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 The multicopper oxidases (MCOs) are a family of enzymes that couple the four 1-electron oxidations of substrate with the four electron reduction of dioxygen utilizing a minimum of 4 copper atoms. Making up these coppers are a trinuclear cluster constructed from Type 2 (normal) and Type 3 (coupled binuclear) copper sites which perform the reductive cleavage of the O-O bond of dioxygen and a Type 1 (blue) copper site that facilitates electron transfer from the trinuclear cluster to substrate over a distance of 13 Å. The primary motivation of my research is to define the catalytic intermediates of dioxygen reduction by the MCOs. This is accomplished through spectroscopic methods including: electronic absorption, electron paramagnetic resonance (EPR), circular dichroism (CD) and magnetic circular dichrosim (MCD) and kinetic methods including stopped-flow absorption spectrophotometry and rapid freeze-quench techniques. In addition to experimental methods, density functional theory calculations also provide important insights into the electronic structure and energetic nature of pertinent catalytic intermediates. |
