a quinone + succinate = a quinol + fumarate Binds 1 [2Fe-2S] cluster. Binds 1 [3Fe-4S] cluster. Binds 1 [4Fe-4S] cluster. Carbohydrate metabolism; tricarboxylic acid cycle; fumarate from succinate (bacterial route): step 1/1. Part of an enzyme complex containing four subunits: a flavoprotein, an iron-sulfur, cytochrome b-556, and a hydrophobic anchor protein. Belongs to the succinate dehydrogenase/fumarate reductase iron-sulfur protein family.