Resonance raman spectroscopic evidence for structural variation among bacterial ferredoxin, HiPIP, and Fe₄S₄(SCH₂Ph)₄^2-*

Resonance Raman spectra have been obtained for C. pasteurianum ferredoxin, Chromatium HiPIP and Fe4S4(SCH2Ph)42-*, all of which contain a cubane-like Fe-S cluster. They show bands assignable to Fe-S stretching vibrations of both bridging and terminal sulfur atoms. The frequencies shift significantly among the three molecules, and an extra polarized band gives evidence of symmetry lowering in the proteins. © 1975 Academic Press, Inc.