title: Crystal structure of dihydropyrimidine dehydrogenase, a major determinant of the pharmacokinetics of the anti-cancer drug 5-fluorouracil.
abstract: Dihydropyrimidine dehydrogenase catalyzes the first step in pyrimidine degradation: the NADPH-dependent reduction of uracil and thymine to the corresponding 5,6-dihydropyrimidines. Its controlled inhibition has become an adjunct target for cancer therapy, since the enzyme is also responsible for the rapid breakdown of the chemotherapeutic drug 5-fluorouracil. The crystal structure of the homodimeric pig liver enzyme (2x 111 kDa) determined at 1.9 A resolution reveals a highly modular subunit organization, consisting of five domains with different folds. Dihydropyrimidine dehydrogenase contains two FAD, two FMN and eight [4Fe-4S] clusters, arranged in two electron transfer chains that pass the dimer interface twice. Two of the Fe-S clusters show a hitherto unobserved coordination involving a glutamine residue. The ternary complex of an inactive mutant of the enzyme with bound NADPH and 5-fluorouracil reveals the architecture of the substrate-binding sites and residues responsible for recognition and binding of the drug.
authors.affiliation: Division of Molecular Structural Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: D
authors.initials: D
authors.lastname: Dobritzsch
authors.forename: G
authors.initials: G
authors.lastname: Schneider
authors.forename: K D
authors.initials: KD
authors.lastname: Schnackerz
authors.forename: Y
authors.initials: Y
authors.lastname: Lindqvist
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000493:pharmacokinetics*; D018360:Crystallography, X-Ray; D042943:Dihydrouracil Dehydrogenase (NADP); D004579:Electron Transport; D005472:Fluorouracil / Q000493:pharmacokinetics*; D008969:Molecular Sequence Data; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D017354:Point Mutation; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013552:Swine
chemical_list: D000964:Antimetabolites, Antineoplastic; D010088:Oxidoreductases; D042943:Dihydrouracil Dehydrogenase (NADP); D005472:Fluorouracil