1d3h
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HUMAN DIHYDROOROTATE DEHYDROGENASE COMPLEXED WITH ANTIPROLIFERATIVE AGENT A771726
OverviewOverview
BACKGROUND: Dihydroorotate dehydrogenase (DHODH) catalyzes the fourth, committed step in the de novo biosynthesis of pyrimidines. As rapidly, proliferating human T cells have an exceptional requirement for de novo, pyrimidine biosynthesis, small molecule DHODH inhibitors constitute an, attractive therapeutic approach to autoimmune diseases, immunosuppression, and cancer. Neither the structure of human DHODH nor any member of its, family was known. RESULTS: The high-resolution crystal structures of human, DHODH in complex with two different inhibitors have been solved. The, initial set of phases was obtained using multiwavelength anomalous, diffraction phasing with selenomethionine-containing DHODH. The structures, have been refined to crystallographic R factors of 16.8% and 16.2% at, resolutions of 1. 6 A and 1.8 A for inhibitors related to brequinar and, leflunomide, respectively. CONCLUSIONS: Human DHODH has two domains: an, alpha/beta-barrel domain containing the active site and an alpha-helical, domain that forms the opening of a tunnel leading to the active site. Both, inhibitors share a common binding site in this tunnel, and differences in, the binding region govern drug sensitivity or resistance. The active site, of human DHODH is generally similar to that of the previously reported, bacterial active site. The greatest differences are that the catalytic, base removing the proton from dihydroorotate is a serine rather than a, cysteine, and that packing of the flavin mononucleotide in its binding, site is tighter.
About this StructureAbout this Structure
1D3H is a Single protein structure of sequence from Homo sapiens with SO4, ACT, A26, FMN and ORO as ligands. Active as Dihydroorotate oxidase, with EC number 1.3.3.1 Full crystallographic information is available from OCA.
ReferenceReference
Structures of human dihydroorotate dehydrogenase in complex with antiproliferative agents., Liu S, Neidhardt EA, Grossman TH, Ocain T, Clardy J, Structure. 2000 Jan 15;8(1):25-33. PMID:10673429
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