1GOH

NOVEL THIOETHER BOND REVEALED BY A 1.7 ANGSTROMS CRYSTAL STRUCTURE OF GALACTOSE OXIDASE

Summary for 1GOH

• Entry DOI: 10.2210/pdb1goh/pdb
• Descriptor: GALACTOSE OXIDASE, SODIUM ION (3 entities in total)
• Functional Keywords: oxidoreductase(oxygen(a))
• Biological source: Hypomyces rosellus
• Total number of polymer chains: 1
• Total formula weight: 68601.58

Authors

Ito, N.,Phillips, S.E.V.,Knowles, P.F. (deposition date: 1993-09-30, release date: 1994-01-31, Last modification date: 2024-10-16)

Primary citation

Ito, N.,Phillips, S.E.,Stevens, C.,Ogel, Z.B.,McPherson, M.J.,Keen, J.N.,Yadav, K.D.,Knowles, P.F.
Novel thioether bond revealed by a 1.7 A crystal structure of galactose oxidase.
Nature, 350:87-90, 1991

PubMed Abstract: 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.

PubMed: 2002850
DOI: 10.1038/350087a0

Experimental method

X-RAY DIFFRACTION (2.2 Å)