1UUO image
Entry Detail
PDB ID:
1UUO
Keywords:
Title:
Rat dihydroorotate dehydrogenase (DHOD)in complex with brequinar
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2004-01-08
Release Date:
2004-04-01
Method Details:
Experimental Method:
Resolution:
2.44 Å
R-Value Free:
0.26
R-Value Work:
0.21
R-Value Observed:
0.21
Space Group:
C 2 2 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:DIHYDROOROTATE DEHYDROGENASE
Chain IDs:A
Chain Length:372
Number of Molecules:1
Biological Source:RATTUS RATTUS
Primary Citation
Inhibitor Binding in a Class 2 Dihydroorotate Dehydrogenase Causes Variations in the Membrane-Associated N-Terminal Domain
Protein Sci. 13 1031 ? (2004)
PMID: 15044733 DOI: 10.1110/PS.03533004

Abstact

The flavin enzyme dihydroorotate dehydrogenase (DHOD; EC 1.3.99.11) catalyzes the oxidation of dihydroorotate to orotate, the fourth step in the de novo pyrimidine biosynthesis of UMP. The enzyme is a promising target for drug design in different biological and clinical applications for cancer and arthritis. The first crystal structure of the class 2 dihydroorotate dehydrogenase from rat has been determined in complex with its two inhibitors brequinar and atovaquone. These inhibitors have shown promising results as anti-proliferative, immunosuppressive, and antiparasitic agents. A unique feature of the class 2 DHODs is their N-terminal extension, which folds into a separate domain comprising two alpha-helices. This domain serves as the binding site for the two inhibitors and the respiratory quinones acting as the second substrate for the class 2 DHODs. The orientation of the first N-terminal helix is very different in the two complexes of rat DHOD (DHODR). Binding of atovaquone causes a 12 A movement of the first residue in the first alpha-helix. Based on the information from the two structures of DHODR, a model for binding of the quinone and the residues important for the interactions could be defined. His 56 and Arg 136, which are fully conserved in all class 2 DHODs, seem to play a key role in the interaction with the electron acceptor. The differences between the membrane-bound rat DHOD and membrane-associated class 2 DHODs exemplified by the Escherichia coli DHOD has been investigated by GRID computations of the hydrophobic probes predicted to interact with the membrane.

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