 04/29/2016] [Indexed: 06/05/2023]
Abstract
The deterioration of biological nutrient removal (BNR) can occur with the release of engineering nanomaterials into wastewater treatment plants (WWTPs). Also, large amounts of waste sludge are generated in WWTPs, which can be reutilized as a useful resource. In this study, the use of sludge fermentation liquid to reduce CuO nanoparticles (NPs) toxicity to municipal wastewater BNR was reported. In the BNR system supplemented with sodium acetate, which was widely used as additional carbon source of municipal wastewater in literatures, the appearance of 2.5 mg/L CuO NPs for 5.5 h decreased the total nitrogen (TN) removal efficiency from 81.4% to 59.0%, but the TN removal was recovered to 78.7% after sodium acetate was replaced by sludge fermentation liquid. It was found that CuO NPs induced excessive generation of reactive nitrogen species (RNS), which led to the disorder of redox status, low levels of energy and reduction equivalents generations, and deterioration of denitrification. Further investigation revealed that cysteine in fermentation liquid played a vital biological role in reducing nanotoxicity by facilitating the synthesis of glutathione, which reduced excessive RNS generation, increased key proteins expression, guaranteed the metabolisms of intracellular energy and substrate smoothly, and finally recovered the BNR performance.
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Affiliation(s)
- Yinglong Su
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
| | - Xiong Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
| | - Rui Wan
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
| | - Haining Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
| | - Mu Li
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
| | - Lijuan Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
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Wang D, Wang Q, Laloo AE, Yuan Z. Reducing N2O Emission from a Domestic-Strength Nitrifying Culture by Free Nitrous Acid-Based Sludge Treatment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:7425-7433. [PMID: 27294698 DOI: 10.1021/acs.est.6b00660] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
An increase of nitrite in the domestic-strength range is generally recognized to stimulate nitrous oxide (N2O) production by ammonia-oxidizing bacteria (AOB). It was found in this study, however, that N2O emission from a mainstream nitritation system (cyclic nitrite = 25-45 mg of N/L) that was established by free nitrous acid (FNA)-based sludge treatment was not higher but much lower than that from the initial nitrifying system with full conversion of NH4(+)-N to NO3(-)-N. Under dissolved oxygen (DO) levels of 2.5-3.0 mg/L, N2O emission from the nitritation stage was 76% lower than that from the initial stage. Even when the DO level was reduced to 0.3-0.8 mg/L, N2O emission from the nitritation stage was still 40% lower. An investigation of the mechanism showed that FNA treatment caused a shift of the stimulation threshold of nitrite on N2O emission. At the nitritation stage, the maximal N2O emission factor occurred at ∼16 mg of N/(L of nitrite). However, it increased with increasing nitrite in the range of 0-56 mg of N/L at the initial stage. FNA treatment decreased the biomass-specific N2O production rate, suggesting that the enzymes relevant to nitrifier denitrification were inhibited. Microbial analysis revealed that FNA treatment decreased the microbial community diversity but increased the abundances of AOB and denitrifiers.
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Affiliation(s)
- Dongbo Wang
- Advanced Water Management Centre (AWMC), The University of Queensland , Brisbane, QLD 4072, Australia
| | - Qilin Wang
- Advanced Water Management Centre (AWMC), The University of Queensland , Brisbane, QLD 4072, Australia
| | - Andrew Elohim Laloo
- Advanced Water Management Centre (AWMC), The University of Queensland , Brisbane, QLD 4072, Australia
| | - Zhiguo Yuan
- Advanced Water Management Centre (AWMC), The University of Queensland , Brisbane, QLD 4072, Australia
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Eady RR, Antonyuk SV, Hasnain SS. Fresh insight to functioning of selected enzymes of the nitrogen cycle. Curr Opin Chem Biol 2016; 31:103-12. [DOI: 10.1016/j.cbpa.2016.02.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 02/18/2016] [Indexed: 11/26/2022]
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Highly diverse nirK genes comprise two major clades that harbour ammonium-producing denitrifiers. BMC Genomics 2016; 17:155. [PMID: 26923558 PMCID: PMC4770552 DOI: 10.1186/s12864-016-2465-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 02/12/2016] [Indexed: 01/09/2023] Open
Abstract
Background Copper dependent nitrite reductase, NirK, catalyses the key step in denitrification, i.e. nitrite reduction to nitric oxide. Distinct structural NirK classes and phylogenetic clades of NirK-type denitrifiers have previously been observed based on a limited set of NirK sequences, however, their environmental distribution or ecological strategies are currently unknown. In addition, environmental nirK-type denitrifiers are currently underestimated in PCR-dependent surveys due to primer coverage limitations that can be attributed to their broad taxonomic diversity and enormous nirK sequence divergence. Therefore, we revisited reported analyses on partial NirK sequences using a taxonomically diverse, full-length NirK sequence dataset. Results Division of NirK sequences into two phylogenetically distinct clades was confirmed, with Clade I mainly comprising Alphaproteobacteria (plus some Gamma- and Betaproteobacteria) and Clade II harbouring more diverse taxonomic groups like Archaea, Bacteroidetes, Chloroflexi, Gemmatimonadetes, Nitrospirae, Firmicutes, Actinobacteria, Planctomycetes and Proteobacteria (mainly Beta and Gamma). Failure of currently available primer sets to target diverse NirK-type denitrifiers in environmental surveys could be attributed to mismatches over the whole length of the primer binding regions including the 3′ site, with Clade II sequences containing higher sequence divergence than Clade I sequences. Simultaneous presence of both the denitrification and DNRA pathway could be observed in 67 % of all NirK-type denitrifiers. Conclusion The previously reported division of NirK into two distinct phylogenetic clades was confirmed using a taxonomically diverse set of full-length NirK sequences. Enormous sequence divergence of nirK gene sequences, probably due to variable nirK evolutionary trajectories, will remain an issue for covering diverse NirK-type denitrifiers in amplicon-based environmental surveys. The potential of a single organism to partition nitrate to either denitrification or dissimilatory nitrate reduction to ammonium appeared to be more widespread than originally anticipated as more than half of all NirK-type denitrifiers were shown to contain both pathways in their genome. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2465-0) contains supplementary material, which is available to authorized users.
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Fukuda Y, Tse KM, Suzuki M, Diederichs K, Hirata K, Nakane T, Sugahara M, Nango E, Tono K, Joti Y, Kameshima T, Song C, Hatsui T, Yabashi M, Nureki O, Matsumura H, Inoue T, Iwata S, Mizohata E. Redox-coupled structural changes in nitrite reductase revealed by serial femtosecond and microfocus crystallography. J Biochem 2016; 159:527-38. [PMID: 26769972 PMCID: PMC4846774 DOI: 10.1093/jb/mvv133] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/19/2015] [Indexed: 11/17/2022] Open
Abstract
Serial femtosecond crystallography (SFX) has enabled the damage-free structural determination of metalloenzymes and filled the gaps of our knowledge between crystallographic and spectroscopic data. Crystallographers, however, scarcely know whether the rising technique provides truly new structural insights into mechanisms of metalloenzymes partly because of limited resolutions. Copper nitrite reductase (CuNiR), which converts nitrite to nitric oxide in denitrification, has been extensively studied by synchrotron radiation crystallography (SRX). Although catalytic Cu (Type 2 copper (T2Cu)) of CuNiR had been suspected to tolerate X-ray photoreduction, we here showed that T2Cu in the form free of nitrite is reduced and changes its coordination structure in SRX. Moreover, we determined the completely oxidized CuNiR structure at 1.43 Å resolution with SFX. Comparison between the high-resolution SFX and SRX data revealed the subtle structural change of a catalytic His residue by X-ray photoreduction. This finding, which SRX has failed to uncover, provides new insight into the reaction mechanism of CuNiR.
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Affiliation(s)
- Yohta Fukuda
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Ka Man Tse
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan;
| | - Mamoru Suzuki
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan; RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan;
| | - Kay Diederichs
- Department of Biology, University of Konstanz, D-78457 Konstanz, Germany;
| | - Kunio Hirata
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan;
| | - Takanori Nakane
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;
| | - Michihiro Sugahara
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan;
| | - Eriko Nango
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan;
| | - Kensuke Tono
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan;
| | - Yasumasa Joti
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan;
| | - Takashi Kameshima
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan;
| | - Changyong Song
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan; Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea; and
| | - Takaki Hatsui
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan;
| | - Makina Yabashi
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan;
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan;
| | - Hiroyoshi Matsumura
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Tsuyoshi Inoue
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan;
| | - So Iwata
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan; Department of Cell Biology, Graduate School of Medicine, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Eiichi Mizohata
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan;
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McGrath AP, Laming EL, Casas Garcia GP, Kvansakul M, Guss JM, Trewhella J, Calmes B, Bernhardt PV, Hanson GR, Kappler U, Maher MJ. Structural basis of interprotein electron transfer in bacterial sulfite oxidation. eLife 2015; 4:e09066. [PMID: 26687009 PMCID: PMC4760952 DOI: 10.7554/elife.09066] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 11/12/2015] [Indexed: 11/13/2022] Open
Abstract
Interprotein electron transfer underpins the essential processes of life and relies on the formation of specific, yet transient protein-protein interactions. In biological systems, the detoxification of sulfite is catalyzed by the sulfite-oxidizing enzymes (SOEs), which interact with an electron acceptor for catalytic turnover. Here, we report the structural and functional analyses of the SOE SorT from Sinorhizobium meliloti and its cognate electron acceptor SorU. Kinetic and thermodynamic analyses of the SorT/SorU interaction show the complex is dynamic in solution, and that the proteins interact with Kd = 13.5 ± 0.8 μM. The crystal structures of the oxidized SorT and SorU, both in isolation and in complex, reveal the interface to be remarkably electrostatic, with an unusually large number of direct hydrogen bonding interactions. The assembly of the complex is accompanied by an adjustment in the structure of SorU, and conformational sampling provides a mechanism for dissociation of the SorT/SorU assembly.
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Affiliation(s)
- Aaron P McGrath
- Structural Biology Program, Centenary Institute, Sydney, Australia
| | - Elise L Laming
- School of Molecular Bioscience, University of Sydney, Sydney, Australia
| | - G Patricia Casas Garcia
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - Marc Kvansakul
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
| | - J Mitchell Guss
- School of Molecular Bioscience, University of Sydney, Sydney, Australia
| | - Jill Trewhella
- School of Molecular Bioscience, University of Sydney, Sydney, Australia
| | - Benoit Calmes
- Centre for Metals in Biology, The University of Queensland, Brisbane, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Paul V Bernhardt
- Centre for Metals in Biology, The University of Queensland, Brisbane, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Graeme R Hanson
- Centre for Metals in Biology, The University of Queensland, Brisbane, Australia
- Centre for Advanced Imaging, University of Queensland, Brisbane, Australia
| | - Ulrike Kappler
- Centre for Metals in Biology, The University of Queensland, Brisbane, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - Megan J Maher
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Australia
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Determining Roles of Accessory Genes in Denitrification by Mutant Fitness Analyses. Appl Environ Microbiol 2015; 82:51-61. [PMID: 26452555 DOI: 10.1128/aem.02602-15] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Accepted: 10/07/2015] [Indexed: 01/06/2023] Open
Abstract
Enzymes of the denitrification pathway play an important role in the global nitrogen cycle, including release of nitrous oxide, an ozone-depleting greenhouse gas. In addition, nitric oxide reductase, maturation factors, and proteins associated with nitric oxide detoxification are used by pathogens to combat nitric oxide release by host immune systems. While the core reductases that catalyze the conversion of nitrate to dinitrogen are well understood at a mechanistic level, there are many peripheral proteins required for denitrification whose basic function is unclear. A bar-coded transposon DNA library from Pseudomonas stutzeri strain RCH2 was grown under denitrifying conditions, using nitrate or nitrite as an electron acceptor, and also under molybdenum limitation conditions, with nitrate as the electron acceptor. Analysis of sequencing results from these growths yielded gene fitness data for 3,307 of the 4,265 protein-encoding genes present in strain RCH2. The insights presented here contribute to our understanding of how peripheral proteins contribute to a fully functioning denitrification pathway. We propose a new low-affinity molybdate transporter, OatABC, and show that differential regulation is observed for two MoaA homologs involved in molybdenum cofactor biosynthesis. We also propose that NnrS may function as a membrane-bound NO sensor. The dominant HemN paralog involved in heme biosynthesis is identified, and a CheR homolog is proposed to function in nitrate chemotaxis. In addition, new insights are provided into nitrite reductase redundancy, nitric oxide reductase maturation, nitrous oxide reductase maturation, and regulation.
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Komori H, Higuchi Y. Structure and molecular evolution of multicopper blue proteins. Biomol Concepts 2015; 1:31-40. [PMID: 25961983 DOI: 10.1515/bmc.2010.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The multicopper blue protein family, which contains cupredoxin-like domains as a structural unit, is one of the most diverse groups of proteins. This protein family is divided into two functionally different types of enzymes: multicopper oxidase and nitrite reductase. Multicopper oxidase catalyzes the oxidation of the substrate and then reduces dioxygen. The structures of many multicopper oxidases are already known, and until recently they were classified into two main groups: the three- and six-domain types. Both function as monomers and have three spectroscopically different copper sites: Types I (blue), II, and III (tri-nuclear). Nitrite reductase is a closely related protein that contains Types I and II (mono-nuclear) coppers but reduces nitrite instead of dioxygen. Nitrite reductase, which consists of two domains, forms a homotrimer. Multicopper oxidase and nitrite reductase share similar structural architectures and also contain Type I copper. Therefore, it is proposed that they have a common ancestor protein. Recently, some two-domain type multicopper oxidases have been found and their crystal structures have been determined. They have a trimeric quaternary structure and contain an active site at the molecular interface such as nitrite reductase. These results support previous hypotheses and provide an insight into the molecular evolution of multicopper blue proteins.
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