Toggle Main Menu Toggle Search


Cofactor processing in galactose oxidase

Lookup NU author(s): Dr Susan Firbank, Dr Margaret Rogers


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


GO (galactose oxidase; E.C. is a monomeric 68 kDa enzyme that contains a single copper ion and an amino acid-derived cofactor. The enzyme is produced by the filamentous fungus Fusarium graminearum as an extracellular enzyme. The enzyme has been extensively studied by structural, spectroscopic, kinetic and mutational approaches that have provided insight into the catalytic mechanism of this radical enzyme. One of the most intriguing features of the enzyme is the post-translational generation of an organic cofactor from active-site amino acid residues. Biogenesis of this cofactor involves the autocatalytic formation of a thioether bond between Cys-228 and Tyr-272, the latter being one of the copper ligands. Formation of this active-site feature is closely linked to the loss of an N-terminal 17 amino acid prosequence. When copper and oxygen are added to this pro-form of GO (pro GO), purified in copper-free conditions from the heterologous host Aspergillus nidulans, mature GO is formed by an autocatalytic process. Structural comparison of pro GO with mature GO reveals overall structural similarity, but with some regions showing significant local differences in main-chain position. Some side chains of the active-site residues differ significantly from their positions in the mature enzyme. These structural effects of the prosequence suggest that it may act as an intramolecular chaperone to provide an open active-site structure conducive to copper binding and chemistry associated with cofactor formation. The prosequence is not mandatory for processing, as a recombinant form of GO lacking this region and purified under copper-free conditions can also be processed in an autocatalytic copper- and oxygen-dependent manner.

Publication metadata

Author(s): Firbank S, Rogers M, Guerrero RH, Dooley DM, Halcrow MA, Phillips SE, Knowles PF, McPherson MJ

Publication type: Article

Journal: Biochemical Society Symposia

Year: 2004

Volume: 71

Pages: 15-25

ISSN (print): 0067-8694

ISSN (electronic): 1744-1439

Publisher: Portland Press Ltd.


PubMed id: 15777009

Notes: GM 27659/GM/United States NIGMS Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S.


    Link to this publication