15N HYSCORE characterization of the fully deprotonated, reduced form of the archaeal Rieske [2Fe-2S] center.
The hyperfine couplings for strongly and weakly coupled 15N nuclei around a reduced Rieske [2Fe-2S] center of uniformly 15N-labeled, hyperthermostable archaeal Rieske protein at pH 13.3 were determined by hyperfine sublevel correlation (HYSCORE) spectroscopy and compared with those at physiological pH. Significant changes in the hyperfine couplings of the terminal histidine Ndelta ligands and Nepsilon nuclei were observed between them, which can be explained by not only the redistribution of the unpaired electron spin density over the ligands but also the difference in the mixed-valence state of the fully deprotonated, reduced cluster. These quantitative data can be used in theoretical analysis for the selection of an appropriate model of the mixed-valence state of the reduced Rieske center at very alkaline pH.
Department of Biochemistry and Molecular Biology, Nippon Medical School, Sendagi, Bunkyo-ku, Tokyo 113-8602, Japan. tiwasaki@nms.ac.jp
Toshio
T
Iwasaki
Asako
A
Kounosu
Rimma I
RI
Samoilova
Sergei A
SA
Dikanov
D019843:Archaeal Proteins / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D014450:Electron Transport Complex III / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D009587:Nitrogen Isotopes / Q000737:chemistry; D011522:Protons; D016944:Sulfolobus / Q000737:chemistry; D016963:Thermus thermophilus / Q000737:chemistry
D019843:Archaeal Proteins; D007506:Iron-Sulfur Proteins; D009587:Nitrogen Isotopes; D011522:Protons; C037989:Rieske iron-sulfur protein; D014450:Electron Transport Complex III