Characterization of the pH-dependent resonance Raman transitions of archaeal and bacterial Rieske [2Fe-2S] proteins

J Am Chem Soc. 2004 Apr 21;126(15):4788-9. doi: 10.1021/ja031976p.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Archaeal Proteins / chemistry*
  • Bacterial Proteins / chemistry*
  • Electron Transport Complex III / chemistry*
  • Ferredoxins / chemistry
  • Hydrogen-Ion Concentration
  • Iron-Sulfur Proteins / chemistry*
  • Oxidation-Reduction
  • Rhodobacter sphaeroides / chemistry
  • Spectrum Analysis, Raman
  • Sulfolobus / chemistry


  • Archaeal Proteins
  • Bacterial Proteins
  • Ferredoxins
  • Iron-Sulfur Proteins
  • Rieske iron-sulfur protein
  • Electron Transport Complex III