Structural snapshots from the oxidative half-reaction of a copper amine oxidase: implications for O2 activation.

ABSTRACT: The mechanism of molecular oxygen activation is the subject of controversy in the copper amine oxidase family. At their active sites, copper amine oxidases contain both a mononuclear copper ion and a protein-derived quinone cofactor. Proposals have been made for the activation of molecular oxygen via both a Cu(II)-aminoquinol catalytic intermediate and a Cu(I)-semiquinone intermediate. Using protein crystallographic freeze-trapping methods under low oxygen conditions combined with single-crystal microspectrophotometry, we have determined structures corresponding to the iminoquinone and semiquinone forms of the enzyme. Methylamine reduction at acidic or neutral pH has revealed protonated and deprotonated forms of the iminoquinone that are accompanied by a bound oxygen species that is likely

SUBMITTER: Johnson BJ 

PROVIDER: S-EPMC3784758 | biostudies-literature | 2013 Sep

REPOSITORIES: biostudies-literature