1.5.5.1	crystal structure analysis	
1.5.5.1	with and without substrate ubiquinone. Molecule forms a single structural domain binding FAD, the 4Fe-4S cluster and ubiquinone in three functional regions that are closely packed and share structural elements	
1.5.5.1	X-ray structure of the (EtfAB/Bcd)4 complex in the dehydrogenase-conducting D-state, alpha-FAD (bound to domain II of EtfA) and delta-FAD (bound to butyryl-CoA dehydrogenase Bcd) being 8 A apart. A rotation of domain II of nearly 80° is observed, further rotation by 10° brings EtfAB into the bifurcating B-state, alpha-FAD and beta-FAD (bound to EtfB) being 14 A apart