6c12
From Proteopedia
SDHA-SDHE complex
Structural highlights
Function[SDHA_ECO57] Two distinct, membrane-bound, FAD-containing enzymes are responsible for the catalysis of fumarate and succinate interconversion; the fumarate reductase is used in anaerobic growth, and the succinate dehydrogenase is used in aerobic growth.[UniProtKB:P0AC41] [SDHE_ECO57] An FAD assembly protein, which accelerates covalent attachment of the cofactor into other proteins. Plays an essential role in the assembly of succinate dehydrogenase (SDH, respiratory complex II), an enzyme complex that is a component of both the tricarboxylic acid cycle and the electron transport chain, and which couples the oxidation of succinate to fumarate with the reduction of ubiquinone (coenzyme Q) to ubiquinol. Required for flavinylation (covalent attachment of FAD) of the flavoprotein subunit SdhA of SDH and other flavinylated proteins as well.[UniProtKB:G4V4G2] Publication Abstract from PubMedSuccinate:quinone oxidoreductase (SQR) functions in energy metabolism, coupling the tricarboxylic acid cycle and electron transport chain in bacteria and mitochondria. The biogenesis of flavinylated SdhA, the catalytic subunit of SQR, is assisted by a highly conserved assembly factor termed SdhE in bacteria via an unknown mechanism. By using X-ray crystallography, we have solved the structure of Escherichia coli SdhE in complex with SdhA to 2.15-A resolution. Our structure shows that SdhE makes a direct interaction with the flavin adenine dinucleotide-linked residue His45 in SdhA and maintains the capping domain of SdhA in an "open" conformation. This displaces the catalytic residues of the succinate dehydrogenase active site by as much as 9.0 A compared with SdhA in the assembled SQR complex. These data suggest that bacterial SdhE proteins, and their mitochondrial homologs, are assembly chaperones that constrain the conformation of SdhA to facilitate efficient flavinylation while regulating succinate dehydrogenase activity for productive biogenesis of SQR. Crystal structure of bacterial succinate:quinone oxidoreductase flavoprotein SdhA in complex with its assembly factor SdhE.,Maher MJ, Herath AS, Udagedara SR, Dougan DA, Truscott KN Proc Natl Acad Sci U S A. 2018 Mar 7. pii: 1800195115. doi:, 10.1073/pnas.1800195115. PMID:29514959[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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