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

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

117 Citations (Scopus)

Abstract

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
Volume27
Issue number3
DOIs
Publication statusPublished - 1995 Jun
Externally publishedYes

Keywords

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

ASJC Scopus subject areas

  • Physiology
  • Cell Biology

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