Aconitase A swivel domain. This is the major form of the TCA cycle enzyme aconitate hydratase, also known as aconitase and citrate hydro-lyase. It includes bacterial and archaeal aconitase A, and the eukaryotic cytosolic form of aconitase. This group also includes sequences that have been shown to act as an iron-responsive element (IRE) binding protein in animals and may have the same role in other eukaryotes. This is the aconitase-like swivel domain, which is believed to undergo swivelling conformational change in the enzyme mechanism.