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Malakar P, Gholami S, Aarabi M, Rivalta I, Sheves M, Garavelli M, Ruhman S. Retinal photoisomerization versus counterion protonation in light and dark-adapted bacteriorhodopsin and its primary photoproduct. Nat Commun 2024; 15:2136. [PMID: 38459010 PMCID: PMC10923925 DOI: 10.1038/s41467-024-46061-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 02/08/2024] [Indexed: 03/10/2024] Open
Abstract
Discovered over 50 years ago, bacteriorhodopsin is the first recognized and most widely studied microbial retinal protein. Serving as a light-activated proton pump, it represents the archetypal ion-pumping system. Here we compare the photochemical dynamics of bacteriorhodopsin light and dark-adapted forms with that of the first metastable photocycle intermediate known as "K". We observe that following thermal double isomerization of retinal in the dark from bio-active all-trans 15-anti to 13-cis, 15-syn, photochemistry proceeds even faster than the ~0.5 ps decay of the former, exhibiting ballistic wave packet curve crossing to the ground state. In contrast, photoexcitation of K containing a 13-cis, 15-anti chromophore leads to markedly multi-exponential excited state decay including much slower stages. QM/MM calculations, aimed to interpret these results, highlight the crucial role of protonation, showing that the classic quadrupole counterion model poorly reproduces spectral data and dynamics. Single protonation of ASP212 rectifies discrepancies and predicts triple ground state structural heterogeneity aligning with experimental observations. These findings prompt a reevaluation of counter ion protonation in bacteriorhodopsin and contribute to the broader understanding of its photochemical dynamics.
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Affiliation(s)
- Partha Malakar
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Samira Gholami
- Dipartimento di Chimica industriale "Toso Montanari", Università di Bologna, Viale del Risorgimento 4, 40136, Bologna, Italy
| | - Mohammad Aarabi
- Dipartimento di Chimica industriale "Toso Montanari", Università di Bologna, Viale del Risorgimento 4, 40136, Bologna, Italy
| | - Ivan Rivalta
- Dipartimento di Chimica industriale "Toso Montanari", Università di Bologna, Viale del Risorgimento 4, 40136, Bologna, Italy
- ENSL, CNRS, Laboratoire de Chimie UMR 5182, 46 allée d'Italie, 69364, Lyon, France
| | - Mordechai Sheves
- Department of Molecular Chemistry and Materials Science, The Weizmann Institute of Science, Rehovot, 7610001, Israel.
| | - Marco Garavelli
- Dipartimento di Chimica industriale "Toso Montanari", Università di Bologna, Viale del Risorgimento 4, 40136, Bologna, Italy.
| | - Sanford Ruhman
- Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel.
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2
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Meng X, Ganapathy S, van Roemburg L, Post M, Brinks D. Voltage Imaging with Engineered Proton-Pumping Rhodopsins: Insights from the Proton Transfer Pathway. ACS PHYSICAL CHEMISTRY AU 2023; 3:320-333. [PMID: 37520318 PMCID: PMC10375888 DOI: 10.1021/acsphyschemau.3c00003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/13/2023] [Accepted: 04/13/2023] [Indexed: 08/01/2023]
Abstract
Voltage imaging using genetically encoded voltage indicators (GEVIs) has taken the field of neuroscience by storm in the past decade. Its ability to create subcellular and network level readouts of electrical dynamics depends critically on the kinetics of the response to voltage of the indicator used. Engineered microbial rhodopsins form a GEVI subclass known for their high voltage sensitivity and fast response kinetics. Here we review the essential aspects of microbial rhodopsin photocycles that are critical to understanding the mechanisms of voltage sensitivity in these proteins and link them to insights from efforts to create faster, brighter and more sensitive microbial rhodopsin-based GEVIs.
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Affiliation(s)
- Xin Meng
- Department
of Imaging Physics, Delft University of
Technology, 2628 CJ Delft, The
Netherlands
| | - Srividya Ganapathy
- Department
of Imaging Physics, Delft University of
Technology, 2628 CJ Delft, The
Netherlands
- Department
of Pediatrics & Cellular and Molecular Medicine, UCSD School of Medicine, La Jolla, California 92093, United States
| | - Lars van Roemburg
- Department
of Imaging Physics, Delft University of
Technology, 2628 CJ Delft, The
Netherlands
| | - Marco Post
- Department
of Imaging Physics, Delft University of
Technology, 2628 CJ Delft, The
Netherlands
| | - Daan Brinks
- Department
of Imaging Physics, Delft University of
Technology, 2628 CJ Delft, The
Netherlands
- Department
of Molecular Genetics, Erasmus University
Medical Center, 3015 GD Rotterdam, The Netherlands
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3
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Iyer ESS, Misra R, Maity A, Liubashevski O, Sudo Y, Sheves M, Ruhman S. Temperature Independence of Ultrafast Photoisomerization in Thermophilic Rhodopsin: Assessment versus Other Microbial Proton Pumps. J Am Chem Soc 2016; 138:12401-7. [DOI: 10.1021/jacs.6b05002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Ramprasad Misra
- Department
of Organic Chemistry, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Arnab Maity
- Institute
of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190501, Israel
| | - Oleg Liubashevski
- Institute
of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190501, Israel
| | - Yuki Sudo
- Division
of Pharmaceutical sciences, Okayama University, Kita-Ku, Okayama 700-0082, Japan
| | - Mordechai Sheves
- Department
of Organic Chemistry, The Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sanford Ruhman
- Institute
of Chemistry, The Hebrew University of Jerusalem, Jerusalem 9190501, Israel
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4
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Roy P, Kantor-Uriel N, Mishra D, Dutta S, Friedman N, Sheves M, Naaman R. Spin-Controlled Photoluminescence in Hybrid Nanoparticles Purple Membrane System. ACS NANO 2016; 10:4525-4531. [PMID: 27018195 PMCID: PMC4850504 DOI: 10.1021/acsnano.6b00333] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 03/27/2016] [Indexed: 05/29/2023]
Abstract
Spin-dependent photoluminescence (PL) quenching of CdSe nanoparticles (NPs) has been explored in the hybrid system of CdSe NP purple membrane, wild-type bacteriorhodopsin (bR) thin film on a ferromagnetic (Ni-alloy) substrate. A significant change in the PL intensity from the CdSe NPs has been observed when spin-specific charge transfer occurs between the retinal and the magnetic substrate. This feature completely disappears in a bR apo membrane (wild-type bacteriorhodopsin in which the retinal protein covalent bond was cleaved), a bacteriorhodopsin mutant (D96N), and a bacteriorhodopsin bearing a locked retinal chromophore (isomerization of the crucial C13═C14 retinal double bond was prevented by inserting a ring spanning this bond). The extent of spin-dependent PL quenching of the CdSe NPs depends on the absorption of the retinal, embedded in wild-type bacteriorhodopsin. Our result suggests that spin-dependent charge transfer between the retinal and the substrate controls the PL intensity from the NPs.
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Affiliation(s)
- Partha Roy
- Department
of Chemical Physics and Department of Organic Chemistry, Weizmann Institute, Rehovot 76100, Israel
| | - Nirit Kantor-Uriel
- Department
of Chemical Physics and Department of Organic Chemistry, Weizmann Institute, Rehovot 76100, Israel
| | - Debabrata Mishra
- Department
of Chemical Physics and Department of Organic Chemistry, Weizmann Institute, Rehovot 76100, Israel
| | - Sansa Dutta
- Department
of Chemical Physics and Department of Organic Chemistry, Weizmann Institute, Rehovot 76100, Israel
| | - Noga Friedman
- Department
of Chemical Physics and Department of Organic Chemistry, Weizmann Institute, Rehovot 76100, Israel
| | - Mordechai Sheves
- Department
of Chemical Physics and Department of Organic Chemistry, Weizmann Institute, Rehovot 76100, Israel
| | - Ron Naaman
- Department
of Chemical Physics and Department of Organic Chemistry, Weizmann Institute, Rehovot 76100, Israel
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5
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Terpugov EL, Degtyareva OV. Photo-induced processes and the reaction dynamics of bacteriorhodopsin. Biophysics (Nagoya-shi) 2015. [DOI: 10.1134/s0006350915020189] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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6
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Cheminal A, Léonard J, Kim S, Jung KH, Kandori H, Haacke S. Steady state emission of the fluorescent intermediate of Anabaena Sensory Rhodopsin as a function of light adaptation conditions. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2013.09.044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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7
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Wand A, Gdor I, Zhu J, Sheves M, Ruhman S. Shedding New Light on Retinal Protein Photochemistry. Annu Rev Phys Chem 2013; 64:437-58. [DOI: 10.1146/annurev-physchem-040412-110148] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Amir Wand
- Institute of Chemistry and the Farkas Center for Light-Induced Processes, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
| | - Itay Gdor
- Institute of Chemistry and the Farkas Center for Light-Induced Processes, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
| | - Jingyi Zhu
- Institute of Chemistry and the Farkas Center for Light-Induced Processes, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
| | - Mordechai Sheves
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sanford Ruhman
- Institute of Chemistry and the Farkas Center for Light-Induced Processes, The Hebrew University of Jerusalem, Jerusalem 91904, Israel;
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8
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Wand A, Loevsky B, Friedman N, Sheves M, Ruhman S. Probing Ultrafast Photochemistry of Retinal Proteins in the Near-IR: Bacteriorhodopsin and Anabaena Sensory Rhodopsin vs Retinal Protonated Schiff Base in Solution. J Phys Chem B 2012; 117:4670-9. [DOI: 10.1021/jp309189y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Amir Wand
- Institute of Chemistry
and the Farkas Center for Light-Induced Processes, The Hebrew University of Jerusalem, Edmond J. Safra
Campus, Givat Ram, Jerusalem 91904, Israel
| | - Boris Loevsky
- Institute of Chemistry
and the Farkas Center for Light-Induced Processes, The Hebrew University of Jerusalem, Edmond J. Safra
Campus, Givat Ram, Jerusalem 91904, Israel
| | - Noga Friedman
- Department of Organic
Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Mordechai Sheves
- Department of Organic
Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sanford Ruhman
- Institute of Chemistry
and the Farkas Center for Light-Induced Processes, The Hebrew University of Jerusalem, Edmond J. Safra
Campus, Givat Ram, Jerusalem 91904, Israel
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9
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Wand A, Friedman N, Sheves M, Ruhman S. Ultrafast Photochemistry of Light-Adapted and Dark-Adapted Bacteriorhodopsin: Effects of the Initial Retinal Configuration. J Phys Chem B 2012; 116:10444-52. [DOI: 10.1021/jp2125284] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Amir Wand
- Institute of Chemistry and the
Farkash Center for Light-Induced Processes, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat
Ram, Jerusalem 91904, Israel
| | - Noga Friedman
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Mordechai Sheves
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sanford Ruhman
- Institute of Chemistry and the
Farkash Center for Light-Induced Processes, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat
Ram, Jerusalem 91904, Israel
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10
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Zgrablić G, Novello AM, Parmigiani F. Population Branching in the Conical Intersection of the Retinal Chromophore Revealed by Multipulse Ultrafast Optical Spectroscopy. J Am Chem Soc 2011; 134:955-61. [DOI: 10.1021/ja205763x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Goran Zgrablić
- T-ReX Laboratory, Sincrotrone Trieste, S.S. 14 km 163.5 in Area Science
Park, I-34012 Basovizza Trieste, Italy
| | - Anna Maria Novello
- T-ReX Laboratory, Sincrotrone Trieste, S.S. 14 km 163.5 in Area Science
Park, I-34012 Basovizza Trieste, Italy
- Department of Condensed Matter
Physics, University of Geneva, Rue du Général-
Dufour 24, 1204 Geneva, Switzerland
| | - Fulvio Parmigiani
- T-ReX Laboratory, Sincrotrone Trieste, S.S. 14 km 163.5 in Area Science
Park, I-34012 Basovizza Trieste, Italy
- Department of Physics, Università degli studi di Trieste, Piazzale
Europa 1, I-34127 Trieste, Italy
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11
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Wand A, Rozin R, Eliash T, Jung KH, Sheves M, Ruhman S. Asymmetric Toggling of a Natural Photoswitch: Ultrafast Spectroscopy of Anabaena Sensory Rhodopsin. J Am Chem Soc 2011; 133:20922-32. [DOI: 10.1021/ja208371g] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Amir Wand
- Institute of Chemistry and Farkash Center for Light-Induced Processes, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Rinat Rozin
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Tamar Eliash
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Kwang-Hwan Jung
- Department of Life Science and Institute of Biological Interfaces, Sogang University, Shinsu-Dong 1, Mapo-Gu, Seoul 121-742, South Korea
| | - Mordechai Sheves
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sanford Ruhman
- Institute of Chemistry and Farkash Center for Light-Induced Processes, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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12
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Groma GI, Colonna A, Martin JL, Vos MH. Vibrational motions associated with primary processes in bacteriorhodopsin studied by coherent infrared emission spectroscopy. Biophys J 2011; 100:1578-86. [PMID: 21402041 DOI: 10.1016/j.bpj.2011.02.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 02/01/2011] [Accepted: 02/04/2011] [Indexed: 11/18/2022] Open
Abstract
The primary energetic processes driving the functional proton pump of bacteriorhodopsin take place in the form of complex molecular dynamic events after excitation of the retinal chromophore into the Franck-Condon state. These early events include a strong electronic polarization, skeletal stretching, and all-trans-to-13-cis isomerization upon formation of the J intermediate. The effectiveness of the photoreaction is ensured by a conical intersection between the electronic excited and ground states, providing highly nonadiabatic coupling to nuclear motions. Here, we study real-time vibrational coherences associated with these motions by analyzing light-induced infrared emission from oriented purple membranes in the 750-1400 cm(-)(1) region. The experimental technique applied is based on second-order femtosecond difference frequency generation on macroscopically ordered samples that also yield information on phase and direction of the underlying motions. Concerted use of several analysis methods resulted in the isolation and characterization of seven different vibrational modes, assigned as C-C stretches, out-of-plane methyl rocks, and hydrogen out-of-plane wags, whereas no in-plane H rock was found. Based on their lifetimes and several other criteria, we deduce that the majority of the observed modes take place on the potential energy surface of the excited electronic state. In particular, the direction sensitivity provides experimental evidence for large intermediate distortions of the retinal plane during the excited-state isomerization process.
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Affiliation(s)
- Géza I Groma
- Laboratory for Optical Biosciences, Ecole Polytechnique, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Palaiseau, France.
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13
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Kraack JP, Buckup T, Hampp N, Motzkus M. Ground- and Excited-State Vibrational Coherence Dynamics in Bacteriorhodopsin Probed With Degenerate Four-Wave-Mixing Experiments. Chemphyschem 2011; 12:1851-9. [DOI: 10.1002/cphc.201100032] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 05/24/2011] [Indexed: 11/06/2022]
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14
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Verhoefen MK, Bamann C, Blöcher R, Förster U, Bamberg E, Wachtveitl J. The photocycle of channelrhodopsin-2: ultrafast reaction dynamics and subsequent reaction steps. Chemphyschem 2011; 11:3113-22. [PMID: 20730849 DOI: 10.1002/cphc.201000181] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The photocycle of channelrhodopsin-2 is investigated in a comprehensive study by ultrafast absorption and fluorescence spectroscopy as well as flash photolysis in the visible spectral range. The ultrafast techniques reveal an excited-state decay mechanism analogous to that of the archaeal bacteriorhodopsin and sensory rhodopsin II from Natronomonas pharaonis. After a fast vibrational relaxation of the excited-state population with 150 fs its decay with mainly 400 fs is observed. Hereby, both the initial all-trans retinal ground state and the 13-cis-retinal K photoproduct are populated. The reaction proceeds with a 2.7 ps component assigned to cooling processes. Small spectral shifts are observed on a 200 ps timescale. They are attributed to conformational rearrangements in the retinal binding pocket. The subsequent dynamics progresses with the formation of an M-like intermediate (7 and 120 μs), which decays into red-shifted states within 3 ms. Ground-state recovery including channel closing and reisomerization of the retinal chromophore occurs in a triexponential manner (6 ms, 33 ms, 3.4 s). To learn more about the energy barriers between the different photocycle intermediates, temperature-dependent flash photolysis measurements are performed between 10 and 30°C. The first five time constants decrease with increasing temperature. The calculated thermodynamic parameters indicate that the closing mechanism is controlled by large negative entropy changes. The last time constant is temperature independent, which demonstrates that the photocycle is most likely completed by a series of individual steps recovering the initial structure.
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Affiliation(s)
- Mirka-Kristin Verhoefen
- Institute of Physical and Theoretical Chemistry, Johann Wolfgang Goethe University Frankfurt, Max von Laue-Straße 7, 60438 Frankfurt am Main, Germany
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15
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Comparing photochemistry of n- and tert-butylamine all-trans retinal protonated Schiff-base: Effects of C N configurational inhomogeneity. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2009.08.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Control of retinal isomerization in bacteriorhodopsin in the high-intensity regime. Proc Natl Acad Sci U S A 2009; 106:10896-900. [PMID: 19564608 DOI: 10.1073/pnas.0904589106] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A learning algorithm was used to manipulate optical pulse shapes and optimize retinal isomerization in bacteriorhodopsin, for excitation levels up to 1.8 x 10(16) photons per square centimeter. Below 1/3 the maximum excitation level, the yield was not sensitive to pulse shape. Above this level the learning algorithm found that a Fourier-transform-limited (TL) pulse maximized the 13-cis population. For this optimal pulse the yield increases linearly with intensity well beyond the saturation of the first excited state. To understand these results we performed systematic searches varying the chirp and energy of the pump pulses while monitoring the isomerization yield. The results are interpreted including the influence of 1-photon and multiphoton transitions. The population dynamics in each intermediate conformation and the final branching ratio between the all-trans and 13-cis isomers are modified by changes in the pulse energy and duration.
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17
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Hayashi S, Tajkhorshid E, Schulten K. Photochemical reaction dynamics of the primary event of vision studied by means of a hybrid molecular simulation. Biophys J 2009; 96:403-16. [PMID: 19167292 DOI: 10.1016/j.bpj.2008.09.049] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2008] [Accepted: 09/26/2008] [Indexed: 11/19/2022] Open
Abstract
The photoisomerization reaction dynamics of a retinal chromophore in the visual receptor rhodopsin was investigated by means of hybrid quantum mechanical/molecular mechanical (QM/MM) molecular dynamics (MD) simulations. The photoisomerization reaction of retinal constitutes the primary step of vision and is known as one of the fastest reactions in nature. To elucidate the molecular mechanism of the high efficiency of the reaction, we carried out hybrid ab initio QM/MM MD simulations of the complete reaction process from the vertically excited state to the photoproduct via electronic transition in the entire chromophore-protein complex. An ensemble of reaction trajectories reveal that the excited-state dynamics is dynamically homogeneous and synchronous even in the presence of thermal fluctuation of the protein, giving rise to the very fast formation of the photoproduct. The synchronous nature of the reaction dynamics in rhodopsin is found to originate from weak perturbation of the protein surroundings and from dynamic regulation of volume-conserving motions of the chromophore. The simulations also provide a detailed view of time-dependent modulations of hydrogen-out-of-plane vibrations during the reaction process, and identify molecular motions underlying the experimentally observed dynamic spectral modulations.
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Affiliation(s)
- Shigehiko Hayashi
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan.
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18
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Schenkl S, Zgrablić G, Portuondo-Campa E, Haacke S, Chergui M. On the excitation wavelength dependence of the fluorescence of bacteriorhodopsin. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.04.086] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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19
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Vogt G, Nuernberger P, Brixner T, Gerber G. Femtosecond pump–shaped-dump quantum control of retinal isomerization in bacteriorhodopsin. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2006.11.028] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Abramczyk H. Femtosecond primary events in bacteriorhodopsin and its retinal modified analogs: Revision of commonly accepted interpretation of electronic spectra of transient intermediates in the bacteriorhodopsin photocycle. J Chem Phys 2004; 120:11120-32. [PMID: 15268142 DOI: 10.1063/1.1737731] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Femtosecond primary events in bacteriorhodopsin (BR) and its retinal modified analogs are discussed. Ultrafast time resolved electronic spectra of the primary intermediates induced in the BR photocycle are discussed along with spectral and kinetic inconsistencies of the previous models proposed in the literature. The theoretical model proposed in this paper based on vibrational coupling between the electronic transition of the chromophore and intramolecular vibrational modes allows us to calculate the equilibrium electronic absorption band shape and the hole burning profiles. The model is able to rationalize the complex pattern of behavior for the primary events in BR and explain the origin of the apparent inconsistencies between the experiment and the previous theoretical models. The model presented in the paper is based on the anharmonic coupling assumption in the adiabatic approximation using the canonical transformation method for diagonalization of the vibrational Hamiltonian instead of the commonly used perturbation theory. The electronic transition occurs between the Born-Oppenheimer potential energy surfaces with the electron involved in the transition being coupled to the intramolecular vibrational modes of the molecule (chromophore). The relaxation of the excited state occurs by indirect damping (dephasing) mechanisms. The indirect dephasing is governed by the time evolution of the anharmonic coupling constant driven by the resonance energy exchange between the intramolecular vibrational mode and the bath. The coupling with the intramolecular vibrational modes results in the Franck-Condon progression of bands that are broadened due to the vibrational dephasing mechanisms. The electronic absorption line shape has been calculated based on the linear response theory whereas the third order nonlinear response functions have been used to analyze the hole burning profiles obtained from the pump-probe time-resolved measurements. The theoretical treatment proposed in this paper provides a basis for a substantial revision of the commonly accepted interpretation of the primary events in the BR photocycle that exists in the literature.
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Affiliation(s)
- Halina Abramczyk
- Technical University, Department of Chemistry, Laboratory of Molecular Laser Spectroscopy at IARC, Wroblewskiego 15 Street, 93-590 Lodz, Poland.
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21
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Glasbeek M, Zhang H. Femtosecond Studies of Solvation and Intramolecular Configurational Dynamics of Fluorophores in Liquid Solution. Chem Rev 2004; 104:1929-54. [PMID: 15080717 DOI: 10.1021/cr0206723] [Citation(s) in RCA: 214] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Max Glasbeek
- Laboratory for Physical Chemistry, University of Amsterdam, Nieuwe Achtergracht 129, 1018 WS Amsterdam, The Netherlands.
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22
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Cembran A, Bernardi F, Olivucci M, Garavelli M. Excited-state singlet manifold and oscillatory features of a nonatetraeniminium retinal chromophore model. J Am Chem Soc 2003; 125:12509-19. [PMID: 14531695 DOI: 10.1021/ja030215j] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this paper we use ab initio multireference Møller-Plesset second-order perturbation theory computations to map the first five singlet states (S(0), S(1), S(2), S(3), and S(4)) along the initial part of the photoisomerization coordinate for the isolated rhodopsin chromophore model 4-cis-gamma-methylnona-2,4,6,8-tetraeniminium cation. We show that this information not only provides an explanation for the spectral features associated to the chromophore in solution but also, subject to a tentative hypothesis on the effect of the protein cavity, may be employed to explain/assign the ultrafast near-IR excited-state absorption, stimulated emission, and transient excited-state absorption bands observed in rhodopsin proteins (e.g. rhodopsin and bacteriorhodopsin). We also show that the results of vibrational frequency computations reveal a general structure for the first (S(1)) excited-state energy surface of PSBs that is consistent with the existence of the coherent oscillatory motions observed both in solution and in bacteriorhodopsin.
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Affiliation(s)
- Alessandro Cembran
- Dipartimento di Chimica, Università di Siena, via Aldo Moro, Siena, I-53100 Italy
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Hayashi S, Tajkhorshid E, Schulten K. Molecular dynamics simulation of bacteriorhodopsin's photoisomerization using ab initio forces for the excited chromophore. Biophys J 2003; 85:1440-9. [PMID: 12944261 PMCID: PMC1303320 DOI: 10.1016/s0006-3495(03)74576-7] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Retinal proteins are photoreceptors found in many living organisms. They possess a common chromophore, retinal, that upon absorption of light isomerizes and thereby triggers biological functions ranging from light energy conversion to phototaxis and vision. The photoisomerization of retinal is extremely fast, highly selective inside the protein matrix, and characterized through optimal sensitivity to incoming light. This article describes the first report of an ab initio quantum mechanical description of the in situ isomerization dynamics of retinal in bacteriorhodopsin, a microbial retinal protein that functions as a light-driven proton pump. The description combines ab initio multi-electronic state molecular dynamics of a truncated retinal chromophore model (N-methyl-gamma-methylpenta-2,4-dieniminium cation fragment) with molecular mechanics of the protein motion and unveils in complete detail the photoisomerization process. The results illustrate the essential role of the protein for the characteristic kinetics and high selectivity of the photoisomerization: the protein arrests inhomogeneous photoisomerization paths and funnels them into a single path that initiates the functional process. Supported by comparison with dynamic spectral modulations observed in femtosecond spectroscopy, the results identify the principal molecular motion during photoisomerization.
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Affiliation(s)
- Shigehiko Hayashi
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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Wang J, Link S, Heyes CD, El-Sayed MA. Comparison of the dynamics of the primary events of bacteriorhodopsin in its trimeric and monomeric states. Biophys J 2002; 83:1557-66. [PMID: 12202380 PMCID: PMC1302253 DOI: 10.1016/s0006-3495(02)73925-8] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
In this paper, femtosecond pump-probe spectroscopy in the visible region of the spectrum has been used to examine the ultrafast dynamics of the retinal excited state in both the native trimeric state and the monomeric state of bacteriorhodopsin (bR). It is found that the excited state lifetime (probed at 490 nm) increases only slightly upon the monomerization of bR. No significant kinetic difference is observed in the recovery process of the bR ground state probed at 570 nm nor in the fluorescent state observed at 850 nm. However, an increase in the relative amplitude of the slow component of bR excited state decay is observed in the monomer, which is due to the increase in the concentration of the 13-cis retinal isomer in the ground state of the light-adapted bR monomer. Our data indicate that when the protein packing around the retinal is changed upon bR monomerization, there is only a subtle change in the retinal potential surface, which is dependent on the charge distribution and the dipoles within the retinal-binding cavity. In addition, our results show that 40% of the excited state bR molecules return to the ground state on three different time scales: one-half-picosecond component during the relaxation of the excited state and the formation of the J intermediate, a 3-ps component as the J changes to the K intermediate where retinal photoisomerization occurs, and a subnanosecond component during the photocycle.
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Affiliation(s)
- Jianping Wang
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400 USA
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Wang J, El-Sayed MA. Time-resolved long-lived infrared emission from bacteriorhodopsin during its photocycle. Biophys J 2002; 83:1589-94. [PMID: 12202383 PMCID: PMC1302256 DOI: 10.1016/s0006-3495(02)73928-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The infrared emission observed below 2000 cm(-1) upon exciting retinal in bacteriorhodopsin (bR) is found to have a rise time in the submicrosecond time regime and to relax with two exponential components on the submillisecond to millisecond time scale. These time scales, together with the assignment of this emission to hot vibrations from the all-trans retinal (in bR) and the 13-cis retinal (in the K intermediate), support the recent assignment of the J-intermediate as an electronically excited species (Atkinson et al., J. Phys. Chem. A. 104:4130-4139, 2000) rather than a vibrationally hot K intermediate. A discussion of these time scales of the observed infrared emission is given in terms of the competition between radiative and nonradiative relaxation processes of the vibrational states involved.
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Affiliation(s)
- Jianping Wang
- Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400 USA
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Ruhman S, Hou B, Friedman N, Ottolenghi M, Sheves M. Following evolution of bacteriorhodopsin in its reactive excited state via stimulated emission pumping. J Am Chem Soc 2002; 124:8854-8. [PMID: 12137538 DOI: 10.1021/ja026426q] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
New information concerning the photochemical dynamics of bacteriorhodopsin (BR) is obtained by impulsively stimulating emission from the reactive fluorescent state. Depletion of the excited-state fluorescence leads to an equal reduction in production of later photoproducts. Accordingly, chromophores which are forced back to the ground state via emission do not continue on in the photocycle, conclusively demonstrating that the fluorescent state is a photocycle intermediate. The insensitivity of depletion dynamics to the "dump" pulse timing, throughout the fluorescent states lifetime, and the biological inactivity of the dumped population suggest that the fluorescent-state structure is constant, well-defined, and significantly different than that where crossing to the ground state takes place naturally. In conjunction with conclusions from comparing the photophysics of BR with those of synthetic analogues containing "locked" retinals, present results show that large-amplitude torsion around C13=C14 is required to go between the above structures.
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Affiliation(s)
- Sanford Ruhman
- Department of Physical Chemistry and The Farkas Center for Light Induced Processes, The Hebrew University, Jerusalem 91904, Israel.
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Ben-Nun M, Molnar F, Schulten K, Martinez TJ. The role of intersection topography in bond selectivity of cis-trans photoisomerization. Proc Natl Acad Sci U S A 2002; 99:1769-73. [PMID: 11854479 PMCID: PMC122268 DOI: 10.1073/pnas.032658099] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ab initio methods are used to characterize the ground and first excited state of the chromophore in the rhodopsin family of proteins: retinal protonated Schiff base. Retinal protonated Schiff base has five double bonds capable of undergoing isomerization. Upon absorption of light, the chromophore isomerizes and the character of the photoproducts (e.g., 13-cis and 11-cis) depends on the environment, protein vs. solution. Our ab initio calculations show that, in the absence of any specific interactions with the environment (e.g., discrete ordered charges in a protein), energetic considerations cannot explain the observed bond selectivity. We instead attribute the origin of bond selectivity to the shape (topography) of the potential energy surfaces in the vicinity of points of true degeneracy (conical intersections) between the ground and first excited electronic states. This provides a molecular example where a competition between two distinct but nearly isoenergetic photochemical reaction pathways is resolved by a topographical difference between two conical intersections.
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Affiliation(s)
- M Ben-Nun
- Departments of Chemistry and Physics, University of Illinois, 600 S. Mathews, Urbana, IL 61801, USA
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Heyne K, Herbst J, Stehlik D, Esteban B, Lamparter T, Hughes J, Diller R. Ultrafast dynamics of phytochrome from the cyanobacterium synechocystis, reconstituted with phycocyanobilin and phycoerythrobilin. Biophys J 2002; 82:1004-16. [PMID: 11806940 PMCID: PMC1301907 DOI: 10.1016/s0006-3495(02)75460-x] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Femtosecond time-resolved transient absorption spectroscopy was employed to characterize for the first time the primary photoisomerization dynamics of a bacterial phytochrome system in the two thermally stable states of the photocycle. The 85-kDa phytochrome Cph1 from the cyanobacterium Synechocystis PCC 6803 expressed in Escherichia coli was reconstituted with phycocyanobilin (Cph1-PCB) and phycoerythrobilin (Cph1-PEB). The red-light-absorbing form Pr of Cph1-PCB shows an approximately 150 fs relaxation in the S(1) state after photoexcitation at 650 nm. The subsequent Z-E isomerization between rings C and D of the linear tetrapyrrole-chromophore is best described by a distribution of rate constants with the first moment at (16 ps)(-1). Excitation at 615 nm leads to a slightly broadened distribution. The reverse E-Z isomerization, starting from the far-red-absorbing form Pfr, is characterized by two shorter time constants of 0.54 and 3.2 ps. In the case of Cph1-PEB, double-bond isomerization does not take place, and the excited-state lifetime extends into the nanosecond regime. Besides a stimulated emission rise time between 40 and 150 fs, no fast relaxation processes are observed. This suggests that the chromophore-protein interaction along rings A, B, and C does not contribute much to the picosecond dynamics observed in Cph1-PCB but rather the region around ring D near the isomerizing C(15) [double bond] C(16) double bond. The primary reaction dynamics of Cph1-PCB at ambient temperature is found to exhibit very similar features as those described for plant type A phytochrome, i.e., a relatively slow Pr, and a fast Pfr, photoreaction. This suggests that the initial reactions were established already before evolution of plant phytochromes began.
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Affiliation(s)
- Karsten Heyne
- Institut für Experimentalphysik, Freie Universität Berlin, Germany
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Schenkl S, Portuondo E, Zgrablić G, Chergui M, Haacke S, Friedman N, Sheves M. Ultrafast energy relaxation in bacteriorhodopsin studied by time-integrated fluorescence. Phys Chem Chem Phys 2002. [DOI: 10.1039/b205453a] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Garavelli M, Page CS, Celani P, Olivucci M, Schmid WE, Trushin SA, Fuss W. Reaction Path of a sub-200 fs Photochemical Electrocyclic Reaction. J Phys Chem A 2001. [DOI: 10.1021/jp010359p] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Garavelli
- Dipartimento Chimico “G. Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy, Dipartimento di Chimica, Università di Siena, via Aldo Moro, I-53100 Siena, Italy, B. I. Stepanov Institute of Physics, Belarus Academy of Sciences, 220602 Minsk, Belarus, and Max-Planck-Institut für Quantenoptik, D-85740 Garching, Germany
| | - C. S. Page
- Dipartimento Chimico “G. Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy, Dipartimento di Chimica, Università di Siena, via Aldo Moro, I-53100 Siena, Italy, B. I. Stepanov Institute of Physics, Belarus Academy of Sciences, 220602 Minsk, Belarus, and Max-Planck-Institut für Quantenoptik, D-85740 Garching, Germany
| | - P. Celani
- Dipartimento Chimico “G. Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy, Dipartimento di Chimica, Università di Siena, via Aldo Moro, I-53100 Siena, Italy, B. I. Stepanov Institute of Physics, Belarus Academy of Sciences, 220602 Minsk, Belarus, and Max-Planck-Institut für Quantenoptik, D-85740 Garching, Germany
| | - M. Olivucci
- Dipartimento Chimico “G. Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy, Dipartimento di Chimica, Università di Siena, via Aldo Moro, I-53100 Siena, Italy, B. I. Stepanov Institute of Physics, Belarus Academy of Sciences, 220602 Minsk, Belarus, and Max-Planck-Institut für Quantenoptik, D-85740 Garching, Germany
| | - W. E. Schmid
- Dipartimento Chimico “G. Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy, Dipartimento di Chimica, Università di Siena, via Aldo Moro, I-53100 Siena, Italy, B. I. Stepanov Institute of Physics, Belarus Academy of Sciences, 220602 Minsk, Belarus, and Max-Planck-Institut für Quantenoptik, D-85740 Garching, Germany
| | - S. A. Trushin
- Dipartimento Chimico “G. Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy, Dipartimento di Chimica, Università di Siena, via Aldo Moro, I-53100 Siena, Italy, B. I. Stepanov Institute of Physics, Belarus Academy of Sciences, 220602 Minsk, Belarus, and Max-Planck-Institut für Quantenoptik, D-85740 Garching, Germany
| | - W. Fuss
- Dipartimento Chimico “G. Ciamician”, Università di Bologna, Via Selmi 2, I-40126 Bologna, Italy, Dipartimento di Chimica, Università di Siena, via Aldo Moro, I-53100 Siena, Italy, B. I. Stepanov Institute of Physics, Belarus Academy of Sciences, 220602 Minsk, Belarus, and Max-Planck-Institut für Quantenoptik, D-85740 Garching, Germany
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