5zfb | pdb_00005zfb
Structure of human dihydroorotate dehydrogenase in complex with ascofuranone (open-form)
Structural highlights
Disease[PYRD_HUMAN] Defects in DHODH are the cause of postaxial acrofacial dysostosis (POADS) [MIM:263750]; also known as Miller syndrome. POADS is characterized by severe micrognathia, cleft lip and/or palate, hypoplasia or aplasia of the posterior elements of the limbs, coloboma of the eyelids and supernumerary nipples. POADS is a very rare disorder: only 2 multiplex families, each consisting of 2 affected siblings born to unaffected, nonconsanguineous parents, have been described among a total of around 30 reported cases.[1] Function[PYRD_HUMAN] Catalyzes the conversion of dihydroorotate to orotate with quinone as electron acceptor. Publication Abstract from PubMedHuman dihydroorotate dehydrogenase (HsDHODH) is a key enzyme of pyrimidine de novo biosynthesis pathway. It is located on the mitochondrial inner membrane and contributes to the respiratory chain by shuttling electrons to the ubiquinone pool. We have discovered ascofuranone (1), a natural compound produced by Acremonium sclerotigenum, and its derivatives are a potent class of HsDHODH inhibitors. We conducted a structure-activity relationship study and have identified functional groups of 1 that are essential for the inhibition of HsDHODH enzymatic activity. Furthermore, the binding mode of 1 and its derivatives to HsDHODH was demonstrated by co-crystallographic analysis and we show that these inhibitors bind at the ubiquinone binding site. In addition, the cytotoxicities of 1 and its potent derivatives 7, 8, and 9 were studied using human cultured cancer cells. Interestingly, they showed selective and strong cytotoxicity to cancer cells cultured under microenvironment (hypoxia and nutrient-deprived) conditions. The selectivity ratio of 8 under this microenvironment show the most potent inhibition which was over 1000-fold higher compared to that under normal culture condition. Our studies suggest that under microenvironment conditions, cancer cells heavily depend on the pyrimidine de novo biosynthesis pathway. We also provide the first evidence that 1 and its derivatives are potential lead candidates for drug development which target the HsDHODH of cancer cells living under a tumor microenvironment. Selective Cytotoxicity of Dihydroorotate Dehydrogenase Inhibitors to Human Cancer Cells Under Hypoxia and Nutrient-Deprived Conditions.,Miyazaki Y, Inaoka DK, Shiba T, Saimoto H, Sakura T, Amalia E, Kido Y, Sakai C, Nakamura M, Moore AL, Harada S, Kita K Front Pharmacol. 2018 Sep 4;9:997. doi: 10.3389/fphar.2018.00997. eCollection, 2018. PMID:30233375[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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