1goh
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| , resolution 2.2Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | |||||||
| Activity: | Galactose oxidase, with EC number 1.1.3.9 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
NOVEL THIOETHER BOND REVEALED BY A 1.7 ANGSTROMS CRYSTAL STRUCTURE OF GALACTOSE OXIDASE
OverviewOverview
Galactose oxidase is an extracellular enzyme secreted by the fungus Dactylium dendroides. It is monomeric, with a relative molecular mass of 68,000, catalyses the stereospecific oxidation of a broad range of primary alcohol substrates and possesses a unique mononuclear copper site essential for catalysing a two-electron transfer reaction during the oxidation of primary alcohols to corresponding aldehydes. Recent evidence arguing against a Cu(III)-Cu(I) couple implies the existence of a second redox-active site proposed to involve pyrroloquinoline quinone or a tyrosine radical. We now report the crystal structure of galactose oxidase at 1.7 A resolution. This reveals a unique structural feature at the copper site with a novel thioether bond linking Cys 228 and Tyr 272 in a stacking interaction with Trp 290. We propose that these molecular components stabilize the protein free-radical species essential for catalysis and thus provide a 'built-in' secondary cofactor. This feature may represent a new mechanism for mediating electron transfer in metalloenzymes in the absence of exogenous cofactors.
About this StructureAbout this Structure
1GOH is a Single protein structure of sequence from Hypomyces rosellus. Full crystallographic information is available from OCA.
ReferenceReference
Novel thioether bond revealed by a 1.7 A crystal structure of galactose oxidase., Ito N, Phillips SE, Stevens C, Ogel ZB, McPherson MJ, Keen JN, Yadav KD, Knowles PF, Nature. 1991 Mar 7;350(6313):87-90. PMID:2002850
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