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Ferreira MP, Castro CB, Honorato J, He S, Gonçalves Guimarães Júnior W, Esmieu C, Castellano EE, de Moura AF, Truzzi DR, Nascimento OR, Simonneau A, Marques Netto CGC. Biomimetic catalysis of nitrite reductase enzyme using copper complexes in chemical and electrochemical reduction of nitrite. Dalton Trans 2023; 52:11254-11264. [PMID: 37526523 DOI: 10.1039/d3dt01091k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Copper nitrite reductase mimetics were synthesized using three new tridentate ligands sharing the same N,N,N motif of coordination. The ligands were based on L-proline modifications, attaching a pyridine and a triazole to the pyrrolidine ring, and differ by a pendant group (R = phenyl, n-butyl and n-propan-1-ol). All complexes coordinate nitrite, as evidenced by cyclic voltammetry, UV-Vis, FTIR and electron paramagnetic resonance (EPR) spectroscopies. The coordination mode of nitrite was assigned by FTIR and EPR as κ2O chelate mode. Upon acidification, EPR experiments indicated a shift from chelate to monodentate κO mode, and 15N NMR experiments of a Zn2+ analogue, suggested that the related Cu(II) nitrous acid complex may be reasonably stable in solution, but in equilibrium with free HONO under non catalytic conditions. Reduction of nitrite to NO was performed both chemically and electrocatalytically, observing the highest catalytic activities for the complex with n-propan-1-ol as pendant group. These results support the hypothesis that a hydrogen bond moiety in the secondary coordination sphere may aid the protonation step.
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Affiliation(s)
- Millena P Ferreira
- Department of Chemistry, Universidade Federal de São Carlos (UFSCar), Rod. Washington Luiz, km 235 s/n, CEP 13565905 São Carlos, SP, Brazil.
| | - Caio B Castro
- Department of Chemistry, Universidade Federal de São Carlos (UFSCar), Rod. Washington Luiz, km 235 s/n, CEP 13565905 São Carlos, SP, Brazil.
| | - João Honorato
- Insitututo de Química, Departamento de Bioquímica, Universidade de São Paulo (USP), Av. Prof. Dr. Lineu Prestes, 748, CEP 05513-970 São Paulo, SP, Brazil
- Instituto de Física, Universidade de São Paulo (USP), Av.João Dagnone, 1100, CEP 13563-120, São Carlos, SP, Brazil
| | - Sheng He
- Department of Chemistry, Emory University, 1515 Dickey Drive, 30322 Atlanta, GA, USA
| | - Walber Gonçalves Guimarães Júnior
- Department of Chemistry, Universidade Federal de São Carlos (UFSCar), Rod. Washington Luiz, km 235 s/n, CEP 13565905 São Carlos, SP, Brazil.
| | - Charlene Esmieu
- LCC-CNRS, Universite de Toulouse, CNRS, UPS, 205 route de Narbonne, F31077 Toulouse cedex 4, France
| | - Eduardo E Castellano
- Instituto de Física, Universidade de São Paulo (USP), Av.João Dagnone, 1100, CEP 13563-120, São Carlos, SP, Brazil
| | - André F de Moura
- Department of Chemistry, Universidade Federal de São Carlos (UFSCar), Rod. Washington Luiz, km 235 s/n, CEP 13565905 São Carlos, SP, Brazil.
| | - Daniela R Truzzi
- Insitututo de Química, Departamento de Bioquímica, Universidade de São Paulo (USP), Av. Prof. Dr. Lineu Prestes, 748, CEP 05513-970 São Paulo, SP, Brazil
| | - Otaciro R Nascimento
- Instituto de Física, Universidade de São Paulo (USP), Av.João Dagnone, 1100, CEP 13563-120, São Carlos, SP, Brazil
| | - Antoine Simonneau
- LCC-CNRS, Universite de Toulouse, CNRS, UPS, 205 route de Narbonne, F31077 Toulouse cedex 4, France
| | - Caterina G C Marques Netto
- Department of Chemistry, Universidade Federal de São Carlos (UFSCar), Rod. Washington Luiz, km 235 s/n, CEP 13565905 São Carlos, SP, Brazil.
- Department of Chemistry, Emory University, 1515 Dickey Drive, 30322 Atlanta, GA, USA
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Bioinspired Electropun Fibrous Materials Based on Poly-3-Hydroxybutyrate and Hemin: Preparation, Physicochemical Properties, and Weathering. Polymers (Basel) 2022; 14:polym14224878. [PMID: 36433006 PMCID: PMC9692885 DOI: 10.3390/polym14224878] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/03/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
The development of innovative fibrous materials with valuable multifunctional properties based on biodegradable polymers and modifying additives presents a challenging direction for modern materials science and environmental safety. In this work, high-performance composite fibrous materials based on semicrystalline biodegradable poly-3-hydroxybutyrate (PHB) and natural iron-containing porphyrin, hemin (Hmi) were prepared by electrospinning. The addition of Hmi to the feed PHB mixture (at concentrations above 3 wt.%) is shown to facilitate the electrospinning process and improve the quality of the electrospun PHB/Hmi materials: the fibers become uniform, their average diameter decreases down to 1.77 µm, and porosity increases to 94%. Structural morphology, phase composition, and physicochemical properties of the Hmi/PHB fibrous materials were studied by diverse physicochemical methods, including electronic paramagnetic resonance, optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, elemental analysis, differential scanning calorimetry, Fourier-transformed infrared spectroscopy, mechanical analysis, etc. The proposed nonwoven Hmi/PHB composites with high porosity, good mechanical properties, and retarded biodegradation due to high antibacterial potential can be used as high-performance and robust materials for biomedical applications, including breathable materials for wound disinfection and accelerated healing, scaffolds for regenerative medicine and tissue engineering.
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Single crystal spectroscopy and multiple structures from one crystal (MSOX) define catalysis in copper nitrite reductases. Proc Natl Acad Sci U S A 2022; 119:e2205664119. [PMID: 35862453 PMCID: PMC9335323 DOI: 10.1073/pnas.2205664119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
X-rays used to collect crystallographic data can change the redox states of transition metals utilized by many biological systems including metalloproteins. This disadvantage has been harnessed to drive a complex chemical reaction requiring the delivery of an electron to the active site and recording the structural changes accompanying catalysis, providing a real-time structural movie of an enzymatic reaction, which has been a dream of enzymologists for decades. By coupling the multiple-structures from one crystal technique with single-crystal and solution optical spectroscopy, we show that the electron transfer between the electron accepting type-1 Cu and catalytic type-2 Cu redox centers is gated in a recently characterized copper nitrite reductase. This combined structural/spectroscopic approach is applicable to many complex redox biological systems. Many enzymes utilize redox-coupled centers for performing catalysis where these centers are used to control and regulate the transfer of electrons required for catalysis, whose untimely delivery can lead to a state incapable of binding the substrate, i.e., a dead-end enzyme. Copper nitrite reductases (CuNiRs), which catalyze the reduction of nitrite to nitric oxide (NO), have proven to be a good model system for studying these complex processes including proton-coupled electron transfer (ET) and their orchestration for substrate binding/utilization. Recently, a two-domain CuNiR from a Rhizobia species (Br2DNiR) has been discovered with a substantially lower enzymatic activity where the catalytic type-2 Cu (T2Cu) site is occupied by two water molecules requiring their displacement for the substrate nitrite to bind. Single crystal spectroscopy combined with MSOX (multiple structures from one crystal) for both the as-isolated and nitrite-soaked crystals clearly demonstrate that inter-Cu ET within the coupled T1Cu-T2Cu redox system is heavily gated. Laser-flash photolysis and optical spectroscopy showed rapid ET from photoexcited NADH to the T1Cu center but little or no inter-Cu ET in the absence of nitrite. Furthermore, incomplete reoxidation of the T1Cu site (∼20% electrons transferred) was observed in the presence of nitrite, consistent with a slow formation of NO species in the serial structures of the MSOX movie obtained from the nitrite-soaked crystal, which is likely to be responsible for the lower activity of this CuNiR. Our approach is of direct relevance for studying redox reactions in a wide range of biological systems including metalloproteins that make up at least 30% of all proteins.
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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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González PJ, Rivas MG, Ferroni FM, Rizzi AC, Brondino CD. Electron transfer pathways and spin–spin interactions in Mo- and Cu-containing oxidoreductases. Coord Chem Rev 2021. [DOI: 10.1016/j.ccr.2021.214202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Ramírez CS, Tolmie C, Opperman DJ, González PJ, Rivas MG, Brondino CD, Ferroni FM. Copper nitrite reductase from Sinorhizobium meliloti 2011: Crystal structure and interaction with the physiological versus a nonmetabolically related cupredoxin-like mediator. Protein Sci 2021; 30:2310-2323. [PMID: 34562300 DOI: 10.1002/pro.4195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 11/08/2022]
Abstract
We report the crystal structure of the copper-containing nitrite reductase (NirK) from the Gram-negative bacterium Sinorhizobium meliloti 2011 (Sm), together with complex structural alignment and docking studies with both non-cognate and the physiologically related pseudoazurins, SmPaz1 and SmPaz2, respectively. S. meliloti is a rhizobacterium used for the formulation of Medicago sativa bionoculants, and SmNirK plays a key role in this symbiosis through the denitrification pathway. The structure of SmNirK, solved at a resolution of 2.5 Å, showed a striking resemblance with the overall structure of the well-known Class I NirKs composed of two Greek key β-barrel domains. The activity of SmNirK is ~12% of the activity reported for classical NirKs, which could be attributed to several factors such as subtle structural differences in the secondary proton channel, solvent accessibility of the substrate channel, and that the denitrifying activity has to be finely regulated within the endosymbiont. In vitro kinetics performed in homogenous and heterogeneous media showed that both SmPaz1 and SmPaz2, which are coded in different regions of the genome, donate electrons to SmNirK with similar performance. Even though the energetics of the interprotein electron transfer (ET) process is not favorable with either electron donors, adduct formation mediated by conserved residues allows minimizing the distance between the copper centers involved in the interprotein ET process.
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Affiliation(s)
- Cintia Soledad Ramírez
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral (UNL). CONICET, Ciudad Universitaria, Santa Fe, Argentina
| | - Carmien Tolmie
- Department of Microbiology and Biochemistry, University of the Free State (UFS), Bloemfontein, South Africa
| | - Diederik Johannes Opperman
- Department of Microbiology and Biochemistry, University of the Free State (UFS), Bloemfontein, South Africa
| | - Pablo Javier González
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral (UNL). CONICET, Ciudad Universitaria, Santa Fe, Argentina
| | - María Gabriela Rivas
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral (UNL). CONICET, Ciudad Universitaria, Santa Fe, Argentina
| | - Carlos Dante Brondino
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral (UNL). CONICET, Ciudad Universitaria, Santa Fe, Argentina
| | - Felix Martín Ferroni
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral (UNL). CONICET, Ciudad Universitaria, Santa Fe, Argentina
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Bernabeu E, Miralles-Robledillo JM, Giani M, Valdés E, Martínez-Espinosa RM, Pire C. In Silico Analysis of the Enzymes Involved in Haloarchaeal Denitrification. Biomolecules 2021; 11:biom11071043. [PMID: 34356667 PMCID: PMC8301774 DOI: 10.3390/biom11071043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/02/2021] [Accepted: 07/09/2021] [Indexed: 12/18/2022] Open
Abstract
During the last century, anthropogenic activities such as fertilization have led to an increase in pollution in many ecosystems by nitrogen compounds. Consequently, researchers aim to reduce nitrogen pollutants following different strategies. Some haloarchaea, owing to their denitrifier metabolism, have been proposed as good model organisms for the removal of not only nitrate, nitrite, and ammonium, but also (per)chlorates and bromate in brines and saline wastewater. Bacterial denitrification has been extensively described at the physiological, biochemical, and genetic levels. However, their haloarchaea counterparts remain poorly described. In previous work the model structure of nitric oxide reductase was analysed. In this study, a bioinformatic analysis of the sequences and the structural models of the nitrate, nitrite and nitrous oxide reductases has been described for the first time in the haloarchaeon model Haloferax mediterranei. The main residues involved in the catalytic mechanism and in the coordination of the metal centres have been explored to shed light on their structural characterization and classification. These results set the basis for understanding the molecular mechanism for haloarchaeal denitrification, necessary for the use and optimization of these microorganisms in bioremediation of saline environments among other potential applications including bioremediation of industrial waters.
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Affiliation(s)
- Eric Bernabeu
- Biochemistry and Molecular Biology Division, Agrochemistry and Biochemistry Department, Faculty of Sciences, University of Alicante, Ap. 99, E-03080 Alicante, Spain; (E.B.); (J.M.M.-R.); (M.G.); (E.V.); (R.M.M.-E.)
| | - Jose María Miralles-Robledillo
- Biochemistry and Molecular Biology Division, Agrochemistry and Biochemistry Department, Faculty of Sciences, University of Alicante, Ap. 99, E-03080 Alicante, Spain; (E.B.); (J.M.M.-R.); (M.G.); (E.V.); (R.M.M.-E.)
| | - Micaela Giani
- Biochemistry and Molecular Biology Division, Agrochemistry and Biochemistry Department, Faculty of Sciences, University of Alicante, Ap. 99, E-03080 Alicante, Spain; (E.B.); (J.M.M.-R.); (M.G.); (E.V.); (R.M.M.-E.)
| | - Elena Valdés
- Biochemistry and Molecular Biology Division, Agrochemistry and Biochemistry Department, Faculty of Sciences, University of Alicante, Ap. 99, E-03080 Alicante, Spain; (E.B.); (J.M.M.-R.); (M.G.); (E.V.); (R.M.M.-E.)
| | - Rosa María Martínez-Espinosa
- Biochemistry and Molecular Biology Division, Agrochemistry and Biochemistry Department, Faculty of Sciences, University of Alicante, Ap. 99, E-03080 Alicante, Spain; (E.B.); (J.M.M.-R.); (M.G.); (E.V.); (R.M.M.-E.)
- Multidisciplinary Institute for Environmental Studies “Ramón Margalef”, University of Alicante, Ap. 99, E-03080 Alicante, Spain
| | - Carmen Pire
- Biochemistry and Molecular Biology Division, Agrochemistry and Biochemistry Department, Faculty of Sciences, University of Alicante, Ap. 99, E-03080 Alicante, Spain; (E.B.); (J.M.M.-R.); (M.G.); (E.V.); (R.M.M.-E.)
- Multidisciplinary Institute for Environmental Studies “Ramón Margalef”, University of Alicante, Ap. 99, E-03080 Alicante, Spain
- Correspondence: ; Tel.: +34-965903400 (ext. 2064)
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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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