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Resonance Raman spectroscopy and enhanced photoreducibility for the 420 nm pulsed form of cytochrome oxidase
Author(s) -
Copeland Robert A.,
Chance Ali Naquit Britton,
Spiro Thomas G.
Publication year - 1985
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(85)80336-7
Subject(s) - heme a , raman spectroscopy , cytochrome c oxidase , chemistry , heme , resonance raman spectroscopy , hemeprotein , resonance (particle physics) , cytochrome , nuclear magnetic resonance , photochemistry , laser , spectroscopy , excitation , enzyme , optics , atomic physics , biochemistry , physics , quantum mechanics , electrical engineering , engineering
Resonance Raman (RR) spectra, with 413.1 nm Kr + laser excitation, are reported for cytochrome oxidase in resting, reduced, and 428 nm (oxygenated) forms, and for the first time, in the 420 nm (pulsed) forms [(1984) J. Biol. Chem. 259, 2073‐2076]. The differences between the resting, 420 nm, and 428 nm forms' RR spectra are small. All these forms contain Fe III only, as indicated by single v 4 bands at ~1371 cm −1 , and the reoxidized forms show partial conversion from high‐ to intermediate‐ or low‐spin heme a 3 (intensity shift from 1575 to 1588 cm −1 for v 2 ). The 420 nm form differs strikingly from both the 428 nm and resting forms, however, in being much more readily photoreduced by the laser illumination. This property is linked to the protein conformational change believed to be responsible for the greater accessibility to exogenous ligands of the heme a 3 in the 420 nm form.