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A Combined Far‐Infrared Spectroscopic and Electrochemical Approach for the Study of Iron–Sulfur Proteins
Author(s) -
El Khoury Youssef,
Hellwig Petra
Publication year - 2011
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201100165
Subject(s) - redox , chemistry , rubredoxin , electrochemistry , infrared , infrared spectroscopy , fourier transform infrared spectroscopy , metalloprotein , spectroscopy , oxidation state , aqueous solution , metal , sulfur , density functional theory , photochemistry , inorganic chemistry , analytical chemistry (journal) , computational chemistry , electrode , chemical engineering , organic chemistry , physics , optics , engineering , quantum mechanics
Herein, we present the development of a far‐infrared spectroscopic approach for studying metalloenzyme active sites in a redox‐dependent manner. An electrochemical cell with 5 mm path and based on silicon windows was found to be appropriate for the measurement of aqueous solutions down to 200 cm −1 . The cell was probed with the infrared redox signature of the metal–ligand vibrations of different iron–sulfur proteins. Each FeS cluster type was found to show a specific spectral signature. As a common feature, a downshift of the frequency of the FeS vibrations was seen upon reduction, in line with the increase of the FeS bond. This downshift was found to be fully reversible. Electrochemically induced FTIR difference spectroscopy in the far infrared is now possible, opening new perspectives on the understanding of metalloproteins in function of the redox state.