Disentangling electron tunneling and protein dynamics of cytochrome c through a rationally designed surface mutation

Alvarez-Paggi D, Meister W, Kuhlmann U, Weidinger IM, Tenger K, Zimanyi L, Rakhely G, Hildebrandt P, Murgida DH (2013)

Publication Type: Journal article

Publication year: 2013

Journal

Journal of Physical Chemistry B American Chemical Society

Book Volume: 117

Pages Range: 6061-6068

Journal Issue: 20

DOI: 10.1021/jp400832m

Abstract

Nonexponential distance dependence of the apparent electron-transfer (ET) rate has been reported for a variety of redox proteins immobilized on biocompatible electrodes, thus posing a physicochemical challenge of possible physiological relevance. We have recently proposed that this behavior may arise not only from the structural and dynamical complexity of the redox proteins but also from their interplay with strong electric fields present in the experimental setups and in vivo (J. Am Chem. Soc. 2010, 132, 5769-5778). Therefore, protein dynamics are finely controlled by the energetics of both specific contacts and the interaction between the protein's dipole moment and the interfacial electric fields. In turn, protein dynamics may govern electron-transfer kinetics through reorientation from low to high donor-acceptor electronic coupling orientations. Here we present a combined computational and experimental study of WT cytochrome c and the surface mutant K87C adsorbed on electrodes coated with self-assembled monolayers (SAMs) of varying thickness (i.e., variable strength of the interfacial electric field). Replacement of the positively charged K87 by a neutral amino acid allowed us to disentangle protein dynamics and electron tunneling from the reaction kinetics and to rationalize the anomalous distance dependence in terms of (at least) two populations of distinct average electronic couplings. Thus, it was possible to recover the exponential distance dependence expected from ET theory. These results pave the way for gaining further insight into the parameters that control protein electron transfer. © 2013 American Chemical Society.

Involved external institutions

Universidad de Buenos Aires (UBA) / University of Buenos Aires AR Argentina (AR) Technische Universität Berlin DE Germany (DE) Biological Research Centre (BRC) of the Hungarian Academy of Sciences / MTA Szegedi Biológiai Központ HU Hungary (HU) University of Szeged / József Attila Tudományegyetem Szeged HU Hungary (HU)

How to cite

APA:

Alvarez-Paggi, D., Meister, W., Kuhlmann, U., Weidinger, I.M., Tenger, K., Zimanyi, L.,... Murgida, D.H. (2013). Disentangling electron tunneling and protein dynamics of cytochrome c through a rationally designed surface mutation. Journal of Physical Chemistry B, 117(20), 6061-6068. https://doi.org/10.1021/jp400832m

MLA:

Alvarez-Paggi, Damian, et al. "Disentangling electron tunneling and protein dynamics of cytochrome c through a rationally designed surface mutation." Journal of Physical Chemistry B 117.20 (2013): 6061-6068.

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