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  • The EMBO Journal (2001) 20, 650 - 660
  • doi:10.1093/emboj/20.4.650

Crystal structure of dihydropyrimidine dehydrogenase, a major determinant of the pharmacokinetics of the anti-cancer drug 5-fluorouracil

Doreen Dobritzsch1, Gunter Schneider1, Klaus D. Schnackerz2,3 and Ylva Lindqvist1

  1. Division of Molecular Structural Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
  2. Theodor-Boveri-Institut für Biowissenschaften, Physiologische Chemie I, Am Hubland, Würzburg, Germany
  3. Present adress: School of Chemistry, University of Birmingham, Birmingham, UK

Correspondence to:

Gunter Schneider, E-mail: gunter@alfa.mbb.ki.se

Ylva Lindqvist, E-mail: ylva@alfa.mbb.ki.se

Received 13 November 2000; Accepted 2 January 2001; Revised 2 January 2001

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 (2times 111 kDa) determined at 1.9 Å 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.

  • Keywords:

    • electron transfer,
    • flavin,
    • iron–sulfur clusters,
    • protein crystallography,
    • pyrimidine metabolism