Electronic structure and properties of model oxy and carboxy ferrous cytochrome P450: Comparison of semiempirical and ab-initio calculations
| Autor: | Gilda H. Loew, Marie-Madeleine Rohmer |
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| Rok vydání: | 2009 |
| Předmět: |
Chemistry
Ligand Electronic structure Dihedral angle Condensed Matter Physics Atomic and Molecular Physics and Optics Transition metal Ab initio quantum chemistry methods Computational chemistry Physical chemistry Physical and Theoretical Chemistry Ground state Parametrization Electric field gradient |
| Zdroj: | International Journal of Quantum Chemistry. 16:93-104 |
| ISSN: | 1097-461X 0020-7608 |
| DOI: | 10.1002/qua.560160707 |
| Popis: | Semiempirical and ab-initio LCAO-MO-SCF calculations are reported for model oxy and carboxy ferrous cytochrome P450 with a methyl mercaptide SCH3− as an axial ligand for a number of conformations of the CO ligand and S-Fe-O-O torsion angle. For the semiempirical calculations a newly developed indo method including transition metal complexes is used with both a theoretical and a spectroscopic evaluation of one- and two-electron integrals. The electronic distributions obtained using the theoretical procedure compare well with the ab-initio results. Spectroscopic parametrization gives distributions and orbital energies which include some relaxation effects. The ground state description obtained with this parameterization yields values for the electric field gradient for both the oxy and the carboxy compounds which are in excellent agreement with experiment. Thus the anomalously large electric field gradient observed for the oxy and the extremely small electric field gradient observed for the carboxy P450 are both accounted for and support the validity of the calculated electronic structure. |
| Databáze: | OpenAIRE |
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