Dioxygen activation by nonheme iron enzymes with the 2-His-1-carboxylate facial triad that generate high-valent oxoiron oxidants

作者：Kal Subhasree; Que Lawrence^*

来源：Journal of Biological Inorganic Chemistry, 2017, 22(2-3): 339-365.

DOI：10.1007/s00775-016-1431-2

• Nonheme iron enzymes
• 2-His-1-carboxylate facial triad
• O-2 activation
• alpha-Ketoglutarate-dependent enzymes
• Halogenases
• Pterin-dependent hydroxylases
• Rieske oxygenases

The 2-His-1-carboxylate facial triad is a widely used scaffold to bind the iron center in mononuclear nonheme iron enzymes for activating dioxygen in a variety of oxidative transformations of metabolic significance. Since the 1990s, over a hundred different iron enzymes have been identified to use this platform. This structural motif consists of two histidines and the side chain carboxylate of an aspartate or a glutamate arranged in a facial array that binds iron(II) at the active site. This triad occupies one face of an iron-centered octahedron and makes the opposite face available for the coordination of O-2 and, in many cases, substrate, allowing the tailoring of the iron-dioxygen chemistry to carry out a plethora of diverse reactions. Activated dioxygen-derived species involved in the enzyme mechanisms include iron(III)-superoxo, iron(III)-peroxo, and high-valent iron(IV)-oxo intermediates. In this article, we highlight the major crystallographic, spectroscopic, and mechanistic advances of the past 20 years that have significantly enhanced our understanding of the mechanisms of O-2 activation and the key roles played by iron-based oxidants.

• 出版日期2017-4