An FAD assembly protein, which accelerates covalent attachment of the cofactor into other proteins (Probable). 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 (By similarity). Required for flavinylation of SdhA, when the SDH operon and this gene are overexpressed in G.oxydans. Flavinylation of SdhA is detected only in the presence of sdhE. Belongs to the SdhE FAD assembly factor family.