Perspectives on Non-Heme Iron Protein Chemistry

Abstract

Publisher Summary Non-heme iron proteins contain a magnificent assortment of iron sites having a multitude of chemical and structural properties. The catalog of iron centers is like the taxonomy of insects, a seemingly limitless variation of a few structural themes, yet each new form sufficiently different to define a new species. This chapter provides an overview of the major classes with an emphasis on proteins, for which a crystal structure is available— namely, mononuclear iron proteins, binuclear octahedral iron proteins, and tetrahedral iron Fe: S proteins. The chapter reviews the types of protein iron structures are surveyed and a discussion of some methods and problems associated with establishing the iron center type. The current status and recent developments for a limited number of proteins from the major iron classes are focused. The diversity of iron center structures and functions are emphasized. A summary of the protein crystallographic structures of non-heme iron centers and ligands is tabulated. Two types of iron prosthetic groups are classified by spectroscopic methods as having nominal octahedral coordination. The hypothesis of what protein structural constraints impose a specific type of Fe: S cluster can be tested by a combination of mutagenesis, spectroscopy, and crystallography of smaller Fe: S proteins.