2prl
From Proteopedia
The structures of apo- and inhibitor bound human dihydroorotate dehydrogenase reveal conformational flexibility within the inhibitor binding site
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. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedInhibitors of dihydroorotate dehydrogenase (DHODH) have been suggested for the treatment of rheumatoid arthritis, psoriasis, autoimmune diseases, Plasmodium, and bacterial and fungal infections. Here we present the structures of N-terminally truncated (residues Met30-Arg396) DHODH in complex with two inhibitors: a brequinar analogue (6) and a novel inhibitor (a fenamic acid derivative) (7), as well as the first structure of the enzyme to be characterized without any bound inhibitor. It is shown that 7 uses the "standard" brequinar binding mode and, in addition, interacts with Tyr356, a residue conserved in most class 2 DHODH proteins. Compared to the inhibitor-free structure, some of the amino acid side chains in the tunnel in which brequinar binds and which was suggested to be the binding site of ubiquinone undergo changes in conformation upon inhibitor binding. Using our data, the loop regions of residues Leu68-Arg72 and Asn212-Leu224, which were disordered in previously studied human DHODH structures, could be built into the electron density. The first of these loops, which is located at the entrance to the inhibitor-binding pocket, shows different conformations in the three structures, suggesting that it may interfere with inhibitor/cofactor binding. The second loop has been suggested to control the access of dihydroorotate to the active site of the enzyme and may be an important player in the enzymatic reaction. These observations provide new insights into the dynamic features of the DHODH reaction and suggest new approaches to the design of inhibitors against DHODH. The structures of human dihydroorotate dehydrogenase with and without inhibitor reveal conformational flexibility in the inhibitor and substrate binding sites.,Walse B, Dufe VT, Svensson B, Fritzson I, Dahlberg L, Khairoullina A, Wellmar U, Al-Karadaghi S Biochemistry. 2008 Aug 26;47(34):8929-36. Epub 2008 Aug 2. PMID:18672895[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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