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Potential‐dependent surface enhanced resonance Raman spectroscopy of cytochrome c 552 from Thermus thermophilus
Author(s) -
Lecomte Sophie,
Wackerbarth Hainer,
Hildebrandt Peter,
Soulimane Tewfik,
Buse Gerhard
Publication year - 1998
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/(sici)1097-4555(199808)29:8<687::aid-jrs290>3.0.co;2-l
Subject(s) - thermus thermophilus , chemistry , raman spectroscopy , electron paramagnetic resonance , electron transfer , resonance raman spectroscopy , heme , resonance (particle physics) , cytochrome c , hemeprotein , analytical chemistry (journal) , adsorption , cytochrome , photochemistry , crystallography , nuclear magnetic resonance , organic chemistry , biochemistry , physics , escherichia coli , optics , mitochondrion , gene , enzyme , particle physics
Surface‐enhanced resonance Raman (SERR) spectroscopy was employed to study the potential‐dependent processes of the electron‐transferring heme protein cytochrome c 552 (Cyt‐ c 552 ) of Thermus thermophilus adsorbed on a silver electrode. In the reduced state, the SERR spectrum of Cyt‐ c 552 is very similar to the resonance Raman (RR) spectrum of the dissolved species, ruling out substantial conformational changes due to adsorption. The adsorbed oxidized form, however, exists in different conformational states including species in a five‐coordinated high‐spin state and a six‐coordinated low‐spin state which is different from that of the dissolved species. Based on the SERR spectra measured in the potential range between 0.0 and ‐0.2 V ( vs . a saturated calomel electrode), an apparent redox potential of ‐0.097 V was obtained which is significantly more negative than the value determined in solution. This discrepancy and the non‐Nernstian behavior could be attributed to the coupling of electron‐transfer reactions and conformational transitions. These findings, which are closely related to those obtained previously for mitochondrial cytochrome c , are discussed on the basis of the specific structural properties of Cyt‐ c 552 . © 1998 John Wiley & Sons. Ltd.