EC Number |
Metals/Ions |
Reference |
---|
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 |
733666 |
4.2.1.157 | Iron |
the enzyme contains 5.7 nonheme iron and 6.1 acid-labile sulfur, determined by chemical analysis |
731782 |
4.2.1.157 | Zn2+ |
besides varying amounts of zinc, other metal ions, particularly molybdenum, are not detected in the dehydratase |
731782 |
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 |
731980 |