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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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Ju TD, Ghiladi RA, Lee DH, van Strijdonck GPF, Woods AS, Cotter RJ, Young VG, Karlin KD. Dioxygen Reactivity of Fully Reduced [LFeII···CuI]+ Complexes Utilizing Tethered Tetraarylporphyrinates: Active Site Models for Heme-Copper Oxidases. Inorg Chem 1999. [DOI: 10.1021/ic9900511] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Telvin D. Ju
- Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Pharmacology and Molecular Sciences, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, and Department of Chemistry, The University of Minnesota, Minneapolis, Minnesota 55455
| | - Reza A. Ghiladi
- Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Pharmacology and Molecular Sciences, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, and Department of Chemistry, The University of Minnesota, Minneapolis, Minnesota 55455
| | - Dong-Heon Lee
- Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Pharmacology and Molecular Sciences, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, and Department of Chemistry, The University of Minnesota, Minneapolis, Minnesota 55455
| | - Gino P. F. van Strijdonck
- Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Pharmacology and Molecular Sciences, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, and Department of Chemistry, The University of Minnesota, Minneapolis, Minnesota 55455
| | - Amina S. Woods
- Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Pharmacology and Molecular Sciences, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, and Department of Chemistry, The University of Minnesota, Minneapolis, Minnesota 55455
| | - Robert J. Cotter
- Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Pharmacology and Molecular Sciences, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, and Department of Chemistry, The University of Minnesota, Minneapolis, Minnesota 55455
| | - Victor G. Young
- Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Pharmacology and Molecular Sciences, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, and Department of Chemistry, The University of Minnesota, Minneapolis, Minnesota 55455
| | - Kenneth D. Karlin
- Department of Chemistry, The Johns Hopkins University, Charles and 34th Streets, Baltimore, Maryland 21218, Department of Pharmacology and Molecular Sciences, The Johns Hopkins School of Medicine, Baltimore, Maryland 21205, and Department of Chemistry, The University of Minnesota, Minneapolis, Minnesota 55455
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