1FIQ

CRYSTAL STRUCTURE OF XANTHINE OXIDASE FROM BOVINE MILK

Summary for 1FIQ

• Entry DOI: 10.2210/pdb1fiq/pdb
• Related: 1FO4
• Descriptor: XANTHINE OXIDASE, FE2/S2 (INORGANIC) CLUSTER, FLAVIN-ADENINE DINUCLEOTIDE, ... (10 entities in total)
• Functional Keywords: xanthine oxidase, oxidoreductase
• Biological source: Bos taurus (cattle); More
• Cellular location: Cytoplasm : P80457 P80457 P80457
• Total number of polymer chains: 3
• Total formula weight: 148953.16

Authors

Enroth, C.,Eger, B.T.,Okamoto, K.,Nishino, T.,Nishino, T.,Pai, E.F. (deposition date: 2000-08-04, release date: 2000-10-04, Last modification date: 2024-02-07)

Primary citation

Enroth, C.,Eger, B.T.,Okamoto, K.,Nishino, T.,Nishino, T.,Pai, E.F.
Crystal structures of bovine milk xanthine dehydrogenase and xanthine oxidase: structure-based mechanism of conversion.
Proc.Natl.Acad.Sci.USA, 97:10723-10728, 2000

PubMed Abstract: 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.

PubMed: 11005854
DOI: 10.1073/pnas.97.20.10723

Experimental method

X-RAY DIFFRACTION (2.5 Å)