Structures of human dihydroorotate dehydrogenase in complex with antiproliferative agents
Structures of human dihydroorotate dehydrogenase in complex with antiproliferative agents
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DOI：
10.1016/s0969-2126(00)00077-0
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发表时间：
2000-01-15
期刊：
影响因子：
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通讯作者：
Clardy, J
中科院分区：
文献类型：
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作者：
Liu, SP;Neidhardt, EA;Clardy, J
背景：二氢乳清酸脱氢酶（DHODH）催化嘧啶类化合物从头生物合成的第四个关键步骤。由于快速增殖的人T细胞对从头嘧啶生物合成具有特殊的需求，因此小分子DHODH抑制剂构成了对自身免疫性疾病、免疫抑制和癌症的有吸引力的治疗方法。结果：得到了人DHODH与两种不同抑制剂复合物的高分辨晶体结构。使用含硒代蛋氨酸的DHODH的多波长异常衍射定相获得初始组相。的结构已被细化到晶体学R因子的16.8%和16.2%，在1.6埃和1.8埃的分辨率有关的抑制剂布喹那和来氟米特，foreign.Conclusions：人DHODH有两个域：一个α/β-桶域包含的活性位点和α-螺旋结构域，形成开口的隧道导致的活性site. Conclusions。两种抑制剂在该隧道中有一个共同的结合位点，而结合区域的差异决定了药物敏感性或耐药性。人DHODH的活性位点与以前报道的细菌活性位点基本相似。最大的区别是，从二氢乳清酸盐中去除质子的催化碱是丝氨酸而不是半胱氨酸，并且黄素单甘肽在其结合位点的堆积更紧密。
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 Angstrom and 1.8 Angstrom 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.