1
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Tichauer RH, Sokolovskii I, Groenhof G. Tuning the Coherent Propagation of Organic Exciton-Polaritons through the Cavity Q-factor. Adv Sci (Weinh) 2023; 10:e2302650. [PMID: 37818758 PMCID: PMC10667804 DOI: 10.1002/advs.202302650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 08/22/2023] [Indexed: 10/13/2023]
Abstract
Transport of excitons in organic materials can be enhanced through polariton formation when the interaction strength between these excitons and the confined light modes of an optical resonator exceeds their decay rates. While the polariton lifetime is determined by the Q(uality)-factor of the optical resonator, the polariton group velocity is not. Instead, the latter is solely determined by the polariton dispersion. Yet, experiments suggest that the Q-factor also controls the polariton propagation velocity. To understand this observation, the authors perform molecular dynamics simulations of Rhodamine chromophores strongly coupled to Fabry-Pérot cavities with various Q-factors. The results suggest that propagation in the aforementioned experiments is initially dominated by ballistic motion of upper polariton states at their group velocities, which leads to a rapid expansion of the wavepacket. Cavity decay in combination with non-adiabatic population transfer into dark states, rapidly depletes these bright states, causing the wavepacket to contract. However, because population transfer is reversible, propagation continues, but as a diffusion process, at lower velocity. By controlling the lifetime of bright states, the Q-factor determines the duration of the ballistic phase and the diffusion coefficient in the diffusive regime. Thus, polariton propagation in organic microcavities can be effectively tuned through the Q-factor.
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Affiliation(s)
- Ruth H. Tichauer
- Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)Universidad Autónoma de MadridMadridE‐28049Spain
| | - Ilia Sokolovskii
- Nanoscience Center and Department of ChemistryUniversity of JyväskyläP.O. Box 35, 40014JyväskyläFinland
| | - Gerrit Groenhof
- Nanoscience Center and Department of ChemistryUniversity of JyväskyläP.O. Box 35, 40014JyväskyläFinland
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2
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Wang YC, Feng S, Liang W, Zhao Y. Comment on "A posteriori localization of many-body excited states through simultaneous diagonalization". J Comput Chem 2023; 44:2158-2159. [PMID: 37452599 DOI: 10.1002/jcc.27188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 06/28/2023] [Indexed: 07/18/2023]
Abstract
We comment on an excited-state localization method recently proposed by Blanc et al. (J. Comput. Chem. 2023, 44, 105). Elaborate comparisons are made to demonstrate that their method is a less-comprehensive version of the diabatization method proposed by us 2 years earlier (J. Phys. Chem. Lett. 2021, 12, 1032).
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Affiliation(s)
- Yu-Chen Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, People's Republic of China
| | - Shishi Feng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, People's Republic of China
| | - WanZhen Liang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, People's Republic of China
| | - Yi Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, People's Republic of China
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3
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Li Z, Zhao C, Lin X, Ouyang G, Liu M. Stepwise Solution-Interfacial Nanoarchitectonics for Assembled Film with Full-Color and White-Light Circularly Polarized Luminescence. ACS Appl Mater Interfaces 2023. [PMID: 37329570 DOI: 10.1021/acsami.3c05803] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
The fabrication of chiral thin films with tunable circularly polarized luminescence (CPL) colors is important in developing chiroptical materials but remains challenging due to the lack of assembly-initiated chiral film formation methodology. Here, by adopting a combined solution aggregation and interfacial assembly strategy, we report the fabrication of chiral film materials with full-color and white-light CPL. A biquinoline glutamic acid ester (abbreviated as BQGE) shows a typical aggregation-induced emission property with blue CPL after solution aggregation. Subsequent interfacial assembly of these solution aggregates on a solid substrate leads to the formation of a CPL active film consisting of nanobelt structures. Since the BQGE molecule has a coordination site, the CPL emission of an individual BQGE film can be extended from blue to green emission upon coordination with a zinc ion, accompanied by morphology transition from nanobelts to nanofibers. Further extension to red-color CPL is successfully achieved by coassembly with an achiral acceptor dye. Interestingly, the proper combination of coordination ratio and acceptor loading ratio provides bright white-light CPL emission from the BQGE/Zn2+/PDA triad composite film. This work provides a new approach to fabricating chiroptical film materials with controlled microscopic morphology and tunable CPL properties.
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Affiliation(s)
- Zujian Li
- Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450052, China
- CAS Key Laboratory of Colloid, Interface and Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, No. 2 North First Street, Zhongguancun, Beijing 100190, China
| | - Chenyang Zhao
- Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450052, China
- CAS Key Laboratory of Colloid, Interface and Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, No. 2 North First Street, Zhongguancun, Beijing 100190, China
| | - Xuerong Lin
- Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450052, China
- CAS Key Laboratory of Colloid, Interface and Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, No. 2 North First Street, Zhongguancun, Beijing 100190, China
| | - Guanghui Ouyang
- CAS Key Laboratory of Colloid, Interface and Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, No. 2 North First Street, Zhongguancun, Beijing 100190, China
| | - Minghua Liu
- Henan Institute of Advanced Technology, Zhengzhou University, Zhengzhou 450052, China
- CAS Key Laboratory of Colloid, Interface and Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, No. 2 North First Street, Zhongguancun, Beijing 100190, China
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4
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Liu X, Li R, Xu X, Jiang Y, Zhu W, Yao Y, Li F, Tao X, Liu S, Huang W, Zhao Q. Lanthanide(III)-Cu 4 I 4 Organic Framework Scintillators Sensitized by Cluster-Based Antenna for High-Resolution X-ray Imaging. Adv Mater 2023; 35:e2206741. [PMID: 36303536 DOI: 10.1002/adma.202206741] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 10/12/2022] [Indexed: 06/16/2023]
Abstract
Scintillator-based X-ray imaging has attracted great attention from industrial quality inspection and security to medical diagnostics. Herein, a series of lanthanide(III)-Cu4 I4 heterometallic organic frameworks (Ln-Cu4 I4 MOFs)-based X-ray scintillators are developed by rationally assembling X-ray absorption centers ([Cu4 I4 ] clusters) and luminescent chromophores (Ln(III) ions) in a specific manner. Under X-ray irradiation, the heavy inorganic units ([Cu4 I4 ] clusters) absorb the X-ray energy to populate triplet excitons via halide-to-ligand charge transfer (XLCT) combined with the metal-to-ligand charge-transfer (MLCT) state (defined as the X/MLCT state), and then the 3 X/MLCT excited state sensitizes Tb3+ for intense X-ray-excited luminescence via excitation energy transfer. The obtained Tb-Cu4 I4 MOF scintillators exhibit high resistance to humidity and radiation, excellent linear response to X-ray dose rate, and high X-ray relative light yield of 29 379 ± 3000 photons MeV-1 . The relative light yield of Tb-Cu4 I4 MOFs is ≈3 times higher than that of the control Tb(III) complex. X-ray imaging tests show that the Tb-Cu4 I4 MOFs-based flexible scintillator film exhibits a high spatial resolution of 12.6 lp mm-1 . These findings not only provide a promising design strategy to develop lanthanide-MOF-based scintillators with excellent scintillation performance, but also exhibit high-resolution X-ray imaging for biological specimens and electronic chips.
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Affiliation(s)
- Xiangmei Liu
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NUPT), 9 Wenyuan, Nanjing, Jiangsu, 210023, P. R. China
| | - Ruhua Li
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NUPT), 9 Wenyuan, Nanjing, Jiangsu, 210023, P. R. China
| | - Xueli Xu
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NUPT), 9 Wenyuan, Nanjing, Jiangsu, 210023, P. R. China
| | - Yangyang Jiang
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NUPT), 9 Wenyuan, Nanjing, Jiangsu, 210023, P. R. China
| | - Wenjuan Zhu
- College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), Nanjing University of Posts & Telecommunications (NUPT), 9 Wenyuan, Nanjing, 210023, P. R. China
| | - Yu Yao
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NUPT), 9 Wenyuan, Nanjing, Jiangsu, 210023, P. R. China
| | - Feiyang Li
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NUPT), 9 Wenyuan, Nanjing, Jiangsu, 210023, P. R. China
| | - Xiaofang Tao
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NUPT), 9 Wenyuan, Nanjing, Jiangsu, 210023, P. R. China
| | - Shujuan Liu
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NUPT), 9 Wenyuan, Nanjing, Jiangsu, 210023, P. R. China
| | - Wei Huang
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NUPT), 9 Wenyuan, Nanjing, Jiangsu, 210023, P. R. China
- Frontiers Science Center for Flexible Electronics (FSCFE), MIIT Key Laboratory of Flexible Electronics (KLoFE), Northwestern Polytechnical University, Xi'an, 710072, P. R. China
| | - Qiang Zhao
- State Key Laboratory of Organic Electronics and Information Displays & Jiangsu Key Laboratory for Biosensors, Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NUPT), 9 Wenyuan, Nanjing, Jiangsu, 210023, P. R. China
- College of Electronic and Optical Engineering & College of Flexible Electronics (Future Technology), Nanjing University of Posts & Telecommunications (NUPT), 9 Wenyuan, Nanjing, 210023, P. R. China
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5
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Cignoni E, Cupellini L, Mennucci B. A fast method for electronic couplings in embedded multichromophoric systems. J Phys Condens Matter 2022; 34:304004. [PMID: 35552268 DOI: 10.1088/1361-648x/ac6f3c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 05/12/2022] [Indexed: 06/15/2023]
Abstract
Electronic couplings are key to understanding exciton delocalization and transport in natural and artificial light harvesting processes. We develop a method to compute couplings in multichromophoric aggregates embedded in complex environments without running expensive quantum chemical calculations. We use a transition charge approximation to represent the quantum mechanical transition densities of the chromophores and an atomistic and polarizable classical model to describe the environment atoms. We extend our framework to estimate transition charges directly from the chromophore geometry, i.e., bypassing completely the quantum mechanical calculations using a regression approach. The method allows to rapidly compute accurate couplings for a large number of geometries along molecular dynamics trajectories.
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Affiliation(s)
- Edoardo Cignoni
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124, Pisa, Italy
| | - Lorenzo Cupellini
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124, Pisa, Italy
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, via G. Moruzzi 13, 56124, Pisa, Italy
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6
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Park JW, Cho KH, Rhee YM. Mechanism of Ir(ppy) 3 Guest Exciton Formation with the Exciplex-Forming TCTA:TPBI Cohost within a Phosphorescent Organic Light-Emitting Diode Environment. Int J Mol Sci 2022; 23:5940. [PMID: 35682617 DOI: 10.3390/ijms23115940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/20/2022] [Accepted: 05/24/2022] [Indexed: 12/04/2022] Open
Abstract
Cohosts based on hole transporting and electron transporting materials often act as exciplexes in the form of intermolecular charge transfer complexes. Indeed, exciplex-forming cohosts have been widely developed as the host materials for efficient phosphorescent organic light-emitting diodes (OLEDs). In host–guest systems of OLEDs, the guest can be excited by two competing mechanisms, namely, excitation energy transfer (EET) and charge transfer (CT). Experimentally, it has been reported that the EET mechanism is dominant and the excitons are primarily formed in the host first and then transferred to the guest in phosphorescent OLEDs based on exciplex-forming cohosts. With this, exciplex-forming cohosts are widely employed for avoiding the formation of trapped charge carriers in the phosphorescent guest. However, theoretical studies are still lacking toward elucidating the relative importance between EET and CT processes in exciting the guest molecules in such systems. Here, we obtain the kinetics of guest excitation processes in a few trimer model systems consisting of an exciplex-forming cohost pair and a phosphorescent guest. We adopt the Förster resonance energy transfer (FRET) rate constants for the electronic transitions between excited states toward solving kinetic master equations. The input parameters for calculating the FRET rate constants are obtained from density functional theory (DFT) and time-dependent DFT. The results show that while the EET mechanism is important, the CT mechanism may still play a significant role in guest excitations. In fact, the relative importance of CT over EET depends strongly on the location of the guest molecule relative to the cohost pair. This is understandable as both the coupling for EET and the interaction energy for CT are strongly influenced by the geometric constraints. Understanding the energy transfer pathways from the exciplex state of cohost to the emissive state of guest may provide insights for improving exciplex-forming materials adopted in OLEDs.
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7
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Yakimov BP, Rubekina AA, Budylin GS, Zherebker AY, Kompanets VO, Chekalin SV, Vainer YG, Fadeev VV, Gorbunov MY, Perminova IV, Shirshin EA. Ultrafast Energy Transfer Determines the Formation of Fluorescence in DOM and Humic Substances. Environ Sci Technol 2021; 55:10365-10377. [PMID: 34260209 DOI: 10.1021/acs.est.1c00998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Humification is a ubiquitous natural process of biomass degradation that creates multicomponent systems of nonliving organic matter, including dissolved organic matter (DOM) and humic substances (HS) in water environments, soils, and organic rocks. Despite significant differences in molecular composition, the optical properties of DOM and HS are remarkably similar, and the reason for this remains largely unknown. Here, we employed fluorescence spectroscopy with (sub)picosecond resolution to elucidate the role of electronic interactions within DOM and HS. We revealed an ultrafast decay component with a characteristic decay lifetime of 0.5-1.5 ps and spectral diffusion originating from excitation energy transfer (EET) in the system. The rate of EET was positively correlated to the fraction of aromatic species and tightness of aromatic species packing. Diminishing the number of EET donor-acceptor pairs by reduction with NaBH4 (decrease of the acceptor number), decrease of pH (decrease of the electron-donating ability), or decrease of the average particle size by filtration (less donor-acceptor pairs within a particle) resulted in a lower impact of the ultrafast component on fluorescence decay. Our results uncover the role of electronic coupling among fluorophores in the formation of DOM and HS optical properties and provide a framework for studying photophysical processes in heterogeneous systems of natural fluorophores.
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Affiliation(s)
- Boris P Yakimov
- Faculty of Physics, M.V. Lomonosov Moscow State University, 1-2 Leninskie Gory, 119991 Moscow, Russia
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", Sechenov First Moscow State Medical University, Trubetskaya Street, 8-2, 119048 Moscow, Russia
| | - Anna A Rubekina
- Faculty of Physics, M.V. Lomonosov Moscow State University, 1-2 Leninskie Gory, 119991 Moscow, Russia
| | - Gleb S Budylin
- Institute of Spectroscopy of the Russian Academy of Sciences, Fizicheskaya Street, 5, Troitsk, 108840 Moscow, Russia
| | - Alexander Y Zherebker
- Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, 3 Nobel Street, Skolkovo, 143026 Moscow, Russia
| | - Victor O Kompanets
- Institute of Spectroscopy of the Russian Academy of Sciences, Fizicheskaya Street, 5, Troitsk, 108840 Moscow, Russia
| | - Sergey V Chekalin
- Institute of Spectroscopy of the Russian Academy of Sciences, Fizicheskaya Street, 5, Troitsk, 108840 Moscow, Russia
| | - Yuri G Vainer
- Institute of Spectroscopy of the Russian Academy of Sciences, Fizicheskaya Street, 5, Troitsk, 108840 Moscow, Russia
| | - Victor V Fadeev
- Faculty of Physics, M.V. Lomonosov Moscow State University, 1-2 Leninskie Gory, 119991 Moscow, Russia
| | - Maxim Y Gorbunov
- Environmental Biology and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, 57 US Highway 1, New Brunswick, New Jersey 08901-8554, United States
| | - Irina V Perminova
- Faculty of Chemistry, M.V. Lomonosov Moscow State University, 1-3 Leninskie Gory, 119991 Moscow, Russia
| | - Evgeny A Shirshin
- Faculty of Physics, M.V. Lomonosov Moscow State University, 1-2 Leninskie Gory, 119991 Moscow, Russia
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", Sechenov First Moscow State Medical University, Trubetskaya Street, 8-2, 119048 Moscow, Russia
- Institute of Spectroscopy of the Russian Academy of Sciences, Fizicheskaya Street, 5, Troitsk, 108840 Moscow, Russia
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8
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Zheng F, Chen L, Gao J, Zhao Y. Fully Quantum Modeling of Exciton Diffusion in Mesoscale Light Harvesting Systems. Materials (Basel) 2021; 14:3291. [PMID: 34198704 PMCID: PMC8232211 DOI: 10.3390/ma14123291] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 06/06/2021] [Accepted: 06/08/2021] [Indexed: 11/16/2022]
Abstract
It has long been a challenge to accurately and efficiently simulate exciton-phonon dynamics in mesoscale photosynthetic systems with a fully quantum mechanical treatment due to extensive computational resources required. In this work, we tackle this seemingly intractable problem by combining the Dirac-Frenkel time-dependent variational method with Davydov trial states and implementing the algorithm in graphic processing units. The phonons are treated on the same footing as the exciton. Tested with toy models, which are nanoarrays of the B850 pigments from the light harvesting 2 complexes of purple bacteria, the methodology is adopted to describe exciton diffusion in huge systems containing more than 1600 molecules. The superradiance enhancement factor extracted from the simulations indicates an exciton delocalization over two to three pigments, in agreement with measurements of fluorescence quantum yield and lifetime in B850 systems. With fractal analysis of the exciton dynamics, it is found that exciton transfer in B850 nanoarrays exhibits a superdiffusion component for about 500 fs. Treating the B850 ring as an aggregate and modeling the inter-ring exciton transfer as incoherent hopping, we also apply the method of classical master equations to estimate exciton diffusion properties in one-dimensional (1D) and two-dimensional (2D) B850 nanoarrays using derived analytical expressions of time-dependent excitation probabilities. For both coherent and incoherent propagation, faster energy transfer is uncovered in 2D nanoarrays than 1D chains, owing to availability of more numerous propagating channels in the 2D arrangement.
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Affiliation(s)
- Fulu Zheng
- Bremen Center for Computational Materials Science, University of Bremen, 28359 Bremen, Germany;
| | - Lipeng Chen
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str., 38, 01187 Dresden, Germany;
| | - Jianbo Gao
- Center for Geodata and Analysis, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China;
- Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Yang Zhao
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
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9
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Lokstein H, Renger G, Götze JP. Photosynthetic Light-Harvesting (Antenna) Complexes-Structures and Functions. Molecules 2021; 26:molecules26113378. [PMID: 34204994 PMCID: PMC8199901 DOI: 10.3390/molecules26113378] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 02/07/2023] Open
Abstract
Chlorophylls and bacteriochlorophylls, together with carotenoids, serve, noncovalently bound to specific apoproteins, as principal light-harvesting and energy-transforming pigments in photosynthetic organisms. In recent years, enormous progress has been achieved in the elucidation of structures and functions of light-harvesting (antenna) complexes, photosynthetic reaction centers and even entire photosystems. It is becoming increasingly clear that light-harvesting complexes not only serve to enlarge the absorption cross sections of the respective reaction centers but are vitally important in short- and long-term adaptation of the photosynthetic apparatus and regulation of the energy-transforming processes in response to external and internal conditions. Thus, the wide variety of structural diversity in photosynthetic antenna “designs” becomes conceivable. It is, however, common for LHCs to form trimeric (or multiples thereof) structures. We propose a simple, tentative explanation of the trimer issue, based on the 2D world created by photosynthetic membrane systems.
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Affiliation(s)
- Heiko Lokstein
- Department of Chemical Physics and Optics, Charles University, Ke Karlovu 3, 12116 Prague, Czech Republic
- Correspondence:
| | - Gernot Renger
- Max-Volmer-Laboratorium, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Jan P. Götze
- Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, D-14195 Berlin, Germany;
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10
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Abstract
Multiscale models combining quantum mechanical and classical descriptions are a very popular strategy to simulate properties and processes of complex systems. Many alternative formulations have been developed, and they are now available in all of the most widely used quantum chemistry packages. Their application to the study of light-driven processes, however, is more recent, and some methodological and numerical problems have yet to be solved. This is especially the case for the polarizable formulation of these models, the recent advances in which we review here. Specifically, we identify and describe the most important specificities that the polarizable formulation introduces into both the simulation of excited-state dynamics and the modeling of excitation energy and electron transfer processes.
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Affiliation(s)
- Michele Nottoli
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, 56124 Pisa, Italy;
| | - Lorenzo Cupellini
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, 56124 Pisa, Italy;
| | - Filippo Lipparini
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, 56124 Pisa, Italy;
| | - Giovanni Granucci
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, 56124 Pisa, Italy;
| | - Benedetta Mennucci
- Dipartimento di Chimica e Chimica Industriale, Università di Pisa, 56124 Pisa, Italy;
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11
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Abstract
Due to the subtle interplay of site-to-site electronic couplings, exciton delocalization, nonadiabatic effects, and vibronic couplings, quantum dynamical studies are needed to elucidate the details of ultrafast photoinduced energy and charge transfer events in organic multichromophoric systems. In this vein, we review an approach that combines first-principles parameterized lattice Hamiltonians with accurate quantum dynamical simulations using advanced multiconfigurational methods. Focusing on the elementary transfer steps in organic functional materials, we address coherent exciton migration and creation of charge transfer excitons in homopolymers, notably representative of the poly(3-hexylthiophene) material, as well as exciton dissociation at polymer:fullerene heterojunctions. We emphasize the role of coherent transfer, trapping effects due to high-frequency phonon modes, and thermal activation due to low-frequency soft modes that drive a diffusive dynamics.
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Affiliation(s)
- Wjatscheslaw Popp
- Institute for Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438 Frankfurt, Germany;
| | - Dominik Brey
- Institute for Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438 Frankfurt, Germany;
| | - Robert Binder
- Institute for Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438 Frankfurt, Germany;
| | - Irene Burghardt
- Institute for Physical and Theoretical Chemistry, Goethe University Frankfurt, 60438 Frankfurt, Germany;
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12
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Nolden O, Fleck N, Lorenzo ER, Wasielewski MR, Schiemann O, Gilch P, Richert S. Excitation Energy Transfer and Exchange-Mediated Quartet State Formation in Porphyrin-Trityl Systems. Chemistry 2020; 27:2683-2691. [PMID: 32681763 PMCID: PMC7898503 DOI: 10.1002/chem.202002805] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Indexed: 01/07/2023]
Abstract
Photogenerated multi‐spin systems hold great promise for a range of technological applications in various fields, including molecular spintronics and artificial photosynthesis. However, the further development of these applications, via targeted design of materials with specific magnetic properties, currently still suffers from a lack of understanding of the factors influencing the underlying excited state dynamics and mechanisms on a molecular level. In particular, systematic studies, making use of different techniques to obtain complementary information, are largely missing. This work investigates the photophysics and magnetic properties of a series of three covalently‐linked porphyrin‐trityl compounds, bridged by a phenyl spacer. By combining the results from femtosecond transient absorption and electron paramagnetic resonance spectroscopies, we determine the efficiencies of the competing excited state reaction pathways and characterise the magnetic properties of the individual spin states, formed by the interaction between the chromophore triplet and the stable radical. The differences observed for the three investigated compounds are rationalised in the context of available theoretical models and the implications of the results of this study for the design of a molecular system with an improved intersystem crossing efficiency are discussed.
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Affiliation(s)
- Oliver Nolden
- Institute of Physical Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Nico Fleck
- Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstraße 12, 53115, Bonn, Germany
| | - Emmaline R Lorenzo
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208-3113, USA
| | - Michael R Wasielewski
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208-3113, USA
| | - Olav Schiemann
- Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstraße 12, 53115, Bonn, Germany
| | - Peter Gilch
- Institute of Physical Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Sabine Richert
- Institute of Physical Chemistry, University of Freiburg, Albertstraße 21, 79104, Freiburg, Germany
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13
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Tamura H, Saito K, Ishikita H. Acquirement of water-splitting ability and alteration of the charge-separation mechanism in photosynthetic reaction centers. Proc Natl Acad Sci U S A 2020; 117:16373-82. [PMID: 32601233 DOI: 10.1073/pnas.2000895117] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In photosynthetic reaction centers from purple bacteria (PbRC) and the water-oxidizing enzyme, photosystem II (PSII), charge separation occurs along one of the two symmetrical electron-transfer branches. Here we report the microscopic origin of the unidirectional charge separation, fully considering electron-hole interaction, electronic coupling of the pigments, and electrostatic interaction with the polarizable entire protein environments. The electronic coupling between the pair of bacteriochlorophylls is large in PbRC, forming a delocalized excited state with the lowest excitation energy (i.e., the special pair). The charge-separated state in the active branch is stabilized by uncharged polar residues in the transmembrane region and charged residues on the cytochrome c 2 binding surface. In contrast, the accessory chlorophyll in the D1 protein (ChlD1) has the lowest excitation energy in PSII. The charge-separated state involves ChlD1 •+ and is stabilized predominantly by charged residues near the Mn4CaO5 cluster and the proceeding proton-transfer pathway. It seems likely that the acquirement of water-splitting ability makes ChlD1 the initial electron donor in PSII.
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14
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Kell A, Khmelnitskiy AY, Reinot T, Jankowiak R. On uncorrelated inter-monomer Förster energy transfer in Fenna-Matthews-Olson complexes. J R Soc Interface 2020; 16:20180882. [PMID: 30958204 DOI: 10.1098/rsif.2018.0882] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The Fenna-Matthews-Olson (FMO) light-harvesting antenna protein of green sulfur bacteria is a long-studied pigment-protein complex which funnels energy from the chlorosome to the reaction centre where photochemistry takes place. The structure of the FMO protein from Chlorobaculum tepidum is known as a homotrimeric complex containing eight bacteriochlorophyll a per monomer. Owing to this structure FMO has strong intra-monomer and weak inter-monomer electronic coupling constants. While long-lived (sub-picosecond) coherences within a monomer have been a prevalent topic of study over the past decade, various experimental evidence supports the presence of subsequent inter-monomer energy transfer on a picosecond time scale. The latter has been neglected by most authors in recent years by considering only sub-picosecond time scales or assuming that the inter-monomer coupling between low-energy states is too weak to warrant consideration of the entire trimer. However, Förster theory predicts that energy transfer of the order of picoseconds is possible even for very weak (less than 5 cm-1) electronic coupling between chromophores. This work reviews experimental data (with a focus on emission and hole-burned spectra) and simulations of exciton dynamics which demonstrate inter-monomer energy transfer. It is shown that the lowest energy 825 nm absorbance band cannot be properly described by a single excitonic state. The energy transfer through FMO is modelled by generalized Förster theory using a non-Markovian, reduced density matrix approach to describe the electronic structure. The disorder-averaged inter-monomer transfer time across the 825 nm band is about 27 ps. While only isolated FMO proteins are presented, the presence of inter-monomer energy transfer in the context of the overall photosystem is also briefly discussed.
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Affiliation(s)
- Adam Kell
- 1 Department of Chemistry, Kansas State University , Manhattan, KS , USA
| | | | - Tonu Reinot
- 1 Department of Chemistry, Kansas State University , Manhattan, KS , USA
| | - Ryszard Jankowiak
- 1 Department of Chemistry, Kansas State University , Manhattan, KS , USA.,2 Department of Physics, Kansas State University , Manhattan, KS , USA
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15
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Müh F, Zouni A. Structural basis of light-harvesting in the photosystem II core complex. Protein Sci 2020; 29:1090-1119. [PMID: 32067287 PMCID: PMC7184784 DOI: 10.1002/pro.3841] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 02/06/2020] [Accepted: 02/06/2020] [Indexed: 12/20/2022]
Abstract
Photosystem II (PSII) is a membrane-spanning, multi-subunit pigment-protein complex responsible for the oxidation of water and the reduction of plastoquinone in oxygenic photosynthesis. In the present review, the recent explosive increase in available structural information about the PSII core complex based on X-ray crystallography and cryo-electron microscopy is described at a level of detail that is suitable for a future structure-based analysis of light-harvesting processes. This description includes a proposal for a consistent numbering scheme of protein-bound pigment cofactors across species. The structural survey is complemented by an overview of the state of affairs in structure-based modeling of excitation energy transfer in the PSII core complex with emphasis on electrostatic computations, optical properties of the reaction center, the assignment of long-wavelength chlorophylls, and energy trapping mechanisms.
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Affiliation(s)
- Frank Müh
- Department of Theoretical Biophysics, Institute for Theoretical Physics, Johannes Kepler University Linz, Linz, Austria
| | - Athina Zouni
- Humboldt-Universität zu Berlin, Institute for Biology, Biophysics of Photosynthesis, Berlin, Germany
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16
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Michalik M, Zbyradowski M, Fiedor L; Heriyanto. Tuning the Photophysical Features of Self-Assembling Photoactive Polypeptides for Light-Harvesting. Materials (Basel) 2019; 12:E3554. [PMID: 31671513 DOI: 10.3390/ma12213554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 10/25/2019] [Accepted: 10/27/2019] [Indexed: 01/03/2023]
Abstract
The LH1 complex is the major light-harvesting antenna of purple photosynthetic bacteria. Its role is to capture photons, and then store them and transfer the excitation energy to the photosynthetic reaction center. The structure of LH1 is modular and it cooperatively self-assembles from the subunits composed of short transmembrane polypeptides that reversibly bind the photoactive cofactors: bacteriochlorophyll and carotenoid. LH1 assembly, the intra-complex interactions and the light-harvesting features of LH1 can be controlled in micellar media by varying the surfactant concentration and by adding carotenoid and/or a co-solvent. By exploiting this approach, we can manipulate the size of the assembly, the intensity of light absorption, and the energy and lifetime of its first excited singlet state. For instance, via the introduction of Ni-substituted bacteriochlorophyll into LH1, the lifetime of this electronic state of the antenna can be shortened by almost three orders of magnitude. On the other hand, via the exchange of carotenoid, light absorption in the visible range can be tuned. These results show how in a relatively simple self-assembling pigment-polypeptide system a sophisticated functional tuning can be achieved and thus they provide guidelines for the construction of bio-inspired photoactive nanodevices.
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17
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Mancini JA, Sheehan M, Kodali G, Chow BY, Bryant DA, Dutton PL, Moser CC. De novo synthetic biliprotein design, assembly and excitation energy transfer. J R Soc Interface 2019; 15:rsif.2018.0021. [PMID: 29618529 DOI: 10.1098/rsif.2018.0021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 03/13/2018] [Indexed: 12/26/2022] Open
Abstract
Bilins are linear tetrapyrrole chromophores with a wide range of visible and near-visible light absorption and emission properties. These properties are tuned upon binding to natural proteins and exploited in photosynthetic light-harvesting and non-photosynthetic light-sensitive signalling. These pigmented proteins are now being manipulated to develop fluorescent experimental tools. To engineer the optical properties of bound bilins for specific applications more flexibly, we have used first principles of protein folding to design novel, stable and highly adaptable bilin-binding four-α-helix bundle protein frames, called maquettes, and explored the minimal requirements underlying covalent bilin ligation and conformational restriction responsible for the strong and variable absorption, fluorescence and excitation energy transfer of these proteins. Biliverdin, phycocyanobilin and phycoerythrobilin bind covalently to maquette Cys in vitro A blue-shifted tripyrrole formed from maquette-bound phycocyanobilin displays a quantum yield of 26%. Although unrelated in fold and sequence to natural phycobiliproteins, bilin lyases nevertheless interact with maquettes during co-expression in Escherichia coli to improve the efficiency of bilin binding and influence bilin structure. Bilins bind in vitro and in vivo to Cys residues placed in loops, towards the amino end or in the middle of helices but bind poorly at the carboxyl end of helices. Bilin-binding efficiency and fluorescence yield are improved by Arg and Asp residues adjacent to the ligating Cys on the same helix and by His residues on adjacent helices.
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Affiliation(s)
- Joshua A Mancini
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Molly Sheehan
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Goutham Kodali
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Brian Y Chow
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - P Leslie Dutton
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
| | - Christopher C Moser
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA, USA
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18
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Wilhelm P, Vogelsang J, Höger S, Lupton JM. Homo-FRET in π-Conjugated Polygons: Intermediate-Strength Dipole-Dipole Coupling Makes Energy Transfer Reversible. Nano Lett 2019; 19:5483-5488. [PMID: 31294999 DOI: 10.1021/acs.nanolett.9b01998] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The concept of homo-FRET is often used to describe energy transfer between like chromophores of molecular aggregates such as in π-conjugated polymers. Homo-FRET is revealed by a dynamic depolarization in fluorescence but strictly only applies to the limit of weak dipole-dipole coupling, where energy transfer occurs on time scales much longer than those of nuclear relaxation. By considering the polarization anisotropy of photoluminescence emission and excitation of model multichromophoric aggregates on the single-molecule level, we demonstrate the transition of energy-transfer dynamics from the case of weak coupling to that of strong coupling, revealing the elusive regime of intermediate-strength coupling where energy transfer between degenerate donor and acceptor chromophores becomes reversible so that information on the excitation route of the emitting chromophore is lost.
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Affiliation(s)
- Philipp Wilhelm
- Institut für Experimentelle und Angewandte Physik , Universität Regensburg , Universitätsstrasse 31 , 93053 Regensburg , Germany
| | - Jan Vogelsang
- Institut für Experimentelle und Angewandte Physik , Universität Regensburg , Universitätsstrasse 31 , 93053 Regensburg , Germany
| | - Sigurd Höger
- Kekulé-Institut für Organische Chemie und Biochemie , Universität Bonn , Gerhard-Domagk-Straße 1 , 53121 Bonn , Germany
| | - John M Lupton
- Institut für Experimentelle und Angewandte Physik , Universität Regensburg , Universitätsstrasse 31 , 93053 Regensburg , Germany
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19
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Bennett DIG, Amarnath K, Park S, Steen CJ, Morris JM, Fleming GR. Models and mechanisms of the rapidly reversible regulation of photosynthetic light harvesting. Open Biol 2019; 9:190043. [PMID: 30966997 PMCID: PMC6501642 DOI: 10.1098/rsob.190043] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 03/07/2019] [Indexed: 02/02/2023] Open
Abstract
The rapid response of photosynthetic organisms to fluctuations in ambient light intensity is incompletely understood at both the molecular and membrane levels. In this review, we describe research from our group over a 10-year period aimed at identifying the photophysical mechanisms used by plants, algae and mosses to control the efficiency of light harvesting by photosystem II on the seconds-to-minutes time scale. To complement the spectroscopic data, we describe three models capable of describing the measured response at a quantitative level. The review attempts to provide an integrated view that has emerged from our work, and briefly looks forward to future experimental and modelling efforts that will refine and expand our understanding of a process that significantly influences crop yields.
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Affiliation(s)
- Doran I. G. Bennett
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Kapil Amarnath
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
| | - Soomin Park
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Labs, Berkeley, CA 94720, USA
| | - Collin J. Steen
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Labs, Berkeley, CA 94720, USA
| | - Jonathan M. Morris
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Labs, Berkeley, CA 94720, USA
| | - Graham R. Fleming
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Labs, Berkeley, CA 94720, USA
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20
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Park S, Steen CJ, Lyska D, Fischer AL, Endelman B, Iwai M, Niyogi KK, Fleming GR. Chlorophyll-carotenoid excitation energy transfer and charge transfer in Nannochloropsis oceanica for the regulation of photosynthesis. Proc Natl Acad Sci U S A 2019; 116:3385-90. [PMID: 30808735 DOI: 10.1073/pnas.1819011116] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Nonphotochemical quenching (NPQ) is a proxy for photoprotective thermal dissipation processes that regulate photosynthetic light harvesting. The identification of NPQ mechanisms and their molecular or physiological triggering factors under in vivo conditions is a matter of controversy. Here, to investigate chlorophyll (Chl)-zeaxanthin (Zea) excitation energy transfer (EET) and charge transfer (CT) as possible NPQ mechanisms, we performed transient absorption (TA) spectroscopy on live cells of the microalga Nannochloropsis oceanica We obtained evidence for the operation of both EET and CT quenching by observing spectral features associated with the Zea S1 and Zea●+ excited-state absorption (ESA) signals, respectively, after Chl excitation. Knockout mutants for genes encoding either violaxanthin de-epoxidase or LHCX1 proteins exhibited strongly inhibited NPQ capabilities and lacked detectable Zea S1 and Zea●+ ESA signals in vivo, which strongly suggests that the accumulation of Zea and active LHCX1 is essential for both EET and CT quenching in N. oceanica.
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21
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Hatanaka M, Wakabayashi T. Theoretical study of lanthanide-based in vivo luminescent probes for detecting hydrogen peroxide. J Comput Chem 2019; 40:500-506. [PMID: 30414197 DOI: 10.1002/jcc.25737] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 09/27/2018] [Accepted: 09/28/2018] [Indexed: 11/06/2022]
Abstract
The 4f-4f emissions from lanthanide trication (Ln3+ ) complexes are widely used in bioimaging probes. The emission intensity from Ln3+ depends on the surroundings, and thus, the design of appropriate photo-antenna ligands is indispensable. In this study, we focus on two probes for detecting hydrogen peroxide, for which emission intensities from Tb3+ are enhanced chemo-selectively by the H2 O2 -mediated oxidation of ligands. To understand the mechanism, the Gibbs free energy profiles of the ground and excited states related to emission and quenching are computed by combining our approximation-called the energy shift method-and density functional theory. The different emission intensities are mainly attributed to different activation barriers for excitation energy transfer from the ligand-centered triplet (T1) to the Tb3+ -centered excited state. Additionally, quenching from T1 to the ground state via intersystem crossing was inhibited by intramolecular hydrogen bonds only in the highly emissive Tb3+ complexes. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Miho Hatanaka
- Institute for Research Initiatives, Division for Research Strategy, Graduate School of Science and Technology, Data Science Center, Nara Institute of Science and Technology, Nara, 630-0192, Japan.,PRESTO, Japan Science and Technology Agency (JST), Saitama, 332-0012, Japan
| | - Tomonari Wakabayashi
- Graduate School of Science and Engineering, Kindai University, Osaka, 577-8502, Japan
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22
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Blau SM, Bennett DIG, Kreisbeck C, Scholes GD, Aspuru-Guzik A. Local protein solvation drives direct down-conversion in phycobiliprotein PC645 via incoherent vibronic transport. Proc Natl Acad Sci U S A 2018; 115:E3342-E3350. [PMID: 29588417 PMCID: PMC5899487 DOI: 10.1073/pnas.1800370115] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The mechanisms controlling excitation energy transport (EET) in light-harvesting complexes remain controversial. Following the observation of long-lived beats in 2D electronic spectroscopy of PC645, vibronic coherence, the delocalization of excited states between pigments supported by a resonant vibration, has been proposed to enable direct excitation transport from the highest-energy to the lowest-energy pigments, bypassing a collection of intermediate states. Here, we instead show that for phycobiliprotein PC645 an incoherent vibronic transport mechanism is at play. We quantify the solvation dynamics of individual pigments using ab initio quantum mechanics/molecular mechanics (QM/MM) nuclear dynamics. Our atomistic spectral densities reproduce experimental observations ranging from absorption and fluorescence spectra to the timescales and selectivity of down-conversion observed in transient absorption measurements. We construct a general model for vibronic dimers and establish the parameter regimes of coherent and incoherent vibronic transport. We demonstrate that direct down-conversion in PC645 proceeds incoherently, enhanced by large reorganization energies and a broad collection of high-frequency vibrations. We suggest that a similar incoherent mechanism is appropriate across phycobiliproteins and represents a potential design principle for nanoscale control of EET.
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Affiliation(s)
- Samuel M Blau
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Doran I G Bennett
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
- Bio-Inspired Solar Energy Program, Canadian Institute for Advanced Research, Toronto, ON M5G 1Z8, Canada
| | - Christoph Kreisbeck
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Gregory D Scholes
- Bio-Inspired Solar Energy Program, Canadian Institute for Advanced Research, Toronto, ON M5G 1Z8, Canada
- Department of Chemistry, Princeton University, Princeton, NJ 08544
| | - Alán Aspuru-Guzik
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138;
- Bio-Inspired Solar Energy Program, Canadian Institute for Advanced Research, Toronto, ON M5G 1Z8, Canada
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23
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Reisch A, Trofymchuk K, Runser A, Fleith G, Rawiso M, Klymchenko AS. Tailoring Fluorescence Brightness and Switching of Nanoparticles through Dye Organization in the Polymer Matrix. ACS Appl Mater Interfaces 2017; 9:43030-43042. [PMID: 29185702 DOI: 10.1021/acsami.7b12292] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Fluorescent nanoparticles (NPs) help to increase spatial and temporal resolution in bioimaging. Advanced microscopy techniques require very bright NPs that exhibit either stable emission for single-particle tracking or complete on/off switching (blinking) for super-resolution imaging. Here, ultrabright dye-loaded polymer NPs with controlled switching properties are developed. To this aim, the salt of a dye (rhodamine B octadecyl ester) with a hydrophobic counterion (fluorinated tetraphenylborate) is encapsulated at very high concentrations up to 30 wt % in NPs made of poly(lactic-co-glycolic acid) (PLGA), poly(methyl methacrylate) (PMMA), and polycaprolactone (PCL) through nanoprecipitation. The obtained 35 nm NPs are nearly 100 times brighter than quantum dots. The nature of the polymer is found to define the collective behavior of the encapsulated dyes so that NPs containing thousands of dyes exhibit either whole particle blinking, for PLGA, or stable emission, for PMMA and PCL. Fluorescence anisotropy measurements together with small-angle X-ray scattering experiments suggest that in less hydrophobic PLGA, dyes tend to cluster, whereas in more hydrophobic PMMA and PCL, dyes are dispersed within the matrix, thus altering the switching behavior of NPs. Experiments using a perylene diimide derivative show a similar effect of the polymer nature. The resulting fluorescent NPs are suitable for a wide range of imaging applications from tracking to super-resolution imaging. The findings on the organization of the load innside NPs will have impact on the development of materials for applications ranging from photovoltaics to drug delivery.
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Affiliation(s)
- Andreas Reisch
- Laboratoire de Biophotonique et Pharmacologie, UMR CNRS 7213, Université de Strasbourg , 74 route du Rhin, 67401 Illkirch Cedex, France
| | - Kateryna Trofymchuk
- Laboratoire de Biophotonique et Pharmacologie, UMR CNRS 7213, Université de Strasbourg , 74 route du Rhin, 67401 Illkirch Cedex, France
| | - Anne Runser
- Laboratoire de Biophotonique et Pharmacologie, UMR CNRS 7213, Université de Strasbourg , 74 route du Rhin, 67401 Illkirch Cedex, France
| | - Guillaume Fleith
- Institut Charles Sadron (CNRS-UdS) , 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France
| | - Michel Rawiso
- Institut Charles Sadron (CNRS-UdS) , 23 rue du Loess, BP 84047, 67034 Strasbourg Cedex 2, France
| | - Andrey S Klymchenko
- Laboratoire de Biophotonique et Pharmacologie, UMR CNRS 7213, Université de Strasbourg , 74 route du Rhin, 67401 Illkirch Cedex, France
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24
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Mancini JA, Kodali G, Jiang J, Reddy KR, Lindsey JS, Bryant DA, Dutton PL, Moser CC. Multi-step excitation energy transfer engineered in genetic fusions of natural and synthetic light-harvesting proteins. J R Soc Interface 2017; 14:rsif.2016.0896. [PMID: 28179548 DOI: 10.1098/rsif.2016.0896] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 01/16/2017] [Indexed: 11/12/2022] Open
Abstract
Synthetic proteins designed and constructed from first principles with minimal reference to the sequence of any natural protein have proven robust and extraordinarily adaptable for engineering a range of functions. Here for the first time we describe the expression and genetic fusion of a natural photosynthetic light-harvesting subunit with a synthetic protein designed for light energy capture and multi-step transfer. We demonstrate excitation energy transfer from the bilin of the CpcA subunit (phycocyanin α subunit) of the cyanobacterial photosynthetic light-harvesting phycobilisome to synthetic four-helix-bundle proteins accommodating sites that specifically bind a variety of selected photoactive tetrapyrroles positioned to enhance energy transfer by relay. The examination of combinations of different bilin, chlorin and bacteriochlorin cofactors has led to identification of the preconditions for directing energy from the bilin light-harvesting antenna into synthetic protein-cofactor constructs that can be customized for light-activated chemistry in the cell.
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Affiliation(s)
- Joshua A Mancini
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Goutham Kodali
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jianbing Jiang
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | | | - Jonathan S Lindsey
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - P Leslie Dutton
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christopher C Moser
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
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25
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Sutradhar S, Patnaik A. Structure and Dynamics of a N-Methylfulleropyrrolidine-Mediated Gold Nanocomposite: A Spectroscopic Ruler. ACS Appl Mater Interfaces 2017; 9:21921-21932. [PMID: 28593769 DOI: 10.1021/acsami.7b02640] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A mechanistic understanding of the structure and dynamics of a chemically tunable N-methylfulleropyrrolidine (8-NMFP)-assisted gold nanocomposite and its aggregation via a controllable interparticle interaction is reported as a function of the molar ratio and pH of the medium. Electronic structure calculations adopting density functional theory methods implied electrostatic interactions to play a dominant role between 8-NMFP and citrate-capped gold nanoparticles. MM+ molecular mechanics force field computations revealed intermolecular gold-gold interactions, contributing toward the formation of spherical composite aggregates. Corroborating these, optical absorption spectra showed the usual surface plasmon band along with a higher-wavelength feature at ∼600-650 nm, indicative of the aggregated nanocomposite. pH-controlled reversible tuning of the plasmonic features in the composite was evident in a pH interval ∼5-6.8, revealing prevalent interparticle electrostatic interactions. In addition, photoluminescence (PL) and time-correlated single-photon counting studies revealed a strong nanocomposite interaction with a pure fluorescent dye, Rhodamine B, indicating excitation energy transfer from the dye to the composite. The dye upon interaction with the nanocomposite showed a significant quenching of its PL intensity and shortening of lifetime. Energy coupling between the metal nanoparticle composite and the emitting molecular dipole resulted in a long-range surface energy transfer (SET) from the donor dye to the surface plasmon modes of the nanoparticle following a donor-acceptor distance dependence of 1/r4. This molecular beacon with correlation between the nanoscale structure and the nonradiative nanometal SET can be used as a spectroscopic/molecular ruler in probing advanced functional materials.
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Affiliation(s)
- Sanjeeb Sutradhar
- Colloid and Interface Chemistry Laboratory, Department of Chemistry, Indian Institute of Technology Madras , Chennai 600036, India
| | - Archita Patnaik
- Colloid and Interface Chemistry Laboratory, Department of Chemistry, Indian Institute of Technology Madras , Chennai 600036, India
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Long Y, Hedley GJ, Ruseckas A, Chowdhury M, Roland T, Serrano LA, Cooke G, Samuel IDW. Effect of Annealing on Exciton Diffusion in a High Performance Small Molecule Organic Photovoltaic Material. ACS Appl Mater Interfaces 2017; 9:14945-14952. [PMID: 28358189 PMCID: PMC5423077 DOI: 10.1021/acsami.6b16487] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 03/30/2017] [Indexed: 05/29/2023]
Abstract
Singlet exciton diffusion was studied in the efficient organic photovoltaic electron donor material DTS(FBTTh2)2. Three complementary time-resolved fluorescence measurements were performed: quenching in planar heterojunctions with an electron acceptor, exciton-exciton annihilation, and fluorescence depolarization. The average exciton diffusivity increases upon annealing from 1.6 × 10-3 to 3.6 × 10-3 cm2 s-1, resulting in an enhancement of the mean two-dimensional exciton diffusion length (LD = (4Dτ)1/2) from 15 to 27 nm. About 30% of the excitons get trapped very quickly in as-cast films. The high exciton diffusion coefficient of the material leads to it being able to harvest excitons efficiently from large donor domains in bulk heterojunctions.
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Affiliation(s)
- Yun Long
- Organic Semiconductor
Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, United Kingdom
| | - Gordon J. Hedley
- Organic Semiconductor
Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, United Kingdom
| | - Arvydas Ruseckas
- Organic Semiconductor
Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, United Kingdom
| | - Mithun Chowdhury
- Organic Semiconductor
Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, United Kingdom
| | - Thomas Roland
- Organic Semiconductor
Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, United Kingdom
| | - Luis A Serrano
- Glasgow
Centre for Physical Organic Chemistry, WESTCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Graeme Cooke
- Glasgow
Centre for Physical Organic Chemistry, WESTCHEM, School of Chemistry, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Ifor D. W. Samuel
- Organic Semiconductor
Centre, SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews, Fife KY16 9SS, United Kingdom
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Suess CJ, Hirst JD, Besley NA. Quantum chemical calculations of tryptophan → heme electron and excitation energy transfer rates in myoglobin. J Comput Chem 2017; 38:1495-1502. [PMID: 28369976 PMCID: PMC5434924 DOI: 10.1002/jcc.24793] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/01/2017] [Accepted: 03/03/2017] [Indexed: 11/10/2022]
Abstract
The development of optical multidimensional spectroscopic techniques has opened up new possibilities for the study of biological processes. Recently, ultrafast two‐dimensional ultraviolet spectroscopy experiments have determined the rates of tryptophan → heme electron transfer and excitation energy transfer for the two tryptophan residues in myoglobin (Consani et al., Science, 2013, 339, 1586). Here, we show that accurate prediction of these rates can be achieved using Marcus theory in conjunction with time‐dependent density functional theory. Key intermediate residues between the donor and acceptor are identified, and in particular the residues Val68 and Ile75 play a critical role in calculations of the electron coupling matrix elements. Our calculations demonstrate how small changes in structure can have a large effect on the rates, and show that the different rates of electron transfer are dictated by the distance between the heme and tryptophan residues, while for excitation energy transfer the orientation of the tryptophan residues relative to the heme is important. © 2017 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Christian J Suess
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Jonathan D Hirst
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
| | - Nicholas A Besley
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, United Kingdom
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Amarnath K, Bennett DI, Schneider AR, Fleming GR. Multiscale model of light harvesting by photosystem II in plants. Proc Natl Acad Sci U S A 2016; 113:1156-61. [PMID: 26787911 DOI: 10.1073/pnas.1524999113] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The first step of photosynthesis in plants is the absorption of sunlight by pigments in the antenna complexes of photosystem II (PSII), followed by transfer of the nascent excitation energy to the reaction centers, where long-term storage as chemical energy is initiated. Quantum mechanical mechanisms must be invoked to explain the transport of excitation within individual antenna. However, it is unclear how these mechanisms influence transfer across assemblies of antenna and thus the photochemical yield at reaction centers in the functional thylakoid membrane. Here, we model light harvesting at the several-hundred-nanometer scale of the PSII membrane, while preserving the dominant quantum effects previously observed in individual complexes. We show that excitation moves diffusively through the antenna with a diffusion length of 50 nm until it reaches a reaction center, where charge separation serves as an energetic trap. The diffusion length is a single parameter that incorporates the enhancing effect of excited state delocalization on individual rates of energy transfer as well as the complex kinetics that arise due to energy transfer and loss by decay to the ground state. The diffusion length determines PSII's high quantum efficiency in ideal conditions, as well as how it is altered by the membrane morphology and the closure of reaction centers. We anticipate that the model will be useful in resolving the nonphotochemical quenching mechanisms that PSII employs in conditions of high light stress.
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Le Quiniou C, van Oort B, Drop B, van Stokkum IHM, Croce R. The High Efficiency of Photosystem I in the Green Alga Chlamydomonas reinhardtii Is Maintained after the Antenna Size Is Substantially Increased by the Association of Light-harvesting Complexes II. J Biol Chem 2015; 290:30587-95. [PMID: 26504081 DOI: 10.1074/jbc.m115.687970] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Indexed: 01/23/2023] Open
Abstract
Photosystems (PS) I and II activities depend on their light-harvesting capacity and trapping efficiency, which vary in different environmental conditions. For optimal functioning, these activities need to be balanced. This is achieved by redistribution of excitation energy between the two photosystems via the association and disassociation of light-harvesting complexes (LHC) II, in a process known as state transitions. Here we study the effect of LHCII binding to PSI on its absorption properties and trapping efficiency by comparing time-resolved fluorescence kinetics of PSI-LHCI and PSI-LHCI-LHCII complexes of Chlamydomonas reinhardtii. PSI-LHCI-LHCII of C. reinhardtii is the largest PSI supercomplex isolated so far and contains seven Lhcbs, in addition to the PSI core and the nine Lhcas that compose PSI-LHCI, together binding ∼ 320 chlorophylls. The average decay time for PSI-LHCI-LHCII is ∼ 65 ps upon 400 nm excitation (15 ps slower than PSI-LHCI) and ∼ 78 ps upon 475 nm excitation (27 ps slower). The transfer of excitation energy from LHCII to PSI-LHCI occurs in ∼ 60 ps. This relatively slow transfer, as compared with that from LHCI to the PSI core, suggests loose connectivity between LHCII and PSI-LHCI. Despite the relatively slow transfer, the overall decay time of PSI-LHCI-LHCII remains fast enough to assure a 96% trapping efficiency, which is only 1.4% lower than that of PSI-LHCI, concomitant with an increase of the absorption cross section of 47%. This indicates that, at variance with PSII, the design of PSI allows for a large increase of its light-harvesting capacities.
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Affiliation(s)
- Clotilde Le Quiniou
- From the Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam and Institute for Lasers, Life and Biophotonics Amsterdam, LaserLaB Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Bart van Oort
- From the Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam and Institute for Lasers, Life and Biophotonics Amsterdam, LaserLaB Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Bartlomiej Drop
- From the Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam and Institute for Lasers, Life and Biophotonics Amsterdam, LaserLaB Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Ivo H M van Stokkum
- From the Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam and Institute for Lasers, Life and Biophotonics Amsterdam, LaserLaB Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Roberta Croce
- From the Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam and Institute for Lasers, Life and Biophotonics Amsterdam, LaserLaB Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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Abstract
An atomistic description is presented of the excited state dynamics in spherical Au/CdS core/shell nanocrystals up to a diameter of 15 nm. Au-core excited states are considered in a multipole plasmon scheme, whereas a tight-binding description combined with a configuration interaction approach is used to compute single electron-hole pair excitations in the CdS-shell. The electron-hole pair energy-shift and screening due to an Au-core polarization is found of minor importance. For the studied system, the energy transfer coupling can be identified as the essential core-shell interaction. Characterizing the CdS-shell excitons by atomic centered transition charges and the Au-core by its multipole plasmon moments, an energy transfer coupling can be introduced that gives a complete microscopic description beyond any dipole-dipole approximation and with values around 10 meV. Together with a considerable plasmon-exciton energy mismatch, these coupling values explain the measured 300 ps lifetime of shell excitons due to energy transfer to the Au-core.
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Affiliation(s)
- Dirk Ziemannn
- Institute für Physik, Humboldt-Universität zu Berlin , Netwonstraße 15, D-12489 Berlin, Germany
| | - Volkhard May
- Institute für Physik, Humboldt-Universität zu Berlin , Netwonstraße 15, D-12489 Berlin, Germany
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Abstract
Recent ultrafast optical experiments show that excitons in large biological light-harvesting complexes are coupled to molecular vibration modes. These high-frequency vibrations will not only affect the optical response, but also drive the exciton transport. Here, using a model dimer system, the frequency of the underdamped vibration is shown to have a strong effect on the exciton dynamics such that quantum coherent oscillations in the system can be present even in the case of strong noise. Two mechanisms are identified to be responsible for the enhanced transport efficiency: critical damping due to the tunable effective strength of the coupling to the bath, and resonance coupling where the vibrational frequency coincides with the energy gap in the system. The interplay of these two mechanisms determines parameters responsible for the most efficient transport, and these optimal control parameters are comparable to those in realistic light-harvesting complexes. Interestingly, oscillations in the excitonic coherence at resonance are suppressed in comparison to the case of an off-resonant vibration.
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Affiliation(s)
- Arend G Dijkstra
- †Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Chen Wang
- ‡Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, Singapore 138602, Singapore
| | - Jianshu Cao
- †Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
- ‡Singapore-MIT Alliance for Research and Technology, 1 CREATE Way, Singapore 138602, Singapore
| | - Graham R Fleming
- §Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- ∥Department of Chemistry, University of California, Berkeley, California 94720, United States
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Abstract
Water oxidation in photosynthesis takes place in photosystem II (PSII). This photosystem is built around a reaction center (RC) where sunlight-induced charge separation occurs. This RC consists of various polypeptides that bind only a few chromophores or pigments, next to several other cofactors. It can handle far more photons than the ones absorbed by its own pigments and therefore, additional excitations are provided by the surrounding light-harvesting complexes or antennae. The RC is located in the PSII core that also contains the inner light-harvesting complexes CP43 and CP47, harboring 13 and 16 chlorophyll pigments, respectively. The core is surrounded by outer light-harvesting complexes (Lhcs), together forming the so-called supercomplexes, at least in plants. These PSII supercomplexes are complemented by some "extra" Lhcs, but their exact location in the thylakoid membrane is unknown. The whole system consists of many subunits and appears to be modular, i.e., both its composition and organization depend on environmental conditions, especially on the quality and intensity of the light. In this review, we will provide a short overview of the relation between the structure and organization of pigment-protein complexes in PSII, ranging from individual complexes to entire membranes and experimental and theoretical results on excitation energy transfer and charge separation. It will become clear that time-resolved fluorescence data can provide invaluable information about the organization and functioning of thylakoid membranes. At the end, an overview will be given of unanswered questions that should be addressed in the near future.
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Affiliation(s)
- Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University, P. O. Box 8128, 6700 ET, Wageningen, The Netherlands,
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Abstract
This review focuses on the light-harvesting properties of photosystem I (PSI) and its LHCI outer antenna. LHCI consists of different chlorophyll a/b binding proteins called Lhca's, surrounding the core of PSI. In total, the PSI-LHCI complex of higher plants contains 173 chlorophyll molecules, most of which are there to harvest sunlight energy and to transfer the created excitation energy to the reaction center (RC) where it is used for charge separation. The efficiency of the complex is based on the capacity to deliver this energy to the RC as fast as possible, to minimize energy losses. The performance of PSI in this respect is remarkable: on average it takes around 50 ps for the excitation to reach the RC in plants, without being quenched in the meantime. This means that the internal quantum efficiency is close to 100% which makes PSI the most efficient energy converter in nature. In this review, we describe the light-harvesting properties of the complex in relation to protein and pigment organization/composition, and we discuss the important parameters that assure its very high quantum efficiency. Excitation energy transfer and trapping in the core and/or Lhcas, as well as in the supercomplexes PSI-LHCI and PSI-LHCI-LHCII are described in detail with the aim of giving an overview of the functional behavior of these complexes.
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Affiliation(s)
- Roberta Croce
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands,
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Abstract
Experimental findings of long-lived quantum coherence in the Fenna-Matthews-Olson (FMO) complex and other photosynthetic complexes have led to theoretical studies searching for an explanation of this unexpected phenomenon. Extending in this regard our own earlier calculations, we performed simulations of the FMO complex in a glycerol-water mixture at 310 K as well as 77 K, matching the conditions of earlier 2D spectroscopic experiments by Engel et al. The calculations, based on an improved quantum procedure employed by us already, yielded spectral densities of each individual pigment of FMO, in water and glycerol-water solvents at ambient temperature that compare well to prior experimental estimates. Due to the slow solvent dynamics at 77 K, the present results strongly indicate the presence of static disorder, i.e., disorder on a time scale beyond that relevant for the construction of spectral densities.
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Kakitani T, Kawatsu T, Kimura A, Yamada A, Yamato T, Yamamoto S. Unique mechanisms of excitation energy transfer, electron transfer and photoisomerization in biological systems. J Biol Phys 2013; 28:367-81. [PMID: 23345782 DOI: 10.1023/a:1020356404203] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We discuss unique mechanisms typical in the elementary processes ofbiological functions. We focus on three topics. Excitation energytransfer in the light-harvesting antenna systems of photosyntheticbacteria is unique in its structure and the energy transfer mechanism. Inthe case of LH2 of Rhodopseudomonas acidophila, the B850 intra-ringenergy transfer and the inter-ring energy transfer between B800 and B850take place by the intermediate coupling mechanism of energy transfer. Theexcitonic coherent domain shows a wave-like movement along the ring, andthis property is expected to play a significant role in the inter-ringenergy transfer between LH2's. The electron transfer in biological systemsis mostly long-range electron transfer that occurs by the electrontunneling through the protein media. There is a long-standing problem thatwhich part of protein media is used for the electron tunneling root. As aresult of our detailed analysis, we found that the global electron tunnelingroot is a little winded with a width of a few angstrom, reflecting theproperty of tertiary and secondary structures of the protein and it isaffected by the thermal fluctuation of protein structure. Photoisomerizationof rhodopsin is very unique: The cis-transphotoisomerization ofrhodopsin occurs only around the C11 = C12 bond in the counterclockwisedirection. Its molecular mechanism is resolved by our MD simulation studyusing the structure of rhodopsin which was recently obtained by the X-raycrystallographic analysis.
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Affiliation(s)
- T Kakitani
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, 464-8602 Japan
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Fujita T, Brookes JC, Saikin SK, Aspuru-Guzik A. Memory-Assisted Exciton Diffusion in the Chlorosome Light-Harvesting Antenna of Green Sulfur Bacteria. J Phys Chem Lett 2012; 3:2357-2361. [PMID: 26292114 DOI: 10.1021/jz3008326] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Chlorosomes are likely the largest and most efficient natural light-harvesting photosynthetic antenna systems. They are composed of large numbers of bacteriochlorophylls organized into supramolecular aggregates. We explore the microscopic origin of the fast excitation energy transfer in the chlorosome using the recently resolved structure and atomistic-detail simulations. Despite the dynamical disorder effects on the electronic transitions of the bacteriochlorophylls, our simulations show that the exciton delocalizes over the entire aggregate in about 200 fs. The memory effects associated to the dynamical disorder assist the exciton diffusion through the aggregates and enhance the diffusion coefficients as a factor of 2 as compared to the model without memory. Furthermore, exciton diffusion in the chlorosome is found to be highly anisotropic with the preferential transfer toward the baseplate, which is the next functional element in the photosynthetic system.
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Affiliation(s)
- Takatoshi Fujita
- †Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Jennifer C Brookes
- †Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
- ‡Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT
| | - Semion K Saikin
- †Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Alán Aspuru-Guzik
- †Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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Schmidt Am Busch M, Müh F, El-Amine Madjet M, Renger T. The Eighth Bacteriochlorophyll Completes the Excitation Energy Funnel in the FMO Protein. J Phys Chem Lett 2011; 2:93-98. [PMID: 26295526 DOI: 10.1021/jz101541b] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The Fenna-Matthews-Olson (FMO) light-harvesting protein connects the outer antenna system (chlorosome/baseplate) with the reaction center complex in green sulfur bacteria. Since its first structure determination in the mid-70s, this pigment-protein complex has become an important model system to study excitation energy transfer. Recently, an additional bacteriochlorophyll a (the eighth) pigment was discovered in each subunit of this homotrimer. Our structure-based calculations of the optical properties of the FMO protein demonstrate that the eighth pigment is the linker to the baseplate, confirming recent suggestions from crystallographic studies.
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Affiliation(s)
- Marcel Schmidt Am Busch
- †Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Strasse 69, 4040 Linz, Austria
| | - Frank Müh
- ‡Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstrasse 36a, D-14195 Berlin, Germany
| | - Mohamed El-Amine Madjet
- ‡Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstrasse 36a, D-14195 Berlin, Germany
| | - Thomas Renger
- †Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Strasse 69, 4040 Linz, Austria
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