6vax | pdb_00006vax
Crystal structure of human SDHA-SDHAF2 assembly intermediate
Structural highlights
DiseaseSDHA_HUMAN Isolated succinate-CoQ reductase deficiency;Leigh syndrome with leukodystrophy;Hereditary pheochromocytoma-paraganglioma;Familial isolated dilated cardiomyopathy;Gastrointestinal stromal tumor. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. The disease is caused by variants affecting the gene represented in this entry. FunctionSDHA_HUMAN Flavoprotein (FP) subunit of succinate dehydrogenase (SDH) that is involved in complex II of the mitochondrial electron transport chain and is responsible for transferring electrons from succinate to ubiquinone (coenzyme Q) (PubMed:24781757). Can act as a tumor suppressor (PubMed:20484225).[1] [2] Publication Abstract from PubMedMitochondrial complex II, also known as succinate dehydrogenase (SDH), is an integral-membrane heterotetramer (SDHABCD) that links two essential energy-producing processes, the tricarboxylic acid (TCA) cycle and oxidative phosphorylation. A significant amount of information is available on the structure and function of mature complex II from a range of organisms. However, there is a gap in our understanding of how the enzyme assembles into a functional complex, and disease-associated complex II insufficiency may result from incorrect function of the mature enzyme or from assembly defects. Here, we investigate the assembly of human complex II by combining a biochemical reconstructionist approach with structural studies. We report an X-ray structure of human SDHA and its dedicated assembly factor SDHAF2. Importantly, we also identify a small molecule dicarboxylate that acts as an essential cofactor in this process and works in synergy with SDHAF2 to properly orient the flavin and capping domains of SDHA. This reorganizes the active site, which is located at the interface of these domains, and adjusts the pKa of SDHA(R451) so that covalent attachment of the flavin adenine dinucleotide (FAD) cofactor is supported. We analyze the impact of disease-associated SDHA mutations on assembly and identify four distinct conformational forms of the complex II flavoprotein that we assign to roles in assembly and catalysis. The roles of SDHAF2 and dicarboxylate in covalent flavinylation of SDHA, the human complex II flavoprotein.,Sharma P, Maklashina E, Cecchini G, Iverson TM Proc Natl Acad Sci U S A. 2020 Sep 22;117(38):23548-23556. doi:, 10.1073/pnas.2007391117. Epub 2020 Sep 4. PMID:32887801[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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