Disentangling electron tunneling and protein dynamics of cytochrome c through a rationally designed surface mutation
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 aris...
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2013
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15206106_v117_n20_p6061_AlvarezPaggi http://hdl.handle.net/20.500.12110/paper_15206106_v117_n20_p6061_AlvarezPaggi |
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paper:paper_15206106_v117_n20_p6061_AlvarezPaggi2023-06-08T16:19:07Z Disentangling electron tunneling and protein dynamics of cytochrome c through a rationally designed surface mutation Amino acids Dynamics Electric fields Electrodes Electron tunneling Reaction kinetics Self assembled monolayers Dynamical complexity Electron transfer Electron transfer kinetics Electronic coupling Experimental studies Positively charged Strong electric fields Varying thickness Proteins 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. 2013 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15206106_v117_n20_p6061_AlvarezPaggi http://hdl.handle.net/20.500.12110/paper_15206106_v117_n20_p6061_AlvarezPaggi |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Amino acids Dynamics Electric fields Electrodes Electron tunneling Reaction kinetics Self assembled monolayers Dynamical complexity Electron transfer Electron transfer kinetics Electronic coupling Experimental studies Positively charged Strong electric fields Varying thickness Proteins |
| spellingShingle |
Amino acids Dynamics Electric fields Electrodes Electron tunneling Reaction kinetics Self assembled monolayers Dynamical complexity Electron transfer Electron transfer kinetics Electronic coupling Experimental studies Positively charged Strong electric fields Varying thickness Proteins Disentangling electron tunneling and protein dynamics of cytochrome c through a rationally designed surface mutation |
| topic_facet |
Amino acids Dynamics Electric fields Electrodes Electron tunneling Reaction kinetics Self assembled monolayers Dynamical complexity Electron transfer Electron transfer kinetics Electronic coupling Experimental studies Positively charged Strong electric fields Varying thickness Proteins |
| description |
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. |
| title |
Disentangling electron tunneling and protein dynamics of cytochrome c through a rationally designed surface mutation |
| title_short |
Disentangling electron tunneling and protein dynamics of cytochrome c through a rationally designed surface mutation |
| title_full |
Disentangling electron tunneling and protein dynamics of cytochrome c through a rationally designed surface mutation |
| title_fullStr |
Disentangling electron tunneling and protein dynamics of cytochrome c through a rationally designed surface mutation |
| title_full_unstemmed |
Disentangling electron tunneling and protein dynamics of cytochrome c through a rationally designed surface mutation |
| title_sort |
disentangling electron tunneling and protein dynamics of cytochrome c through a rationally designed surface mutation |
| publishDate |
2013 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_15206106_v117_n20_p6061_AlvarezPaggi http://hdl.handle.net/20.500.12110/paper_15206106_v117_n20_p6061_AlvarezPaggi |
| _version_ |
1768546644764131328 |