1
|
Consiglio G, Gorcyński A, Petralia S, Forte G. Predicting the dye-sensitized solar cell performance of novel linear carbon chain-based dyes: insights from DFT simulations. Dalton Trans 2023; 52:15995-16004. [PMID: 37847522 DOI: 10.1039/d3dt01856c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Abstract
In this paper, we employ density functional theory (DFT) simulations to predict the energy conversion efficiency of a novel class of organic dyes based on linear carbon chain (LCC) linkers for application in dye-sensitized solar cells (DSSCs). We investigate the role of the anchoring group, which serves as a bridge connecting the linker and the surface. Specifically, we compare the performance of cyanoacrylic acid, dyes PY-4N and PY-3N, with that of phosphonate derivatives, dyes PY-4NP and PY-3NP, wherein the carboxylic group of the cyanoacrylic moiety is replaced with phosphonic acid. The observed variations in the UV/VIS absorption spectra have a slight impact on the light harvesting efficiency (LHE). Based on the empirical parameters we have taken into account, the electron injection efficiency (Φinj) and electron collection efficiency (ηcoll) values do not impact the short-circuit current density (JSC) values of all the studied dyes. The open-circuit voltage (Voc) is theoretically predicted using the improved normal model (INM) method. Among the dyes, PY-4N and PY-3N demonstrate the highest Voc values. This can be attributed to a more favorable recombination rate value, which is related to the energy gap between the HOMO level of the dyes and the conduction band minimum (CBM) of the surface. Dyes PY-4N and PY-3N are predicted to demonstrate remarkably high photoelectric conversion efficiency (PCE) values of approximately 21.79% and 16.52%, respectively, and therefore, they are expected to be potential candidates as organic dyes for applications in DSSCs. It is worth noting that PY-4NP and PY-3NP exhibit strong adsorption energy on the surface and interesting PCE values of 11.66% and 8.29%, respectively. This opens up possibilities for their application in DSSCs either as standalone sensitizers or as co-sensitizers alongside metal-free organic dyes or organic-inorganic perovskite solar cells.
Collapse
Affiliation(s)
- Giuseppe Consiglio
- Department of Chemical Sciences, University of Catania, Via S. Sofia 64, 95125, Italy
| | - Adam Gorcyński
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland
| | - Salvatore Petralia
- Department of Drug Sciences and Health, University of Catania, Via S. Sofia 64, 95125, Italy.
| | - Giuseppe Forte
- Department of Drug Sciences and Health, University of Catania, Via S. Sofia 64, 95125, Italy.
| |
Collapse
|
2
|
Di Rocco G, Ranieri A, Borsari M, Sola M, Bortolotti CA, Battistuzzi G. Assessing the Functional and Structural Stability of the Met80Ala Mutant of Cytochrome c in Dimethylsulfoxide. Molecules 2022; 27:molecules27175630. [PMID: 36080396 PMCID: PMC9458088 DOI: 10.3390/molecules27175630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 12/02/2022] Open
Abstract
The Met80Ala variant of yeast cytochrome c is known to possess electrocatalytic properties that are absent in the wild type form and that make it a promising candidate for biocatalysis and biosensing. The versatility of an enzyme is enhanced by the stability in mixed aqueous/organic solvents that would allow poorly water-soluble substrates to be targeted. In this work, we have evaluated the effect of dimethylsulfoxide (DMSO) on the functionality of the Met80Ala cytochrome c mutant, by investigating the thermodynamics and kinetics of electron transfer in mixed water/DMSO solutions up to 50% DMSO v/v. In parallel, we have monitored spectroscopically the retention of the main structural features in the same medium, focusing on both the overall protein structure and the heme center. We found that the organic solvent exerts only minor effects on the redox and structural properties of the mutant mostly as a result of the modification of the dielectric constant of the solvent. This would warrant proper functionality of this variant also under these potentially hostile experimental conditions, that differ from the physiological milieu of cytochrome c.
Collapse
Affiliation(s)
- Giulia Di Rocco
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
| | - Antonio Ranieri
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
| | - Marco Borsari
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
| | - Marco Sola
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
| | - Carlo Augusto Bortolotti
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
- Correspondence: (C.A.B.); (G.B.); Tel.: +39-0592058608 (C.A.B.); +39-059208639 (G.B.)
| | - Gianantonio Battistuzzi
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
- Correspondence: (C.A.B.); (G.B.); Tel.: +39-0592058608 (C.A.B.); +39-059208639 (G.B.)
| |
Collapse
|
3
|
Shen W, Teo RD, Beratan DN, Warren JJ. Cofactor Dynamics Couples the Protein Surface to the Heme in Cytochrome c, Facilitating Electron Transfer. J Phys Chem B 2022; 126:3522-3529. [PMID: 35507916 PMCID: PMC9867876 DOI: 10.1021/acs.jpcb.2c01632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Electron transport through biomolecules and in biological transport networks is of great importance to bioenergetics and biocatalysis. More generally, it is of crucial importance to understand how the pathways that connect buried metallocofactors to other cofactors, and to protein surfaces, affect the biological chemistry of metalloproteins. In terms of electron transfer (ET), the strongest coupling pathways usually comprise covalent and hydrogen bonded networks, with a limited number of through-space contacts. Herein, we set out to determine the relative roles of hydrogen bonds involved in ET via an established heme-to-surface tunneling pathway in cytochrome (cyt) c (i.e., heme-W59-D60-E61-N62). A series of cyt c variants were produced where a ruthenium tris(diimine) photooxidant was placed at position 62 via covalent modification of the N62C residue. Surprisingly, variants where the H-bonding residues W59 and D60 were replaced (i.e., W59F and D60A) showed no change in ET rate from the ferrous heme to Ru(III). In contrast, changing the composition of an alternative tunneling pathway (i.e., heme-M64-N63-C62) with the M64L substitution shows a factor of 2 decrease in the rate of heme-to-Ru ET. This pathway involves a through-space tunneling step between the heme and M64 residue, and such steps are usually disfavored. To rationalize why the heme-M64-N63-C62 is preferred, molecular dynamics (MD) simulations and Pathways analysis were employed. These simulations show that the change in heme-Ru ET rates is attributed to different conformations with compressed donor-acceptor distances, by ∼2 Å in pathway distance, in the M64-containing protein as compared to the M64L protein. The change in distance is correlated with changes in the electronic coupling that are in accord with the experimentally observed heme-Ru ET rates. Remarkably, the M64L variation at the core of the protein translates to changes in cofactor dynamics at the protein surface. The surface changes identified by MD simulations include dynamic anion-π and dipole-dipole interactions. These interactions influence the strength of tunneling pathways and ET rates by facilitating decreases in through-space tunneling distances in key coupling pathways.
Collapse
Affiliation(s)
- William Shen
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby CA V5A 1S6, Canada
| | - Ruijie D. Teo
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - David N. Beratan
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States., Department of Physics, Duke University, Durham, North Carolina 27708, United States., Department of Biochemistry, Duke University, Durham, North Carolina 27710, United States
| | - Jeffrey J. Warren
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby CA V5A 1S6, Canada,Corresponding Author
| |
Collapse
|
4
|
Chattopadhyay S, Mukherjee M, Kandemir B, Bowman SEJ, Bren KL, Dey A. Contributions to cytochrome c inner- and outer-sphere reorganization energy. Chem Sci 2021; 12:11894-11913. [PMID: 34659730 PMCID: PMC8442690 DOI: 10.1039/d1sc02865k] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 08/05/2021] [Indexed: 11/21/2022] Open
Abstract
Cytochromes c are small water-soluble proteins that catalyze electron transfer in metabolism and energy conversion processes. Hydrogenobacter thermophilus cytochrome c552 presents a curious case in displaying fluxionality of its heme axial methionine ligand; this behavior is altered by single point mutation of the Q64 residue to N64 or V64, which fixes the ligand in a single configuration. The reorganization energy (λ) of these cytochrome c552 variants is experimentally determined using a combination of rotating disc electrochemistry, chronoamperometry and cyclic voltammetry. The differences between the λ determined from these complementary techniques helps to deconvolute the contribution of the active site and its immediate environment to the overall λ (λTotal). The experimentally determined λ values in conjunction with DFT calculations indicate that the differences in λ among the protein variants are mainly due to the differences in contributions from the protein environment and not just inner-sphere λ. DFT calculations indicate that the position of residue 64, responsible for the orientation of the axial methionine, determines the geometric relaxation of the redox active molecular orbital (RAMO). The orientation of the RAMO with respect to the heme is key to determining electron transfer coupling (HAB) which results in higher ET rates in the wild-type protein relative to the Q64V mutant despite a 150 mV higher λTotal in the former. Efficient delocalization of the redox-active molecular orbital (RAMO) in HtWT results in an increase in HAB value which in turn accelerates the electron transfer (ET) rate in spite of the higher reorganization energy (λ) than the HtQ64V mutant.![]()
Collapse
Affiliation(s)
- Samir Chattopadhyay
- School of Chemical Sciences, Indian Association for the Cultivation of Science 2A Raja SC Mullick Road Kolkata WB 700032 India
| | - Manjistha Mukherjee
- School of Chemical Sciences, Indian Association for the Cultivation of Science 2A Raja SC Mullick Road Kolkata WB 700032 India
| | - Banu Kandemir
- Department of Chemistry, University of Rochester Rochester NY 14627-0216 USA
| | - Sarah E J Bowman
- Department of Chemistry, University of Rochester Rochester NY 14627-0216 USA
| | - Kara L Bren
- Department of Chemistry, University of Rochester Rochester NY 14627-0216 USA
| | - Abhishek Dey
- School of Chemical Sciences, Indian Association for the Cultivation of Science 2A Raja SC Mullick Road Kolkata WB 700032 India
| |
Collapse
|
5
|
Al-Qurashi O, Wazzan N. Prediction of Power Conversion Efficiencies of Diphenylthienylamine-Based Dyes Adsorbed on the Titanium Dioxide Nanotube. ACS OMEGA 2021; 6:8967-8975. [PMID: 33842767 PMCID: PMC8028126 DOI: 10.1021/acsomega.0c06340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 03/11/2021] [Indexed: 06/12/2023]
Abstract
The power conversion efficiency (η) is the most important key to determine the efficiency of dye-sensitized solar cell (DSSC) devices. However, the calculation of η theoretically is a challenging issue since it depends on a large number of experimental and theoretical parameters with extensive related data. In this work, η was successfully predicted using the improved normal model with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) for eight diphenylthienylamine-based (DP-based) dyes with various π-bridge adsorbed on titanium dioxide. The titanium dioxide is represented by a nanotube surface (TiO2NT); this surface is rarely investigated in the literature. The π-linker consists of five (DP1)- or six (DP2)-membered rings and contains none to three nitrogen atoms (D0-D3). The reliability of the estimated values was confirmed by the excellent agreement with those available for the two experimentally tested ones (DP2-D0 and DP2-D2). The deviations between the experimental and estimated values were in the ranges of 0.03 to 0.06 mA cm-2, 0.05 to 0.3 mV, and 0.37 to 0.18% for short-circuits current density (J sc), open-circuit voltage (V oc), power conversion efficiency (%η), respectively. More importantly, the results revealed that using pyridine (DP2-D1), pyrimidine (DP2-D2), and 1,2,4-triazine (DP2-D3) improves the power conversion efficiencies in the range of 6.03 to 6.90%. However, the cyclopenta-1,3-diene (DP1-D0) shows superior performance with a predicted η value that reaches 9.55%.
Collapse
Affiliation(s)
- Ohoud
S. Al-Qurashi
- Chemistry
Department, Faculty of Science, King Abdulaziz
University, P. O. Box 42805 Jeddah 21589, Saudi Arabia
- Department
of Chemistry, Faculty of Science, University
of Jeddah, Jeddah 21959, Saudi Arabia
| | - Nuha Wazzan
- Chemistry
Department, Faculty of Science, King Abdulaziz
University, P. O. Box 42805 Jeddah 21589, Saudi Arabia
| |
Collapse
|
6
|
Koronkiewicz B, Swierk J, Regan K, Mayer JM. Shallow Distance Dependence for Proton-Coupled Tyrosine Oxidation in Oligoproline Peptides. J Am Chem Soc 2020; 142:12106-12118. [PMID: 32510937 PMCID: PMC7545454 DOI: 10.1021/jacs.0c01429] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We have explored the kinetic effect of increasing electron transfer (ET) distance in a biomimetic, proton-coupled electron-transfer (PCET) system. Biological ET often occurs simultaneously with proton transfer (PT) in order to avoid the high-energy, charged intermediates resulting from the stepwise transfer of protons and electrons. These concerted proton-electron-transfer (CPET) reactions are implicated in numerous biological ET pathways. In many cases, PT is coupled to long-range ET. While many studies have shown that the rate of ET is sensitive to the distance between the electron donor and acceptor, extensions to biological CPET reactions are sparse. The possibility of a unique ET distance dependence for CPET reactions deserves further exploration, as this could have implications for how we understand biological ET. We therefore explored the ET distance dependence for the CPET oxidation of tyrosine in a model system. We prepared a series of metallopeptides with a tyrosine separated from a Ru(bpy)32+ complex by an oligoproline bridge of increasing length. Rate constants for intramolecular tyrosine oxidation were measured using the flash-quench transient absorption technique in aqueous solutions. The rate constants for tyrosine oxidation decreased by 125-fold with three added proline residues between tyrosine and the oxidant. By comparison, related intramolecular ET rate constants in very similar constructs were reported to decrease by 4-5 orders of magnitude over the same number of prolines. The observed shallow distance dependence for tyrosine oxidation is proposed to originate in part from the requirement for stronger oxidants, leading to a smaller hole-transfer effective tunneling barrier height. The shallow distance dependence observed here and extensions to distance-dependent CPET reactions have potential implications for long-range charge transfers.
Collapse
Affiliation(s)
- Brian Koronkiewicz
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - John Swierk
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - Kevin Regan
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| | - James M Mayer
- Department of Chemistry, Yale University, New Haven, Connecticut 06520-8107, United States
| |
Collapse
|
7
|
Huang J, Zarzycki J, Gunner MR, Parson WW, Kern JF, Yano J, Ducat DC, Kramer DM. Mesoscopic to Macroscopic Electron Transfer by Hopping in a Crystal Network of Cytochromes. J Am Chem Soc 2020; 142:10459-10467. [DOI: 10.1021/jacs.0c02729] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jingcheng Huang
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Jan Zarzycki
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - M. R. Gunner
- Department of Physics, City College of New York, New York, New York 10031, United States
| | - William W. Parson
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, United States
| | - Jan F. Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Daniel C. Ducat
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - David M. Kramer
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| |
Collapse
|
8
|
Marguet SC, Stevenson MJ, Shafaat HS. Intramolecular Electron Transfer Governs Photoinduced Hydrogen Evolution by Nickel-Substituted Rubredoxin: Resolving Elementary Steps in Solar Fuel Generation. J Phys Chem B 2019; 123:9792-9800. [DOI: 10.1021/acs.jpcb.9b08048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Sean C. Marguet
- The Ohio State University, 100 W. 18th Avenue, Columbus, Ohio 43210, United States
| | - Michael J. Stevenson
- The Ohio State University, 100 W. 18th Avenue, Columbus, Ohio 43210, United States
| | - Hannah S. Shafaat
- The Ohio State University, 100 W. 18th Avenue, Columbus, Ohio 43210, United States
| |
Collapse
|
9
|
Heng P, Xu J, Mao L, Wang L, Wu W, Zhang J. Rational design of D-π-A organic dyes to prevent "trade off" effect in dye-sensitized solar cells. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2019; 221:117167. [PMID: 31170604 DOI: 10.1016/j.saa.2019.117167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 05/22/2019] [Accepted: 05/26/2019] [Indexed: 06/09/2023]
Abstract
It is an easy task to simulate the spectrum properties for the organic dyes applied in dye-sensitized solar cells (DSSCs) if the suitable method is chosen. However, it is still difficult to quantitatively determine the overall performance for them. In this work, the short-circuit photocurrent density (JSC) and open circuit photovoltage (VOC) are quantitatively calculated by combination of the density functional theory and first principle for DSSCs based on four different organic dyes, 2-((4'-((4-(bis(4-methoxyphenyl)amino)phenyl)diazenyl)biphenyl-4-yl)methylene)but-3-ynoic acid (1), 2-((5-(4-((4-(bis(4-methoxyphenyl)amino)phenyl)diazenyl)phenyl)thiophen-2-yl)methylene)but-3-ynoic acid (2), 3-(7-(4-((4-(bis(4-methoxyphenyl)amino)phenyl)diazenyl)-4H-cyclopenta[2,1-b:3,4-b']-dithiophene)-2-cyanoacrylic acid (3), and 3-(7-(4-((4-(bis(4-methoxyphenyl)amino)phenyl)diazenyl)phenyl)-2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-2-cyanoacrylic acid (4), in which the triarylamine is donor and the cyanoacrylic acid is acceptor along with variable π group. The 3 and 4 are new theoretically designed organic dyes on the basis of 1 and 2 with different electron-rich group as π group. Both JSC and VOC of 3 and 4 are improved as compared with those of 1 and 2, which breaks the normal "trade-off" rule. As a result, the power conversion efficiency (PCE) of 3 and 4 is improved, especially for 3. The aggregation effect is also considered to evaluate the overall performance, which is favorable to further enhance the reliability of theoretical design.
Collapse
Affiliation(s)
- Panpan Heng
- Institute of Upconversion Nanoscale Materials, PR China; Henan Provincial Engineering Research Center of Green Anticorrosion, Technology for Magnesium Alloys, PR China; Henan Provincial Engineering Research Center of Corrosion and Protection for Magnesium Alloys, PR China; College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China
| | - Jianbin Xu
- Institute of Physics and Electronic, Henan University, Kaifeng, Henan 475004, PR China
| | - Lemin Mao
- Institute of Upconversion Nanoscale Materials, PR China; Henan Provincial Engineering Research Center of Green Anticorrosion, Technology for Magnesium Alloys, PR China; Henan Provincial Engineering Research Center of Corrosion and Protection for Magnesium Alloys, PR China; College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China
| | - Li Wang
- Institute of Upconversion Nanoscale Materials, PR China; Henan Provincial Engineering Research Center of Green Anticorrosion, Technology for Magnesium Alloys, PR China; Henan Provincial Engineering Research Center of Corrosion and Protection for Magnesium Alloys, PR China; College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China.
| | - Wenpeng Wu
- Institute of Upconversion Nanoscale Materials, PR China; Henan Provincial Engineering Research Center of Green Anticorrosion, Technology for Magnesium Alloys, PR China; Henan Provincial Engineering Research Center of Corrosion and Protection for Magnesium Alloys, PR China; College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China.
| | - Jinglai Zhang
- Institute of Upconversion Nanoscale Materials, PR China; Henan Provincial Engineering Research Center of Green Anticorrosion, Technology for Magnesium Alloys, PR China; Henan Provincial Engineering Research Center of Corrosion and Protection for Magnesium Alloys, PR China; College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China.
| |
Collapse
|
10
|
Maróti P. Thermodynamic View of Proton Activated Electron Transfer in the Reaction Center of Photosynthetic Bacteria. J Phys Chem B 2019; 123:5463-5473. [PMID: 31181159 DOI: 10.1021/acs.jpcb.9b03506] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The temperature dependence of the sequential coupling of proton transfer to the second interquinone electron transfer is studied in the reaction center proteins of photosynthetic bacteria modified by different mutations and treatment by divalent cations. The Eyring plots of kinetics were evaluated by the Marcus theory of electron and proton transfer. In mutants of electron transfer limitation (including the wild type), the observed thermodynamic parameters had to be corrected for those of the fast proton pre-equilibrium. The electron transfer is nonadiabatic with transmission coefficient 6 × 10-4, and the reorganization energy amounts to 1.2 eV. If the proton transfer is the rate limiting step, the reorganization energy and the works terms fall in the range of 200-500 meV, depending on the site of damage in the proton transfer chain. The product term is 100-150 meV larger than the reactant term. While the electron transfer mutants have a low free energy of activation (∼200 meV), the proton transfer variants show significantly elevated levels of the free energy barrier (∼500 meV). The second electron transfer in the bacterial reaction center can serve as a model system of coupled electron and proton transfer in other proteins or ion channels.
Collapse
Affiliation(s)
- Péter Maróti
- Institute of Medical Physics , University of Szeged , Rerrich Béla tér 1 , Szeged , H-6720 , Hungary
| |
Collapse
|
11
|
Liu H, Liu L, Fu Y, Liu E, Xue B. Theoretical Design of D-π-A-A Sensitizers with Narrow Band Gap and Broad Spectral Response Based on Boron Dipyrromethene for Dye-Sensitized Solar Cells. J Chem Inf Model 2019; 59:2248-2256. [PMID: 30908031 DOI: 10.1021/acs.jcim.9b00187] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Dye-sensitized solar cells based on boron dipyrromethene (BODIPY) have gained widespread attention in recent years because of their easy structural modification, strong light absorption, and photostability. In this paper, a series of dyes with single or double acceptors based on the BODIPY framework have been designed and compared by density functional theory calculation. Results show that the dyes with double acceptors exhibit smaller band gap and broader red-shift absorption peaks than their counterparts with single acceptors. To further improve the dye performance, polythiophenes and electron donating groups are successively introduced into BODIPY and donor moieties of double-acceptor dyes. The introduction of polythiophene effectively improved the light harvesting efficiency (LHE) from 0.79 to 0.96. And, the stronger electron donating groups create a narrow band gap, resulting in a broad absorption band in the range of 400-1600 nm. These modifications not only broaden the absorption range but also facilitate electron injection, thereby improving the photoelectric conversion efficiency, which is beneficial for the potential application of BODIPY sensitizers in the field of photovoltaics.
Collapse
Affiliation(s)
- Haizhen Liu
- School of Chemistry and Material Science , Shanxi Normal University , Linfen 041000 , P.R. China
| | - Liping Liu
- School of Chemistry and Material Science , Shanxi Normal University , Linfen 041000 , P.R. China
| | - Yan Fu
- School of Chemistry and Material Science , Shanxi Normal University , Linfen 041000 , P.R. China
| | - Erbao Liu
- School of Chemistry and Material Science , Shanxi Normal University , Linfen 041000 , P.R. China
| | - Bingchun Xue
- School of Chemistry and Material Science , Shanxi Normal University , Linfen 041000 , P.R. China
| |
Collapse
|
12
|
Gao Y, Lockart M, Kispert LD, Bowman MK. Photo-induced charge separation in hydroxycoumarins on TiO2 and F–TiO2. Dalton Trans 2019; 48:10881-10891. [DOI: 10.1039/c9dt01455a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Efficiency of charge separation in a dye on a semiconductor increases when the dye acts as a H-bond donor.
Collapse
Affiliation(s)
- Yunlong Gao
- College of Sciences
- Nanjing Agricultural University
- Nanjing
- China
| | - Molly Lockart
- Department of Chemistry
- BOX 870336
- University of Alabama
- Tuscaloosa
- USA
| | | | | |
Collapse
|
13
|
Fahim ZME, Bouzzine SM, Ait Aicha Y, Bouachrine M, Hamidi M. The bridged effect on the geometric, optoelectronic and charge transfer properties of the triphenylamine–bithiophene-based dyes: a DFT study. RESEARCH ON CHEMICAL INTERMEDIATES 2017. [DOI: 10.1007/s11164-017-3211-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
|
14
|
Lee DN, Bae S, Han K, Shin IS, Kim SK, Hong JI. Electrostatic Modification for Promotion of Flavin-Mediated Oxidation of a Probe for Flavin Detection. Chemistry 2017; 23:16078-16084. [PMID: 28850747 DOI: 10.1002/chem.201703466] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Indexed: 12/12/2022]
Abstract
Electrostatic effects on the redox photochemistry of synthetic probes (1, 2, and 1-Zn) are examined by adjusting the thermodynamic driving force of their oxidation reactions. The redox photochemistry was simply controlled by introducing a zinc binding site (2,2'-dipicolylamine (DPA)) on the coumarin moiety of probe 2. Zinc complexation produced a positively charged environment on the coumarin (1-Zn), which lowered the electron density of a nearby 9 H-xanthene ring, attenuating the auto-oxidation of 1-Zn by 45 % compared with that of probe 1 at 298 K. The positive net charge of 1-Zn also provided an attractive Coulombic force toward the phosphate of flavin mononucleotide and flavin adenine dinucleotide, which lowered the reduction potential of the electron acceptor (isoalloxazine) and improved intermolecular electron transfer from the 9 H-xanthene ring to isoalloxazine. The flavin-mediated oxidation rate of 1-Zn was increased to 1.5 times that of probe 2. Probe 1-Zn showed highly selective sensing behaviour toward flavins, producing an intense brightness (ϵΦF =2.80×103 m-1 cm-1 ) in the long-wavelength regions (λmax =588 nm) upon flavin-mediated oxidation. Furthermore, probes 1-Zn and 2 were successfully applied to eosinophil imaging and the differential diagnosis of eosinophilia; this demonstrates their use as diagnostic tools.
Collapse
Affiliation(s)
- Dong-Nam Lee
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Sohyeon Bae
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Kyungja Han
- Department of Laboratory Medicine, Medical College, Catholic University, Seoul, 06591, Republic of Korea
| | - Ik-Soo Shin
- Department of Chemistry, College of Natural Sciences, Soongsil University, Seoul, 06978, Republic of Korea
| | - Seong Keun Kim
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Jong-In Hong
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| |
Collapse
|
15
|
Soltau SR, Dahlberg PD, Niklas J, Poluektov OG, Mulfort KL, Utschig LM. Ru-protein-Co biohybrids designed for solar hydrogen production: understanding electron transfer pathways related to photocatalytic function. Chem Sci 2016; 7:7068-7078. [PMID: 28451142 PMCID: PMC5355951 DOI: 10.1039/c6sc03121h] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 08/05/2016] [Indexed: 12/12/2022] Open
Abstract
Two ruthenium-protein-cobaloxime biohybrids produce photocatalytic hydrogen through different catalytic pathways characterized by EPR and transient optical spectroscopies.
A series of Ru–protein–Co biohybrids have been prepared using the electron transfer proteins ferredoxin (Fd) and flavodoxin (Fld) as scaffolds for photocatalytic hydrogen production. The light-generated charge separation within these hybrids has been monitored by transient optical and electron paramagnetic resonance spectroscopies. Two distinct electron transfer pathways are observed. The Ru–Fd–Co biohybrid produces up to 650 turnovers of H2 utilizing an oxidative quenching mechanism for Ru(ii)* and a sequential electron transfer pathway via the native [2Fe–2S] cluster to generate a Ru(iii)–Fd–Co(i) charge separated state that lasts for ∼6 ms. In contrast, a direct electron transfer pathway occurs for the Ru–ApoFld–Co biohybrid, which lacks an internal electron relay, generating Ru(i)–ApoFld–Co(i) charge separated state that persists for ∼800 μs and produces 85 turnovers of H2 by a reductive quenching mechanism for Ru(ii)*. This work demonstrates the utility of protein architectures for linking donor and catalytic function via direct or sequential electron transfer pathways to enable stabilized charge separation which facilitates photocatalysis for solar fuel production.
Collapse
Affiliation(s)
- Sarah R Soltau
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , IL 60439 , USA . ; Tel: +1-630-252-3544
| | - Peter D Dahlberg
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , IL 60439 , USA . ; Tel: +1-630-252-3544.,Graduate Program in Biophysics , The University of Chicago , Chicago , IL 60637 , USA
| | - Jens Niklas
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , IL 60439 , USA . ; Tel: +1-630-252-3544
| | - Oleg G Poluektov
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , IL 60439 , USA . ; Tel: +1-630-252-3544
| | - Karen L Mulfort
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , IL 60439 , USA . ; Tel: +1-630-252-3544
| | - Lisa M Utschig
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , IL 60439 , USA . ; Tel: +1-630-252-3544
| |
Collapse
|
16
|
|
17
|
Olshansky L, Stubbe J, Nocera DG. Charge-Transfer Dynamics at the α/β Subunit Interface of a Photochemical Ribonucleotide Reductase. J Am Chem Soc 2016; 138:1196-205. [PMID: 26710997 PMCID: PMC4924928 DOI: 10.1021/jacs.5b09259] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ribonucleotide reductase (RNR) catalyzes the conversion of ribonucleotides to deoxyribonucleotides to provide the monomeric building blocks for DNA replication and repair. Nucleotide reduction occurs by way of multistep proton-coupled electron transfer (PCET) over a pathway of redox active amino acids spanning ∼35 Å and two subunits (α2 and β2). Despite the fact that PCET in RNR is rapid, slow conformational changes mask examination of the kinetics of these steps. As such, we have pioneered methodology in which site-specific incorporation of a [Re(I)] photooxidant on the surface of the β2 subunit (photoβ2) allows photochemical oxidation of the adjacent PCET pathway residue β-Y356 and time-resolved spectroscopic observation of the ensuing reactivity. A series of photoβ2s capable of performing photoinitiated substrate turnover have been prepared in which four different fluorotyrosines (FnYs) are incorporated in place of β-Y356. The FnYs are deprotonated under biological conditions, undergo oxidation by electron transfer (ET), and provide a means by which to vary the ET driving force (ΔG°) with minimal additional perturbations across the series. We have used these features to map the correlation between ΔG° and kET both with and without the fully assembled photoRNR complex. The photooxidation of FnY356 within the α/β subunit interface occurs within the Marcus inverted region with a reorganization energy of λ ≈ 1 eV. We also observe enhanced electronic coupling between donor and acceptor (HDA) in the presence of an intact PCET pathway. Additionally, we have investigated the dynamics of proton transfer (PT) by a variety of methods including dependencies on solvent isotopic composition, buffer concentration, and pH. We present evidence for the role of α2 in facilitating PT during β-Y356 photooxidation; PT occurs by way of readily exchangeable positions and within a relatively "tight" subunit interface. These findings show that RNR controls ET by lowering λ, raising HDA, and directing PT both within and between individual polypeptide subunits.
Collapse
Affiliation(s)
- Lisa Olshansky
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- Department of Chemistry and Chemical Biology, 12 Oxford St., Harvard University, Cambridge, Massachusetts 02138, United States
| | - JoAnne Stubbe
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Daniel G. Nocera
- Department of Chemistry and Chemical Biology, 12 Oxford St., Harvard University, Cambridge, Massachusetts 02138, United States
| |
Collapse
|
18
|
Dow BA, Davidson VL. Converting the bis-FeIV state of the diheme enzyme MauG to Compound I decreases the reorganization energy for electron transfer. Biochem J 2016; 473:67-72. [PMID: 26494530 PMCID: PMC4860820 DOI: 10.1042/bj20150998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 10/22/2015] [Indexed: 11/17/2022]
Abstract
The electron transfer (ET) properties of two types of high-valent hemes were studied within the same protein matrix; the bis-Fe(IV) state of MauG and the Compound I state of Y294H MauG. The latter is formed as a consequence of mutation of the tyrosine which forms the distal axial ligand of the six-coordinate heme that allows it to stabilize Fe(IV) in the absence of an external ligand. The rates of the ET reaction of each high-valent species with the type I copper protein, amicyanin, were determined at different temperatures and analysed by ET theory. The reaction with bis-Fe(IV) wild-type (WT) MauG exhibited a reorganization energy (λ) that was 0.39 eV greater than that for the reaction of Compound I Y295H MauG. It is concluded that the delocalization of charge over the two hemes in the bis-Fe(IV) state is responsible for the larger λ, relative to the Compound I state in which the Fe(V) equivalent is isolated on one heme. Although the increase in λ decreases the rate of ET, the delocalization of charge decreases the ET distance to its natural substrate protein, thus increasing the ET rate. This describes how proteins can balance different ET properties of complex redox cofactors to optimize each system for its particular ET or catalytic reaction.
Collapse
Affiliation(s)
- Brian A Dow
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, U.S.A
| | - Victor L Davidson
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, U.S.A.
| |
Collapse
|
19
|
Blumberger J. Recent Advances in the Theory and Molecular Simulation of Biological Electron Transfer Reactions. Chem Rev 2015; 115:11191-238. [DOI: 10.1021/acs.chemrev.5b00298] [Citation(s) in RCA: 238] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Jochen Blumberger
- Department of Physics and
Astronomy, University College London, Gower Street, London WC1E 6BT, U.K
| |
Collapse
|
20
|
Solid-state electron transport via cytochrome c depends on electronic coupling to electrodes and across the protein. Proc Natl Acad Sci U S A 2014; 111:5556-61. [PMID: 24706771 DOI: 10.1073/pnas.1319351111] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Electronic coupling to electrodes, Γ, as well as that across the examined molecules, H, is critical for solid-state electron transport (ETp) across proteins. Assessing the importance of each of these couplings helps to understand the mechanism of electron flow across molecules. We provide here experimental evidence for the importance of both couplings for solid-state ETp across the electron-mediating protein cytochrome c (CytC), measured in a monolayer configuration. Currents via CytC are temperature-independent between 30 and ∼130 K, consistent with tunneling by superexchange, and thermally activated at higher temperatures, ascribed to steady-state hopping. Covalent protein-electrode binding significantly increases Γ, as currents across CytC mutants, bound covalently to the electrode via a cysteine thiolate, are higher than those through electrostatically adsorbed CytC. Covalent binding also reduces the thermal activation energy, Ea, of the ETp by more than a factor of two. The importance of H was examined by using a series of seven CytC mutants with cysteine residues at different surface positions, yielding distinct electrode-protein(-heme) orientations and separation distances. We find that, in general, mutants with electrode-proximal heme have lower Ea values (from high-temperature data) and higher conductance at low temperatures (in the temperature-independent regime) than those with a distal heme. We conclude that ETp across these mutants depends on the distance between the heme group and the top or bottom electrode, rather than on the total separation distance between electrodes (protein width).
Collapse
|
21
|
Wallrapp FH, Voityuk AA, Guallar V. In-silico assessment of protein-protein electron transfer. a case study: cytochrome c peroxidase--cytochrome c. PLoS Comput Biol 2013; 9:e1002990. [PMID: 23555224 PMCID: PMC3605091 DOI: 10.1371/journal.pcbi.1002990] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 01/28/2013] [Indexed: 11/28/2022] Open
Abstract
The fast development of software and hardware is notably helping in closing the gap between macroscopic and microscopic data. Using a novel theoretical strategy combining molecular dynamics simulations, conformational clustering, ab-initio quantum mechanics and electronic coupling calculations, we show how computational methodologies are mature enough to provide accurate atomistic details into the mechanism of electron transfer (ET) processes in complex protein systems, known to be a significant challenge. We performed a quantitative study of the ET between Cytochrome c Peroxidase and its redox partner Cytochrome c. Our results confirm the ET mechanism as hole transfer (HT) through residues Ala194, Ala193, Gly192 and Trp191 of CcP. Furthermore, our findings indicate the fine evolution of the enzyme to approach an elevated turnover rate of 5.47×106 s−1 for the ET between Cytc and CcP through establishment of a localized bridge state in Trp191. We have developed a protocol capable of describing long-range electron transfer mechanisms at an atomic detailed level. We demonstrate the maturity of the computational techniques in obtaining a quantitative view of the Cytochrome c Peroxidase/Cytochrome c electron transfer process, known to be a significant challenge. In excellent agreement with experimental data, our results allow for the description of the electron transfer pathway, its mechanism and the electron transfer rate at a quantitative level. The overall protocol is free of parameterization and can be applied to any complex electron transfer process. Furthermore, the results reveal the fine enzyme evolution of this protein-protein complex to optimize its electron transfer rate by a localized bridge state.
Collapse
Affiliation(s)
- Frank H. Wallrapp
- Department of Life Sciences, Barcelona Supercomputing Center, Nexus II Building, Barcelona, Spain
| | - Alexander A. Voityuk
- Department of Computational Chemistry, University of Girona, Girona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Victor Guallar
- Department of Life Sciences, Barcelona Supercomputing Center, Nexus II Building, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
- * E-mail:
| |
Collapse
|
22
|
Ma W, Jiao Y, Meng S. Modeling charge recombination in dye-sensitized solar cells using first-principles electron dynamics: effects of structural modification. Phys Chem Chem Phys 2013; 15:17187-94. [DOI: 10.1039/c3cp52458b] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
23
|
Millett F, Havens J, Rajagukguk S, Durham B. Design and use of photoactive ruthenium complexes to study electron transfer within cytochrome bc1 and from cytochrome bc1 to cytochrome c. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1827:1309-19. [PMID: 22985600 DOI: 10.1016/j.bbabio.2012.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 08/29/2012] [Accepted: 09/03/2012] [Indexed: 10/27/2022]
Abstract
The cytochrome bc1 complex (ubiquinone:cytochrome c oxidoreductase) is the central integral membrane protein in the mitochondrial respiratory chain as well as the electron-transfer chains of many respiratory and photosynthetic prokaryotes. Based on X-ray crystallographic studies of cytochrome bc1, a mechanism has been proposed in which the extrinsic domain of the iron-sulfur protein first binds to cytochrome b where it accepts an electron from ubiquinol in the Qo site, and then rotates by 57° to a position close to cytochrome c1 where it transfers an electron to cytochrome c1. This review describes the development of a ruthenium photooxidation technique to measure key electron transfer steps in cytochrome bc1, including rapid electron transfer from the iron-sulfur protein to cytochrome c1. It was discovered that this reaction is rate-limited by the rotational dynamics of the iron-sulfur protein rather than true electron transfer. A conformational linkage between the occupant of the Qo ubiquinol binding site and the rotational dynamics of the iron-sulfur protein was discovered which could play a role in the bifurcated oxidation of ubiquinol. A ruthenium photoexcitation method is also described for the measurement of electron transfer from cytochrome c1 to cytochrome c. This article is part of a Special Issue entitled: Respiratory Complex III and related bc complexes.
Collapse
Key Words
- 2,2′-bipyrazine
- 2,2′-bipyridine
- 2,2′:4′,4″:2″,2‴-quaterpyridine
- 2Fe2S
- 3,3′-bipyridazine
- 4,4′-dimethyl-2,2′-bipridine
- Cc
- CcO
- Cytochrome bc(1)
- Cytochrome c
- Electron transfer
- ISP
- JG144
- MOAS
- P(f)
- P(m)
- Q
- Q(i)
- Q(o)
- Q(o) site inhibitor which fixes ISP in b state
- Q(o) site inhibitor which promotes mobile state of ISP
- QH(2)
- R. sphaeroides
- Rhodobacter sphaeroides
- Rieske iron–sulfur center
- Ru(2)D
- Ruthenium
- S-3-anilino-5-methyl-5-(4,6-difluorophenyl)-1,3-oxazolidine-2,4-dione
- [Ru(bpy)(2)](2)qpy(4+)
- bpd
- bpy
- bpz
- cyt bc(1)
- cytochrome bc(1)
- cytochrome c
- cytochrome c oxidase
- dmb
- inside ubiquinone binding site
- iron–sulfur protein
- methoxyacrylate stilbene
- outside ubiquinol binding site
- qpy
- ubiquinol
- ubiquionone
- yCc
- yeast Cc
Collapse
Affiliation(s)
- Francis Millett
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA.
| | | | | | | |
Collapse
|
24
|
Nazmutdinov RR, Bronshtein MD, Zinkicheva TT, Chi Q, Zhang J, Ulstrup J. Modeling and computations of the intramolecular electron transfer process in the two-heme protein cytochrome c(4). Phys Chem Chem Phys 2012; 14:5953-65. [PMID: 22430606 DOI: 10.1039/c2cp24084j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The di-heme protein Pseudomonas stutzeri cytochrome c(4) (cyt c(4)) has emerged as a useful model for studying long-range protein electron transfer (ET). Recent experimental observations have shown a dramatically different pattern of intramolecular ET between the two heme groups in different local environments. Intramolecular ET in homogeneous solution is too slow (>10 s) to be detected but fast (ms-μs) intramolecular ET in an electrochemical environment has recently been achieved by controlling the molecular orientation of the protein assembled on a gold electrode surface. In this work we have performed computational modeling of the intramolecular ET process by a combination of density functional theory (DFT) and quantum mechanical charge transfer theory to disclose reasons for this difference. We first address the electronic structures of the model heme core with histidine and methionine axial ligands in both low- and high-spin states by structure-optimized DFT. The computations enable estimating the intramolecular reorganization energy of the ET process for different combinations of low- and high-spin heme couples. Environmental reorganization free energies, work terms ("gating") and driving force were determined using dielectric continuum models. We then calculated the electronic transmission coefficient of the intramolecular ET rate using perturbation theory combined with the electronic wave functions determined by the DFT calculations for different heme group orientations and Fe-Fe separations. The reactivity of low- and high-spin heme groups was notably different. The ET rate is exceedingly low for the crystallographic equilibrium orientation but increases by several orders of magnitude for thermally accessible non-equilibrium configurations. Deprotonation of the propionate carboxyl group was also found to enhance the ET rate significantly. The results are discussed in relation to the observed surface immobilization effect and support the notion of conformationally gated ET.
Collapse
Affiliation(s)
- Renat R Nazmutdinov
- Kazan National Research Technological University, 420015 Kazan, Republic Tatarstan, Russian Federation
| | | | | | | | | | | |
Collapse
|
25
|
Conductivity by Electron Pairs. Chem Phys 2012. [DOI: 10.1201/b11524-20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
26
|
Krishtalik LI. The medium reorganization energy for the charge transfer reactions in proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:1444-56. [DOI: 10.1016/j.bbabio.2011.07.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2011] [Revised: 06/30/2011] [Accepted: 07/04/2011] [Indexed: 10/18/2022]
|
27
|
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]
|
28
|
Tipmanee V, Oberhofer H, Park M, Kim KS, Blumberger J. Prediction of Reorganization Free Energies for Biological Electron Transfer: A Comparative Study of Ru-Modified Cytochromes and a 4-Helix Bundle Protein. J Am Chem Soc 2010; 132:17032-40. [DOI: 10.1021/ja107876p] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Varomyalin Tipmanee
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom, Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom, and Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology (POSTECH), San 31, Hyojadong, Namgu, Pohang (790-784), Korea
| | - Harald Oberhofer
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom, Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom, and Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology (POSTECH), San 31, Hyojadong, Namgu, Pohang (790-784), Korea
| | - Mina Park
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom, Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom, and Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology (POSTECH), San 31, Hyojadong, Namgu, Pohang (790-784), Korea
| | - Kwang S. Kim
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom, Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom, and Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology (POSTECH), San 31, Hyojadong, Namgu, Pohang (790-784), Korea
| | - Jochen Blumberger
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom, Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom, and Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology (POSTECH), San 31, Hyojadong, Namgu, Pohang (790-784), Korea
| |
Collapse
|
29
|
Eckermann AL, Feld DJ, Shaw JA, Meade TJ. Electrochemistry of redox-active self-assembled monolayers. Coord Chem Rev 2010; 254:1769-1802. [PMID: 20563297 PMCID: PMC2885823 DOI: 10.1016/j.ccr.2009.12.023] [Citation(s) in RCA: 359] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Redox-active self-assembled monolayers (SAMs) provide an excellent platform for investigating electron transfer kinetics. Using a well-defined bridge, a redox center can be positioned at a fixed distance from the electrode and electron transfer kinetics probed using a variety of electrochemical techniques. Cyclic voltammetry, AC voltammetry, electrochemical impedance spectroscopy, and chronoamperometry are most commonly used to determine the rate of electron transfer of redox-activated SAMs. A variety of redox species have been attached to SAMs, and include transition metal complexes (e.g., ferrocene, ruthenium pentaammine, osmium bisbipyridine, metal clusters) and organic molecules (e.g., galvinol, C(60)). SAMs offer an ideal environment to study the outer-sphere interactions of redox species. The composition and integrity of the monolayer and the electrode material influence the electron transfer kinetics and can be investigated using electrochemical methods. Theoretical models have been developed for investigating SAM structure. This review discusses methods and monolayer compositions for electrochemical measurements of redox-active SAMs.
Collapse
|
30
|
Bracco LL, Féliz MR, Wolcan E. On the quenching of MLCT luminescence by amines: The effect of nanoaggregation in the decrease of the reorganization energy. J Photochem Photobiol A Chem 2010. [DOI: 10.1016/j.jphotochem.2009.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
31
|
Blumberger J. Free energies for biological electron transfer from QM/MM calculation: method, application and critical assessment. Phys Chem Chem Phys 2008; 10:5651-67. [PMID: 18956100 DOI: 10.1039/b807444e] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Computer simulations of biological electron transfer reactions are reviewed with a focus on the calculation of reaction free energy (driving force) and reorganization free energy. Then a mixed quantum mechanical/molecular mechanical (QM/MM) approach is described which is designed for computation of these quantities for pure electron transfer reactions with large donor-acceptor separation distances. The method is applied to intra-protein electron transfer in Ru(bpy)(2)(im)His33 cytochrome c and the results compared to experimental data. Several modeling aspects which are important for successful calculation of free energies with QM/MM are discussed in detail.
Collapse
|
32
|
Finikova OS, Troxler T, Senes A, DeGrado WF, Hochstrasser RM, Vinogradov SA. Energy and electron transfer in enhanced two-photon-absorbing systems with triplet cores. J Phys Chem A 2007; 111:6977-90. [PMID: 17608457 PMCID: PMC2441487 DOI: 10.1021/jp071586f] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Enhanced two-photon-absorbing (2PA) systems with triplet cores are currently under scrutiny for several biomedical applications, including photodynamic therapy (PDT) and two-photon microscopy of oxygen. The performance of so far developed molecules, however, is substantially below expected. In this study we take a detailed look at the processes occurring in these systems and propose ways to improve their performance. We focus on the interchromophore distance tuning as a means for optimization of two-photon sensors for oxygen. In these constructs, energy transfer from several 2PA chromophores is used to enhance the effective 2PA cross section of phosphorescent metalloporphyrins. Previous studies have indicated that intramolecular electron transfer (ET) can act as an effective quencher of phosphorescence, decreasing the overall sensor efficiency. We studied the interplay between 2PA, energy transfer, electron transfer, and phosphorescence emission using Rhodamine B-Pt tetrabenzoporphyrin (RhB-PtTBP) adducts as model compounds. 2PA cross sections (sigma2) of tetrabenzoporphyrins (TBPs) are in the range of several tens of GM units (near 800 nm), making TBPs superior 2PA chromophores compared to regular porphyrins (sigma2 values typically 1-2 GM). Relatively large 2PA cross sections of rhodamines (about 200 GM in 800-850 nm range) and their high photostabilities make them good candidates as 2PA antennae. Fluorescence of Rhodamine B (lambda(fl) = 590 nm, phi(fl) = 0.5 in EtOH) overlaps with the Q-band of phosphorescent PtTBP (lambda(abs) = 615 nm, epsilon = 98 000 M(-1) cm(-1), phi(p) approximately 0.1), suggesting that a significant amplification of the 2PA-induced phosphorescence via fluorescence resonance energy transfer (FRET) might occur. However, most of the excitation energy in RhB-PtTBP assemblies is consumed in several intramolecular ET processes. By installing rigid nonconducting decaproline spacers (Pro10) between RhB and PtTBP, the intramolecular ETs were suppressed, while the chromophores were kept within the Förster r0 distance in order to maintain high FRET efficiency. The resulting assemblies exhibit linear amplification of their 2PA-induced phosphorescence upon increase in the number of 2PA antenna chromophores and show high oxygen sensitivity. We also have found that PtTBPs possess unexpectedly strong forbidden S0 --> T1 bands (lambda(max) = 762 nm, epsilon = 120 M-1 cm-1). The latter may overlap with the laser spectrum and lead to unwanted linear excitation.
Collapse
Affiliation(s)
- Olga S Finikova
- Departments of Biochemistry and Biophysics and Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | | | | | | |
Collapse
|
33
|
|
34
|
Anula HM, Myshkin E, Guliaev A, Luman C, Danilov EO, Castellano FN, Bullerjahn GS, Rodgers MAJ. Photo Processes on Self-Associated Cationic Porphyrins and Plastocyanin Complexes 1. Ligation of Plastocyanin Tyrosine 83 onto Metalloporphyrins and Electron-Transfer Fluorescence Quenching. J Phys Chem A 2006; 110:2545-59. [PMID: 16480316 DOI: 10.1021/jp054712t] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The spectroscopic properties of the self-associated complexes formed between the anionic surface docking site of spinach plastocyanin and the cationic metalloporphyrins, in which the tyrosine 83 (Y83) moiety is placed just below the docking site, tetrakis(N-methyl-4-pyridyl)porphyrin (Pd(II)TMPyP(4+) and Zn(II)TMPyP(4+)), have been studied and reported herein. The fluorescence quenching phenomenon of the self-assembled complex of Zn(II)TMPyP(4+)/plastocyanin has also been discovered. The observed red-shifting of the Soret and Q-bands of the UV-visible spectra, ca. 9 nm for Pd(II)TMPyP(4+)/plastocyanin and ca. 6 nm for the Zn(II)TMPyP(4+)/plastocyanin complexes, was explained in terms of exciton theory coupled with the Gouterman model. Thus, the hydroxyphenyl terminus of the Y83 residue of the self-associated plastocyanin/cationic porphyrin complexes was implicated in the charge-transfer ligation with the central metal atoms of these metalloporphyrins. Moreover, ground-state spectrometric-binding studies between Pd(II)TMPyP(4+) and the Y83 mutant plastocyanin (Y83F-PC) system proved that Y83 moiety of plastocyanin played a critical role in the formation of such ion-pair complexes. Difference absorption spectra and the Job's plots showed that the electrostatic attractions between the cationic porphyrins and the anionic patch of plastocyanin, bearing the nearby Y83 residue, led to the predominant formation of a self-associated 1:1 complex in the ground-state with significantly high binding constants (K = (8.0 +/- 1.1) x 10(5) M(-1) and (2.7 +/- 0.8) x 10(6) M(-1) for Pd(II)TMPyP(4+) and zinc variant, respectively) in low ionic strength buffer, 1 mM KCl and 1 mM phosphate buffer (pH 7.4). Molecular modeling calculations supported the formation of a 1:1 self-associated complex between the porphyrin and plastocyanin with an average distance of ca. 9 A between the centers of mass of the porphyrin and Y83 positioned just behind the anionic surface docking site on the protein surface. The photoexcited singlet state of Zn(II)TMPyP(4+) was quenched by the Y83 residue of the self-associated plastocyanin in a static mechanism as evidenced by steady-state and time-resolved fluorescence experiments. Even when all the porphyrin was complexed (more than 97%), significant residual fluorescence from the complex was observed such that the amplitude of quenching of the singlet state of uncomplexed species was enormously obscured.
Collapse
Affiliation(s)
- Hewa M Anula
- The Center for Photochemical Sciences and Departments of Chemistry and Biological Sciences, Bowling Green State University, Bowling Green, Ohio 43403, USA
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Katz E, Zayats M, Willner I, Lisdat F. Controlling the direction of photocurrents by means of CdS nanoparticles and cytochrome c-mediated biocatalytic cascades. Chem Commun (Camb) 2006:1395-7. [PMID: 16550278 DOI: 10.1039/b517332a] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cathodic or anodic photocurrents are generated by a monolayer of CdS nanoparticles in the presence of the oxidized or reduced states of cytochrome c, respectively, and the photocurrents are amplified by enzyme-generated biocatalytic cascades mediated by cytochrome c.
Collapse
Affiliation(s)
- Eugenii Katz
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 91904, Israel
| | | | | | | |
Collapse
|
36
|
|
37
|
Bertrand P. Application of electron transfer theories to biological systems. STRUCTURE AND BONDING 2005. [DOI: 10.1007/3-540-53260-9_1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
|
38
|
Amashukeli X, Gruhn NE, Lichtenberger DL, Winkler JR, Gray HB. Inner-Sphere Electron-Transfer Reorganization Energies of Zinc Porphyrins. J Am Chem Soc 2004; 126:15566-71. [PMID: 15563186 DOI: 10.1021/ja0351037] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Inner-sphere electron-transfer reorganization energies of Zn(protoporphyrin IX) and Zn(octaethylporphyrin) are determined from band-shape analyses of the first ionization obtained by gas-phase valence photoelectron spectroscopy. The experimentally determined total inner-sphere reorganization energies for self-exchange (120-140 meV) indicate that structural changes upon oxidation are largely confined to the porphyrin ring, and substituents on the ring or solvent and other environmental factors make smaller contributions. Computational estimates by different models vary over a wide range and are sensitive to numerical precision factors for these low reorganization energies. Of current computational models that are widely available and practical for molecules of this size, functionals that contain a mixture of Hartree-Fock exchange and DFT exchange-correlation appear to be the most applicable.
Collapse
Affiliation(s)
- Xenia Amashukeli
- Division of Chemistry and Chemical Engineering and the Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | | | | | | | | |
Collapse
|
39
|
Khoshtariya DE, Wei J, Liu H, Yue H, Waldeck DH. Charge-transfer mechanism for cytochrome c adsorbed on nanometer thick films. Distinguishing frictional control from conformational gating. J Am Chem Soc 2003; 125:7704-14. [PMID: 12812512 DOI: 10.1021/ja034719t] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Using nanometer thick tunneling barriers with specifically attached cytochrome c, the electron-transfer rate constant was studied as a function of the SAM composition (alkane versus terthiophene), the omega-terminating group type (pyridine, imidazole, nitrile), and the solution viscosity. At large electrode-reactant separations, the pyridine terminated alkanethiols exhibit an exponential decline of the rate constant with increasing electron-transfer distance. At short separations, a plateau behavior, analogous to systems involving -COOH terminal groups to which cytochrome c can be attached electrostatically, is observed. The dependence of the rate constant in the plateau region on system properties is investigated. The rate constant is insensitive to the mode of attachment to the surface but displays a significant viscosity dependence, change with spacer composition (alkane versus terthiophene), and nature of the solvent (H(2)O versus D(2)O). Based on these findings and others, the conclusion is drawn that the charge-transfer rate constant at short distance is determined by polarization relaxation processes in the structure, rather than the electron tunneling probability or large-amplitude conformational rearrangement (gating). The transition in reaction mechanism with distance reflects a gradual transition between the tunneling and frictional mechanisms. This conclusion is consistent with data from a number of other sources as well.
Collapse
|
40
|
Chang IJ, Lee JC, Winkler JR, Gray HB. The protein-folding speed limit: intrachain diffusion times set by electron-transfer rates in denatured Ru(NH3)5(His-33)-Zn-cytochrome c. Proc Natl Acad Sci U S A 2003; 100:3838-40. [PMID: 12646702 PMCID: PMC153008 DOI: 10.1073/pnas.0637283100] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The kinetics of electron transfer from the triplet-excited Zn-porphyrin to a Ru(NH(3))(5)(His-33)(3+) complex have been measured in Zn-substituted ruthenium-modified cytochrome c under denaturing conditions. In the folded protein, the electron-tunneling rate constant is 7.5 x 10(5) s(-1). As the protein is denatured with guanidine hydrochloride, a faster adiabatic electron-transfer reaction appears (4.0 x 10(6) s(-1), [guanidine hydrochloride] = 5.4 M) that is limited by the rate of intrachain diffusion to bring the Zn-porphyrin and Ru complex into contact. The 250-ns contact time for formation of a 15-residue loop in denatured cytochrome c is in accord with a statistical model developed by Camacho and Thirumalai [Camacho, C. J. & Thirumalai, D. (1995) Proc. Natl. Acad. Sci. USA 92, 1277-1281] that predicts that the most probable transient loops formed in denatured proteins are comprised of 10 amino acids. Extrapolation of the cytochrome c contact time to a 10-residue loop sets the folding speed limit at approximately 10(7) s(-1).
Collapse
Affiliation(s)
- I-Jy Chang
- Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | | | | | | |
Collapse
|
41
|
Smitha MA, Prasad E, Gopidas KR. Photoinduced electron transfer in hydrogen bonded donor--acceptor systems. Free energy and distance dependence studies and an analysis of the role of diffusion. J Am Chem Soc 2001; 123:1159-65. [PMID: 11456669 DOI: 10.1021/ja001108h] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The free energy dependence of electron transfer in a few small-molecule donor--acceptor systems having hydrogen-bonding appendages was studied to evaluate the role of diffusion in masking the inverted region in bimolecular PET reactions. A small fraction of the probe molecules associate and this led to the simultaneous observation of unimolecular and diffusion-mediated quenching of the probe fluorescence. Free energy dependence studies showed that the unimolecular electron transfer obeys Marcus behavior and the diffusion-mediated electron transfer obeys Rehm--Weller behavior. The absence of an inverted region in bimolecular PET reactions is thus attributed to diffusion. The results of the free energy dependence studies suggest that distance dependence of electron transfer plays a role in masking the inverted region. To ascertain this aspect we have carried out a study of the distance dependence of electron transfer in the hydrogen-bonded donor--acceptor systems. For a system in the normal region an exponential rate decrease was observed. For a system in the inverted region it was observed that the rate depends very feebly on distance. Thus distance dependence studies did not confirm the prediction of enhanced rates at larger distances in the inverted region.
Collapse
Affiliation(s)
- M A Smitha
- Photochemistry Research Unit, Regional Research Laboratory (CSIR), Trivandrum 695 019, India
| | | | | |
Collapse
|
42
|
Radiation chemistry of proteins. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s0167-6881(01)80022-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
|
43
|
Sevrioukova IF, Immoos CE, Poulos TL, Farmer P. Electron transfer in the ruthenated heme domain of cytochrome P450BM-3. Isr J Chem 2000. [DOI: 10.1560/vrgj-de54-xdnm-5ph3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
44
|
Prasad E, Gopidas KR. Photoinduced Electron Transfer in Hydrogen Bonded Donor−Acceptor Systems. Study of the Dependence of Rate on Free Energy and Simultaneous Observation of the Marcus and Rehm−Weller Behaviors. J Am Chem Soc 2000. [DOI: 10.1021/ja993872d] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- E. Prasad
- Contribution from the Photochemistry Unit, Regional Research Laboratory (CSIR), Trivandrum 695 019, India
| | - K. R. Gopidas
- Contribution from the Photochemistry Unit, Regional Research Laboratory (CSIR), Trivandrum 695 019, India
| |
Collapse
|
45
|
Modelling intramolecular electron transfer reactions in cytochromes and in photosynthetic bacteria reaction centres. J Photochem Photobiol A Chem 1998. [DOI: 10.1016/s1010-6030(98)00367-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
46
|
Dick LA, Malfant I, Kuila D, Nebolsky S, Nocek JM, Hoffman BM, Ratner MA. Cryogenic Electron Tunneling within Mixed-Metal Hemoglobin Hybrids: Protein Glassing and Electron-Transfer Energetics. J Am Chem Soc 1998. [DOI: 10.1021/ja982032g] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lisa A. Dick
- Contribution from the Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | - Isabelle Malfant
- Contribution from the Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | - Debasish Kuila
- Contribution from the Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | - Shannon Nebolsky
- Contribution from the Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | - Judith M. Nocek
- Contribution from the Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | - Brian M. Hoffman
- Contribution from the Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| | - Mark A. Ratner
- Contribution from the Department of Chemistry, Northwestern University, Evanston, Illinois 60208
| |
Collapse
|
47
|
Venturoli G, Drepper F, Williams JC, Allen JP, Lin X, Mathis P. Effects of temperature and deltaGo on electron transfer from cytochrome c2 to the photosynthetic reaction center of the purple bacterium Rhodobacter sphaeroides. Biophys J 1998; 74:3226-40. [PMID: 9635776 PMCID: PMC1299663 DOI: 10.1016/s0006-3495(98)78029-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The kinetics of electron transfer from cytochrome c2 to the primary donor (P) of the reaction center from the photosynthetic purple bacterium Rhodobacter sphaeroides have been investigated by time-resolved absorption spectroscopy. Rereduction of P+ induced by a laser pulse has been measured at temperatures from 300 K to 220 K in a series of specifically mutated reaction centers characterized by altered midpoint redox potentials of P+/P varying from 410 mV to 765 mV (as compared to 505 mV for wild type). Rate constants for first-order electron donation within preformed reaction center-cytochrome c2 complexes and for the bimolecular oxidation of free cytochrome c2 have been obtained by multiexponential deconvolution of the kinetics. At all temperatures the rate of the fastest intracomplex electron transfer increases by more than two orders of magnitude as the driving force -deltaGo is varied over a range of 350 meV. The temperature and deltaGo dependences of the rate constant fit the Marcus equation well. Global analysis yields a reorganization energy lambda = 0.96 +/- 0.07 eV and a set of electronic matrix elements, specific for each mutant, ranging from 1.2 10(-4) eV to 2.5 10(-4) eV. Analysis in terms of the Jortner equation indicates that the best fit is obtained in the classical limit and restricts the range of coupled vibrational modes to frequencies lower than approximately 200 cm(-1). An additional slower kinetic component of P+ reduction, attributed to electron transfer from cyt c2 docked in a nonoptimal configuration of the complex, displays a Marcus type dependence of the rate constant upon deltaGo, characterized by a similar value of lambda (0.8 +/- 0.1 eV) and by an average electronic matrix element smaller by more than one order of magnitude. In all of the mutants, as the temperature is decreased below 260 K, both intracomplex reactions are abruptly inhibited, their rate being negligible at 220 K. The free energy dependence of the second-order rate constant for oxidation of cyt c2 in solution suggests that the collisional reaction is partially diffusion controlled, reaching the diffusion limit at exothermicities between 150 and 250 meV over the temperature range investigated.
Collapse
Affiliation(s)
- G Venturoli
- Dipartimento di Biologia, Università di Bologna, Italy.
| | | | | | | | | | | |
Collapse
|
48
|
Sun J, Wishart JF. Intramolecular Electron Transfer in Tetraammine(L)ruthenium(III)-Modified Manganocytochromes c. Inorg Chem 1998. [DOI: 10.1021/ic971169p] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ji Sun
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973
| | - James F. Wishart
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973
| |
Collapse
|
49
|
Sharp KA. Calculation of electron transfer reorganization energies using the finite difference Poisson-Boltzmann model. Biophys J 1998; 74:1241-50. [PMID: 9512022 PMCID: PMC1299472 DOI: 10.1016/s0006-3495(98)77838-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A description is given of a method to calculate the electron transfer reorganization energy (lambda) in proteins using the linear or nonlinear Poisson-Boltzmann (PB) equation. Finite difference solutions to the linear PB equation are then used to calculate lambda for intramolecular electron transfer reactions in the photosynthetic reaction center from Rhodopseudomonas viridis and the ruthenated heme proteins cytochrome c, myoglobin, and cytochrome b and for intermolecular electron transfer between two cytochrome c molecules. The overall agreement with experiment is good considering both the experimental and computational difficulties in estimating lambda. The calculations show that acceptor/donor separation and position of the cofactors with respect to the protein/solvent boundary are equally important and, along with the overall polarizability of the protein, are the major determinants of lambda. In agreement with previous studies, the calculations show that the protein provides a low reorganization environment for electron transfer. Agreement with experiment is best if the protein polarizability is modeled with a low (<8) average effective dielectric constant. The effect of buried waters on the reorganization energy of the photosynthetic reaction center was examined and found to make a contribution ranging from 0.05 eV to 0.27 eV, depending on the donor/acceptor pair.
Collapse
Affiliation(s)
- K A Sharp
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia 19104-6059, USA.
| |
Collapse
|
50
|
Bimolecular photoinduced electron transfer in the Marcus inverted region involving the [Re(CO)3(4-phenylpyridine)3]+ metal-to-ligand charge transfer excited state, amines and their corresponding radical products. J Photochem Photobiol A Chem 1997. [DOI: 10.1016/s1010-6030(97)00059-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|