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Neupane B, Dang NC, Kelley RF, Wasielewski MR, Jankowiak R. Low-Temperature Frequency Domain Study of Excitation Energy Transfer in Ethynyl-Linked Chlorophyll Trefoils and Aggregates. J Phys Chem B 2011; 115:10391-9. [DOI: 10.1021/jp2027252] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bhanu Neupane
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Nhan C. Dang
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
| | - Richard F. Kelley
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Michael R. Wasielewski
- Department of Chemistry and Argonne-Northwestern Solar Energy Research (ANSER) Center, Northwestern University, Evanston, Illinois 60208, United States
| | - Ryszard Jankowiak
- Department of Chemistry, Kansas State University, Manhattan, Kansas 66506, United States
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Şener M, Strümpfer J, Hsin J, Chandler D, Scheuring S, Hunter CN, Schulten K. Förster energy transfer theory as reflected in the structures of photosynthetic light-harvesting systems. Chemphyschem 2011; 12:518-31. [PMID: 21344591 DOI: 10.1002/cphc.201000944] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Förster’s theory of resonant energy transfer underlies a fundamental process in nature, namely the harvesting of sunlight by photosynthetic life forms. The theoretical framework developed by Förster and others describes how electronic excitation migrates in the photosynthetic apparatus of plants, algae, and bacteria from light absorbing pigments to reaction centers where light energy is utilized for the eventual conversion into chemical energy. The demand for highest possible efficiency of light harvesting appears to have shaped the evolution of photosynthetic species from bacteria to plants which, despite a great variation in architecture, display common structural themes founded on the quantum physics of energy transfer as described first by Förster. Herein, Förster’s theory of excitation transfer is summarized, including recent extensions, and the relevance of the theory to photosynthetic systems as evolved in purple bacteria, cyanobacteria, and plants is demonstrated. Förster’s energy transfer formula, as used widely today in many fields of science, is also derived.
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Affiliation(s)
- Melih Şener
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Mielke SP, Kiang NY, Blankenship RE, Gunner MR, Mauzerall D. Efficiency of photosynthesis in a Chl d-utilizing cyanobacterium is comparable to or higher than that in Chl a-utilizing oxygenic species. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:1231-6. [PMID: 21708123 DOI: 10.1016/j.bbabio.2011.06.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Revised: 06/09/2011] [Accepted: 06/13/2011] [Indexed: 10/18/2022]
Abstract
The cyanobacterium Acaryochloris marina uses chlorophyll d to carry out oxygenic photosynthesis in environments depleted in visible and enhanced in lower-energy, far-red light. However, the extent to which low photon energies limit the efficiency of oxygenic photochemistry in A. marina is not known. Here, we report the first direct measurements of the energy-storage efficiency of the photosynthetic light reactions in A. marina whole cells, and find it is comparable to or higher than that in typical, chlorophyll a-utilizing oxygenic species. This finding indicates that oxygenic photosynthesis is not fundamentally limited at the photon energies employed by A. marina, and therefore is potentially viable in even longer-wavelength light environments.
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Affiliation(s)
- S P Mielke
- NASA Goddard Institute for Space Studies, Columbia University, New York, NY, USA.
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54
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Cohen-Ofri I, van Gastel M, Grzyb J, Brandis A, Pinkas I, Lubitz W, Noy D. Zinc-Bacteriochlorophyllide Dimers in de Novo Designed Four-Helix Bundle Proteins. A Model System for Natural Light Energy Harvesting and Dissipation. J Am Chem Soc 2011; 133:9526-35. [DOI: 10.1021/ja202054m] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ilit Cohen-Ofri
- Plant Sciences Department, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Maurice van Gastel
- Max Planck Institute for Bioinorganic Chemistry, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Joanna Grzyb
- Plant Sciences Department, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Alexander Brandis
- Plant Sciences Department, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Iddo Pinkas
- Plant Sciences Department, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Wolfgang Lubitz
- Max Planck Institute for Bioinorganic Chemistry, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Dror Noy
- Plant Sciences Department, Weizmann Institute of Science, Rehovot 76100, Israel
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Koshiyama T, Shirai M, Hikage T, Tabe H, Tanaka K, Kitagawa S, Ueno T. Post-Crystal Engineering of Zinc-Substituted Myoglobin to Construct a Long-Lived Photoinduced Charge-Separation System. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201008004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Koshiyama T, Shirai M, Hikage T, Tabe H, Tanaka K, Kitagawa S, Ueno T. Post-crystal engineering of zinc-substituted myoglobin to construct a long-lived photoinduced charge-separation system. Angew Chem Int Ed Engl 2011; 50:4849-52. [PMID: 21495132 DOI: 10.1002/anie.201008004] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Revised: 02/14/2011] [Indexed: 12/30/2022]
Affiliation(s)
- Tomomi Koshiyama
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University iCeMS Lab Funai Center, Kyoto University Katsura, Kyoto 615-8510, Japan
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Dube N, Presley AD, Shu JY, Xu T. Amphiphilic Peptide-Polymer Conjugates with Side-Conjugation. Macromol Rapid Commun 2011; 32:344-53. [DOI: 10.1002/marc.201000603] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 11/23/2010] [Indexed: 11/08/2022]
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Bombarda E, Ullmann GM. Continuum electrostatic investigations of charge transfer processes in biological molecules using a microstate description. Faraday Discuss 2011; 148:173-93; discussion 207-28. [DOI: 10.1039/c003905e] [Citation(s) in RCA: 15] [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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Brown KA, Dayal S, Ai X, Rumbles G, King PW. Controlled assembly of hydrogenase-CdTe nanocrystal hybrids for solar hydrogen production. J Am Chem Soc 2010; 132:9672-80. [PMID: 20583755 DOI: 10.1021/ja101031r] [Citation(s) in RCA: 222] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We present a study of the self-assembly, charge-transfer kinetics, and catalytic properties of hybrid complexes of CdTe nanocrystals (nc-CdTe) and Clostridium acetobutylicum [FeFe]-hydrogenase I (H(2)ase). Molecular assembly of nc-CdTe and H(2)ase was mediated by electrostatic interactions and resulted in stable, enzymatically active complexes. The assembly kinetics was monitored by nc-CdTe photoluminescence (PL) spectroscopy and exhibited first-order Langmuir adsorption behavior. PL was also used to monitor the transfer of photogenerated electrons from nc-CdTe to H(2)ase. The extent to which the intramolecular electron transfer (ET) contributed to the relaxation of photoexcited nc-CdTe relative to the intrinsic radiative and nonradiative (heat dissipation and surface trapping) recombination pathways was shown by steady-state PL spectroscopy to be a function of the nc-CdTe/H(2)ase molar ratio. When the H(2)ase concentration was lower than the nc-CdTe concentration during assembly, the resulting contribution of ET to PL bleaching was enhanced, which resulted in maximal rates of H(2) photoproduction. Photoproduction of H(2) was also a function of the nc-CdTe PL quantum efficiency (PLQE), with higher-PLQE nanocrystals producing higher levels of H(2), suggesting that photogenerated electrons are transferred to H(2)ase directly from core nanocrystal states rather than from surface-trap states. The duration of H(2) photoproduction was limited by the stability of nc-CdTe under the reactions conditions. A first approach to optimization with ascorbic acid present as a sacrificial donor resulted in photon-to-H(2) efficiencies of 9% under monochromatic light and 1.8% under AM 1.5 white light. In summary, nc-CdTe and H(2)ase spontaneously assemble into complexes that upon illumination transfer photogenerated electrons from core nc-CdTe states to H(2)ase, with low H(2)ase coverages promoting optimal orientations for intramolecular ET and solar H(2) production.
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Affiliation(s)
- Katherine A Brown
- Biosciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, USA
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Fron E, Puhl L, Oesterling I, Li C, Müllen K, De Schryver FC, Hofkens J, Vosch T. Energy Transfer Pathways in a Rylene‐Based Triad. Chemphyschem 2010; 12:595-608. [DOI: 10.1002/cphc.201000665] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Indexed: 11/05/2022]
Affiliation(s)
- Eduard Fron
- Department of Chemistry and Institute for Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee (Belgium)
| | - Larissa Puhl
- Max‐Planck‐Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz (Germany)
| | - Ingo Oesterling
- Max‐Planck‐Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz (Germany)
| | - Chen Li
- Max‐Planck‐Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz (Germany)
| | - Klaus Müllen
- Max‐Planck‐Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz (Germany)
| | - Frans C. De Schryver
- Department of Chemistry and Institute for Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee (Belgium)
| | - Johan Hofkens
- Department of Chemistry and Institute for Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee (Belgium)
| | - Tom Vosch
- Nano‐Science Center, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen (Denmark), Fax: (+45) 353‐20‐322
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Şener M, Strümpfer J, Timney JA, Freiberg A, Hunter CN, Schulten K. Photosynthetic vesicle architecture and constraints on efficient energy harvesting. Biophys J 2010; 99:67-75. [PMID: 20655834 PMCID: PMC2895385 DOI: 10.1016/j.bpj.2010.04.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 03/16/2010] [Accepted: 04/05/2010] [Indexed: 11/24/2022] Open
Abstract
Photosynthetic chromatophore vesicles found in some purple bacteria constitute one of the simplest light-harvesting systems in nature. The overall architecture of chromatophore vesicles and the structural integration of vesicle function remain poorly understood despite structural information being available on individual constituent proteins. An all-atom structural model for an entire chromatophore vesicle is presented, which improves upon earlier models by taking into account the stoichiometry of core and antenna complexes determined by the absorption spectrum of intact vesicles in Rhodobacter sphaeroides, as well as the well-established curvature-inducing properties of the dimeric core complex. The absorption spectrum of low-light-adapted vesicles is shown to correspond to a light-harvesting-complex 2 to reaction center ratio of 3:1. A structural model for a vesicle consistent with this stoichiometry is developed and used in the computation of excitonic properties. Considered also is the packing density of antenna and core complexes that is high enough for efficient energy transfer and low enough for quinone diffusion from reaction centers to cytochrome bc(1) complexes.
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Affiliation(s)
- Melih Şener
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Johan Strümpfer
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - John A. Timney
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Arvi Freiberg
- Institute of Physics, University of Tartu, Tartu, Estonia
- Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia
| | - C. Neil Hunter
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Klaus Schulten
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois
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Grozema FC, Berlin YA, Siebbeles LDA, Ratner MA. Effect of Electrostatic Interactions and Dynamic Disorder on the Distance Dependence of Charge Transfer in Donor−Bridge−Acceptor Systems. J Phys Chem B 2010; 114:14564-71. [DOI: 10.1021/jp1023422] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Ferdinand C. Grozema
- Opto-electronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL, Delft, The Netherlands, and Center for Nanofabrication and Molecular Self-Assembly, Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113
| | - Yuri A. Berlin
- Opto-electronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL, Delft, The Netherlands, and Center for Nanofabrication and Molecular Self-Assembly, Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113
| | - Laurens D. A. Siebbeles
- Opto-electronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL, Delft, The Netherlands, and Center for Nanofabrication and Molecular Self-Assembly, Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113
| | - Mark A. Ratner
- Opto-electronic Materials Section, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL, Delft, The Netherlands, and Center for Nanofabrication and Molecular Self-Assembly, Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113
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Shu JY, Huang YJ, Tan C, Presley AD, Chang J, Xu T. Amphiphilic Peptide−Polymer Conjugates Based on the Coiled-Coil Helix Bundle. Biomacromolecules 2010; 11:1443-52. [DOI: 10.1021/bm100009e] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jessica Y. Shu
- Departments of Materials Science and Engineering and Chemistry, University of California, Berkeley, California 94720, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Yu-Ja Huang
- Departments of Materials Science and Engineering and Chemistry, University of California, Berkeley, California 94720, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Cen Tan
- Departments of Materials Science and Engineering and Chemistry, University of California, Berkeley, California 94720, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Andrew D. Presley
- Departments of Materials Science and Engineering and Chemistry, University of California, Berkeley, California 94720, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Joseph Chang
- Departments of Materials Science and Engineering and Chemistry, University of California, Berkeley, California 94720, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Ting Xu
- Departments of Materials Science and Engineering and Chemistry, University of California, Berkeley, California 94720, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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Nocek JM, Knutson AK, Xiong P, Co NP, Hoffman BM. Photoinitiated singlet and triplet electron transfer across a redesigned [myoglobin, cytochrome b5] interface. J Am Chem Soc 2010; 132:6165-75. [PMID: 20392066 PMCID: PMC2868514 DOI: 10.1021/ja100499j] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe a strategy by which reactive binding of a weakly bound, 'dynamically docked (DD)' complex without a known structure can be strengthened electrostatically through optimized placement of surface charges, and discuss its use in modulating complex formation between myoglobin (Mb) and cytochrome b(5) (b(5)). The strategy employs paired Brownian dynamics (BD) simulations, one which monitors overall binding, the other reactive binding, to examine [X --> K] mutations on the surface of the partners, with a focus on single and multiple [D/E --> K] charge reversal mutations. This procedure has been applied to the [Mb, b(5)] complex, indicating mutations of Mb residues D44, D60, and E85 to be the most promising, with combinations of these showing a nonlinear enhancement of reactive binding. A novel method of displaying BD profiles shows that the 'hits' of b(5) on the surfaces of Mb(WT), Mb(D44K/D60K), and Mb(D44K/D60K/E85K) progressively coalesce into two 'clusters': a 'diffuse' cluster of hits that are distributed over the Mb surface and have negligible electrostatic binding energy and a 'reactive' cluster of hits with considerable stability that are localized near its heme edge, with short Fe-Fe distances favorable to electron transfer (ET). Thus, binding and reactivity progressively become correlated by the mutations. This finding relates to recent proposals that complex formation is a two-step process, proceeding through the formation of a weakly bound encounter complex to a well-defined bound complex. The design procedure has been tested through measurements of photoinitiated ET between the Zn-substituted forms of Mb(WT), Mb(D44K/D60K), and Mb(D44K/D60K/E85K) and Fe(3+)b(5). Both mutants convert the complex from the DD regime exhibited by Mb(WT), in which the transient complex is in fast kinetic exchange with its partners, k(off) >> k(et), to the slow-exchange regime, k(et) >> k(off), and both mutants exhibit rapid intracomplex ET from the triplet excited state to Fe(3+)b(5) (rate constant, k(et) approximately 10(6) s(-1)). The affinity constants of the mutant Mbs cannot be derived through conventional analysis procedures because intracomplex singlet ET quenching causes the triplet-ground absorbance difference to progressively decrease during a titration, but this effect has been incorporated into a new procedure for computing binding constants. Most importantly, these measurements reveal the presence of fast photoinduced singlet ET across the protein-protein interface, (1)k(et) approximately 2 x 10(8) s(-1).
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de Groot HJM. Integration of Catalysis with Storage for the Design of Multi-Electron Photochemistry Devices for Solar Fuel. APPLIED MAGNETIC RESONANCE 2010; 37:497-503. [PMID: 19960066 PMCID: PMC2784072 DOI: 10.1007/s00723-009-0097-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 07/17/2009] [Indexed: 05/28/2023]
Abstract
Decarbonization of the transport system and a transition to a new diversified energy system that is scalable and sustainable, requires a widespread implementation of carbon-neutral fuels. In biomimetic supramolecular nanoreactors for solar-to-fuel conversion, water-splitting catalysts can be coupled to photochemical units to form complex electrochemical nanostructures, based on a systems integration approach and guided by magnetic resonance knowledge of the operating principles of biological photosynthesis, to bridge between long-distance energy transfer on the short time scale of fluorescence, ~10(-9) s, and short-distance proton-coupled electron transfer and storage on the much longer time scale of catalysis, ~10(-3) s. A modular approach allows for the design of nanostructured optimized topologies with a tunneling bridge for the integration of storage with catalysis and optimization of proton chemical potentials, to mimic proton-coupled electron transfer processes in photosystem II and hydrogenase.
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Affiliation(s)
- Huub J. M. de Groot
- Gorlaeus Laboratories, Leiden Institute of Chemistry, POB 9502, 2300 RA Leiden, The Netherlands
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66
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LeBard DN, Matyushov DV. Protein–water electrostatics and principles of bioenergetics. Phys Chem Chem Phys 2010; 12:15335-48. [DOI: 10.1039/c0cp01004a] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
The rational design of artificial enzymes, either by applying physico-chemical intuition of protein structure and function or with the aid of computational methods, is a promising area of research with the potential to tremendously impact medicine, industrial chemistry and energy production. Designed proteins also provide a powerful platform for dissecting enzyme mechanisms of natural systems. Artificial enzymes have come a long way from simple α-helical peptide catalysts to proteins that facilitate multistep chemical reactions designed by state-of-the-art computational methods. Looking forward, we examine strategies employed by natural enzymes that could be used to improve the speed and selectivity of artificial catalysts.
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68
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Conlan B, Cox N, Su JH, Hillier W, Messinger J, Lubitz W, Dutton PL, Wydrzynski T. Photo-catalytic oxidation of a di-nuclear manganese centre in an engineered bacterioferritin ‘reaction centre’. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1112-21. [DOI: 10.1016/j.bbabio.2009.04.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 04/16/2009] [Accepted: 04/21/2009] [Indexed: 11/15/2022]
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69
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Eng MP, Albinsson B. The dependence of the electronic coupling on energy gap and bridge conformation – Towards prediction of the distance dependence of electron transfer reactions. Chem Phys 2009. [DOI: 10.1016/j.chemphys.2008.12.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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70
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Williams JC, Allen JP. Directed Modification of Reaction Centers from Purple Bacteria. THE PURPLE PHOTOTROPHIC BACTERIA 2009. [DOI: 10.1007/978-1-4020-8815-5_18] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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71
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Peng X, Chen J, Misewich JA, Wong SS. Carbon nanotube–nanocrystal heterostructures. Chem Soc Rev 2009; 38:1076-98. [DOI: 10.1039/b811424m] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Olsen JD, Tucker JD, Timney JA, Qian P, Vassilev C, Hunter CN. The organization of LH2 complexes in membranes from Rhodobacter sphaeroides. J Biol Chem 2008; 283:30772-9. [PMID: 18723509 PMCID: PMC2662159 DOI: 10.1074/jbc.m804824200] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 08/22/2008] [Indexed: 11/06/2022] Open
Abstract
The mapping of the photosynthetic membrane of Rhodobacter sphaeroides by atomic force microscopy (AFM) revealed a unique organization of arrays of dimeric reaction center-light harvesting I-PufX (RC-LH1-PufX) core complexes surrounded and interconnected by light-harvesting LH2 complexes (Bahatyrova, S., Frese, R. N., Siebert, C. A., Olsen, J. D., van der Werf, K. O., van Grondelle, R., Niederman, R. A., Bullough, P. A., Otto, C., and Hunter, C. N. (2004) Nature 430, 1058-1062). However, membrane regions consisting solely of LH2 complexes were under-represented in these images because these small, highly curved areas of membrane rendered them difficult to image even using gentle tapping mode AFM and impossible with contact mode AFM. We report AFM imaging of membranes prepared from a mutant of R. sphaeroides, DPF2G, that synthesizes only the LH2 complexes, which assembles spherical intracytoplasmic membrane vesicles of approximately 53 nm diameter in vivo. By opening these vesicles and adsorbing them onto mica to form small, < or =120 nm, largely flat sheets we have been able to visualize the organization of these LH2-only membranes for the first time. The transition from highly curved vesicle to the planar sheet is accompanied by a change in the packing of the LH2 complexes such that approximately half of the complexes are raised off the mica surface by approximately 1 nm relative to the rest. This vertical displacement produces a very regular corrugated appearance of the planar membrane sheets. Analysis of the topographs was used to measure the distances and angles between the complexes. These data are used to model the organization of LH2 complexes in the original, curved membrane. The implications of this architecture for the light harvesting function and diffusion of quinones in native membranes of R. sphaeroides are discussed.
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Affiliation(s)
- John D Olsen
- Department of Molecular Biology, The University of Sheffield, Sheffield S10 2TN, UK.
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Conlan B. Designing photosystem II: molecular engineering of photo-catalytic proteins. PHOTOSYNTHESIS RESEARCH 2008; 98:687-700. [PMID: 18777102 DOI: 10.1007/s11120-008-9355-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Accepted: 08/11/2008] [Indexed: 05/26/2023]
Abstract
Biological photosynthesis utilizes membrane-bound pigment/protein complexes to convert light into chemical energy through a series of electron-transfer events. In the unique photosystem II (PSII) complex these electron-transfer events result in the oxidation of water to molecular oxygen. PSII is an extremely complex enzyme and in order to exploit its unique ability to convert sunlight into chemical energy it will be necessary to make a minimal model. Here we will briefly describe how PSII functions and identify those aspects that are essential in order to catalyze the oxidation of water into O(2), and review previous attempts to design simple photo-catalytic proteins and summarize our current research exploiting the E. coli bacterioferritin protein as a scaffold into which multiple cofactors can be bound, to oxidize a manganese metal center upon illumination. Through the reverse engineering of PSII and light driven water splitting reactions it may be possible to provide a blueprint for catalysts that can produce clean green fuel for human energy needs.
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Affiliation(s)
- Brendon Conlan
- Research School of Biological Science, Australian National University, Canberra, ACT 0200, Australia.
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74
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Koay M, Antonkine M, Gärtner W, Lubitz W. Modelling Low-Potential [Fe4S4] Clusters in Proteins. Chem Biodivers 2008; 5:1571-1587. [DOI: 10.1002/cbdv.200890145] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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75
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LeBard DN, Kapko V, Matyushov DV. Energetics and kinetics of primary charge separation in bacterial photosynthesis. J Phys Chem B 2008; 112:10322-42. [PMID: 18636767 DOI: 10.1021/jp8016503] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We report the results of molecular dynamics (MD) simulations and formal modeling of the free-energy surfaces and reaction rates of primary charge separation in the reaction center of Rhodobacter sphaeroides. Two simulation protocols were used to produce MD trajectories. Standard force-field potentials were employed in the first protocol. In the second protocol, the special pair was made polarizable to reproduce a high polarizability of its photoexcited state observed by Stark spectroscopy. The charge distribution between covalent and charge-transfer states of the special pair was dynamically adjusted during the simulation run. We found from both protocols that the breadth of electrostatic fluctuations of the protein/water environment far exceeds previous estimates, resulting in about 1.6 eV reorganization energy of electron transfer in the first protocol and 2.5 eV in the second protocol. Most of these electrostatic fluctuations become dynamically frozen on the time scale of primary charge separation, resulting in much smaller solvation contributions to the activation barrier. While water dominates solvation thermodynamics on long observation times, protein emerges as the major thermal bath coupled to electron transfer on the picosecond time of the reaction. Marcus parabolas were obtained for the free-energy surfaces of electron transfer by using the first protocol, while a highly asymmetric surface was obtained in the second protocol. A nonergodic formulation of the diffusion-reaction electron-transfer kinetics has allowed us to reproduce the experimental results for both the temperature dependence of the rate and the nonexponential decay of the population of the photoexcited special pair.
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Affiliation(s)
- David N LeBard
- Center for Biological Physics, Arizona State University, Tempe, AZ 85287-1604, USA
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76
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Ma YZ, Miller RA, Fleming GR, Francis MB. Energy Transfer Dynamics in Light-Harvesting Assemblies Templated by the Tobacco Mosaic Virus Coat Protein. J Phys Chem B 2008; 112:6887-92. [DOI: 10.1021/jp8006393] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ying-Zhong Ma
- Department of Chemistry, University of California, Berkeley, and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460, and Department of Chemistry, University of California, Berkeley, California 94720-1460, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460
| | - Rebekah A. Miller
- Department of Chemistry, University of California, Berkeley, and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460, and Department of Chemistry, University of California, Berkeley, California 94720-1460, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460
| | - Graham R. Fleming
- Department of Chemistry, University of California, Berkeley, and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460, and Department of Chemistry, University of California, Berkeley, California 94720-1460, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460
| | - Matthew B. Francis
- Department of Chemistry, University of California, Berkeley, and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460, and Department of Chemistry, University of California, Berkeley, California 94720-1460, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720-1460
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77
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Eng M, Mårtensson J, Albinsson B. Temperature Dependence of Electronic Coupling through Oligo-p-phenyleneethynylene Bridges. Chemistry 2008; 14:2819-26. [DOI: 10.1002/chem.200701477] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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78
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LeBard DN, Matyushov DV. Glassy Protein Dynamics and Gigantic Solvent Reorganization Energy of Plastocyanin. J Phys Chem B 2008; 112:5218-27. [DOI: 10.1021/jp709586e] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David N. LeBard
- Center for Biological Physics, Arizona State University, P.O. Box 871604, Tempe, Arizona 85287-1604
| | - Dmitry V. Matyushov
- Center for Biological Physics, Arizona State University, P.O. Box 871604, Tempe, Arizona 85287-1604
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79
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Noy D. Natural photosystems from an engineer's perspective: length, time, and energy scales of charge and energy transfer. PHOTOSYNTHESIS RESEARCH 2008; 95:23-35. [PMID: 17968671 DOI: 10.1007/s11120-007-9269-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2007] [Accepted: 10/03/2007] [Indexed: 05/25/2023]
Abstract
The vast structural and functional information database of photosynthetic enzymes includes, in addition to detailed kinetic records from decades of research on physical processes and chemical reaction-pathways, a variety of high and medium resolution crystal structures of key photosynthetic enzymes. Here, it is examined from an engineer's point of view with the long-term goal of reproducing the key features of natural photosystems in novel biological and non-biological solar-energy conversion systems. This survey reveals that the basic physics of the transfer processes, namely, the time constraints imposed by the rates of incoming photon flux and the various decay processes allow for a large degree of tolerance in the engineering parameters. Furthermore, the requirements to guarantee energy and electron transfer rates that yield high efficiency in natural photosystems are largely met by control of distance between chromophores and redox cofactors. This underlines a critical challenge for projected de novo designed constructions, that is, the control of spatial organization of cofactor molecules within dense array of different cofactors, some well within 1 nm from each other.
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Affiliation(s)
- Dror Noy
- Plant Sciences Department, Weizmann Institute of Science, Rehovot, 76100, Israel.
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80
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Gradinaru C, Crane BR. Comparison of intra- vs intermolecular long-range electron transfer in crystals of ruthenium-modified azurin. J Phys Chem B 2007; 110:20073-6. [PMID: 17034174 DOI: 10.1021/jp0644309] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Selective metal-ion incorporation and ligand substitution are employed to control whether electrons tunnel over intra- or intermolecular separations in crystals of P. aeruginosa azurin modified with Ru-polypyridine complexes. Cu(1+)-to-Ru3+ electron transfer (ET) across a specific protein-protein interface in the crystal lattice has a time constant 5-10 times longer than ET between the same donor and acceptor within a single protein (tauET = 5 vs 0.5-1.0 micros). Slower intermolecular ET agrees well with a longer distance between redox centers across the inter-protein (18.9 A) compared to the intra-protein separation (17.0 A) and indicates that the closest donor/acceptor pair dominates crystal ET. Lowering the crystal pH accelerates inter-protein ET (tauET = 1.0 micros) but not intra-protein ET. Faster inter-protein ET likely results from a pH-induced peptide bond flip that perturbs hydrogen bonding in the path between Ru and Cu centers on adjacent molecules.
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81
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Albinsson B, Eng MP, Pettersson K, Winters MU. Electron and energy transfer in donor-acceptor systems with conjugated molecular bridges. Phys Chem Chem Phys 2007; 9:5847-64. [PMID: 17989792 DOI: 10.1039/b706122f] [Citation(s) in RCA: 170] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron and energy transfer reactions in covalently connected donor-bridge-acceptor assemblies are strongly dependent, not only on the donor-acceptor distance, but also on the electronic structure of the bridge. In this article we describe some well characterised systems where the bridges are pi-conjugated chromophores, and where, specifically, the interplay between bridge length and energy plays an important role for the donor-acceptor electronic coupling. For any application that relies on the transport of electrons, for example molecule based solar cells or molecular scale electronics, it will be imperative to predict the electron transfer capabilities of different molecular structures. The potential difficulties with making such predictions and the lack of suitable models are also discussed.
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Affiliation(s)
- Bo Albinsson
- Department of Chemical and Biological Engineering/Physical Chemistry, Chalmers University of Technology, SE-412 96, Göteborg, Sweden.
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82
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Crofts AR, Rose S. Marcus treatment of endergonic reactions: a commentary. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:1228-32. [PMID: 17720135 PMCID: PMC2238675 DOI: 10.1016/j.bbabio.2007.06.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Revised: 06/14/2007] [Accepted: 06/20/2007] [Indexed: 10/23/2022]
Abstract
Two forms of the equation for expression of the rate constant for electron transfer through a Marcus-type treatment are discussed. In the first (exergonic) form, the Arrhenius exponential term was replaced by its classical Marcus term; in the second (endergonic) form, the forward rate constant was replaced by the reverse rate constant (the forward rate constant in the exergonic direction), which was expanded to an equivalent Marcus term and multiplied by the equilibrium constant. When the classical Marcus treatment was used, these two forms of the rate equation give identical curves relating the logarithm of the rate constant to the driving force. The Marcus term for the relation between activation free-energy, DeltaG#, reorganization energy, lambda, and driving force, DeltaG(o), derived from parabolas for the reactant and product states, was identical when starting from exergonic or endergonic parabolas. Moser and colleagues introduced a quantum mechanical correction factor to the Marcus term in order to fit experimental data. When the same correction factor was applied in the treatment for the endergonic direction by Page and colleagues, a different curve was obtained from that found with the exergonic form. We show that the difference resulted from an algebraic error in development of the endergonic equation.
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Affiliation(s)
- Antony R Crofts
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Avenue, Urbana, IL 61801, USA.
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83
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Paddock ML, Flores M, Isaacson R, Chang C, Abresch EC, Selvaduray P, Okamura MY. Trapped conformational states of semiquinone (D+*QB-*) formed by B-branch electron transfer at low temperature in Rhodobacter sphaeroides reaction centers. Biochemistry 2006; 45:14032-42. [PMID: 17115698 PMCID: PMC2259235 DOI: 10.1021/bi060854h] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reaction center (RC) from Rhodobacter sphaeroides captures light energy by electron transfer between quinones QA and QB, involving a conformational gating step. In this work, conformational states of D+*QB-* were trapped (80 K) and studied using EPR spectroscopy in native and mutant RCs that lack QA in which QB was reduced by the bacteriopheophytin along the B-branch. In mutant RCs frozen in the dark, a light induced EPR signal due to D+*QB-* formed in 30% of the sample with low quantum yield (0.2%-20%) and decayed in 6 s. A small signal with similar characteristics was also observed in native RCs. In contrast, the EPR signal due to D+*QB-* in mutant RCs illuminated while freezing formed in approximately 95% of the sample did not decay (tau >107 s) at 80 K (also observed in the native RC). In all samples, the observed g-values were the same (g = 2.0026), indicating that all active QB-*'s were located in a proximal conformation coupled with the nonheme Fe2+. We propose that before electron transfer at 80 K, the majority (approximately 70%) of QB, structurally located in the distal site, was not stably reducible, whereas the minority (approximately 30%) of active configurations was in the proximal site. The large difference in the lifetimes of the unrelaxed and relaxed D+*QB-* states is attributed to the relaxation of protein residues and internal water molecules that stabilize D+*QB-*. These results demonstrate energetically significant conformational changes involved in stabilizing the D+*QB-* state. The unrelaxed and relaxed states can be considered to be the initial and final states along the reaction coordinate for conformationally gated electron transfer.
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Affiliation(s)
- M L Paddock
- Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.
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