The first long-term objective of this research is to understand the catalytic mechanism of the terminal oxidase, cytochrome c oxidase. This is to be accomplished by synthesizing and characterizing functional models of the dioxygen binding activation site in cytochrome c oxidase. Newly developed methods will be used to prepare Fe porphyrins fitted with tridentate Cu complexes on the distal face of the porphyrin and imidazole axial ligands covalently attached to the proximal face. These models will be characterized by X-ray diffraction and a range of spectroscopic methods. Each model complex will be examined as a putative electrode catalyst for the 4-electron reduction of O2. The mechanism of these electrocatalytic reactions will be explored; each stage will be examined separately; intermediates will be characterized. It is hoped that the function of these catalysts will help us understand the enzymatic reaction, especially the role of CuB. A second objective is to understand the role which distal residues play in controlling the relative equilibrium binding of three naturally occurring gaseous ligands: O2, CO, and NO. This will be accomplished by studying new cavity porphyrin sandwiches and dendrite porphyrins. The role of distal steric effects and of H-bonding will be explored. The NO binding has relevance to many medical problems related to activation by the gaseous hormone, NO. Examples include vasodilation and neurotransmission.
| Collman, James P; Ghosh, Somdatta (2010) Recent applications of a synthetic model of cytochrome c oxidase: beyond functional modeling. Inorg Chem 49:5798-810 |
| Collman, James P; Ghosh, Somdatta; Dey, Abhishek et al. (2009) Using a functional enzyme model to understand the chemistry behind hydrogen sulfide induced hibernation. Proc Natl Acad Sci U S A 106:22090-5 |
| Collman, James P; Ghosh, Somdatta; Dey, Abhishek et al. (2009) Catalytic reduction of O2 by cytochrome C using a synthetic model of cytochrome C oxidase. J Am Chem Soc 131:5034-5 |
| Collman, James P; Dey, Abhishek; Yang, Ying et al. (2009) O2 reduction by a functional heme/nonheme bis-iron NOR model complex. Proc Natl Acad Sci U S A 106:10528-33 |
| Collman, James P; Decréau, Richard A; Lin, Hengwei et al. (2009) Role of a distal pocket in the catalytic O2 reduction by cytochrome c oxidase models immobilized on interdigitated array electrodes. Proc Natl Acad Sci U S A 106:7320-3 |
| Collman, James P; Dey, Abhishek; Barile, Christopher J et al. (2009) Inhibition of electrocatalytic O(2) reduction of functional CcO models by competitive, non-competitive, and mixed inhibitors. Inorg Chem 48:10528-34 |
| Collman, James P; Decreau, Richard A; Dey, Abhishek et al. (2009) Water may inhibit oxygen binding in hemoprotein models. Proc Natl Acad Sci U S A 106:4101-5 |
| Collman, James P; Dey, Abhishek; Decreau, Richard A et al. (2008) Model studies of azide binding to functional analogues of CcO. Inorg Chem 47:2916-8 |
| Collman, James P; Decreau, Richard A (2008) Functional biomimetic models for the active site in the respiratory enzyme cytochrome c oxidase. Chem Commun (Camb) :5065-76 |
| Collman, James P; Dey, Abhishek; Decreau, Richard A et al. (2008) Interaction of nitric oxide with a functional model of cytochrome c oxidase. Proc Natl Acad Sci U S A 105:9892-6 |
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