Four-electron reduction of dioxygen by a multicopper oxidase, CueO, and roles of Asp112 and Glu506 located adjacent to the trinuclear copper center.

ABSTRACT: The mechanism of the four-electron reduction of dioxygen by a multicopper oxidase, CueO, was studied based on reactions of single and double mutants with Cys(500), a type I copper ligand, and the noncoordinating Asp(112) and Glu(506), which form hydrogen bonds with the trinuclear copper center directly and indirectly via a water molecule. The reaction of C500S containing a vacant type I copper center produced intermediate I in an EPR-silent peroxide-bound form. The formation of intermediate I from C500S/D112N was restricted due to a reduction in the affinity of the trinuclear copper center for dioxygen. The state of intermediate I was realized to be the resting form of C500S/E506Q and C500S of the truncated mutant Deltaalpha5-7CueO, in which the 50 amino acids covering the substrate-bindin

SUBMITTER: Kataoka K 

PROVIDER: S-EPMC2682889 | biostudies-literature | 2009 May

REPOSITORIES: biostudies-literature