Iron-sulfur proteins resonance Raman spectra

Indeed it may be that 3Fe clusters are always extruded as [2Fe-2S] clusters, an observation that would have structural implications. The use of resonance Raman and MCD spectroscopy814 has allowed valuable distinctions to be made between these clusters, while ESR techniques seem to be of particular value. Thus, the first indication of a 3Fe cluster in an iron-sulfur protein has usually been the observation of a g = 2.01 signal in the ESR spectrum, but it should be noted that there may be confusion with oxidized HiPIP clusters. 

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