Electron transfer in ruthenium-modified proteins

Morten J. Bjerrum, Danilo R. Casimiro, I. Jy Chang, Angel J. Di Bilio, Harry B. Gray, Michael G. Hill, Ralf Langen, Gary A. Mines, Lars K. Skov, Jay R. Winkler, Deborah S. Wuttke

Research output: Contribution to journalArticlepeer-review

113 Citations (Scopus)


Photochemical techniques have been used to measure the kinetics of intramolecular electron transfer in Ru(bpy)2(im)(His)2+-modified (bpy = 2,2′-bipyridine; im = imidazole) cytochrome c and azurin. A driving-force study with the His33 derivatives of cytochrome c indicates that the reorganization energy (γ) for Fe2+→Ru3+ ET reactions is 0.8 eV. Reductions of the ferriheme by either an excited complex,*Ru2+, or a reduced complex, Ru+, are anomalously fast and may involve formation of an electronically excited ferroheme. The distance dependence of Fe2+→Ru3+ and Cu+→Ru3+ electron transfer in 12 different Ru-modified cytochromes and azurins has been analyzed using a tunneling-pathway model. The ET rates in 10 of the 12 systems exhibit an exponential dependence on metal-metal separation (decay constant of 1.06 å-1) that is consistent with predictions of the pathway model.

Original languageEnglish
Pages (from-to)295-302
Number of pages8
JournalJournal of Bioenergetics and Biomembranes
Issue number3
Publication statusPublished - 1995 Jun 1


  • Electron transfer
  • azurin
  • cytochrome c
  • driving-force dependence
  • electronic coupling
  • ruthenium

ASJC Scopus subject areas

  • Physiology
  • Cell Biology


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