Compound ES of cytochrome c peroxidase contains a Trp {pi}-cation radical. Characterization by CW and pulsed Q-band ENDOR spectroscopy

Journal Article · Wed Sep 06 04:00:00 EDT 1995 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja00140a021· OSTI ID:105288

Huyett, J E; Doan, P E; Gurbiel, R; Houseman, A L.P.; Sivaraja, M; Hoffman, B M ^[1]; Goodin, D B ^[2]

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1. Northwestern Univ., Evanston, IL (United States)
2. Scripps Research Inst., La Jolla, CA (United States)

The fully oxidized state of cytochrome c peroxidase (CcP), called ES, contains two oxidizing equivalents, one as an oxyferryl heme and the other as an organic radical on an amino acid residue. The unusual electron paramagnetic resonance spectrum of ES has been shown to be due to a weak distributed exchange coupling between the two paramagnetic redox centers. Various residues have been proposed as the radical site over the years. In this paper continuous wave and pulsed Q-band electron nuclear double resonance (ENDOR) spectroscopy confirms that the radical is located on Trp-191, as previously proposed. The paper completes the characterization of the active site of compound ES as being comprized of an oxyferryl heme coupled to the Trp-191 {pi}-cation radical by a weak spin exchange. 47 refs., 11 figs., 2 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 105288
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 35 Vol. 117; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
CARBON 13
CATALYSIS
CATIONS
CYTOCHROMES
ELECTRON SPECTROSCOPY
NITROGEN 14
NITROGEN 15
NUCLEAR MAGNETIC RESONANCE
NUMERICAL DATA
OXIDATION
PEROXIDASES
PULSE TECHNIQUES
RADICALS
YEASTS