Cross-link formation of the cysteine 228-tyrosine 272 catalytic cofactor of galactose oxidase does not require dioxygen.

ABSTRACT: Galactose oxidase (GO) belongs to a class of proteins that self-catalyze assembly of their redox-active cofactors from active site amino acids. Generation of enzymatically active GO appears to require at least four sequential post-translational modifications: cleavage of a secretion signal sequence, copper-dependent cleavage of an N-terminal pro sequence, copper-dependent formation of a C228-Y272 thioether bond, and generation of the Y272 radical. The last two processes were investigated using a truncated protein (termed premat-GO) lacking the pro sequence and purified under copper-free conditions. Reactions of premat-GO with Cu(II) were investigated using optical, EPR, and resonance Raman spectroscopy, SDS-PAGE, and X-ray crystallography. Premat-GO reacted anaerobically with excess Cu(II)

SUBMITTER: Rogers MS 

PROVIDER: S-EPMC2762401 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature