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Cvjetan N, Schuler LD, Ishikawa T, Walde P. Optimization and Enhancement of the Peroxidase-like Activity of Hemin in Aqueous Solutions of Sodium Dodecylsulfate. ACS OMEGA 2023; 8:42878-42899. [PMID: 38024761 PMCID: PMC10652838 DOI: 10.1021/acsomega.3c05915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/10/2023] [Accepted: 10/13/2023] [Indexed: 12/01/2023]
Abstract
Iron porphyrins play several important roles in present-day living systems and probably already existed in very early life forms. Hemin (= ferric protoporphyrin IX = ferric heme b), for example, is the prosthetic group at the active site of heme peroxidases, catalyzing the oxidation of a number of different types of reducing substrates after hemin is first oxidized by hydrogen peroxide as the oxidizing substrate of the enzyme. The active site of heme peroxidases consists of a hydrophobic pocket in which hemin is embedded noncovalently and kept in place through coordination of the iron atom to a proximal histidine side chain of the protein. It is this partially hydrophobic local environment of the enzyme which determines the efficiency with which the sequential reactions of the oxidizing and reducing substrates proceed at the active site. Free hemin, which has been separated from the protein moiety of heme peroxidases, is known to aggregate in an aqueous solution and exhibits low catalytic activity. Based on previous reports on the use of surfactant micelles to solubilize free hemin in a nonaggregated state, the peroxidase-like activity of hemin in the presence of sodium dodecyl sulfate (SDS) at concentrations below and above the critical concentration for SDS micelle formation (critical micellization concentration (cmc)) was systematically investigated. In most experiments, 3,3',5,5'-tetramethylbenzidine (TMB) was applied as a reducing substrate at pH = 7.2. The presence of SDS clearly had a positive effect on the reaction in terms of initial reaction rate and reaction yield, even at concentrations below the cmc. The highest activity correlated with the cmc value, as demonstrated for reactions at three different HEPES concentrations. The 4-(2-hydroxyethyl)-1-piperazineethanesulfonate salt (HEPES) served as a pH buffer substance and also had an accelerating effect on the reaction. At the cmc, the addition of l-histidine (l-His) resulted in a further concentration-dependent increase in the peroxidase-like activity of hemin until a maximal effect was reached at an optimal l-His concentration, probably corresponding to an ideal mono-l-His ligation to hemin. Some of the results obtained can be understood on the basis of molecular dynamics simulations, which indicated the existence of intermolecular interactions between hemin and HEPES and between hemin and SDS. Preliminary experiments with SDS/dodecanol vesicles at pH = 7.2 showed that in the presence of the vesicles, hemin exhibited similar peroxidase-like activity as in the case of SDS micelles. This supports the hypothesis that micelle- or vesicle-associated ferric or ferrous iron porphyrins may have played a role as primitive catalysts in membranous prebiotic compartment systems before cellular life emerged.
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Affiliation(s)
- Nemanja Cvjetan
- Department
of Materials, ETH-Zürich, Leopold-Ruzicka-Weg 4, 8093 Zürich, Switzerland
| | | | - Takashi Ishikawa
- Department
of Biology and Chemistry, Paul Scherrer Institute and Department of
Biology, ETH-Zürich, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland
| | - Peter Walde
- Department
of Materials, ETH-Zürich, Leopold-Ruzicka-Weg 4, 8093 Zürich, Switzerland
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2
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Abstract
Ferric heme b (= ferric protoporphyrin IX = hemin) is an important prosthetic group of different types of enzymes, including the intensively investigated and widely applied horseradish peroxidase (HRP). In HRP, hemin is present in monomeric form in a hydrophobic pocket containing among other amino acid side chains the two imidazoyl groups of His170 and His42. Both amino acids are important for the peroxidase activity of HRP as an axial ligand of hemin (proximal His170) and as an acid/base catalyst (distal His42). A key feature of the peroxidase mechanism of HRP is the initial formation of compound I under heterolytic cleavage of added hydrogen peroxide as a terminal oxidant. Investigations of free hemin dispersed in aqueous solution showed that different types of hemin dimers can form, depending on the experimental conditions, possibly resulting in hemin crystallization. Although it has been recognized already in the 1970s that hemin aggregation can be prevented in aqueous solution by using micelle-forming amphiphiles, it remains a challenge to prepare hemin-containing micellar and vesicular systems with peroxidase-like activities. Such systems are of interest as cheap HRP-mimicking catalysts for analytical and synthetic applications. Some of the key concepts on which research in this fascinating and interdisciplinary field is based are summarized, along with major accomplishments and possible directions for further improvement. A systematic analysis of the physico-chemical properties of hemin in aqueous micellar solutions and vesicular dispersions must be combined with a reliable evaluation of its catalytic activity. Future studies should show how well the molecular complexity around hemin in HRP can be mimicked by using micelles or vesicles. Because of the importance of heme b in virtually all biological systems and the fact that porphyrins and hemes can be obtained under potentially prebiotic conditions, ideas exist about the possible role of heme-containing micellar and vesicular systems in prebiotic times.
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Blagodarov SV, Zheltukhina GA, Romanova YM, Alekseeva NV, Iskhakova LD, Semashko MI, Tolordava ER, Nebolsin VE. Improving the synthesis of hemin derivatives and their effect on bacterial biofilms. J PORPHYR PHTHALOCYA 2022. [DOI: 10.1142/s1088424622500079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The emergence of antibiotic-resistant bacterial strains has recently resulted in a large focus on designing new antimicrobial agents, including those based on natural compounds. We have previously synthesized two disubstituted arginine-containing derivatives of hemin (HD) (4) and (5) that demonstrated pronounced antimicrobial activity against planktonic cells in vitro [1, 2]. These HDs are leading and promising for the creation of antibacterial agents on their basis. This research is aimed at improving the synthesis of HDs (4) and (5) to increase their yield, simplify the process and minimize the side reactions, as well as to establish their antimicrobial and destructive effect on biofilms, including those consisting of antibiotic-resistant bacteria. As a result, we were able to increase the yields of the protected dipeptide of ZArg(Z[Formula: see text]SerNH2 (3) and the corresponding HD (4) up to 97 and 93%, respectively, and also to minimize the side reaction of the formation of ornithine-containing HD. For the arginine amide modified HD (5), we have also proposed an improved synthesis scheme. The ability of HD to cause the bacteria death in the composition of formed biofilms, including those consisting of resistant bacteria, was shown. After the effect of HDs on the biofilm at concentrations of 80 and 100 [Formula: see text]g/ml, the CFU decrease was 3–5/ml. The fluorescent microscopy confirmed the bacteria mortality in the biofilm. Electron microscopy showed structural damage (fragmentation) of the formed bacterial biofilm under the effect of HDs.
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Affiliation(s)
- Sergey V. Blagodarov
- MIREA — Russian Technological University (MITHT), Vernadsky Av., 86, Moscow, 119571, Russian Federation
| | - Galina A. Zheltukhina
- MIREA — Russian Technological University (MITHT), Vernadsky Av., 86, Moscow, 119571, Russian Federation
| | - Yuliya M. Romanova
- National Research Center for Epidemiology and Microbiology named after the honorary academician N. F. Gamaleya, 18 Gamaleya St., Moscow, 123098, Russian Federation
| | - Natalia V. Alekseeva
- National Research Center for Epidemiology and Microbiology named after the honorary academician N. F. Gamaleya, 18 Gamaleya St., Moscow, 123098, Russian Federation
| | - Lyudmila D. Iskhakova
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Dianov Fiber Optics Research Center, 38 Vavilov St., 119333 Moscow, Russian Federation
| | - Maria I. Semashko
- MIREA — Russian Technological University (MITHT), Vernadsky Av., 86, Moscow, 119571, Russian Federation
| | - Eteri R. Tolordava
- National Research Center for Epidemiology and Microbiology named after the honorary academician N. F. Gamaleya, 18 Gamaleya St., Moscow, 123098, Russian Federation
| | - Vladimir E. Nebolsin
- LTD “Pharmenterprises”, Territory of the Innovation Center Skolkovo, Bolshoi Boulevard, 42, Bld. 1, Office 771, 772, 143026, Moscow, Russian Federation
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4
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Bacchella C, Brewster JT, Bähring S, Dell’Acqua S, Root HD, Thiabaud GD, Reuther JF, Monzani E, Sessler JL, Casella L. Condition-Dependent Coordination and Peroxidase Activity of Hemin-Aβ Complexes. Molecules 2020; 25:E5044. [PMID: 33143109 PMCID: PMC7662341 DOI: 10.3390/molecules25215044] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/24/2020] [Accepted: 10/26/2020] [Indexed: 01/07/2023] Open
Abstract
The peroxidase activity of hemin-peptide complexes remains a potential factor in oxidative damage relevant to neurodegeneration. Here, we present the effect of temperature, ionic strength, and pH relevant to pathophysiological conditions on the dynamic equilibrium between high-spin and low-spin hemin-Aβ40 constructs. This influence on peroxidase activity was also demonstrated using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and dopamine (DA) oxidation rate analyses with increasing ratios of Aβ16 and Aβ40 (up to 100 equivalents). Interaction and reactivity studies of aggregated Aβ40-hemin revealed enhanced peroxidase activity versus hemin alone. Comparison of the results obtained using Aβ16 and Aβ40 amyloid beta peptides revealed marked differences and provide insight into the potential effects of hemin-Aβ on neurological disease progression.
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Affiliation(s)
- Chiara Bacchella
- Department of Chemistry, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy; (C.B.); (S.D.); (E.M.)
| | - James T. Brewster
- Department of Chemistry, The University of Texas at Austin, 105 East 24th, Street-Stop A5300, Austin, TX 78712-1224, USA; (J.T.B.II); (H.D.R.); (G.D.T.); (J.F.R.)
| | - Steffen Bähring
- Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark
| | - Simone Dell’Acqua
- Department of Chemistry, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy; (C.B.); (S.D.); (E.M.)
| | - Harrison D. Root
- Department of Chemistry, The University of Texas at Austin, 105 East 24th, Street-Stop A5300, Austin, TX 78712-1224, USA; (J.T.B.II); (H.D.R.); (G.D.T.); (J.F.R.)
| | - Gregory D. Thiabaud
- Department of Chemistry, The University of Texas at Austin, 105 East 24th, Street-Stop A5300, Austin, TX 78712-1224, USA; (J.T.B.II); (H.D.R.); (G.D.T.); (J.F.R.)
| | - James F. Reuther
- Department of Chemistry, The University of Texas at Austin, 105 East 24th, Street-Stop A5300, Austin, TX 78712-1224, USA; (J.T.B.II); (H.D.R.); (G.D.T.); (J.F.R.)
- Department of Chemistry, University of Massachusetts Lowell, Lowell, MA 01854, USA
| | - Enrico Monzani
- Department of Chemistry, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy; (C.B.); (S.D.); (E.M.)
| | - Jonathan L. Sessler
- Department of Chemistry, The University of Texas at Austin, 105 East 24th, Street-Stop A5300, Austin, TX 78712-1224, USA; (J.T.B.II); (H.D.R.); (G.D.T.); (J.F.R.)
| | - Luigi Casella
- Department of Chemistry, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy; (C.B.); (S.D.); (E.M.)
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Dell’Acqua S, Massardi E, Monzani E, Di Natale G, Rizzarelli E, Casella L. Interaction between Hemin and Prion Peptides: Binding, Oxidative Reactivity and Aggregation. Int J Mol Sci 2020; 21:ijms21207553. [PMID: 33066163 PMCID: PMC7589926 DOI: 10.3390/ijms21207553] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 10/06/2020] [Accepted: 10/10/2020] [Indexed: 11/16/2022] Open
Abstract
We investigate the interaction of hemin with four fragments of prion protein (PrP) containing from one to four histidines (PrP106-114, PrP95-114, PrP84-114, PrP76-114) for its potential relevance to prion diseases and possibly traumatic brain injury. The binding properties of hemin-PrP complexes have been evaluated by UV-visible spectrophotometric titration. PrP peptides form a 1:1 adduct with hemin with affinity that increases with the number of histidines and length of the peptide; the following log K1 binding constants have been calculated: 6.48 for PrP76-114, 6.1 for PrP84-114, 4.80 for PrP95-114, whereas for PrP106-114, the interaction is too weak to allow a reliable binding constant calculation. These constants are similar to that of amyloid-β (Aβ) for hemin, and similarly to hemin-Aβ, PrP peptides tend to form a six-coordinated low-spin complex. However, the concomitant aggregation of PrP induced by hemin prevents calculation of the K2 binding constant. The turbidimetry analysis of [hemin-PrP76-114] shows that, once aggregated, this complex is scarcely soluble and undergoes precipitation. Finally, a detailed study of the peroxidase-like activity of [hemin-(PrP)] shows a moderate increase of the reactivity with respect to free hemin, but considering the activity over long time, as for neurodegenerative pathologies, it might contribute to neuronal oxidative stress.
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Affiliation(s)
- Simone Dell’Acqua
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy; (E.M.); (E.M.)
- Correspondence: (S.D.); (L.C.)
| | - Elisa Massardi
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy; (E.M.); (E.M.)
| | - Enrico Monzani
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy; (E.M.); (E.M.)
| | - Giuseppe Di Natale
- Istituto di Cristallografia, s.s. Catania, Consiglio Nazionale delle Ricerche, via Paolo Gaifami 18, 95126 Catania, Italy; (G.D.N.); (E.R.)
| | - Enrico Rizzarelli
- Istituto di Cristallografia, s.s. Catania, Consiglio Nazionale delle Ricerche, via Paolo Gaifami 18, 95126 Catania, Italy; (G.D.N.); (E.R.)
| | - Luigi Casella
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy; (E.M.); (E.M.)
- Correspondence: (S.D.); (L.C.)
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6
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Yan J, Li Z, Liu M, Sun X, Ma L, Wang Z, Zhao Z, Huang X, Yuan L. Activity adaptability of a DhHP-6 peroxidase-mimic in wide pH and temperature ranges and solvent media. Catal Sci Technol 2020. [DOI: 10.1039/c9cy01855g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Deuterohemin-β-Ala-His-Thr-Val-Glu-Lys (DhHp-6): peroxidase with high activity.
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Affiliation(s)
- Jiaqing Yan
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education
- College of Life Science
- Jilin University
- Changchun 130012
- China
| | - Zhengqiang Li
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education
- College of Life Science
- Jilin University
- Changchun 130012
- China
| | - Min Liu
- Hospital of Stomatology
- Jilin University
- Changchun
- China
| | - Xiaoli Sun
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- China
| | - Li Ma
- Department of Physics
- Georgia Southern University
- Statesboro
- USA
| | - Zhi Wang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education
- College of Life Science
- Jilin University
- Changchun 130012
- China
| | - Zijian Zhao
- Institute of Agro-food Technology
- Jilin Academy of Agricultural Sciences
- Changchun
- China
| | - Xuri Huang
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- China
| | - Long Yuan
- Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education
- College of Physics
- Jilin Normal University
- Changchun 130103
- China
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7
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Abstract
In this study, we reported on a novel mimetic peroxidase, deuterohemin–Ala–His–Glu, (Dh–A–H–E). The kinetic parameters of Dh–A–H–E suggested that it was a mimetic peroxidase and followed the ping–pong mechanism. Compared to horseradish peroxidase, Dh–A–H–E exhibited excellent stability when tested at different pH and temperatures, and using different organic solvents. Based on our above results, a new method using Dh–A–H–E has successfully been developed for the fast and quantitative detection of trace amounts of glucose.
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8
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Pirota V, Monzani E, Dell'Acqua S, Casella L. Interactions between heme and tau-derived R1 peptides: binding and oxidative reactivity. Dalton Trans 2016; 45:14343-51. [PMID: 27539650 DOI: 10.1039/c6dt02183b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The interaction of hemin with the first 18-amino acid repeat in tau protein has been investigated at both the N-terminal free-amine (R1τ) and N-acetylated (AcR1τ) forms for its potential relevance in traumatic brain injury and possibly other neurodegenerative diseases. The binding properties of hemin-R1τ and hemin-AcR1τ were compared with those of the hemin complex with amyloid-β peptide fragment 1-16 (Aβ16) and synthetic hemins. AcR1τ and R1τ bind with moderate affinity to both monomeric and dimeric hemin to form 1 : 1 complexes, but for the acetylated peptide, the affinity is one order of magnitude larger (K1 = 3.3 × 10(6) M(-1)). The binding constants were similar to that of Aβ16 for hemin, but unlike the latter, neither of the two R1τ peptides forms a 2 : 1 complex with hemin. This is mostly due to electrostatic repulsion between R1τ chains, and in particular the C-terminal proline-15 kink, while structural features of the hemin-R1τ complexes do not seem to play a role. In fact, the same features are observed for the interaction between ferric heme and peptide R1τ*, where the P15 residue is replaced by an alanine. Imidazole neither binds to [hemin(R1τ)] nor [hemin(AcR1τ)], whereas small ligands such as CN and CO easily bind to the ferric and ferrous forms of the complexes, respectively. A detailed comparative study of the peroxidase activity of [hemin(R1τ)] and [hemin(AcR1τ)] shows that such activity is very low. Thus, the association between heme and unfolded neuronal peptides does not, per se, involve a significant gain of toxic pseudo-enzymatic activity. However, under conditions of heavy heme release occurring on traumatic brain injury or when this activity is prolonged for long time, it can contribute to neuronal oxidative stress. In addition, the presence of hemin increases the aggregation propensity of R1τ.
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Affiliation(s)
- V Pirota
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy.
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9
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Pirota V, Gennarini F, Dondi D, Monzani E, Casella L, Dell'Acqua S. Dinuclear heme and non-heme metal complexes as bioinspired catalysts for oxidation reactions. NEW J CHEM 2014. [DOI: 10.1039/c3nj01279d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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10
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Venanzi M, Cianfanelli S, Palleschi A. Mimicking hemoproteins: a new synthetic metalloenzyme based on a Fe(III)-mesoporphyrin functionalized by two helical decapeptides. J Pept Sci 2013; 20:36-45. [DOI: 10.1002/psc.2586] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 10/15/2013] [Accepted: 10/16/2013] [Indexed: 01/16/2023]
Affiliation(s)
- Mariano Venanzi
- Department of Chemical Sciences and Technologies; University of Rome Tor Vergata; Rome Italy
| | - Sabrina Cianfanelli
- Department of Chemical Sciences and Technologies; University of Rome Tor Vergata; Rome Italy
| | - Antonio Palleschi
- Department of Chemical Sciences and Technologies; University of Rome Tor Vergata; Rome Italy
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11
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Thiabaud G, Pizzocaro S, Garcia-Serres R, Latour JM, Monzani E, Casella L. Heme binding induces dimerization and nitration of truncated β-amyloid peptide Aβ16 under oxidative stress. Angew Chem Int Ed Engl 2013; 52:8041-4. [PMID: 23788407 DOI: 10.1002/anie.201302989] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Indexed: 01/17/2023]
Affiliation(s)
- Grégory Thiabaud
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
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12
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Thiabaud G, Pizzocaro S, Garcia-Serres R, Latour JM, Monzani E, Casella L. Heme Binding Induces Dimerization and Nitration of Truncated β-Amyloid Peptide Aβ16 Under Oxidative Stress. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201302989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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13
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ROZHKOVA ELENAA, EVSTIGNEEVA RIMAP, NEMYKIN VICTORN. Solution Coordination Chemistry of Protohaemin IX Peptide Derivatives. J PORPHYR PHTHALOCYA 2012. [DOI: 10.1002/(sici)1099-1409(199912)3:8<691::aid-jpp142>3.0.co;2-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
As part of an investigation aimed at developing artificial models for mimicking haemoprotein activity, four C-aminoacyl protohaemin IX derivatives with one or two -L-Leu-L- HisOMe (complexes 3 and 1) or -β-Ala-L- HisOMe (complexes 4 and 2) peptide fragments have been studied by means of electronic and ESR spectroscopy. The bis-His complexes 1 and 2 are predominantly low-spin ( S = 1/2) species, while the mono-His complexes 3 and 4 are predominantly high-spin ( S = 5/2) species. Products of the treatment of starting complexes 1–4 with trichloroacetic acid, acetic acid, methylimidazole, sodium cyanide and sodium hydroxide have been analysed by electronic spectroscopy. Weak-field ligands lead to predominantly high-spin hexacoordinated complexes, while strong-field ligands result in predominantly low-spin ones.
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Affiliation(s)
- ELENA A. ROZHKOVA
- M. V. Lomonosov Moscow State Academy of Fine Chemical Technology, 86 Vernadskii Avenue, 117571 Moscow, Russia
| | - RIMA P. EVSTIGNEEVA
- M. V. Lomonosov Moscow State Academy of Fine Chemical Technology, 86 Vernadskii Avenue, 117571 Moscow, Russia
| | - VICTOR N. NEMYKIN
- V. I. Vernadskii Institute of General and Inorganic Chemistry, 32/34 Palladin Avenue, 252680 Kiev 142, Ukraine
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14
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Nastri F, Lista L, Ringhieri P, Vitale R, Faiella M, Andreozzi C, Travascio P, Maglio O, Lombardi A, Pavone V. A Heme–Peptide Metalloenzyme Mimetic with Natural Peroxidase‐Like Activity. Chemistry 2011; 17:4444-53. [DOI: 10.1002/chem.201003485] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Indexed: 11/08/2022]
Affiliation(s)
- Flavia Nastri
- Department of Chemistry, Complesso Universitario Monte S. Angelo, University of Naples Federico II, Via Cintia, 80126 Naples (Italy), Fax: (+39) 081‐674090
| | - Liliana Lista
- Department of Chemistry, Complesso Universitario Monte S. Angelo, University of Naples Federico II, Via Cintia, 80126 Naples (Italy), Fax: (+39) 081‐674090
| | - Paola Ringhieri
- Department of Chemistry, Complesso Universitario Monte S. Angelo, University of Naples Federico II, Via Cintia, 80126 Naples (Italy), Fax: (+39) 081‐674090
| | - Rosa Vitale
- Department of Chemistry, Complesso Universitario Monte S. Angelo, University of Naples Federico II, Via Cintia, 80126 Naples (Italy), Fax: (+39) 081‐674090
| | - Marina Faiella
- Department of Chemistry, Complesso Universitario Monte S. Angelo, University of Naples Federico II, Via Cintia, 80126 Naples (Italy), Fax: (+39) 081‐674090
| | - Concetta Andreozzi
- Department of Chemistry, Complesso Universitario Monte S. Angelo, University of Naples Federico II, Via Cintia, 80126 Naples (Italy), Fax: (+39) 081‐674090
| | - Paola Travascio
- Department of Chemistry, Complesso Universitario Monte S. Angelo, University of Naples Federico II, Via Cintia, 80126 Naples (Italy), Fax: (+39) 081‐674090
| | - Ornella Maglio
- Department of Chemistry, Complesso Universitario Monte S. Angelo, University of Naples Federico II, Via Cintia, 80126 Naples (Italy), Fax: (+39) 081‐674090
- Permanent address: IBB, CNR, Via Mezzocannone 16, 80134 Napoli (Italy)
| | - Angela Lombardi
- Department of Chemistry, Complesso Universitario Monte S. Angelo, University of Naples Federico II, Via Cintia, 80126 Naples (Italy), Fax: (+39) 081‐674090
| | - Vincenzo Pavone
- Department of Chemistry, Complesso Universitario Monte S. Angelo, University of Naples Federico II, Via Cintia, 80126 Naples (Italy), Fax: (+39) 081‐674090
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15
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Davis RB, Lecomte JTJ. Structural propensities in the heme binding region of apocytochrome b5. II. Heme conjugates. Biopolymers 2008; 90:556-66. [PMID: 18398854 DOI: 10.1002/bip.20995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In the absence of heme cofactor, the water-soluble domain of rat microsomal cytochrome b5 (cyt b5) contains a long flexible region within its 42-residue heme-binding loop. Heme capture induces this region to fold into a well-defined structure containing helices H3-H5, each separated by a turn, with His39 and His63 serving as axial ligands to the heme iron. We have shown that the H4 region of the apoprotein has the greatest tendency for disorder within the isolated binding loop. Here, the effect of the His63-iron bond and proximity of heme plane on the population of helical conformation in H4 and H5 was investigated by synthesis and characterization of a peptide-sandwiched mesoheme construct in which two H4-H5 peptides were covalently attached to a single cofactor. Spectroscopic data indicated that a holoprotein-like bis-histidine coordination state was achieved over a pH range from 7 to 9. Trifluoroethanol titrations of the construct and the analogous free peptide under these pH conditions revealed that heme proximity and iron ligation were insufficient to promote helix formation in H4 and H5. These observations were used to assess the role of disordered regions in heme capture and the loop-scaffold interface in holoprotein folding and stability.
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Affiliation(s)
- Ronald B Davis
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
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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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17
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Dallacosta C, Alves WA, da Costa Ferreira AM, Monzani E, Casella L. A new dinuclear heme-copper complex derived from functionalized protoporphyrin IX. Dalton Trans 2007:2197-206. [PMID: 17514341 DOI: 10.1039/b703240d] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new biomimetic model for the heterodinuclear heme/copper center of respiratory oxidases is described. It is derived from iron(III) protoporphyrin IX by covalent attachment of a Gly-L-His-OMe residue to one propionic acid substituent and an amino-bis(benzimidazole) residue to the other propionic acid substituent of the porphyrin ring, yielding the Fe(III) complex 1, and subsequent addition of a copper(II) or copper(I) ion, according to needs. The fully oxidized Fe(III)/Cu(II) complex, 2, binds azide more strongly than 1, and likely contains azide bound as a bridging ligand between Fe(III) and Cu(II). The two metal centers also cooperate in the reaction with hydrogen peroxide, as the peroxide adducts obtained at low temperature for 1 and 2 display different optical features. Support to this interpretation comes from the investigation of the peroxidase activity of the complexes, where the activation of hydrogen peroxide has been studied through the phenol coupling reaction of p-cresol. Here the presence of Cu(II) improves the catalytic performance of complex 2 with respect to 1 at acidic pH, where the positive charge of the Cu(II) ion is useful to promote O-O bond cleavage of the iron-bound hydroperoxide, but it depresses the activity at basic pH because it can stabilize an intramolecular hydroxo bridge between Fe(III) and Cu(II). The reactivity to dioxygen of the reduced complexes has been studied at low temperature starting from the carbonyl adducts of the Fe(II) complex, 3, and Fe(II)/Cu(I) complex, 4. Also in this case the adducts derived from the Fe(II) and Fe(II)/Cu(I) complexes, that we formulate as Fe(III)-superoxo and Fe(III)/Cu(II)-peroxo exhibit slightly different spectral properties, showing that the copper center participates in a weak interaction with the dioxygen moiety.
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Affiliation(s)
- Corrado Dallacosta
- Dipartimento di Chimica Generale, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
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De Sanctis G, Fasciglione GF, Marini S, Sinibaldi F, Santucci R, Monzani E, Dallacosta C, Casella L, Coletta M. pH-dependent redox and CO binding properties of chelated protoheme-l-histidine and protoheme-glycyl-l-histidine complexes. J Biol Inorg Chem 2005; 11:153-67. [PMID: 16341900 DOI: 10.1007/s00775-005-0060-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2005] [Accepted: 11/04/2005] [Indexed: 10/25/2022]
Abstract
The pH dependence of redox properties, spectroscopic features and CO binding kinetics for the chelated protohemin-6(7)-L-histidine methyl ester (heme-H) and the chelated protohemin-6(7)-glycyl-L-histidine methyl ester (heme-GH) systems has been investigated between pH 2.0 and 12.0. The two heme systems appear to be modulated by four protonating groups, tentatively identified as coordinated H(2)O, one of heme's propionates, N(epsilon) of the coordinating imidazole, and the carboxylate of the histidine residue upon hydrolysis of the methyl ester group (in acid medium). The pK (a) values are different for the two hemes, thus reflecting structural differences. In particular, the different strain at the Fe-N(epsilon) bond, related to the different length of the coordinating arm, results in a dramatic alteration of the bond strength, which is much smaller in heme-H than in heme-GH. It leads to a variation in the variation of the pKa for the protonation of the N(epsilon) of the axial imidazole as well as in the proton-linked behavior of the other protonating groups, envisaging a cross-talk communication mechanism among different groups of the heme, which can be operative and relevant also in the presence of the protein matrix.
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Affiliation(s)
- Giampiero De Sanctis
- Department of Molecular, Cellular and Animal Biology, University of Camerino, Via F. Camerini 2, 62032 Camerino, Italy
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19
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Ryabova ES, Nordlander E. Synthesis and reactivity studies of a manganese 'microperoxidase' containing b-type heme. Dalton Trans 2005:1228-33. [PMID: 15782258 DOI: 10.1039/b417331g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mn(III)protoporphyrin IX-6(7)-gly-gly-his methyl ester (MnGGH) has been prepared by condensation of glycyl-glycyl-L-histidine methyl ester with the propionic side chains of Mn(III)protoporphyrin IX. It was characterised by mass spectrometry and UV/VIS spectroscopy. Stopped-flow spectrophotometry was used to study the reaction of the Mn 'microperoxidase' with hydrogen peroxide. The formation of active intermediates analogous to previously described metal-hydroperoxo (compound 0) and metal-oxo (compound I) intermediates of the 'natural' Fe(III) microperoxidase-8 and Mn(III) microperoxidase-8 was observed. The rate of formation of the MnGGH-based compound I analogue was found to increase dramatically with increasing pH. A steady-state kinetic analysis of the catalytic peroxidase activity of MnGGH towards K4[Fe(CN)6], L-tyrosine methyl ester, o-dianisidine, o-methoxyphenol and ascorbic acid showed that the peroxidase reaction proceeds via the formation of a microperoxidase-substrate complex followed by electron transfer from the substrate to the metal. The reactivity of MnGGH depends on the size and hydrophobicity of the substrate, and these properties appear to influence the rate of the electron transfer, which is the rate-limiting step for the whole process. MnGGH showed higher reactivity towards reducing substrates than its Fe(iii) analogue.
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Affiliation(s)
- Ekaterina S Ryabova
- Inorganic Chemistry, Chemical Center, Lund University, PO Box 124, SE-22100, Lund, Sweden
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Ryabova ES, Rydberg P, Kolberg M, Harbitz E, Barra AL, Ryde U, Andersson KK, Nordlander E. A comparative reactivity study of microperoxidases based on hemin, mesohemin and deuterohemin. J Inorg Biochem 2005; 99:852-63. [PMID: 15708807 DOI: 10.1016/j.jinorgbio.2004.12.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2004] [Revised: 12/22/2004] [Accepted: 12/24/2004] [Indexed: 11/28/2022]
Abstract
Three microperoxidases--hemin-6(7)-gly-gly-his methyl ester (HGGH), mesohemin-6(7)-gly-gly-his methyl ester (MGGH) and deuterohemin-6(7)-gly-gly-his methyl ester (DGGH)--have been prepared as models for heme-containing peroxidases by condensation of glycyl-glycyl-L-histidine methyl ester with the propionic side chains of hemin, mesohemin and deuterohemin, respectively. The three microperoxidases differ in two substituents, R, of the protoporphyrin IX framework (HGGH: R=vinyl, MGGH: R=ethyl, DGGH: R=H). X-band and high field EPR spectra show that the microperoxidases exhibit spectroscopic properties similar to those of metmyoglobin, i.e. a high spin ferric S=5/2 signal at g(perpendicular)=6 and g parallel)=2 and an estimated D value of 7.5+/-1cm(-1). The catalytic activities of the microperoxidases towards K4[Fe(CN)6], L-tyrosine methyl ester and 2,2'-azino(bis(3-ethylbenzothiazoline-6-sulfonic acid)) (ABTS) have been investigated. It was found that all three microperoxidases exhibit peroxidase activity and that the reactions follow the generally accepted peroxidase reaction scheme [Biochem. J. 145 (1975) 93-103] with the exception that the initial formation of a Compound I analogue is the rate-limiting step for the whole process. The general activity trend was found to be MGGH approximately DGGH>HGGH. For each microperoxidase, DFT calculations (B3LYP) were made on the reactions of compounds 0, I and II with H+, e- and H+ + e-, respectively, in order to probe the possible relationship between the nature of the 2- and 4-substituents of the hemin and the observed reactivity. The computational modeling indicates that the relative energy differences are very small; solvation and electrostatic effects may be factors that decide the relative activities of the microperoxidases.
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Affiliation(s)
- Ekaterina S Ryabova
- Inorganic Chemistry, Center for Chemistry and Chemical Engineering, Lund University, Box 124, SE-221 00 Lund, Sweden
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Affiliation(s)
- Charles J Reedy
- Department of Chemistry, Columbia University, 3000 Broadway, MC 3121, New York, New York 10027, USA
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Ryabova ES, Dikiy A, Hesslein AE, Bjerrum MJ, Ciurli S, Nordlander E. Preparation and reactivity studies of synthetic microperoxidases containing b-type heme. J Biol Inorg Chem 2004; 9:385-95. [PMID: 15042435 DOI: 10.1007/s00775-004-0532-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2003] [Accepted: 02/19/2004] [Indexed: 10/26/2022]
Abstract
In order to create a heme environment that permits biomimicry of heme-containing peroxidases, a number of new hemin-peptide complexes--hemin-2(18)-glycyl-L-histidine methyl ester (HGH), hemin-2(18)-glycyl-glycyl-L-histidine methyl ester (HGGH), and hemin-2,18-bis(glycyl-glycyl-L-histidine methyl ester) (H2GGH)--have been prepared by condensation of glycyl-L-histidine methyl ester or glycyl-glycyl-L-histidine methyl ester with the propionic side chains of hemin. Characterization by means of UV/vis- and 1H NMR spectroscopy as well as cyclic- and differential pulse voltammetry indicates the formation of five-coordinate complexes in the case of HGH and HGGH, with histidine as an axial ligand. In the case of H2GGH, a six-coordinate complex with both imidazoles coordinated to the iron center appears to be formed. However, 1H NMR of H2GGH reveals the existence of an equilibrium between low-spin six-coordinate and high-spin five-coordinate species in solution. The catalytic activity of the hemin-peptide complexes towards several organic substrates, such as p-cresol, L-tyrosine methyl ester, and ABTS, has been investigated. It was found that not only the five-coordinate HGH and HGGH complexes, but also the six-coordinate H2GGH, catalyze the oxidation of substrates by H2O2. The longer and less strained peptide arm provides the HGGH complex with a slightly higher catalytic efficiency, as compared with HGH, due to formation of more stable intermediate complexes.
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Affiliation(s)
- Ekaterina S Ryabova
- Inorganic Chemistry, Chemical Center, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
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Paul D, Melin F, Hirtz C, Wytko J, Ochsenbein P, Bonin M, Schenk K, Maltese P, Weiss J. Induced fit process in the selective distal binding of imidazoles in zinc(II) porphyrin receptors. Inorg Chem 2003; 42:3779-87. [PMID: 12793814 DOI: 10.1021/ic0341643] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The respective affinities of various imidazole derivatives, imidazole (ImH), 2-methylimidazole (2-MeImH), 2-phenylimidazole (2-PhImH), N-methylimidazole (N-MeIm), 2-methylbenzimidazole (2-MeBzImH), and 4,5-dimethylbenzimidazole (4,5-Me(2)BzImH), for two phenanthroline (Phen) strapped zinc(II) porphyrin receptors porphen-Zn 1-Zn and 2-Zn have been studied. The formation of a supplementary H-bond considerably enhances the affinity of the zinc(II)-porphen receptor for imidazoles unsubstituted on the pyrrolic nitrogen (ImH) versus N-substituted imidazoles such as N-MeIm. The ImHs subset porphen-Zn complexes are formed with association constants up to 4 orders of magnitude superior to those measured either for N-MeIm as substrate or TPP-Zn as receptor. Distal or proximal binding of the substrates was determined by (1)H NMR measurements and titration. In two cases, the very high stability of the inclusion complex enabled the use of 2D NMR techniques. Excellent correlation between solution and solid-state structures has been obtained. A total of six X-ray structures are detailed in this article showing that the evolution of the shape of the zinc(II) receptor is mostly dependent on the steric constraints induced by the substitution on the imidazole. Hindered guests also progressively induce considerable mobility restrictions and severe distortions on the receptor, especially in the case of 2-MeBzImH and 2-PhImH.
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Affiliation(s)
- Dharam Paul
- Laboratoire d'Electrochimie, UMR 7512 au CNRS, Université Louis Pasteur, 4 rue Blaise Pascal, F-67070 Strasbourg, France
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Affiliation(s)
- A Lombardi
- Department of Chemistry, University of Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cynthia 45, I-80126 Napoli, Italy.
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Casella L, De Gioia L, Silvestri GF, Monzani E, Redaelli C, Roncone R, Santagostini L. Covalently modified microperoxidases as heme-peptide models for peroxidases. J Inorg Biochem 2000; 79:31-40. [PMID: 10830844 DOI: 10.1016/s0162-0134(99)00243-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Microperoxidase-8 (MP8) and microperoxidase-9 (MP9) have been covalently modified by attachment of proline-containing residues to the amino terminal peptide chain in order to obtain new peroxidase model systems. The catalytic activities of these derivatives in the oxidation of p-cresol by hydrogen peroxide have been compared to that of MP8. The presence of steric hindrance above the heme reduces the formation rate of the catalytically active species, while the reactivity is increased when the amino group of a proline residue is close to the iron. The modification of the catalyst affects the rate of degradation processes undergone by the heme group during catalysis. A bulky aromatic group on the distal side decreases the stability of the complex because it reduces the mobility of a phenoxy radical species formed during catalysis, while the presence of proline residues increases the number of turnovers of the heme catalysts before degradation. The complex Pro2-MP8 obtained by addition of two proline residues to MP8 exhibits the best catalytic performance in terms of activity and chemical stability.
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Affiliation(s)
- L Casella
- Dipartimento di Chimica Generale, Università di Pavia, Italy
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Inoue MB, Navarro RE, Inoue M, Fernando Q. Potentiometric and spectroscopic studies of reactions of histidine with 13-membered amide-based macrocyclic Cu2+ chelates. Inorganica Chim Acta 1999. [DOI: 10.1016/s0020-1693(99)00330-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lombardi A, Nastri F, Sanseverino M, Maglio O, Pedone C, Pavone V. Miniaturized hemoproteins: design, synthesis and characterization of mimochrome II. Inorganica Chim Acta 1998. [DOI: 10.1016/s0020-1693(97)06180-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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28
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Synthesis, characterization and stereoselective catalytic oxidations of chelated deuterohaemin-glycyl-L-histidine complexes. Inorganica Chim Acta 1998. [DOI: 10.1016/s0020-1693(97)06029-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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29
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Froidevaux J, Ochsenbein P, Bonin M, Schenk K, Maltese P, Gisselbrecht JP, Weiss J. Side Selection of the Fifth Coordinate with a Single Strapped Zinc(II) Porphyrin Host: Full Characterization of Two Imidazole Complexes. J Am Chem Soc 1997. [DOI: 10.1021/ja9723646] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- J. Froidevaux
- Laboratoire d'Electrochimie UMR 7512 and Laboratoire de Chimie Supramoléculaire Faculté de Chimie, Université Louis Pasteur, 4 rue Blaise Pascal, F-67000 Strasbourg, France Département Sciences Physiques, Université de Lausanne CH-1015 Lausanne-Dorigny Universität Bern, CH-3012 Bern, Switzerland
| | - P. Ochsenbein
- Laboratoire d'Electrochimie UMR 7512 and Laboratoire de Chimie Supramoléculaire Faculté de Chimie, Université Louis Pasteur, 4 rue Blaise Pascal, F-67000 Strasbourg, France Département Sciences Physiques, Université de Lausanne CH-1015 Lausanne-Dorigny Universität Bern, CH-3012 Bern, Switzerland
| | - M. Bonin
- Laboratoire d'Electrochimie UMR 7512 and Laboratoire de Chimie Supramoléculaire Faculté de Chimie, Université Louis Pasteur, 4 rue Blaise Pascal, F-67000 Strasbourg, France Département Sciences Physiques, Université de Lausanne CH-1015 Lausanne-Dorigny Universität Bern, CH-3012 Bern, Switzerland
| | - K. Schenk
- Laboratoire d'Electrochimie UMR 7512 and Laboratoire de Chimie Supramoléculaire Faculté de Chimie, Université Louis Pasteur, 4 rue Blaise Pascal, F-67000 Strasbourg, France Département Sciences Physiques, Université de Lausanne CH-1015 Lausanne-Dorigny Universität Bern, CH-3012 Bern, Switzerland
| | - P. Maltese
- Laboratoire d'Electrochimie UMR 7512 and Laboratoire de Chimie Supramoléculaire Faculté de Chimie, Université Louis Pasteur, 4 rue Blaise Pascal, F-67000 Strasbourg, France Département Sciences Physiques, Université de Lausanne CH-1015 Lausanne-Dorigny Universität Bern, CH-3012 Bern, Switzerland
| | - J.-P. Gisselbrecht
- Laboratoire d'Electrochimie UMR 7512 and Laboratoire de Chimie Supramoléculaire Faculté de Chimie, Université Louis Pasteur, 4 rue Blaise Pascal, F-67000 Strasbourg, France Département Sciences Physiques, Université de Lausanne CH-1015 Lausanne-Dorigny Universität Bern, CH-3012 Bern, Switzerland
| | - J. Weiss
- Laboratoire d'Electrochimie UMR 7512 and Laboratoire de Chimie Supramoléculaire Faculté de Chimie, Université Louis Pasteur, 4 rue Blaise Pascal, F-67000 Strasbourg, France Département Sciences Physiques, Université de Lausanne CH-1015 Lausanne-Dorigny Universität Bern, CH-3012 Bern, Switzerland
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Inoue MB, Machi L, Inoue M, Fernando Q. Coordination of histamine and imidazole with macrocyclic Zn2+, Cd2+ and Cu2+ chelates of dioxotetraazacycloalkanediacetates. Inorganica Chim Acta 1997. [DOI: 10.1016/s0020-1693(96)05580-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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31
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Monzani E, Casella L, Gullotti M, Panigada N, Franceschi F, Papaefthymiou V. Cytochrome c oxidase models. Dinuclear iron/copper complexes derived from covalently modified deuteroporphyrins. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s1381-1169(96)00252-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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