Succinate Dehydrogenase: Difference between revisions
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<StructureSection load='2wdv' size='500' side='right' caption='Succinate dehydrogenase complex with FAD, protoporphrin, malate, Na+ ion, Fe2S2, Fe3S4, Fe4S4, [[2wdv]] ' scene=''> | |||
[[Succinate Dehydrogenase]] (PDB = [[2wdv]] with empty ubiquinone binding site; PDB = [[1nek]] with ubiquinone bound), also called succinate-coenzyme Q reductase (SQR) or Complex II, is a tetrameric enzyme found in the cell membrane of some bacteria and the inner mitochondrial membrane of mammalian cells. It is classified as an α+β protein, as it contains <scene name='Michael_Vick_Sandbox_2/2wdv_sec_structure/1'>segregated regions</scene> of α helices and antiparallel β sheets. It is involved in two aspects of digestion; it catalyzes the oxidation of succinate to fumarate in the citric acid cycle by simultaneously reducing ubiquinone to ubiquinol in the electron transport chain <ref>PMID:14672929</ref>. | [[Succinate Dehydrogenase]] (PDB = [[2wdv]] with empty ubiquinone binding site; PDB = [[1nek]] with ubiquinone bound), also called succinate-coenzyme Q reductase (SQR) or Complex II, is a tetrameric enzyme found in the cell membrane of some bacteria and the inner mitochondrial membrane of mammalian cells. It is classified as an α+β protein, as it contains <scene name='Michael_Vick_Sandbox_2/2wdv_sec_structure/1'>segregated regions</scene> of α helices and antiparallel β sheets. It is involved in two aspects of digestion; it catalyzes the oxidation of succinate to fumarate in the citric acid cycle by simultaneously reducing ubiquinone to ubiquinol in the electron transport chain <ref>PMID:14672929</ref>. | ||
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The binding site for ubiquinone, in which the substrate is reduced to ubiquinol, is bordered by subunits B, C, and D. Residues His207 of SdhB, Ser27 and Arg31 of SdhC, and Tyr83 of SdhD stabilize ubiquinone, while residues Pro160, Trp163, Trp164, and Ile209 of SdhB and Ser27 and Ile28 of SdhC provide the necessary hydrophobic environment that stabilizes the ring <ref name="def" />. In the associated figure from PDB 1nek, the | The binding site for ubiquinone, in which the substrate is reduced to ubiquinol, is bordered by subunits B, C, and D. Residues His207 of SdhB, Ser27 and Arg31 of SdhC, and Tyr83 of SdhD stabilize ubiquinone, while residues Pro160, Trp163, Trp164, and Ile209 of SdhB and Ser27 and Ile28 of SdhC provide the necessary hydrophobic environment that stabilizes the ring <ref name="def" />. In the associated figure from PDB 1nek, the | ||
<scene name='Michael_Vick_Sandbox_2/Sec_structure_ligs_colored/2'>ligands are color-coded</scene> as follows: orange indicates the FAD cofactor, green shows the Fe-S clusters, cyan indicates ubiquinone in its binding site, yellow shows Ca2+ ions, navy blue indicates oxaloacetate, pink is cardiolipin, brown is ephrin, and the heme group is indicated by the lime green structure. The exact function of some of these ligands with regard to succinate dehydrogenase remains unclear; ephrin, for example is suspected to be involved in certain cell signaling pathways in animal development <ref>PMID:11741094</ref>. | <scene name='Michael_Vick_Sandbox_2/Sec_structure_ligs_colored/2'>ligands are color-coded</scene> as follows: orange indicates the FAD cofactor, green shows the Fe-S clusters, cyan indicates ubiquinone in its binding site, yellow shows Ca2+ ions, navy blue indicates oxaloacetate, pink is cardiolipin, brown is ephrin, and the heme group is indicated by the lime green structure. The exact function of some of these ligands with regard to succinate dehydrogenase remains unclear; ephrin, for example is suspected to be involved in certain cell signaling pathways in animal development <ref>PMID:11741094</ref>. | ||
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===Mechanisms=== | ===Mechanisms=== | ||