Homoaconitase swivel domain. This family includes homoaconitase and other uncharacterized proteins of the Aconitase family. Homoaconitase is part of an unusual lysine biosynthesis pathway found only in filamentous fungi, in which lysine is synthesized via the alpha-aminoadipate pathway. In this pathway, homoaconitase catalyzes the conversion of cis-homoaconitic acid into homoisocitric acid. The reaction mechanism is believed to be similar to that of other aconitases. This is the swivel domain, which is believed to undergo swivelling conformational change in the enzyme mechanism.