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Adam SM, Wijeratne GB, Rogler PJ, Diaz DE, Quist DA, Liu JJ, Karlin KD. Synthetic Fe/Cu Complexes: Toward Understanding Heme-Copper Oxidase Structure and Function. Chem Rev 2018; 118:10840-11022. [PMID: 30372042 PMCID: PMC6360144 DOI: 10.1021/acs.chemrev.8b00074] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Heme-copper oxidases (HCOs) are terminal enzymes on the mitochondrial or bacterial respiratory electron transport chain, which utilize a unique heterobinuclear active site to catalyze the 4H+/4e- reduction of dioxygen to water. This process involves a proton-coupled electron transfer (PCET) from a tyrosine (phenolic) residue and additional redox events coupled to transmembrane proton pumping and ATP synthesis. Given that HCOs are large, complex, membrane-bound enzymes, bioinspired synthetic model chemistry is a promising approach to better understand heme-Cu-mediated dioxygen reduction, including the details of proton and electron movements. This review encompasses important aspects of heme-O2 and copper-O2 (bio)chemistries as they relate to the design and interpretation of small molecule model systems and provides perspectives from fundamental coordination chemistry, which can be applied to the understanding of HCO activity. We focus on recent advancements from studies of heme-Cu models, evaluating experimental and computational results, which highlight important fundamental structure-function relationships. Finally, we provide an outlook for future potential contributions from synthetic inorganic chemistry and discuss their implications with relevance to biological O2-reduction.
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Affiliation(s)
- Suzanne M. Adam
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Gayan B. Wijeratne
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Patrick J. Rogler
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Daniel E. Diaz
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - David A. Quist
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Jeffrey J. Liu
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kenneth D. Karlin
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
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Zucca P, Rescigno A, Rinaldi AC, Sanjust E. Biomimetic metalloporphines and metalloporphyrins as potential tools for delignification: Molecular mechanisms and application perspectives. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.molcata.2013.09.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Stephenson NA, Bell AT. Mechanistic study of iron(III) [tetrakis(pentafluorophenyl)porphyrin triflate (F(20)TPP)Fe(OTf) catalyzed cyclooctene epoxidation by hydrogen peroxide. Inorg Chem 2007; 46:2278-85. [PMID: 17311372 DOI: 10.1021/ic060757c] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have recently proposed a mechanism for the epoxidation of cyclooctene by H2O2 catalyzed by iron(III) [tetrakis(pentafluorophenyl)]porphyrin chloride, (F20TPP)FeCl, in solvent containing methanol [Stephenson, N. A.; Bell, A.T. Inorg. Chem. 2006, 45, 2758-2766]. In that study, we found that catalysis did not occur unless (F20TPP)FeCl first dissociated, a process facilitated by the solvation of the Cl- anion by methanol and the coordination of methanol to the (F20TPP)Fe+ cation. Methanol as well as other alcohols was also found to facilitate the heterolytic cleavage of the O-O bond of H2O2 coordinated to the (F20TPP)Fe+ cation via a generalized acid mechanism. In the present study, we have shown that catalytic activity of the (F20TPP)Fe+ cation can be achieved in aprotic solvent by displacing the tightly bound chloride anion with a weakly bound triflate anion. By working in an aprotic solvent, acetonitrile, it was possible to determine the rate of heterolytic O-O bond cleavage in coordinated H2O2 unaffected by the interaction of the peroxide with methanol. A mechanism is proposed for this system and is shown to be valid over a range of reaction conditions. The mechanisms for cyclooctene epoxidation and H2O2 decomposition for the aprotic and protic solvent systems are similar with the only difference being the mechanism of proton-transfer prior to heterolytic cleavage of the oxygen-oxygen bond of coordinated hydrogen peroxide. Comparison of the rate parameters indicates that the utilization of hydrogen peroxide for cyclooctene epoxidation is higher in a protic solvent than in an aprotic solvent and results in a smaller extent of porphyrin degradation due to free radical attack. It was also shown that water can coordinate to the iron porphyrin cation in aprotic systems resulting in catalyst deactivation; this effect was not observed when methanol was present, since methanol was found to displace all of the coordinated water.
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Affiliation(s)
- Ned A Stephenson
- Chemical Sciences Division, Lawrence Berkeley Laboratory and Department of Chemical Engineering, University of California, Berkeley, California 94720-1462
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Hirst J, Wilcox SK, Williams PA, Blankenship J, McRee DE, Goodin DB. Replacement of the axial histidine ligand with imidazole in cytochrome c peroxidase. 1. Effects on structure. Biochemistry 2001; 40:1265-73. [PMID: 11170452 DOI: 10.1021/bi002089r] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Replacement of the axial histidine ligand with exogenous imidazole has been accomplished in a number of heme protein mutants, where it often serves to complement the functional properties of the protein. In this paper, we describe the effects of pH and buffer ion on the crystal structure of the H175G mutant of cytochrome c peroxidase, in which the histidine tether between the heme and the protein backbone is replaced by bound imidazole. The structures show that imidazole can occupy the proximal H175G cavity under a number of experimental conditions, but that the details of the interaction with the protein and the coordination to the heme are markedly dependent on conditions. Replacement of the tethered histidine ligand with imidazole permits the heme to shift slightly in its pocket, allowing it to adopt either a planar or distally domed conformation. H175G crystallized from both high phosphate and imidazole concentrations exists as a novel, 5-coordinate phosphate bound state, in which the proximal imidazole is dissociated and the distal phosphate is coordinated to the iron. To accommodate this bound phosphate, the side chains of His-52 and Asn-82 alter their positions and a significant conformational change in the surrounding protein backbone occurs. In the absence of phosphate, imidazole binds to the proximal H175G cavity in a pH-dependent fashion. At pH 7, imidazole is directly coordinated to the heme (d(Fe--Im) = 2.0 A) with a nearby distal water (d(Fe--HOH) = 2.4 A). This is similar to the structure of WT CCP except that the iron lies closer in the heme plane, and the hydrogen bond between imidazole and Asp-235 (d(Im--Asp) = 3.1 A) is longer than for WT CCP (d(His--Asp) = 2.9 A). As the pH is dropped to 5, imidazole dissociates from the heme (d(Fe--Im) = 2.9 A), but remains in the proximal cavity where it is strongly hydrogen bonded to Asp-235 (d(Im--Asp) = 2.8 A). In addition, the heme is significantly domed toward the distal pocket where it may coordinate a water molecule. Finally, the structure of H175G/Im, pH 6, at low temperature (100 K) is very similar to that at room temperature, except that the water above the distal heme face is not present. This study concludes that steric restrictions imposed by the covalently tethered histidine restrain the heme and its ligand coordination from distortions that would arise in the absence of the restricted tether. Coupled with the functional and spectroscopic properties described in the following paper in this issue, these structures help to illustrate how the delicate and critical interactions between protein, ligand, and metal modulate the function of heme enzymes.
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Affiliation(s)
- J Hirst
- Department of Molecular Biology, MB8, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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Mahy JP, Desfosses B, de Lauzon S, Quilez R, Desfosses B, Lion L, Mansuy D. Hemoabzymes. Different strategies for obtaining artificial hemoproteins based on antibodies. Appl Biochem Biotechnol 1998; 75:103-27. [PMID: 10214700 DOI: 10.1007/bf02787712] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Besides existing models of chemical or biotechnological origin for hemoproteins like peroxidases and cytochromes P450, catalytic antibodies (Abs) with a metalloporphyrin cofactor represent a promising alternative route to catalysts tailored for selective oxidation reactions. A brief overview of the literature shows that, until now, the first strategy for obtaining such artificial hemoproteins has been to produce antiporphyrin Abs, raised against various free-base, N-substituted, Sn-, Pd-, or Fe-porphyrins. Four of them exhibited, in the presence of the corresponding Fe-porphyrin cofactor, a significant peroxidase activity, with kcat/K(m) values of 10(2) to 5 x 10(3)/M/s. This value remained low when compared to that of peroxidases, probably because neither a proximal ligand of the Fe, nor amino acid residues participating in the catalysis of the heterolytic cleavage of the O-O bond of H2O2, have been induced in those Abs. This strategy has been shown to be insufficient for the elaboration of effective models of cytochromes P450, because only one set of Abs, raised against meso-tetrakis(para-carboxyvinylphenyl)porphyrin, was reported to catalyze the nonstereoselective oxidation of styrene by iodosyl benzene using a Mn-porphyrin cofactor, and attempts to generate Abs having binding sites for both the substrate and the metalloporphyrin cofactor, using as a hapten a porphyrin covalently linked to the substrate, were not successful. A second strategy is then proposed, which involves the chemical labeling of antisubstrate Abs with a metalloporphyrin. As an example, preliminary results are presented on the covalent linkage of an Fe-porphyrin to an antiestradiol Ab, in order to obtain semisynthetic catalytic Abs able to catalyze the selective oxidation of steroids.
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Affiliation(s)
- J P Mahy
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, URA 400 CNRS, Université René Descartes, Paris, France.
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Gonsalves AM, Pereira MM. State of the art in the development of biomimetic oxidation catalysts. ACTA ACUST UNITED AC 1996. [DOI: 10.1016/s1381-1169(96)00050-7] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Mohajer D, Tangestaninejad S. Efficient olefin epoxidation with tetrabutylammonium periodate catalyzed by manganese porphyrin in the presence of imidazole. Tetrahedron Lett 1994. [DOI: 10.1016/s0040-4039(00)76007-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Preparation of functionalized polyhalogenated tetraaryl-porphyrins by selective substitution of the p-Fluorines of meso-tetra-(pentafluorophenyl)porphyrins. Tetrahedron Lett 1991. [DOI: 10.1016/0040-4039(91)80641-i] [Citation(s) in RCA: 102] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Larroque C, Lange R, Maurin L, Bienvenue A, van Lier JE. On the nature of the cytochrome P450scc "ultimate oxidant": characterization of a productive radical intermediate. Arch Biochem Biophys 1990; 282:198-201. [PMID: 2171430 DOI: 10.1016/0003-9861(90)90104-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The electron paramagnetic (EPR) properties of a transient species detected during a cytochrome P450 (P450)-mediated peroxidative reaction have been compared with those of peroxidases Compound I and model metalloporphyrins. The reaction which was studied with cholesterol-specific P450scc and (20R)-20-hydroperoxycholesterol, occurred without enzyme denaturation. The resulting transient species, which reached its maximum after 50 s reaction, was characterized by a one-line EPR spectrum, g = 2.0035, delta 1/2 = 1.08 mT. The decay of this radical was concomitant with the production of (20R)-20,21-dihydroxycholesterol. The reaction (almost 100% yield) conserved the stereo-specificity of the natural pathway. We suggest this intermediate is a candidate for the in vivo ultimate oxidant in the P450-mediated hydroxylation process. The comparison of the observed EPR spectrum with those of peroxidase Compound I and related synthetic models allows us to propose a FeIV porphyrin II cation radical structure for the intermediate.
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Affiliation(s)
- C Larroque
- Institut National de la Santé et de la Recherche Médicale, Unité 128, Montpellier, France
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Mansuy D, Battioni P, Battioni JP. Chemical model systems for drug-metabolizing cytochrome-P-450-dependent monooxygenases. EUROPEAN JOURNAL OF BIOCHEMISTRY 1989; 184:267-85. [PMID: 2676531 DOI: 10.1111/j.1432-1033.1989.tb15017.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- D Mansuy
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, Institut National de la Santé et de la Recherche Médicale, no. 400, Université René Descartes, Paris
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Abstract
The microsomal mixed function oxidase system contains the cytochrome P-450 oxidative drug metabolizing family of enzymes. The catalytic cycle of cytochrome P-450 is believed to involve the formation of an active iron-oxygen species which is responsible for oxygen transfer to the substrate. This assumption is supported by the fact that a number of peroxidative agents can replace NADPH, the reductase, and oxygen as co-reactants in most oxidative reactions of microsomal cytochrome P-450. We have found that a mixture of either ferrous or ferric ions with hydrogen peroxide (Fenton and Ruff reagents) can serve as biomimetic models for cytochrome P-450 in hydroxylation, exposidation, sulfoxidation, and N-demethylation of various drugs. The existance of an iron-oxo active species in both Fenton and Ruff type reactions has been postulated and provides reaction cycles similar to those of cytochrome p-450. Other model systems for the hepatic hydroxylation and epoxidation using transition metal complexes with porphyrin are also discussed. The present paper reviews the various biomimetic models of the heme cytochrome P-450 and emphasizes their simulation of hepatic drug metabolism and their potential medical and industrial applications.
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Affiliation(s)
- S Zbaida
- Department of Pharmacy, School of Pharmacy, Hebrew University of Jerusalem, Israel
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