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Guo C, Chadwick RJ, Foulis A, Bedendi G, Lubskyy A, Rodriguez KJ, Pellizzoni MM, Milton RD, Beveridge R, Bruns N. Peroxidase Activity of Myoglobin Variants Reconstituted with Artificial Cofactors. Chembiochem 2022; 23:e202200197. [PMID: 35816250 PMCID: PMC9545363 DOI: 10.1002/cbic.202200197] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 07/08/2022] [Indexed: 02/02/2023]
Abstract
Myoglobin (Mb) can react with hydrogen peroxide (H2 O2 ) to form a highly active intermediate compound and catalyse oxidation reactions. To enhance this activity, known as pseudo-peroxidase activity, previous studies have focused on the modification of key amino acid residues of Mb or the heme cofactor. In this work, the Mb scaffold (apo-Mb) was systematically reconstituted with a set of cofactors based on six metal ions and two ligands. These Mb variants were fully characterised by UV-Vis spectroscopy, circular dichroism (CD) spectroscopy, inductively coupled plasma mass spectrometry (ICP-MS) and native mass spectrometry (nMS). The steady-state kinetics of guaiacol oxidation and 2,4,6-trichlorophenol (TCP) dehalogenation catalysed by Mb variants were determined. Mb variants with iron chlorin e6 (Fe-Ce6) and manganese chlorin e6 (Mn-Ce6) cofactors were found to have improved catalytic efficiency for both guaiacol and TCP substrates in comparison with wild-type Mb, i. e. Fe-protoporphyrin IX-Mb. Furthermore, the selected cofactors were incorporated into the scaffold of a Mb mutant, swMb H64D. Enhanced peroxidase activity for both substrates were found via the reconstitution of Fe-Ce6 into the mutant scaffold.
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Affiliation(s)
- Chao Guo
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetG1 1XLGlasgowUK
| | - Robert J. Chadwick
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetG1 1XLGlasgowUK
| | - Adam Foulis
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetG1 1XLGlasgowUK
| | - Giada Bedendi
- Department of Inorganic and Analytical ChemistryUniversity of Geneva1211Geneva 4Switzerland
| | - Andriy Lubskyy
- Adolphe Merkle InstituteUniversity of FribourgChemin des Verdiers 41700FribourgSwitzerland
| | - Kyle J. Rodriguez
- Adolphe Merkle InstituteUniversity of FribourgChemin des Verdiers 41700FribourgSwitzerland
| | - Michela M. Pellizzoni
- Adolphe Merkle InstituteUniversity of FribourgChemin des Verdiers 41700FribourgSwitzerland
| | - Ross D. Milton
- Department of Inorganic and Analytical ChemistryUniversity of Geneva1211Geneva 4Switzerland
| | - Rebecca Beveridge
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetG1 1XLGlasgowUK
| | - Nico Bruns
- Department of Pure and Applied ChemistryUniversity of Strathclyde295 Cathedral StreetG1 1XLGlasgowUK,Department of ChemistryTechnical University of DarmstadtAlarich-Weiss-Str. 464287DarmstadtGermany
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Rapid Myoglobin Aggregation through Glucosamine-Induced α-Dicarbonyl Formation. PLoS One 2015; 10:e0139022. [PMID: 26406447 PMCID: PMC4583429 DOI: 10.1371/journal.pone.0139022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/07/2015] [Indexed: 12/25/2022] Open
Abstract
The extent of glycation and conformational changes of horse myoglobin (Mb) upon glycation with N-acetyl-glucosamine (GlcNAc), glucose (Glc) and glucosamine (GlcN) were investigated. Among tested sugars, the rate of glycation with GlcN was the most rapid as shown by MALDI and ESI mass spectrometries. Protein oxidation, as evaluated by the amount of carbonyl groups present on Mb, was found to increase exponentially in Mb-Glc conjugates over time, whereas in Mb-GlcN mixtures the carbonyl groups decreased significantly after maximum at 3 days of the reaction. The reaction between GlcN and Mb resulted in a significantly higher amount of α-dicarbonyl compounds, mostly glucosone and 3-deoxyglucosone, ranging from and 27 to 332 mg/L and from 14 to 304 mg/L, respectively. Already at 0.5 days, tertiary structural changes of Mb-GlcN conjugate were observed by altered tryptophan fluorescence. A reduction of metmyoglobin to deoxy-and oxymyoglobin forms was observed on the first day of reaction, coinciding with the greatest amount of glucosone produced. In contrast to native α-helical myoglobin, 41% of the glycated protein sequence was transformed into a β-sheet conformation, as determined by circular dichroism spectropolarimetry. Transmission electron microscopy demonstrated that Mb glycation with GlcN causes the formation of amorphous or fibrous aggregates, started already at 3 reaction days. These aggregates bind to an amyloid-specific dye thioflavin T. With the aid of α-dicarbonyl compounds and advanced products of reaction, this study suggests that the Mb glycation with GlcN induces the unfolding of an initially globular protein structure into amyloid fibrils comprised of a β-sheet structure.
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Nicolis S, Monzani E, Pezzella A, Ascenzi P, Sbardella D, Casella L. Neuroglobin Modification by Reactive Quinone Species. Chem Res Toxicol 2013; 26:1821-31. [DOI: 10.1021/tx4001896] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Stefania Nicolis
- Dipartimento
di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Enrico Monzani
- Dipartimento
di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Alessandro Pezzella
- Dipartimento
di Scienze Chimiche, Università di Napoli ‘Federico II’, Via Cintia 4, 80126 Napoli, Italy
| | - Paolo Ascenzi
- Laboratorio
Interdipartimentale di Microscopia Elettronica, Università Roma Tre, Via della Vasca Navale 79, 00146 Roma, Italy
| | - Diego Sbardella
- Dipartimento
di Scienze Cliniche e Medicina Traslazionale, Università di Roma ‘Tor Vergata’, Via Montpellier 1, 00133 Roma, Italy
- Consorzio Interuniversitario per la Ricerca sulla Chimica dei Metalli nei Sistemi Biologici, Via C. Ulpiani
27, 70126 Bari, Italy
| | - Luigi Casella
- Dipartimento
di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
- Consorzio Interuniversitario per la Ricerca sulla Chimica dei Metalli nei Sistemi Biologici, Via C. Ulpiani
27, 70126 Bari, Italy
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Gómez-Mingot M, Alcaraz LA, Heptinstall J, Donaire A, Piccioli M, Montiel V, Iniesta J. Electrochemical nitration of myoglobin at tyrosine 103: Structure and stability. Arch Biochem Biophys 2013. [DOI: 10.1016/j.abb.2012.10.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Wojaczyńska E, Wojaczyński J. Enantioselective synthesis of sulfoxides: 2000-2009. Chem Rev 2010; 110:4303-56. [PMID: 20415478 DOI: 10.1021/cr900147h] [Citation(s) in RCA: 314] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Elzbieta Wojaczyńska
- Department of Organic Chemistry, Faculty of Chemistry, Wrocław University of Technology, Wybrzeze Wyspiańskiego 27, 50 370 Wrocław, Poland.
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Song HY, Liu JZ, Weng LP, Ji LN. Activity, stability, and unfolding of reconstituted horseradish peroxidase with modified heme. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.molcatb.2008.06.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Feng JY, Liu JZ, Ji LN. Thermostability, solvent tolerance, catalytic activity and conformation of cofactor modified horseradish peroxidase. Biochimie 2008; 90:1337-46. [PMID: 18439429 DOI: 10.1016/j.biochi.2008.03.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Accepted: 03/26/2008] [Indexed: 10/22/2022]
Abstract
Artificial prosthetic groups, HeminD1 and HeminD2, were designed and synthesized, which contain one benzene ring and one carboxylic group or two carboxylic groups at the terminal of each propionate side chain of hemin, respectively. HeminD1 and HeminD2 were reconstituted with apo-HRP successfully to produce the two novel HRPs, rHRP1 and rHRP2, respectively. The thermal and solvent tolerances of native and reconstituted HRPs were compared. The cofactor modification increased the thermostability both in aqueous buffer and some organic solvents, and also enhanced the tolerance of some organic solvents. To determine the conformation stability, the unfolding of native and reconstituted HRPs by heat was investigated. Tm was increased from 70.0 degrees C of nHRP to 75.4 degrees C of rHRP1 and 76.5 degrees C of rHRP2 after cofactor modification. Kinetic studies indicated that the cofactor modification increased the substrate affinity and catalytic efficiency both in aqueous buffer and some organic solvents. The catalytic efficiency for phenol oxidation was increased by approximately 55% for rHRP1 in aqueous buffer, and it was also increased by approximately 70% for rHRP1 in 10% ACN. Spectroscopic studies proved that the cofactor modification changed the microenvironment of both heme and tryptophan, increased alpha-helix content, and increased the tertiary structure around the aromatic residue in HRP. The improvements of catalytic properties are related to these changes of the conformation. The introduction of the hydrophobic domain as well as the retention of the moderate carboxylic group in active site is an efficient method to improve the thermodynamic and catalytic efficiency of HRP.
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Affiliation(s)
- Jiu-Ying Feng
- Key Laboratory of Gene Engineering of Ministry of Education and Biotechnology Research Center, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275, PR China
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Ricoux R, Dubuc R, Dupont C, Marechal JD, Martin A, Sellier M, Mahy JP. Hemozymes Peroxidase Activity Of Artificial Hemoproteins Constructed From the Streptomyces lividans Xylanase A and Iron(III)-Carboxy-Substituted Porphyrins. Bioconjug Chem 2008; 19:899-910. [DOI: 10.1021/bc700435a] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rémy Ricoux
- Institut de Chimie Moléculaire et des Matériaux d’Orsay, UMR 8182 CNRS, Laboratoire de Chimie Bioorganique et Bioinorganique, Bât. 420, Université Paris XI, 91405 Orsay Cedex, France, Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, H7V 1B7, Canada, and Unitat de Química Física, Departament de Química, Universitat Autònoma de Barcelona, Edifici C.n., 08193 Cerdonyola (Barcelona), Spain
| | - Roger Dubuc
- Institut de Chimie Moléculaire et des Matériaux d’Orsay, UMR 8182 CNRS, Laboratoire de Chimie Bioorganique et Bioinorganique, Bât. 420, Université Paris XI, 91405 Orsay Cedex, France, Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, H7V 1B7, Canada, and Unitat de Química Física, Departament de Química, Universitat Autònoma de Barcelona, Edifici C.n., 08193 Cerdonyola (Barcelona), Spain
| | - Claude Dupont
- Institut de Chimie Moléculaire et des Matériaux d’Orsay, UMR 8182 CNRS, Laboratoire de Chimie Bioorganique et Bioinorganique, Bât. 420, Université Paris XI, 91405 Orsay Cedex, France, Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, H7V 1B7, Canada, and Unitat de Química Física, Departament de Química, Universitat Autònoma de Barcelona, Edifici C.n., 08193 Cerdonyola (Barcelona), Spain
| | - Jean-Didier Marechal
- Institut de Chimie Moléculaire et des Matériaux d’Orsay, UMR 8182 CNRS, Laboratoire de Chimie Bioorganique et Bioinorganique, Bât. 420, Université Paris XI, 91405 Orsay Cedex, France, Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, H7V 1B7, Canada, and Unitat de Química Física, Departament de Química, Universitat Autònoma de Barcelona, Edifici C.n., 08193 Cerdonyola (Barcelona), Spain
| | - Aurore Martin
- Institut de Chimie Moléculaire et des Matériaux d’Orsay, UMR 8182 CNRS, Laboratoire de Chimie Bioorganique et Bioinorganique, Bât. 420, Université Paris XI, 91405 Orsay Cedex, France, Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, H7V 1B7, Canada, and Unitat de Química Física, Departament de Química, Universitat Autònoma de Barcelona, Edifici C.n., 08193 Cerdonyola (Barcelona), Spain
| | - Marion Sellier
- Institut de Chimie Moléculaire et des Matériaux d’Orsay, UMR 8182 CNRS, Laboratoire de Chimie Bioorganique et Bioinorganique, Bât. 420, Université Paris XI, 91405 Orsay Cedex, France, Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, H7V 1B7, Canada, and Unitat de Química Física, Departament de Química, Universitat Autònoma de Barcelona, Edifici C.n., 08193 Cerdonyola (Barcelona), Spain
| | - Jean-Pierre Mahy
- Institut de Chimie Moléculaire et des Matériaux d’Orsay, UMR 8182 CNRS, Laboratoire de Chimie Bioorganique et Bioinorganique, Bât. 420, Université Paris XI, 91405 Orsay Cedex, France, Institut National de la Recherche Scientifique, INRS-Institut Armand-Frappier, 531 Boulevard des Prairies, Laval, Québec, H7V 1B7, Canada, and Unitat de Química Física, Departament de Química, Universitat Autònoma de Barcelona, Edifici C.n., 08193 Cerdonyola (Barcelona), Spain
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Nicolis S, Monzani E, Ciaccio C, Ascenzi P, Moens L, Casella L. Reactivity and endogenous modification by nitrite and hydrogen peroxide: does human neuroglobin act only as a scavenger? Biochem J 2007; 407:89-99. [PMID: 17600531 PMCID: PMC2267408 DOI: 10.1042/bj20070372] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
NGB (human neuroglobin), a recently discovered haem protein of the globin family containing a six-co-ordinated haem, is expressed in nervous tissue, but the physiological function of NGB is currently unknown. As well as playing a role in neuronal O2 homoeostasis, NGB is thought to act as a scavenger of reactive species. In the present study, we report on the reactivity of metNGB (ferric-NGB), which accumulates in vivo as a result of the reaction of oxyNGB (oxygenated NGB) with NO, towards NO2- and H2O2. NO2- co-ordination of the haem group accounts for the activity of metNGB in the nitration of phenolic substrates. The two different metNGB forms, with and without the internal disulfide bond between Cys46 (seventh residue on the inter-helix region between helices C and D) and Cys55 (fifth residue on helix D), exhibit different reactivity, the former being more efficient in activating NO2-. The kinetics of the reactions, the NO2--binding studies and the analysis of the nitrated products from different substrates all support the hypothesis that metNGB is able to generate an active species with the chemical properties of peroxynitrite, at pathophysiological concentrations of NO2- and H2O2. Without external substrates, the targets of the reactive species generated by the metNGB/NO2-/H2O2 system are endogenous tyrosine (resulting in the production of 3-nitrotyrosine) and cysteine (oxidized to sulfinic acid and sulfonic acid) residues. These endogenous modifications were characterized by HPLC-MS/MS (tandem MS) analysis of metNGB after reaction with NO2- and H2O2 under various conditions. The internal S-S bond affects the functional properties of the protein. Therefore metNGB acts not only as scavenger of toxic species, but also as a target of the self-generated reactive species. Self-modification of the protein may be related to or inhibit its postulated neuroprotective activity.
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Affiliation(s)
- Stefania Nicolis
- Dipartimento di Chimica Generale, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
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Battistuzzi G, Bellei M, Casella L, Bortolotti CA, Roncone R, Monzani E, Sola M. Redox reactivity of the heme Fe3+/Fe2+ couple in native myoglobins and mutants with peroxidase-like activity. J Biol Inorg Chem 2007; 12:951-8. [PMID: 17576605 DOI: 10.1007/s00775-007-0267-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2007] [Accepted: 05/21/2007] [Indexed: 10/23/2022]
Abstract
The reaction enthalpy and entropy for the one-electron reduction of the ferric heme in horse heart and sperm whale aquometmyoglobins (Mb) have been determined exploiting a spectroelectrochemical approach. Also investigated were the T67R, T67K, T67R/S92D and T67R/S92D Mb-H variants (the latter containing a protoheme-L: -histidine methyl ester) of sperm whale Mb, which feature peroxidase-like activity. The reduction potential (E degrees ') in all species consists of an enthalpic term which disfavors Fe(3+) reduction and a larger entropic contribution which instead selectively stabilizes the reduced form. This behavior differs from that of the heme redox enzymes and electron transport proteins investigated so far. The reduction thermodynamics in the series of sperm whale Mb variants show an almost perfect enthalpy-entropy compensation, indicating that the mutation-induced changes in DeltaH(o')(rc) and DeltaS(o')(rc) are dominated by reduction-induced solvent reorganization effects. The modest changes in E degrees ' originate from the enthalpic effects of the electrostatic interactions of the heme with the engineered charged residues. The small influence that the mutations exert on the reduction potential of myoglobin suggests that the increased peroxidase activity of the variants is not related to changes in the redox reactivity of the heme iron, but are likely related to a more favored substrate orientation within the distal heme cavity.
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Affiliation(s)
- Gianantonio Battistuzzi
- Department of Chemistry, University of Modena and Reggio Emilia, Via Campi 183, 41100 Modena, Italy
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Ichikawa Y, Nakajima H, Watanabe Y. Characterization of peroxide-bound heme species generated in the reaction of thermally tolerant cytochrome c552 with hydrogen peroxide. Chembiochem 2007; 7:1582-9. [PMID: 16921577 DOI: 10.1002/cbic.200600135] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Peroxide-bound heme species have been considered difficult to detect under physiological conditions because of their intrinsically transient properties. Cytochrome c552 (cyt c552), from Thermus thermophirus HB8, bearing a mutation to an alanine at Met69 (M69A) reacts with hydrogen peroxide (H(2)O(2)) to generate a detectable hydroperoxo-ferric heme ([Fe(3+)--OOH]) species at ambient temperature. EPR measurements during appropriate reaction periods reveal that the [Fe(3+)--OOH] species is in a preequilibrium state between the resting form of the cyt c552 variant and a subsequent intermediate, compound II with a protein radical. Addition of ascorbic acid to the reaction mixture of the cyt c552 variant and H(2)O(2) does not affect the formation of the [Fe(3+)--OOH] species,a result suggesting that the species is incompetent for the oxidation of even an oxidatively fragile substrate such as ascorbic acid. Another variant bearing an additional mutation to aspartic acid at Val49 (V49D/M69A) reveals that a highly hydrophobic heme cavity in cyt c552 accounts for the generation of the durable [Fe(3+)--OOH] species. The less polar environment inside the cavity is expected to prevent H(2)O from approaching the cavity. This would suppress protonation of the distal oxygen atom of the [Fe(3+)--OOH] species and retard subsequent dissociation of H(2)O from the OOH moiety.
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Affiliation(s)
- Yusuke Ichikawa
- Department of Chemistry, Graduate School of Science Nagoya University, 464-8602 Nagoya, Japan
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Nicolis S, Casella L, Roncone R, Dallacosta C, Monzani E. Heme-peptide complexes as peroxidase models. CR CHIM 2007. [DOI: 10.1016/j.crci.2006.09.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Nicolis S, Pennati A, Perani E, Monzani E, Sanangelantoni AM, Casella L. Easy Oxidation and Nitration of Human Myoglobin by Nitrite and Hydrogen Peroxide. Chemistry 2006; 12:749-57. [PMID: 16216040 DOI: 10.1002/chem.200500361] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The modification of human myoglobin (HMb) by reaction with nitrite and hydrogen peroxide has been investigated. This reaction is important because NO(2) (-) and H(2)O(2) are formed in vivo under conditions of oxidative and nitrative stress, where protein derivatization has been often observed. The abundance of HMb in tissues and in the heart makes it a potential source and target of reactive species generated in the body. The oxidant and nitrating species produced by HMb/H(2)O(2)/NO(2) (-) are nitrogen dioxide and peroxynitrite, which can react with exogenous substrates and endogenous protein residues. Tandem mass analysis of HMb modified by stoichiometric amounts of H(2)O(2) and NO(2) (-) indicated the presence of two endogenous derivatizations: oxidation of C110 to sulfinic acid (76 %) and nitration of Y103 to 3-nitrotyrosine (44 %). When higher concentrations of NO(2) (-) and H(2)O(2) were used, nitration of Y146 and of the heme were also observed. The two-dimensional gel-electrophoretic analysis of the modified HMbs showed spots more acidic than that of wild-type HMb, a result in agreement with the formation of sulfinic acid and nitrotyrosine residues. By contrast, the reaction showed no evidence for the formation of protein homodimers, as observed in the reaction of HMb with H(2)O(2) alone. Both HMb and the modified HMb are active in the H(2)O(2)/NO(2) (-)-dependent nitration of exogenous phenols. Their catalytic activity is quite similar and the endogenous modifications of HMb therefore have little effect on the reactivity of the protein intermediates.
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Hitomi Y, Mukai H, Yoshimura H, Tanaka T, Funabiki T. Non-covalent modification of the heme-pocket of apomyoglobin by a 1,10-phenanthroline derivative. Bioorg Med Chem Lett 2006; 16:248-51. [PMID: 16249084 DOI: 10.1016/j.bmcl.2005.10.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2005] [Revised: 10/04/2005] [Accepted: 10/06/2005] [Indexed: 11/18/2022]
Abstract
To expand the repertoire of artificial enzymes that are constructed by replacing the natural prosthetic group of hemoproteins with non-natural cofactors, we examined incorporation of a non-porphyrinic ligand (1) into the heme-pocket of apomyoglobin in a non-covalent fashion. Ligand 1 is a highly conjugated 1,10-phenanthroline derivative, which shares some structural features with protoporphyrin IX; for example, molecular size and arrangement of hydrophobic and anionic parts. Addition of apomyoglobin to a solution of 1 induces clear changes in the absorption spectrum of 1, suggesting one-to-one incorporation of 1 into the heme cavity of apomyoglobin with an affinity of 6.3 x 10(6)M(-1). We found that the hydrolytic activity of apomyoglobin toward p-nitrophenyl hexanoate was greatly suppressed because of the incorporation of 1 into the heme-pocket.
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Affiliation(s)
- Yutaka Hitomi
- Department of Molecular Engineering, Kyoto University, Kyoto Daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
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