1fo4

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spinqualitylabelsall models 1fo4, resolution 2.1Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF XANTHINE DEHYDROGENASE ISOLATED FROM BOVINE MILK

Overview

Mammalian xanthine oxidoreductases, which catalyze the last two steps in, the formation of urate, are synthesized as the dehydrogenase form xanthine, dehydrogenase (XDH) but can be readily converted to the oxidase form, xanthine oxidase (XO) by oxidation of sulfhydryl residues or by, proteolysis. Here, we present the crystal structure of the dimeric (M(r), 290,000) bovine milk XDH at 2.1-A resolution and XO at 2.5-A resolution, and describe the major changes that occur on the proteolytic, transformation of XDH to the XO form. Each molecule is composed of an, N-terminal 20-kDa domain containing two iron sulfur centers, a central, 40-kDa flavin adenine dinucleotide domain, and a C-terminal 85-kDa, molybdopterin-binding domain with the four redox centers aligned in an, almost linear fashion. Cleavage of surface-exposed loops of XDH causes, major structural rearrangement of another loop close to the flavin ring, (Gln 423Lys 433). This movement partially blocks access of the NAD, substrate to the flavin adenine dinucleotide cofactor and changes the, electrostatic environment of the active site, reflecting the switch of, substrate specificity observed for the two forms of this enzyme.

About this Structure

1FO4 is a Single protein structure of sequence from Bos taurus with CA, FES, MTE, MOS, SAL, FAD and GOL as ligands. Active as Xanthine dehydrogenase, with EC number 1.17.1.4 Full crystallographic information is available from OCA.

Reference

Crystal structures of bovine milk xanthine dehydrogenase and xanthine oxidase: structure-based mechanism of conversion., Enroth C, Eger BT, Okamoto K, Nishino T, Nishino T, Pai EF, Proc Natl Acad Sci U S A. 2000 Sep 26;97(20):10723-8. PMID:11005854

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