| Literature DB >> 15080677 |
Toshio Iwasaki1, Asako Kounosu, Derrick R J Kolling, Antony R Crofts, Sergei A Dikanov, Akihisa Jin, Takeo Imai, Akio Urushiyama.
Abstract
The pH-dependent resonance Raman (RR) spectral changes of the cytochrome bc1-associated, high-potential Rieske proteins have frequently been invoked to explain the redox-linked ionization behavior. We report herein RR spectral data of archaeal and bacterial Rieske proteins that directly demonstrate the pH-dependent changes near and above pKa,ox2, but not around pKa,ox1, of the visible circular dichroism (CD) transitions. The RR spectral changes are attributed to modification of the immediate [2Fe-2S] cluster environment due to deprotonation of some exchangeable amide groups in the polypeptide backbone, rather than previously assumed simple changes of the Fe-Nimid stretching vibrations.Entities:
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Year: 2004 PMID: 15080677 DOI: 10.1021/ja031976p
Source DB: PubMed Journal: J Am Chem Soc ISSN: 0002-7863 Impact factor: 15.419