Catalyzes the isomerization of citrate to isocitrate via cis-aconitate. Contributes to oxidative stress tolerance (PubMed:17013749). May have a role in respiration (PubMed:25061985). citrate = D-threo-isocitrate Binds 1 [4Fe-4S] cluster per subunit. Carbohydrate metabolism; tricarboxylic acid cycle; isocitrate from oxaloacetate: step 2/2. Monomer. A number of isoforms are produced. According to EST sequences. Mostly expressed in roots, stems and leaves, also present in stems and flowers. Slight level decrease after 3 days of iron starvation. Reduced cytosolic and mitochondrial aconitase (ACO) activities by 70 and 20 precent, respectively (PubMed:17013749, PubMed:17437406). Increased tolerance to oxidative stress mediated by paraquat, a superoxide-generating agent (PubMed:17013749). Slightly higher production of CO(2) (PubMed:25061985). Belongs to the aconitase/IPM isomerase family. Extended N-terminus.