Thermal Fluctuations Determine the Electron Transfer Rates of Cytochrome c in Electrostatic and Covalent Complexes.

HOANG KHOA; MARCELO A MARTI; DIEGO F MARTIN; DAMIAN ALVAREZ PAGGI; WIEBKE MEISTER; ANJA KRANICH; INEZ WEIDINGER; PETER HILDEBRANDT; DANIEL H MURGIDA

Chemphyschem

WILEY-V C H VERLAG GMBH

Año: 2010 p. 1225 - 1235

1439-4235

The heterogeneous electron transfer (ET) reaction of cytochrome c   distribution and dynamics that leads to a nearly distance-independent(Cyt-c) electrostatically or covalently immobilized on electrodes   rate constant at short distances. Qualitatively the same behavior iscoated with self-assembled monolayers (SAMs) of ω-functionalised    found for covalently bound Cyt-c although the apparent ET rates inalkanethiols was analysed by surface enhanced resonance Raman       the plateau region are lower since protein mobility is restricted due to(SERR) spectroscopy and molecular dynamics (MD) simulations.        formation of amide bonds between the protein and the SAM. TheElectrostatically bound Cyt-c on pure carboxyl-terminated and mixed experimental findings are consistent with the results of MDcarboxyl-/hydroxyl-terminated SAMs reveals the same distance-       simulations indicating that thermal fluctuations of the protein anddependence of the rate constants, i.e. electron tunneling at long   interfacial solvent molecules can effectively modulate the electrondistances and a regime controlled by the protein orientational      tunnelling probability.