Complex kinetics of the electron transfer between the photoactive redox label TUPS and the heme of cytochrome c

Katalin Tenger, Petro Khoroshyy, Balázs Leitgeb, Gábor Rákhely, Natalia Borovok, Alexander Kotlyar, Dmitry A. Dolgikh, László Zimányi*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The photoinduced covalent redox label 8-thiouredopyrene-1,3,6-trisulfonate (TUPS) has been attached to two lysine residues (K8 and K39) at opposite sides of horse heart cytochrome c, as well as to cysteines, at the same positions, introduced by site-directed mutagenesis. Electron transfer between TUPS and the heme of cytochrome c deviates from the expected monoexponential kinetic behavior. Neither the overall rate nor the individual exponential components of electron transfer, as followed by kinetic absorption spectroscopy, correlate with the length of the covalent link connecting the dye with the protein. Molecular dynamics calculations show that TUPS can approach the protein surface and occupy several such positions. This heterogeneity may explain the multiexponential electron-transfer kinetics. The calculated optimal electron-transfer pathways do not follow the covalent link but involve through space jumps from the dye to the protein moiety, effectively decoupling the length of the covalent link and the electron-transfer rates.

Original languageEnglish
Pages (from-to)1520-1526
Number of pages7
JournalJournal of Chemical Information and Modeling
Volume45
Issue number6
DOIs
StatePublished - 2005

Fingerprint

Dive into the research topics of 'Complex kinetics of the electron transfer between the photoactive redox label TUPS and the heme of cytochrome c'. Together they form a unique fingerprint.

Cite this