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.
| Original language | English |
|---|---|
| Pages (from-to) | 1950-1955 |
| Number of pages | 6 |
| Journal | Inorganic Chemistry |
| Volume | 56 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - Feb 20 2017 |
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All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry
Cite this
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.
In: Inorganic Chemistry, Vol. 56, No. 4, 20.02.2017, p. 1950-1955.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Redox Potentials of Cobalt Corrinoids with Axial Ligands Correlate with Heterolytic Co-C Bond Dissociation Energies
AU - Morita, Yoshitsugu
AU - Oohora, Koji
AU - Sawada, Akiyoshi
AU - Kamachi, Takashi
AU - Yoshizawa, Kazunari
AU - Hayashi, Takashi
PY - 2017/2/20
Y1 - 2017/2/20
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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U2 - 10.1021/acs.inorgchem.6b02482
DO - 10.1021/acs.inorgchem.6b02482
M3 - Article
VL - 56
SP - 1950
EP - 1955
JO - Inorganic Chemistry
JF - Inorganic Chemistry
SN - 0020-1669
IS - 4
ER -