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Beissel T, Buerger KS, Voigt G, Wieghardt K, Butzlaff C, Trautwein AX. (1,4,7-Tris(4-tert-butyl-2-mercaptobenzyl)-1,4,7-triazacyclononane)iron(III): a model for the iron-sulfur center in nitrile hydratase from Brevibacterium, sp. Inorg Chem 2002. [DOI: 10.1021/ic00054a002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bominaar EL, Ding XQ, Gismelseed A, Bill E, Winkler H, Trautwein AX, Nasri H, Fischer J, Weiss R. Structural, Moessbauer, and EPR investigations on two oxidation states of a five-coordinate, high-spin synthetic heme. Quantitative interpretation of zero-field parameters and large quadrupole splitting. Inorg Chem 2002. [DOI: 10.1021/ic00036a023] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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53
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Auerbach U, Weyhermueller T, Wieghardt K, Nuber B, Bill E, Butzlaff C, Trautwein AX. First-row transition metal complexes of the hexadentate macrocycle 1,4,7-tris(5-tert-butyl-2-hydroxybenzyl)-1,4,7-triazacyclononane (LH3). Crystal structures of [LTiIV]BPh4, [LCrIII], [LFeIII], and [(LH)2FeIII2](ClO4)2.2H2O. Inorg Chem 2002. [DOI: 10.1021/ic00057a005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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54
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Morgenstern-Badarau I, Laroque D, Bill E, Winkler H, Trautwein AX, Robert F, Jeannin Y. Magnetic susceptibility, EPR, Moessbauer, and x-ray investigations of heteropolynuclear clusters containing iron(III) and copper(II) ions: {Cu(Mesalen)}2 Fe(acac) (NO3)2 and {Cu(Mesalen)}3 Fe(acac) (PF6)2. Inorg Chem 2002. [DOI: 10.1021/ic00016a015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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55
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Kueppers HJ, Wieghardt K, Nuber B, Weiss JW, Bill E, Trautwein AX. Crown thioether chemistry of iron(II/III). Synthesis and characterization of low-spin bis(1,4,7-trithiacyclononane)iron(III) and crystal structure of [FeII([9]aneS3)([9]aneS3(O))](ClO4)2.2NaClO4.H2O. Inorg Chem 2002. [DOI: 10.1021/ic00269a028] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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56
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Paulsen H, Rusanov V, Benda R, Herta C, Schünemann V, Janiak C, Dorn T, Chumakov AI, Winkler H, Trautwein AX. Metastable isonitrosyl structure of the nitroprusside anion confirmed by nuclear inelastic scattering. J Am Chem Soc 2002; 124:3007-11. [PMID: 11902892 DOI: 10.1021/ja016239c] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nuclear inelastic scattering (NIS) measurements were performed on a guanidium nitroprusside ((CN(3)H(6))(2)[Fe(CN)(5)NO], GNP) monocrystal at 77 K after the sample was illuminated with blue light (450 nm) at 50 K to populate the two metastable states, MS(1) and MS(2), of the nitroprusside anion. A second measurement was performed at 77 K after warming up the illuminated crystal to 250 K where the metastable states decay to the groundstate. The measured spectra were compared with simulated NIS spectra that were calculated by using density functional methods. Comparison of measured and simulated spectra provides strong evidence for the isonitrosyl structure of the metastable MS(1) state proposed by Carducci et al. (Carducci, M. D.; Pressprich, M. R.; Coppens, P. J. Am. Chem. Soc. 1997, 119, 2669-2678).
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Mekmouche Y, Hummel H, Ho RYN, Que L, Schünemann V, Thomas F, Trautwein AX, Lebrun C, Gorgy K, Leprêtre JC, Collomb MN, Deronzier A, Fontecave M, Ménage S. Sulfide oxidation by hydrogen peroxide catalyzed by iron complexes: two metal centers are better than one. Chemistry 2002; 8:1196-204. [PMID: 11891908 DOI: 10.1002/1521-3765(20020301)8:5<1196::aid-chem1196>3.0.co;2-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Peroxoiron species have been proposed to be involved in catalytic cycles of iron-dependent oxygenases and in some cases as the active intermediates during oxygen-transfer reactions. The catalytic properties of a mononuclear iron complex, [Fe(II)(pb)(2)(CH(3)CN)(2)] (pb=(-)4,5-pinene-2,2'-bipyridine), have been compared to those of its related dinuclear analogue. Each system generates specific peroxo adducts, which are responsible for the oxidation of sulfides to sulfoxides. The dinuclear catalyst was found to be more reactive and (enantio)selective than its mononuclear counterpart, suggesting that a second metal site affords specific advantages for stereoselective catalysis. These results might help for the design of future enantioselective iron catalysts.
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Hummel H, Mekmouche Y, Duboc-Toia C, Ho RYN, Que, Jr. L, Schünemann V, Thomas F, Trautwein AX, Lebrun C, Fontecave M, Ménage S. A Diferric Peroxo Complex with an Unprecedented Spin Configuration: AnS=2 System Arising from anS=5/2, 1/2 Pair. Angew Chem Int Ed Engl 2002. [DOI: 10.1002/1521-3773(20020215)41:4<617::aid-anie617>3.0.co;2-q] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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59
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Hummel H, Mekmouche Y, Duboc-Toia C, Ho RYN, Que, Jr. L, Schünemann V, Thomas F, Trautwein AX, Lebrun C, Fontecave M, Ménage S. A Diferric Peroxo Complex with an Unprecedented Spin Configuration: AnS=2 System Arising from anS=5/2, 1/2 Pair. Angew Chem Int Ed Engl 2002. [DOI: 10.1002/1521-3757(20020215)114:4<639::aid-ange639>3.0.co;2-v] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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60
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Rauscher L, Expert D, Matzanke BF, Trautwein AX. Chrysobactin-dependent iron acquisition in Erwinia chrysanthemi. Functional study of a homolog of the Escherichia coli ferric enterobactin esterase. J Biol Chem 2002; 277:2385-95. [PMID: 11694506 DOI: 10.1074/jbc.m107530200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Under iron limitation, the plant pathogen Erwinia chrysanthemi produces the catechol-type siderophore chrysobactin, which acts as a virulence factor. It can also use enterobactin as a xenosiderophore. We began this work by sequencing the 5'-upstream region of the fct-cbsCEBA operon, which encodes the ferric chrysobactin receptor and proteins involved in synthesis of the catechol moiety. We identified a new iron-regulated gene (cbsH) transcribed divergently relative to the fct gene, the translated sequence of which is 45.6% identical to that of Escherichia coli ferric enterobactin esterase. Insertions within this gene interrupt the chrysobactin biosynthetic pathway by exerting a polar effect on a downstream gene with some sequence identity to the E. coli enterobactin synthase gene. These mutations had no effect on the ability of the bacterium to obtain iron from enterobactin, showing that a functional cbsH gene is not required for iron removal from ferric enterobactin in E. chrysanthemi. The cbsH-negative mutants were less able to utilize ferric chrysobactin, and this effect was not caused by a defect in transport per se. In a nonpolar cbsH-negative mutant, chrysobactin accumulated intracellularly. These defects were rescued by the cbsH gene supplied on a plasmid. The amino acid sequence of the CbsH protein revealed characteristics of the S9 prolyl oligopeptidase family. Ferric chrysobactin hydrolysis was detected in cell extracts from a cbsH-positive strain that was inhibited by diisopropyl fluorophosphate. These data are consistent with the fact that chrysobactin is a d-lysyl-l-serine derivative. Mössbauer spectroscopy of whole cells at various states of (57)Fe-labeled chrysobactin uptake showed that this enzyme is not required for iron removal from chrysobactin in vivo. The CbsH protein may therefore be regarded as a peptidase that prevents the bacterial cells from being intracellularly iron-depleted by chrysobactin.
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Saalfrank RW, Glaser H, Demleitner B, Hampel F, Chowdhry MM, Schünemann V, Trautwein AX, Vaughan GBM, Yeh R, Davis AV, Raymond KN. Cover Picture. Chemistry 2002. [DOI: 10.1002/1521-3765(20020118)8:2<323::aid-chem323>3.0.co;2-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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62
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Saalfrank RW, Glaser H, Demleitner B, Hampel F, Chowdhry MM, Schünemann V, Trautwein AX, Vaughan GBM, Yeh R, Davis AV, Raymond KN. Self-assembly of tetrahedral and trigonal antiprismatic clusters [Fe4(L4)4] and [Fe6(L5)6] on the basis of trigonal tris-bidentate chelators. Chemistry 2002; 8:493-7. [PMID: 11858175 DOI: 10.1002/1521-3765(20020118)8:2<493::aid-chem493>3.0.co;2-5] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In a one-pot reaction, the tetranuclear iron chelate complex [Fe4(L4)4] 6 was generated from benzene-1,3,5-tricarboxylic acid trichloride (4), bis-tert-butyl malonate (5a), methyllithium, and iron(II) dichloride under aerobic conditions. Alternatively, hexanuclear iron chelate complex [Fe(L5)6] 7 was formed starting from bis-para-tolyl malonate (5b) by employing identical reaction conditions to those applied for the synthesis of 6. The clusters 6 and 7 are present as racemic mixtures of homoconfigurational (delta,delta,delta,delta)/(lambda,lambda,lambda,lambda)-fac or (delta,delta,delta,delta,delta,delta)/(lambda,lambda,lambda,lambda,lambda,lambda)-fac stereoisomers. The structures of 6 and 7 were unequivocally resolved by single-crystal X-ray analyses. The all-iron(III) character of 6 and 7 was determined by Mössbauer spectroscopy.
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Kopriva S, Büchert T, Fritz G, Suter M, Weber M, Benda R, Schaller J, Feller U, Schürmann P, Schünemann V, Trautwein AX, Kroneck PM, Brunold C. Plant adenosine 5'-phosphosulfate reductase is a novel iron-sulfur protein. J Biol Chem 2001; 276:42881-6. [PMID: 11553635 DOI: 10.1074/jbc.m107424200] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Adenosine 5'-phosphosulfate reductase (APR) catalyzes the two-electron reduction of adenosine 5'-phosphosulfate to sulfite and AMP, which represents the key step of sulfate assimilation in higher plants. Recombinant APRs from both Lemna minor and Arabidopsis thaliana were overexpressed in Escherichia coli and isolated as yellow-brown proteins. UV-visible spectra of these recombinant proteins indicated the presence of iron-sulfur centers, whereas flavin was absent. This result was confirmed by quantitative analysis of iron and acid-labile sulfide, suggesting a [4Fe-4S] cluster as the cofactor. EPR spectroscopy of freshly purified enzyme showed, however, only a minor signal at g = 2.01. Therefore, Mössbauer spectra of (57)Fe-enriched APR were obtained at 4.2 K in magnetic fields of up to 7 tesla, which were assigned to a diamagnetic [4Fe-4S](2+) cluster. This cluster was unusual because only three of the iron sites exhibited the same Mössbauer parameters. The fourth iron site gave, because of the bistability of the fit, a significantly smaller isomer shift or larger quadrupole splitting than the other three sites. Thus, plant assimilatory APR represents a novel type of adenosine 5'-phosphosulfate reductase with a [4Fe-4S] center as the sole cofactor, which is clearly different from the dissimilatory adenosine 5'-phosphosulfate reductases found in sulfate reducing bacteria.
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64
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Stadler C, Daub JÃ, Köhler JÃ, Saalfrank RW, Coropceanu V, Schünemann V, Ober C, Trautwein AX, Parker SF, Poyraz M, Inomata T, Cannon RD. Electron transfer in a trinuclear oxo-centred mixed-valence iron complex, in solid and solution statesDedicated to Professor Dieter Sellmann on the occasion of his 60th birthday. ACTA ACUST UNITED AC 2001. [DOI: 10.1039/b100780g] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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65
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Weiss R, Bulach V, Gold A, Terner J, Trautwein AX. Valence-tautomerism in high-valent iron and manganese porphyrins. J Biol Inorg Chem 2001; 6:831-45. [PMID: 11713691 DOI: 10.1007/s007750100277] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2001] [Accepted: 05/29/2001] [Indexed: 10/27/2022]
Abstract
Iron and manganese hemes are "high-valent" when the valence state of the metal exceeds III. Redox chemistry of the high valent metal complexes involves redistribution of holes and electrons over the metal ion and the porphyrin and axial ligands, defined as valence tautomerism. Thus, catalytic pathways of heme-containing biomolecules such as peroxidases, catalases and cytochromes P450 involve valence tautomerism, as do pathways of biomimetic oxygen transfer catalysis by manganese porphyrins, robust catalysts with potential commercial value. Determinants of the site of electron abstraction are key to understanding valence tautomerism. In model systems, metal-centered oxidation is supported by hard anionic axial ligands that are also strongly pi-donating, such as oxo, aryl, bix-methoxy and bis-fluoro groups. Manganese(IV) is more stable than iron(IV) and metal-centered one-electron oxidations occur with weaker pi-donating axial ligands such as bisazido, -isocyanato, -hypochlorito and bis chloro groups. Virtually all known high-valent iron porphyrin complexes oxidized by two-electrons above the ferric state are coordinated by the strongly pi-donating oxo or nitrido ligands. In all well-characterized oxo complexes, iron is in the ferryl state and the second oxidizing equivalent resides on the porphyrin. Complexes with iron(V) have not been definitively characterized. One-electron oxidation of oxomanganese(IV) porphyrin complexes gives the oxomanganese(IV) porphyrin pi-cation redicals. In aqueous solution, oxidation of Mn(III) complexes of tetra cationic N-methylpyridiniumylporphyrin isomers by monooxygen donors yields a transient oxomanganese(V) species.
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Padovani D, Thomas F, Trautwein AX, Mulliez E, Fontecave M. Activation of class III ribonucleotide reductase from E. coli. The electron transfer from the iron-sulfur center to S-adenosylmethionine. Biochemistry 2001; 40:6713-9. [PMID: 11389585 DOI: 10.1021/bi002936q] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The anaerobic ribonucleotide reductase (ARR) from E. coli is the prototype for enzymes that use the combination of S-adenosylmethionine (AdoMet) and an iron-sulfur center for generating catalytically essential free radicals. ARR is a homodimeric alpha2 protein which acquires a glycyl radical during anaerobic incubation with a [4Fe-4S]-containing activating enzyme (beta) and AdoMet under reducing conditions. Here we show that the EPR-active S = 1/2 reduced [4Fe-4S]+ cluster is competent for AdoMet reductive cleavage, yielding 1 equiv of methionine and almost 1 equiv of glycyl radical. These data support the proposal that the glycyl radical results from a one-electron oxidation of the reduced cluster by AdoMet. Reduced protein beta alone is also able to reduce AdoMet but only in the presence of DTT. However, in that case, 2 equiv of methionine per reduced cluster was formed. This unusual stoichiometry and combined EPR and Mössbauer spectroscopic analysis are used to tentatively propose that AdoMet reductive cleavage proceeds by an alternative mechanism involving catalytically active [3Fe-4S] intermediate clusters.
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Paulsen H, Duelund L, Winkler H, Toftlund H, Trautwein AX. Free energy of spin-crossover complexes calculated with density functional methods. Inorg Chem 2001; 40:2201-3. [PMID: 11304167 DOI: 10.1021/ic000954q] [Citation(s) in RCA: 215] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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68
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Zecca L, Gallorini M, Schünemann V, Trautwein AX, Gerlach M, Riederer P, Vezzoni P, Tampellini D. Iron, neuromelanin and ferritin content in the substantia nigra of normal subjects at different ages: consequences for iron storage and neurodegenerative processes. J Neurochem 2001; 76:1766-73. [PMID: 11259494 DOI: 10.1046/j.1471-4159.2001.00186.x] [Citation(s) in RCA: 280] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Information on the molecular distribution and ageing trend of brain iron in post-mortem material from normal subjects is scarce. Because it is known that neuromelanin and ferritin form stable complexes with iron(III), in this study we measured the concentration of iron, ferritin and neuromelanin in substantia nigra from normal subjects, aged between 1 and 90 years, dissected post mortem. Iron levels in substantia nigra were 20 ng/mg in the first year of life, had increased to 200 ng/mg by the fourth decade and remained stable until 90 years of age. The H-ferritin concentration was also very low (29 ng/mg) during the first year of life but increased rapidly to values of approximately 200 ng/mg at 20 years of age, which then remained constant until the eighth decade of life. L-Ferritin also showed an increasing trend during life although the concentrations were approximately 50% less than that of H-ferritin at each age point. Neuromelanin was not detectable during the first year, increased to approximately 1000 ng/mg in the second decade and then increased continuously to 3500 ng/mg in the 80th year. A Mössbauer study revealed that the high-spin trivalent iron is probably arranged in a ferritin-like iron--oxyhydroxide cluster form in the substantia nigra. Based on this data and on the low H- and L-ferritin content in neurones it is concluded that neuromelanin is the major iron storage in substantia nigra neurones in normal individuals.
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Paulsen H, Benda R, Herta C, Schünemann V, Chumakov AI, Duelund L, Winkler H, Toftlund H, Trautwein AX. Anisotropic nuclear inelastic scattering of an iron(II) molecular crystal. PHYSICAL REVIEW LETTERS 2001; 86:1351-1354. [PMID: 11178081 DOI: 10.1103/physrevlett.86.1351] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2000] [Indexed: 05/23/2023]
Abstract
Nuclear inelastic scattering (NIS) spectra were recorded for a monocrystal of the spin-crossover complex [Fe(tptMetame)] (ClO (4))(2) (tptMetame = 1,1,1-tris([N-(2-pyridylmethyl)-N-methylamino]-methyl)ethane) at T = 30 K (low-spin state) and at room temperature (high-spin state) for different crystal orientations. The high energy resolution (0.65 meV) allowed us to resolve individual molecular vibrations which were unambiguously identified by density functional calculations. From the NIS spectra for the first time the angular-resolved iron-partial density of phonon states (PDOS) was extracted. The PDOS corroborates a vibrational entropy difference as driving force of the spin transition.
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Zakhariev O, Trautwein AX, Veeger C. Porphyrin-Fe(III)-hydroperoxide and porphyrin-Fe(III)-peroxide anion as catalytic intermediates in cytochrome P450-catalyzed hydroxylation reactions: a molecular orbital study. Biophys Chem 2000; 88:11-34. [PMID: 11152267 DOI: 10.1016/s0301-4622(00)00194-0] [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: 11/21/2022]
Abstract
The hydroxylation of fluorobenzene and aniline, catalyzed by the porphyrin-Fe(III)-peroxide anion with either a cysteinate- or a histidyl-type of axial ligand as well as the hydroxylation of fluorobenzene, catalyzed by porphyrin-Fe(III)-hydroperoxide with a cysteinate-type of axial ligand as catalytic intermediates, have been investigated by electronic structure calculations in local spin-density approximation. Non-repulsive potential curves are, in contrast with porphyrin-Fe(III)-hydroperoxide, obtained only in the case of porphyrin-Fe(III)-peroxide anion as catalytic intermediate. The mutual substrate-porphyrin orientation with a dihedral angle between the plane of the substrate and the porphyrin plane of 45 degrees is more favorable compared with the parallel orientation between these two planes. This orientation differs for the case of fluorobenzene hydroxylation from the corresponding one calculated by us with the ferryl-oxo-pi-cation radical complex as a catalytic intermediate. The calculated reaction profiles show also the effectiveness of the histidyl-type coordinated porphyrin-Fe(III)-peroxide involved in P450 type of hydroxylation reactions. The calculations demonstrate the predominant role of the O1-O2 moiety of the porphyrin-Fe(III)-peroxide anion in the hydroxylation process of the substrates. The results indicate that the porphyrin-Fe(III)-peroxide anion is an effective catalytic species in hydroxylation reactions. In all the studied cases irrespective of the substrate and the nature of the axial ligand, the potential curves reach minimum at approximately 130-140 pm, expressing the length of an aromatic C-O bond.
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Müller A, Das SK, Kögerler P, Bögge H, Schmidtmann M, Trautwein AX, Schünemann V, Krickemeyer E, Preetz W. A New Type of Supramolecular Compound: Molybdenum-Oxide-Based Composites Consisting of Magnetic Nanocapsules with Encapsulated Keggin-Ion Electron Reservoirs Cross-Linked to a Two-Dimensional Network We thank Prof. Dr. H. U. Güdel (Bern), Dr. L. Cronin (Birmingham), and Dr. E. Diemann (Bielefeld) for helpful discussions. Angew Chem Int Ed Engl 2000; 39:3413-3417. [PMID: 11091372 DOI: 10.1002/1521-3773(20001002)39:19<3413::aid-anie3413>3.0.co;2-q] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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72
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Schünemann V, Jung C, Trautwein AX, Mandon D, Weiss R. Intermediates in the reaction of substrate-free cytochrome P450cam with peroxy acetic acid. FEBS Lett 2000; 479:149-54. [PMID: 10981725 DOI: 10.1016/s0014-5793(00)01886-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Freeze-quenched intermediates of substrate-free cytochrome 57Fe-P450(cam) in reaction with peroxy acetic acid as oxidizing agent have been characterized by EPR and Mossbauer spectroscopy. After 8 ms of reaction time the reaction mixture consists of approximately 90% of ferric low-spin iron with g-factors and hyperfine parameters of the starting material; the remaining approximately 10% are identified as a free radical (S' = 1/2) by its EPR and as an iron(IV) (S= 1) species by its Mossbauer signature. After 5 min of reaction time the intermediates have disappeared and the Mossbauer and EPR-spectra exhibit 100% of the starting material. We note that the spin-Hamiltonian analysis of the spectra of the 8 ms reactant clearly reveals that the two paramagnetic species, e.g. the ferryl (iron(IV)) species and the radical, are not exchanged coupled. This led to the conclusion that under the conditions used, peroxy acetic acid oxidized a tyrosine residue (probably Tyr-96) into a tyrosine radical (Tyr*-96), and the iron(III) center of substrate-free P450(cam) to iron(IV).
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Schünemann V, Benda R, Trautwein AX, Walker FA. Mössbauer spectroscopic studies of the six-coordinate heme-nitric oxide complex of iron(III) octaethylporphyrinN-methylimidazole, the first model of the nitrophorin-no complexes. Isr J Chem 2000. [DOI: 10.1002/ijch.5680400103] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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74
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Coropceanu V, Meier C, Trautwein AX. The instability of states with full electron (hole) delocalisation in mixed-valence Fe4S4 clusters. The role of symmetry distortions. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)00502-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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75
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Simonneaux G, Schünemann V, Morice C, Carel L, Toupet L, Winkler H, Trautwein AX, Walker FA. Structural, Magnetic, and Dynamic Characterization of the (dxz,dyz)4(dxy)1 Ground-State Low-Spin Iron(III) Tetraphenylporphyrinate Complex [(p-TTP)Fe(2,6-XylylNC)2]CF3SO3. J Am Chem Soc 2000. [DOI: 10.1021/ja994190t] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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