4.2.1.157	Iron	the enzyme contains 5.7 nonheme iron and 6.1 acid-labile sulfur, determined by chemical analysis	
4.2.1.157	Iron	the complex of the heterodimeric dehydratase and the homodimeric activator complex contains per mol 8.5 mol Fe corresponding to the sum of 5.0 mol Fe/mol dehydratase and 3.7 mol Fe/mol activator	
4.2.1.157	Zn2+	besides varying amounts of zinc, other metal ions, particularly molybdenum, are not detected in the dehydratase	
4.2.1.157	[4Fe-4S] center	the crystal structure reveals that the heterodimeric protein contains two [4Fe-4S] clusters at a distance of 12 A, each coordinated by three cysteines and one terminal ligand. The cluster in the alpha-subunit is part of the active site. In the absence of substrate, a water/hydroxide ion acts as the fourth ligand. The substrate replaces this ligand and coordinates the cluster via the carbonyl-oxygen of the thioester group. The cluster in the beta-subunit has a terminal sulfhydryl/sulfido ligand and can act as a reservoir to protect the electron from unwanted side reactions via a recycling mechanism