Discovery of novel iron clusters in proteins by Mössbauer spectroscopy

Iron clusters are the catalytically active groups of many proteins. The basis building blocks of these clusters are few; they are all variants of three archetypal patterns: [Fe-O-Fe], [2Fe-2S], and [4Fe-4S]. Mössbauer spectroscopy, in conjunction with EPR spectroscopy, susceptometry and EXAFS, plays an important role in characterizing type, number, oxidation states and magnetic properties of such clusters in newly discovered proteins, and in detecting how valency and magnetism vary by passing through the catalytical cycle of these proteins. In this contribution we present the characterization of a novel iron cluster with unusual bridging and terminal ligands and metal coordinations.