Redox Potentials of Cobalt Corrinoids with Axial Ligands Correlate with Heterolytic Co-C Bond Dissociation Energies

Yoshitsugu Morita, Koji Oohora, Akiyoshi Sawada, Takashi Kamachi, Kazunari Yoshizawa, Takashi Hayashi

研究成果: ジャーナルへの寄稿記事

7 引用 (Scopus)

抄録

We investigate the correlations between the redox potentials of nonalkylated cobalt corrinoids and the Co-C bond dissociation energies (BDEs) of the methylated species with an aqua or histidine axial ligand. A set of cobalt corrinoids, cobalamin, and its model systems, which include new version of myoglobin reconstituted with cobalt didehydrocorrin, are investigated. The Co(III)/Co(II) and Co(II)/Co(I) redox potentials of myoglobin reconstituted with cobalt tetradehydrocorrin and didehydrocorrin and the bare cofactors were determined. Density functional theory (DFT) calculations were performed to estimate the Co-C BDEs of the methylated species. It is found that the redox potentials correlate well with the heterolytic BDEs, which are dependent on the electronegativity of the corrinoid frameworks. The present study offers two important insights into our understanding of how enzymes promote the reactions: (i) homolysis is promoted by strong axial ligation and (ii) heterolysis is controlled by the redox potentials, which are regulated by the saturated framework and axial ligation in the enzyme.

元の言語英語
ページ(範囲)1950-1955
ページ数6
ジャーナルInorganic Chemistry
56
発行部数4
DOI
出版物ステータス出版済み - 2 20 2017

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Corrinoids
Cobalt
cobalt
dissociation
Ligands
myoglobin
ligands
Myoglobin
enzymes
Electronegativity
energy
histidine
Enzymes
Vitamin B 12
Histidine
Density functional theory
density functional theory
Oxidation-Reduction
estimates

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

これを引用

Redox Potentials of Cobalt Corrinoids with Axial Ligands Correlate with Heterolytic Co-C Bond Dissociation Energies. / Morita, Yoshitsugu; Oohora, Koji; Sawada, Akiyoshi; Kamachi, Takashi; Yoshizawa, Kazunari; Hayashi, Takashi.

:: Inorganic Chemistry, 巻 56, 番号 4, 20.02.2017, p. 1950-1955.

研究成果: ジャーナルへの寄稿記事

Morita, Yoshitsugu ; Oohora, Koji ; Sawada, Akiyoshi ; Kamachi, Takashi ; Yoshizawa, Kazunari ; Hayashi, Takashi. / Redox Potentials of Cobalt Corrinoids with Axial Ligands Correlate with Heterolytic Co-C Bond Dissociation Energies. :: Inorganic Chemistry. 2017 ; 巻 56, 番号 4. pp. 1950-1955.
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abstract = "We investigate the correlations between the redox potentials of nonalkylated cobalt corrinoids and the Co-C bond dissociation energies (BDEs) of the methylated species with an aqua or histidine axial ligand. A set of cobalt corrinoids, cobalamin, and its model systems, which include new version of myoglobin reconstituted with cobalt didehydrocorrin, are investigated. The Co(III)/Co(II) and Co(II)/Co(I) redox potentials of myoglobin reconstituted with cobalt tetradehydrocorrin and didehydrocorrin and the bare cofactors were determined. Density functional theory (DFT) calculations were performed to estimate the Co-C BDEs of the methylated species. It is found that the redox potentials correlate well with the heterolytic BDEs, which are dependent on the electronegativity of the corrinoid frameworks. The present study offers two important insights into our understanding of how enzymes promote the reactions: (i) homolysis is promoted by strong axial ligation and (ii) heterolysis is controlled by the redox potentials, which are regulated by the saturated framework and axial ligation in the enzyme.",
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AU - Sawada, Akiyoshi

AU - Kamachi, Takashi

AU - Yoshizawa, Kazunari

AU - Hayashi, Takashi

PY - 2017/2/20

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N2 - We investigate the correlations between the redox potentials of nonalkylated cobalt corrinoids and the Co-C bond dissociation energies (BDEs) of the methylated species with an aqua or histidine axial ligand. A set of cobalt corrinoids, cobalamin, and its model systems, which include new version of myoglobin reconstituted with cobalt didehydrocorrin, are investigated. The Co(III)/Co(II) and Co(II)/Co(I) redox potentials of myoglobin reconstituted with cobalt tetradehydrocorrin and didehydrocorrin and the bare cofactors were determined. Density functional theory (DFT) calculations were performed to estimate the Co-C BDEs of the methylated species. It is found that the redox potentials correlate well with the heterolytic BDEs, which are dependent on the electronegativity of the corrinoid frameworks. The present study offers two important insights into our understanding of how enzymes promote the reactions: (i) homolysis is promoted by strong axial ligation and (ii) heterolysis is controlled by the redox potentials, which are regulated by the saturated framework and axial ligation in the enzyme.

AB - We investigate the correlations between the redox potentials of nonalkylated cobalt corrinoids and the Co-C bond dissociation energies (BDEs) of the methylated species with an aqua or histidine axial ligand. A set of cobalt corrinoids, cobalamin, and its model systems, which include new version of myoglobin reconstituted with cobalt didehydrocorrin, are investigated. The Co(III)/Co(II) and Co(II)/Co(I) redox potentials of myoglobin reconstituted with cobalt tetradehydrocorrin and didehydrocorrin and the bare cofactors were determined. Density functional theory (DFT) calculations were performed to estimate the Co-C BDEs of the methylated species. It is found that the redox potentials correlate well with the heterolytic BDEs, which are dependent on the electronegativity of the corrinoid frameworks. The present study offers two important insights into our understanding of how enzymes promote the reactions: (i) homolysis is promoted by strong axial ligation and (ii) heterolysis is controlled by the redox potentials, which are regulated by the saturated framework and axial ligation in the enzyme.

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