Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2051788 | FEBS Letters | 2005 | 4 Pages |
Abstract
The structural properties of a key transient oxygen intermediate of cytochrome c oxidase, PR, remain an enigma, although inferences have been drawn from its equilibrium analogues, PCO/O2PCO/O2, PH and PM. With resonance Raman spectroscopy, an oxygen isotope-sensitive band at 806 cm−1 was observed in PCO/O2PCO/O2 produced by adding CO and O2 to the resting enzyme. The vibrational band shifted to 771 cm−1 upon isotopic substitution of 16O2 with 18O2. The same modes at 806 and 771 cm−1 were present simultaneously when the mixed isotope, 18O16O, was employed, indicating that in PCO/O2PCO/O2 the O–O bond is cleaved, resulting in a Fe4+O2− structure. This result unifies the nature of the three equilibrium analogues of the PR intermediate.
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Authors
Hong Ji, Syun-Ru Yeh, Denis L. Rousseau,