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X-ray snapshots of quinone cofactor biogenesis in bacterial copper amine oxidase.

Research paper by Misa M Kim, Toshihide T Okajima, Seiichiro S Kishishita, Megumi M Yoshimura, Asako A Kawamori, Katsuyuki K Tanizawa, Hiroshi H Yamaguchi

Indexed on: 23 Jul '02Published on: 23 Jul '02Published in: Nature structural biology



Abstract

The quinone cofactor TPQ in copper amine oxidase is generated by posttranslational modification of an active site tyrosine residue. Using X-ray crystallography, we have probed the copper-dependent autooxidation process of TPQ in the enzyme from Arthrobacter globiformis. Apo enzyme crystals were anaerobically soaked with copper; the structure determined from this crystal provides a view of the initial state: the unmodified tyrosine coordinated to the bound copper. Exposure of the copper-bound crystals to oxygen led to the formation of freeze-trapped intermediates; structural analyses indicate that these intermediates contain dihydroxyphenylalanine quinone and trihydroxyphenylalanine. These are the first visualized intermediates during TPQ biogenesis in copper amine oxidase.