Abstract
Quantum mechanical/molecular mechanical (QM/MM) theoretical calculations were performed for the pentacoordinate Mn(III) and water-bound resting states of the Mn-reconstituted mutant of cytochrome P450cam (Mn-P450 cam) in order to obtain insights into their characters, especially, their spin state ordering. The QM/MM study was carried out by use of the B3LYP and BLYP density functional theory (DFT) methods coupled to the CHARMM force field. Although the relative energies of possible spin states for the Mn-P450cam species varied depending on the functional, this dependence was less significant compared with previous calculations on the corresponding intermediates of wild-type P450cam. The results suggested that both Mn-P450cam intermediates have quintet ground states. Additional time-dependent DFT (TDDFT) calculations were carried out for the quintet states of these species using the B3LYP and BP86 functionals with the electrostatic environmental effect included. The TDDFT results enabled us to assign the origins of the peaks observed in optical absorption spectra (Makris et al. in J. Inorg. Biochem. 100:507-518, 2006).
Original language | English |
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Pages (from-to) | 521-530 |
Number of pages | 10 |
Journal | Journal of Biological Inorganic Chemistry |
Volume | 13 |
Issue number | 4 |
DOIs | |
State | Published - May 2008 |
Keywords
- Cytochrome P450
- Manganese porphyrin
- P450 mutant
- Quantum mechanical/molecular mechanical
- Spin states