Issue 40, 2011

Electron transfer dynamics of Rhodothermus marinus caa3 cytochrome c domains on biomimetic films

Abstract

The subunit II of the caa3 oxygen reductase from Rhodothermus marinus contains, in addition to the CuA center, a c-type heme group in the cytochrome c domain (Cyt-D) that is the putative primary electron acceptor of the enzyme. In this work we have combined surface-enhanced resonance Raman (SERR) spectroelectrochemistry, molecular dynamics (MD) simulations and electron pathway calculations to assess the most likely interaction domains and electron entry/exit points of the truncated Cyt-D of subunit II in the reactions with its electron donor, HiPIP and electron acceptor, CuA. The results indicate that the transient interaction between Cyt-D and HiPIP relies upon a delicate balance of hydrophobic and polar contacts for establishing an optimized electron transfer pathway that involves the exposed edge of the heme group and guaranties efficient inter-protein electron transfer on the nanosecond time scale. The reorganization energy of ca. 0.7 eV was determined by time-resolved SERR spectroelectrochemistry. The intramolecular electron transfer pathway in integral subunit II from Cyt-D to the CuA redox center most likely involves the iron ligand histidine 20 as an electron exit point in Cyt-D.

Graphical abstract: Electron transfer dynamics of Rhodothermus marinus caa3 cytochrome c domains on biomimetic films

Supplementary files

Article information

Article type
Paper
Submitted
13 Jun 2011
Accepted
26 Aug 2011
First published
15 Sep 2011

Phys. Chem. Chem. Phys., 2011,13, 18088-18098

Electron transfer dynamics of Rhodothermus marinus caa3 cytochrome c domains on biomimetic films

M. F. Molinas, A. De Candia, S. H. Szajnman, J. B. Rodríguez, M. Martí, M. Pereira, M. Teixeira, S. Todorovic and D. H. Murgida, Phys. Chem. Chem. Phys., 2011, 13, 18088 DOI: 10.1039/C1CP21925A

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