2h89
Avian Respiratory Complex II with Malonate Bound
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OverviewOverview
Mitochondrial Complex II (succinate:ubiquinone oxidoreductase) is purified, in a partially inactivated state, which can be activated by removal of, tightly bound oxaloacetate (E.B. Kearney, et al., Biochem. Biophys. Res., Commun. 49 1115-1121). We crystallized Complex II in the presence of, oxaloacetate or with the endogenous inhibitor bound. The structure showed, a ligand essentially identical to the "malate-like intermediate" found in, Shewanella Flavocytochrome c crystallized with fumarate (P. Taylor, et, al., Nat. Struct. Biol. 6 1108-1112) Crystallization of Complex II in the, presence of excess fumarate also gave the malate-like intermediate or a, mixture of that and fumarate at the active site. In order to more, conveniently monitor the occupation state of the dicarboxylate site, we, are developing a library of UV/Vis spectral effects induced by binding, different ligands to the site. Treatment with fumarate results in rapid, development of the fumarate difference spectrum and then a very slow, conversion into a species spectrally similar to the OAA-liganded complex., Complex II is known to be capable of oxidizing malate to the enol form of, oxaloacetate (Y.O. Belikova, et al., Biochim. Biophys. Acta 936 1-9). The, observations above suggest it may also be capable of interconverting, fumarate and malate. It may be useful for understanding the mechanism and, regulation of the enzyme to identify the malate-like intermediate and its, pathway of formation from oxaloacetate or fumarate.
About this StructureAbout this Structure
2H89 is a Protein complex structure of sequences from Gallus gallus with , , , , , , , , and as ligands. Active as Succinate dehydrogenase (ubiquinone), with EC number 1.3.5.1 Full crystallographic information is available from OCA.
ReferenceReference
Crystallographic studies of the binding of ligands to the dicarboxylate site of Complex II, and the identity of the ligand in the "oxaloacetate-inhibited" state., Huang LS, Shen JT, Wang AC, Berry EA, Biochim Biophys Acta. 2006 Sep-Oct;1757(9-10):1073-83. Epub 2006 Jul 12. PMID:16935256
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