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Lebègue E, Smida H, Flinois T, Vié V, Lagrost C, Barrière F. An optimal surface concentration of pure cardiolipin deposited onto glassy carbon electrode promoting the direct electron transfer of cytochrome-c. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2017.12.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Alvarez-Paggi D, Hannibal L, Castro MA, Oviedo-Rouco S, Demicheli V, Tórtora V, Tomasina F, Radi R, Murgida DH. Multifunctional Cytochrome c: Learning New Tricks from an Old Dog. Chem Rev 2017; 117:13382-13460. [DOI: 10.1021/acs.chemrev.7b00257] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Damián Alvarez-Paggi
- Departamento
de Química Inorgánica, Analítica y Química
Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, Buenos Aires C1428EHA, Argentina
| | - Luciana Hannibal
- Department
of Pediatrics, Universitätsklinikum Freiburg, Mathildenstrasse 1, Freiburg 79106, Germany
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - María A. Castro
- Departamento
de Química Inorgánica, Analítica y Química
Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, Buenos Aires C1428EHA, Argentina
| | - Santiago Oviedo-Rouco
- Departamento
de Química Inorgánica, Analítica y Química
Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, Buenos Aires C1428EHA, Argentina
| | - Veronica Demicheli
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - Veronica Tórtora
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - Florencia Tomasina
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - Rafael Radi
- Departamento
de Bioquímica and Center for Free Radical and Biomedical Research,
Facultad de Medicina, Universidad de la República, Av.
Gral. Flores 2125, Montevideo 11800, Uruguay
| | - Daniel H. Murgida
- Departamento
de Química Inorgánica, Analítica y Química
Física and INQUIMAE (CONICET-UBA), Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, Buenos Aires C1428EHA, Argentina
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Dolidze TD, Shushanyan M, Khoshtariya DE. Electron transfer with myoglobin in free and strongly confined regimes: disclosing diverse mechanistic role of the Fe-coordinated water by temperature- and pressure-assisted voltammetric studies. J COORD CHEM 2015. [DOI: 10.1080/00958972.2015.1068937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Tinatin D. Dolidze
- Department of Biophysics, I. Beritashvili Center for Experimental Biomedicine, Tbilisi, Georgia
- Department of Physics, Institute for Biophysics and Bionanosciences, I. Javakhishvili Tbilisi State University, Tbilisi, Georgia
- Department of Chemistry and Pharmacy, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
| | - Mikhael Shushanyan
- Department of Biophysics, I. Beritashvili Center for Experimental Biomedicine, Tbilisi, Georgia
- Department of Physics, Institute for Biophysics and Bionanosciences, I. Javakhishvili Tbilisi State University, Tbilisi, Georgia
| | - Dimitri E. Khoshtariya
- Department of Biophysics, I. Beritashvili Center for Experimental Biomedicine, Tbilisi, Georgia
- Department of Physics, Institute for Biophysics and Bionanosciences, I. Javakhishvili Tbilisi State University, Tbilisi, Georgia
- Department of Chemistry and Pharmacy, Friedrich-Alexander University of Erlangen-Nuremberg, Erlangen, Germany
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Khoshtariya DE, Dolidze TD, Shushanyan M, van Eldik R. Long-range electron transfer with myoglobin immobilized at Au/mixed-SAM junctions: mechanistic impact of the strong protein confinement. J Phys Chem B 2014; 118:692-706. [PMID: 24369906 DOI: 10.1021/jp4101569] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Horse muscle myoglobin (Mb) was tightly immobilized at Au-deposited ~15-Å-thick mixed-type (1:1) alkanethiol SAMs, HS-(CH₂)₁₁-COOH/HS-(CH₂)₁₁-OH, and placed in contact with buffered H₂O or D₂O solutions. Fast-scan cyclic voltammetry (CV) and a Marcus-equation-based analysis were applied to determine unimolecular standard rate constants and reorganization free energies for electron transfer (ET), under variable-temperature (15-55 °C) and -pressure (0.01-150 MPa) conditions. The CV signal was surprisingly stable and reproducible even after multiple temperature and pressure cycles. The data analysis revealed the following values: standard rate constant, 33 s⁻¹ (25 °C, 0.01 MPa, H₂O); reorganization free energy, 0.5 ± 0.1 eV (throughout); activation enthalpy, 12 ± 3 kJ mol⁻¹; activation volume, -3.1 ± 0.2 cm³ mol⁻¹; and pH-dependent solvent kinetic isotope effect (k(H)⁰/k(D)⁰), 0.7-1.4. Furthermore, the values for the rate constant and reorganization free energy are very similar to those previously found for cytochrome c electrostatically immobilized at the monocomponent Au/HS-(CH₂)₁₁-COOH junction. In vivo, Mb apparently forms a natural electrostatic complex with cytochrome b₅ (cyt-b₅) through the "dynamic" (loose) docking pattern, allowing for a slow ET that is intrinsically coupled to the water's removal from the "defective" heme iron (altogether shaping the biological repair mechanism for Mb's "met" form). In contrary, our experiments rather mimic the case of a "simple" (tight) docking of the redesigned (mutant) Mb with cyt-b₅ (Nocek et al. J. Am. Chem. Soc. 2010, 132, 6165-6175). According to our analysis, in this configuration, Mb's distal pocket (linked to the "ligand channel") seems to be arrested within the restricted configuration, allowing the rate-determining reversible ET process to be coupled only to the inner-sphere reorganization (minimal elongation/shortening of an Fe-OH₂ bond) rather than the pronounced detachment (rebinding) of water and, hence, to be much faster.
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Affiliation(s)
- Dimitri E Khoshtariya
- Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg , 91058 Erlangen, Germany
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5
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Khoshtariya DE, Dolidze TD, Tretyakova T, Waldeck DH, van Eldik R. Electron transfer with azurin at Au–SAM junctions in contact with a protic ionic melt: impact of glassy dynamics. Phys Chem Chem Phys 2013; 15:16515-26. [DOI: 10.1039/c3cp51896e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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6
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Shushanyan M, Khoshtariya DE, Tretyakova T, Makharadze M, van Eldik R. Diverse role of conformational dynamics in carboxypeptidase A-driven peptide and ester hydrolyses: Disclosing the “Perfect Induced Fit” and “Protein Local Unfolding” pathways by altering protein stability. Biopolymers 2011; 95:852-70. [DOI: 10.1002/bip.21688] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Accepted: 06/05/2011] [Indexed: 11/11/2022]
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7
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Waldeck DH, Khoshtariya DE. Fundamental Studies of Long- and Short-Range Electron Exchange Mechanisms between Electrodes and Proteins. MODERN ASPECTS OF ELECTROCHEMISTRY 2011. [DOI: 10.1007/978-1-4614-0347-0_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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8
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Khoshtariya DE, Dolidze TD, Shushanyan M, Davis KL, Waldeck DH, van Eldik R. Fundamental signatures of short- and long-range electron transfer for the blue copper protein azurin at Au/SAM junctions. Proc Natl Acad Sci U S A 2010; 107:2757-62. [PMID: 20133645 PMCID: PMC2840312 DOI: 10.1073/pnas.0910837107] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The blue copper protein from Pseudomonas aeruginosa, azurin, immobilized at gold electrodes through hydrophobic interaction with alkanethiol self-assembled monolayers (SAMs) of the general type [-S-(CH(2))(n)-CH(3)] (n = 4, 10, and 15) was employed to gain detailed insight into the physical mechanisms of short- and long-range biomolecular electron transfer (ET). Fast scan cyclic voltammetry and a Marcus equation analysis were used to determine unimolecular standard rate constants and reorganization free energies for variable n, temperature (2-55 degrees C), and pressure (5-150 MPa) conditions. A novel global fitting procedure was found to account for the reduced ET rate constant over almost five orders of magnitude (covering different n, temperature, and pressure) and revealed that electron exchange is a direct ET process and not conformationally gated. All the ET data, addressing SAMs with thickness variable over ca. 12 A, could be described by using a single reorganization energy (0.3 eV), however, the values for the enthalpies and volumes of activation were found to vary with n. These data and their comparison with theory show how to discriminate between the fundamental signatures of short- and long-range biomolecular ET that are theoretically anticipated for the adiabatic and nonadiabatic ET mechanisms, respectively.
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Affiliation(s)
- Dimitri E. Khoshtariya
- Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
- Institute for Biophysics and Bio-Nanosciences, Department of Physics, Tbilisi State University, 0128 Tbilisi, Georgian Republic
- Department of Molecular Biophysics, Institute of Molecular Biology and Biophysics, 0160 Tbilisi, Georgian Republic; and
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260
| | - Tina D. Dolidze
- Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
- Institute for Biophysics and Bio-Nanosciences, Department of Physics, Tbilisi State University, 0128 Tbilisi, Georgian Republic
- Department of Molecular Biophysics, Institute of Molecular Biology and Biophysics, 0160 Tbilisi, Georgian Republic; and
| | - Mikhael Shushanyan
- Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
- Institute for Biophysics and Bio-Nanosciences, Department of Physics, Tbilisi State University, 0128 Tbilisi, Georgian Republic
| | - Kathryn L. Davis
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260
| | - David H. Waldeck
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260
| | - Rudi van Eldik
- Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, 91058 Erlangen, Germany
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9
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Sarauli D, Tanne J, Xu C, Schulz B, Trnkova L, Lisdat F. Insights into the formation and operation of polyaniline sulfonate/cytochrome c multilayer electrodes: contributions of polyelectrolytes’ properties. Phys Chem Chem Phys 2010; 12:14271-7. [DOI: 10.1039/c0cp00793e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Central to theories of electron transfer (ET) is the idea that nuclear motion generates a transition state that enables electron flow to proceed, but nuclear motion also induces fluctuations in the donor-acceptor (DA) electronic coupling that is the rate-limiting parameter for nonadiabatic ET. The interplay between the DA energy gap and DA coupling fluctuations is particularly noteworthy in biological ET, where flexible protein and mobile water bridges take center stage. Here, we discuss the critical timescales at play for ET reactions in fluctuating media, highlighting issues of the Condon approximation, average medium versus fluctuation-controlled electron tunneling, gated and solvent relaxation controlled electron transfer, and the influence of inelastic tunneling on electronic coupling pathway interferences. Taken together, one may use this framework to establish principles to describe how macromolecular structure and structural fluctuations influence ET reactions. This framework deepens our understanding of ET chemistry in fluctuating media. Moreover, it provides a unifying perspective for biophysical charge-transfer processes and helps to frame new questions associated with energy harvesting and transduction in fluctuating media.
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Affiliation(s)
| | - David H. Waldeck
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260;
| | - David N. Beratan
- Departments of Chemistry and Biochemistry, Duke University, Durham, North Carolina 27708;
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11
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Dolidze TD, Khoshtariya DE, Illner P, Kulisiewicz L, Delgado A, van Eldik R. High-Pressure Testing of Heterogeneous Charge Transfer in a Room-Temperature Ionic Liquid: Evidence for Solvent Dynamic Control. J Phys Chem B 2008; 112:3085-100. [DOI: 10.1021/jp077734j] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tina D. Dolidze
- Inorganic Chemistry, Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany, Institute of Molecular Biology and Biophysics, Gotua 12, 0160 Tbilisi, Georgia, Institute of Inorganic Chemistry and Electrochemistry, Mindeli 11, 0186 Tbilisi, Georgia, and Institute of Fluid Mechanics, University of Erlangen-Nürnberg, Cauerstrasse 4, 91058 Erlangen, Germany
| | - Dimitri E. Khoshtariya
- Inorganic Chemistry, Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany, Institute of Molecular Biology and Biophysics, Gotua 12, 0160 Tbilisi, Georgia, Institute of Inorganic Chemistry and Electrochemistry, Mindeli 11, 0186 Tbilisi, Georgia, and Institute of Fluid Mechanics, University of Erlangen-Nürnberg, Cauerstrasse 4, 91058 Erlangen, Germany
| | - Peter Illner
- Inorganic Chemistry, Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany, Institute of Molecular Biology and Biophysics, Gotua 12, 0160 Tbilisi, Georgia, Institute of Inorganic Chemistry and Electrochemistry, Mindeli 11, 0186 Tbilisi, Georgia, and Institute of Fluid Mechanics, University of Erlangen-Nürnberg, Cauerstrasse 4, 91058 Erlangen, Germany
| | - Leszek Kulisiewicz
- Inorganic Chemistry, Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany, Institute of Molecular Biology and Biophysics, Gotua 12, 0160 Tbilisi, Georgia, Institute of Inorganic Chemistry and Electrochemistry, Mindeli 11, 0186 Tbilisi, Georgia, and Institute of Fluid Mechanics, University of Erlangen-Nürnberg, Cauerstrasse 4, 91058 Erlangen, Germany
| | - Antonio Delgado
- Inorganic Chemistry, Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany, Institute of Molecular Biology and Biophysics, Gotua 12, 0160 Tbilisi, Georgia, Institute of Inorganic Chemistry and Electrochemistry, Mindeli 11, 0186 Tbilisi, Georgia, and Institute of Fluid Mechanics, University of Erlangen-Nürnberg, Cauerstrasse 4, 91058 Erlangen, Germany
| | - Rudi van Eldik
- Inorganic Chemistry, Department of Chemistry and Pharmacy, University of Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany, Institute of Molecular Biology and Biophysics, Gotua 12, 0160 Tbilisi, Georgia, Institute of Inorganic Chemistry and Electrochemistry, Mindeli 11, 0186 Tbilisi, Georgia, and Institute of Fluid Mechanics, University of Erlangen-Nürnberg, Cauerstrasse 4, 91058 Erlangen, Germany
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Takahashi I, Inomata T, Funahashi Y, Ozawa T, Masuda H. Electron-Transfer Reactions through the Associated Interaction between Cytochromec and Self-Assembled Monolayers of Optically Active Cobalt(III) Complexes: Molecular Recognition Ability Induced by the Chirality of the Cobalt(III) Units. Chemistry 2007; 13:8007-17. [PMID: 17616958 DOI: 10.1002/chem.200700155] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Self-assembled monolayers (SAMs) of optically active Co(III) complexes ((S)-2/(R)-2) that contain (S)- or (R)-phenylalanine derivatives as a molecular recognition site were constructed on Au electrodes ((S)-2-Au/(R)-2-Au). Molecular recognition characteristics induced by the S and R configurations were investigated by measurements of electron-transfer reactions with horse heart cytochrome c (cyt c). The electrochemical studies indicate that the maximum current of cyt c reduction is obtained when the Au electrode is modified by 2 with a moderate coverage of approximately 4.0 x 10(-11) mol cm(-2). Since the Au electrode is not densely packed with the Co(III) units at this concentration, we conclude that the penetrative association process between cyt c and the Co(III) unit plays an important role in this electron-transfer system. The differences in the electron-transfer rates of (S)-2-Au and (R)-2-Au increase with increasing scan rates, a result indicating that the chiral ligand has an influence on the rate of association of the complexes with cyt c. 3-Au has a mixed monolayer composed of 2 and hexanethiol and exhibits electron-transfer behavior comparable to 2-Au. The difference in the association rates of (S)-3-Au and (R)-3-Au is larger than that between (S)-2-Au and (R)-2-Au, which indicates that the molecular recognition ability of 3-Au has been enhanced by filling the gap between molecules of 2 with hexanethiols. The differences in the oxidation rates of cyt c(II) between (S)-2-Au and (R)-2-Au and between (S)-3-Au and (R)-3-Au were larger than the differences in the rates of the reduction of cyt c(III); this suggests that the size of the heme crevice varies according to the oxidation state of cyt c.
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Affiliation(s)
- Isao Takahashi
- Department of Applied Chemistry, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan
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13
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Dolidze TD, Rondinini S, Vertova A, Waldeck DH, Khoshtariya DE. Impact of self-assembly composition on the alternate interfacial electron transfer for electrostatically immobilized cytochromec. Biopolymers 2007; 87:68-73. [PMID: 17549694 DOI: 10.1002/bip.20789] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We report on the effects of self-assembled monolayer (SAM) dilution and thickness on the electron transfer (ET) event for cytochrome c (CytC) electrostatically immobilized on carboxyl terminated groups. We observed biphasic kinetic behavior for a logarithmic dependence of the rate constant on the SAM carbon number (ET distance) within the series of mixed SAMs of C(5)COOH/C(2)OH, C(10)COOH/C(6)OH, and C(15)COOH/C(11)OH that is in overall similar to that found earlier for the undiluted SAM assemblies. However, in the case of C(15)COOH/C(11)OH and C(10)COOH/C(6)OH mixed SAMs a notable increase of the ET standard rate constant was observed, in comparison with the corresponding unicomponent (omega-COOH) SAMs. In the case of the C(5)COOH/C(2)OH composite SAM a decrease of the rate constant versus the unicomponent analogue was observed. The value of the reorganization free energy deduced through the Marcus-like data analysis did not change throughout the series; this fact along with the other observations indicates uncomplicated rate-determining unimolecular ET in all cases. Our results are consistent with a model that considers a changeover between the alternate, tunneling and adiabatic intrinsic ET mechanisms. The physical mechanism behind the observed fine kinetic effects in terms of the protein-rigidifying omega-COOH/CytC interactions arising in the case of mixed SAMs are also discussed.
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Affiliation(s)
- Tina D Dolidze
- Institute of Molecular Biology and Biophysics, Gotua 12, Tbilisi 0160, Georgia (Republic)
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Khoshtariya DE, Dolidze TD, Seifert S, Sarauli D, Lee G, van Eldik R. Kinetic, Thermodynamic, and Mechanistic Patterns for Free (Unbound) Cytochromec at Au/SAM Junctions: Impact of Electronic Coupling, Hydrostatic Pressure, and Stabilizing/Denaturing Additives. Chemistry 2006; 12:7041-56. [PMID: 16888736 DOI: 10.1002/chem.200600059] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Combined kinetic (electrochemical) and thermodynamic (calorimetric) investigations were performed for an unbound (intact native-like) cytochrome c (CytC) freely diffusing to and from gold electrodes modified by hydroxyl-terminated self-assembled monolayer films (SAMs), under a unique broad range of experimental conditions. Our approach included: 1) fine-tuning of the charge-transfer (CT) distance by using the extended set of Au-deposited hydroxyl-terminated alkanethiol SAMs [-S-(CH(2))(n)-OH] of variable thickness (n=2, 3, 4, 6, 11); 2) application of a high-pressure (up to 150 MPa) kinetic strategy toward the representative Au/SAM/CytC assemblies (n=3, 4, 6); 3) complementary electrochemical and microcalorimetric studies on the impact of some stabilizing and denaturing additives. We report for the first time a mechanistic changeover detected for "free" CytC by three independent kinetic methods, manifested through 1) the abrupt change in the dependence of the shape of the electron exchange standard rate constant (k(o)) versus the SAM thickness (resulting in a variation of estimated actual CT range within ca. 15 to 25 A including ca. 11 A of an "effective" heme-to-omega-hydroxyl distance). The corresponding values of the electronic coupling matrix element vary within the range from ca. 3 to 0.02 cm(-1); 2) the change in activation volume from +6.7 (n=3), to approximately 0 (n=4), and -5.5 (n=6) cm(3) mol(-1) (disclosing at n=3 a direct pressure effect on the protein's internal viscosity); 3) a "full" Kramers-type viscosity dependence for k(o) at n=2 and 3 (demonstrating control of an intraglobular friction through the external dynamic properties), and its gradual transformation to the viscosity independent (nonadiabatic) regime at n=6 and 11. Multilateral cross-testing of "free" CytC in a native-like, glucose-stabilized and urea-destabilized (molten-globule-like) states revealed novel intrinsic links between local/global structural and functional characteristics. Importantly, our results on the high-pressure and solution-viscosity effects, together with matching literature data, strongly support the concept of "dynamic slaving", which implies that fluctuations involving "small" solution components control the proteins' intrinsic dynamics and function in a highly cooperative manner as far as CT processes under adiabatic conditions are concerned.
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Affiliation(s)
- Dimitri E Khoshtariya
- Institute for Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstrasse 1, 91058 Erlangen, Germany.
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Khoshtariya DE, Dolidze TD, Sarauli D, van Eldik R. High-Pressure Probing of a Changeover in the Charge-Transfer Mechanism for Intact Cytochromec at Gold/Self-Assembled Monolayer Junctions. Angew Chem Int Ed Engl 2006; 45:277-81. [PMID: 16311995 DOI: 10.1002/anie.200502386] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Dimitri E Khoshtariya
- Institute for Inorganic Chemistry, University of Erlangen-Nürnberg, Egerlandstr. 1, 91058 Erlangen, Germany
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16
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Khoshtariya DE, Dolidze TD, Sarauli D, van Eldik R. High-Pressure Probing of a Changeover in the Charge-Transfer Mechanism for Intact Cytochromec at Gold/Self-Assembled Monolayer Junctions. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200502386] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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Dolidze TD, Khoshtariya DE, Behm M, Lindbergh G, Glaser J. Two-equivalent electrochemical reduction of a cyano-complex [TlIII(CN)2]+ and the novel di-nuclear compound [(CN)5PtII−TlIII]0. Electrochim Acta 2005. [DOI: 10.1016/j.electacta.2005.02.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Swaddle TW. Homogeneous versus Heterogeneous Self-Exchange Electron Transfer Reactions of Metal Complexes: Insights from Pressure Effects. Chem Rev 2005; 105:2573-608. [PMID: 15941222 DOI: 10.1021/cr030727g] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Thomas W Swaddle
- Department of Chemistry, University of Calgary, Alberta, Canada.
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Murgida DH, Hildebrandt P. Redox and redox-coupled processes of heme proteins and enzymes at electrochemical interfaces. Phys Chem Chem Phys 2005; 7:3773-84. [PMID: 16358026 DOI: 10.1039/b507989f] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Modern bioelectrochemical methods rely upon the immobilisation of redox proteins and enzymes on electrodes coated with biocompatible materials to prevent denaturation. However, even when protein denaturation is effectively avoided, heterogeneous protein electron transfer is often coupled to non-Faradaic processes like reorientation, conformational transitions or acid-base equilibria. Disentangling these processes requires methods capable of probing simultaneously the structure and reaction dynamics of the adsorbed species. Here we provide an overview of the recent developments in Raman and infrared surface-enhanced spectroelectrochemical techniques applied to the study of soluble and membrane bound redox heme proteins and enzymes. Possible biological implications of the findings are critically discussed.
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Affiliation(s)
- Daniel H Murgida
- Technische Universität Berlin, Institut für Chemie, Max-Volmer-Laboratorium für Biophysikalische Chemie, Sekr. PC14, Strasse des 17. Juni 135, D-10623, Berlin, Germany.
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