6b58 | pdb_00006b58

FrdA-SdhE assembly intermediate

spinqualitylabelsall models 6b58, resolution 2.61Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6b58 is a 4 chain structure with sequence from "bacillus_coli"_migula_1895 "bacillus coli" migula 1895. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ACT, EDO, FAD, GOL, K, MLI, PEG NonStd Res: PBF Activity: Fumarate reductase (quinol), with EC number 1.3.5.4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [FRDA_ECOLI] 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. [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 PubMed Flavin is covalently attached to the protein scaffold in ~10% of flavoenzymes. However, the mechanism of covalent modification is unclear, due in part to challenges in stabilizing assembly intermediates. Here, we capture the structure of an assembly intermediate of the Escherichia coli Complex II (quinol:fumarate reductase (FrdABCD)). The structure contains the E. coli FrdA subunit bound to covalent FAD and crosslinked with its assembly factor, SdhE. The structure contains two global conformational changes as compared to prior structures of the mature protein: the rotation of a domain within the FrdA subunit, and the destabilization of two large loops of the FrdA subunit, which may create a tunnel to the active site. We infer a mechanism for covalent flavinylation. As supported by spectroscopic and kinetic analyses, we suggest that SdhE shifts the conformational equilibrium of the FrdA active site to disfavor succinate/fumarate interconversion and enhance covalent flavinylation. Crystal structure of an assembly intermediate of respiratory Complex II.,Sharma P, Maklashina E, Cecchini G, Iverson TM Nat Commun. 2018 Jan 18;9(1):274. doi: 10.1038/s41467-017-02713-8. PMID:29348404 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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