1
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Kaziannis S, Broser M, van Stokkum IHM, Dostal J, Busse W, Munhoven A, Bernardo C, Kloz M, Hegemann P, Kennis JTM. Multiple retinal isomerizations during the early phase of the bestrhodopsin photoreaction. Proc Natl Acad Sci U S A 2024; 121:e2318996121. [PMID: 38478688 PMCID: PMC10962995 DOI: 10.1073/pnas.2318996121] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 02/13/2024] [Indexed: 03/27/2024] Open
Abstract
Bestrhodopsins constitute a class of light-regulated pentameric ion channels that consist of one or two rhodopsins in tandem fused with bestrophin ion channel domains. Here, we report on the isomerization dynamics in the rhodopsin tandem domains of Phaeocystis antarctica bestrhodopsin, which binds all-trans retinal Schiff-base (RSB) absorbing at 661 nm and, upon illumination, converts to the meta-stable P540 state with an unusual 11-cis RSB. The primary photoproduct P682 corresponds to a mixture of highly distorted 11-cis and 13-cis RSB directly formed from the excited state in 1.4 ps. P673 evolves from P682 in 500 ps and contains highly distorted 13-cis RSB, indicating that the 11-cis fraction in P682 converts to 13-cis. Next, P673 establishes an equilibrium with P595 in 1.2 µs, during which RSB converts to 11-cis and then further proceeds to P560 in 48 µs and P540 in 1.0 ms while remaining 11-cis. Hence, extensive isomeric switching occurs on the early ground state potential energy surface (PES) on the hundreds of ps to µs timescale before finally settling on a metastable 11-cis photoproduct. We propose that P682 and P673 are trapped high up on the ground-state PES after passing through either of two closely located conical intersections that result in 11-cis and 13-cis RSB. Co-rotation of C11=C12 and C13=C14 bonds results in a constricted conformational landscape that allows thermal switching between 11-cis and 13-cis species of highly strained RSB chromophores. Protein relaxation may release RSB strain, allowing it to evolve to a stable 11-cis isomeric configuration in microseconds.
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Affiliation(s)
- Spyridon Kaziannis
- The Extreme Light Infrastructure ERIC, Dolní Břežany252 41, Czech Republic
- Department of Physics, University of Ioannina, IoanninaGr-45110, Greece
| | - Matthias Broser
- Faculty of Life Sciences, Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, BerlinD-10115, Germany
| | - Ivo H. M. van Stokkum
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam1081 HV, The Netherlands
| | - Jakub Dostal
- The Extreme Light Infrastructure ERIC, Dolní Břežany252 41, Czech Republic
| | - Wayne Busse
- Faculty of Life Sciences, Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, BerlinD-10115, Germany
| | - Arno Munhoven
- Faculty of Life Sciences, Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, BerlinD-10115, Germany
| | - Cesar Bernardo
- The Extreme Light Infrastructure ERIC, Dolní Břežany252 41, Czech Republic
| | - Miroslav Kloz
- The Extreme Light Infrastructure ERIC, Dolní Břežany252 41, Czech Republic
| | - Peter Hegemann
- Faculty of Life Sciences, Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, BerlinD-10115, Germany
| | - John T. M. Kennis
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam1081 HV, The Netherlands
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2
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Gruber E, Kabylda AM, Nielsen MB, Rasmussen AP, Teiwes R, Kusochek PA, Bochenkova AV, Andersen LH. Light Driven Ultrafast Bioinspired Molecular Motors: Steering and Accelerating Photoisomerization Dynamics of Retinal. J Am Chem Soc 2022; 144:69-73. [PMID: 34958197 DOI: 10.1021/jacs.1c10752] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photoisomerization of retinal protonated Schiff base in microbial and animal rhodopsins are strikingly ultrafast and highly specific. Both protein environments provide conditions for fine-tuning the photochemistry of their chromophores. Here, by combining time-resolved action absorption spectroscopy and high-level electronic structure theory, we show that similar control can be gained in a synthetically engineered retinal chromophore. By locking the dimethylated retinal Schiff base at the C11═C12 double bond in its trans configuration (L-RSB), the excited-state decay is rendered from a slow picosecond to an ultrafast subpicosecond regime in the gas phase. Steric hindrance and pretwisting of L-RSB are found to be important for a significant reduction in the excited-state energy barriers, where isomerization of the locked chromophore proceeds along C9═C10 rather than the preferred C11═C12 isomerization path. Remarkably, the accelerated excited-state dynamics also becomes steered. We show that L-RSB is capable of unidirectional 360° rotation from all-trans to 9-cis and from 9-cis to all-trans in only two distinct steps induced by consecutive absorption of two 600 nm photons. This opens a way for the rational design of red-light-driven ultrafast molecular rotary motors based on locked retinal chromophores.
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Affiliation(s)
- Elisabeth Gruber
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Adil M Kabylda
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | | | - Anne P Rasmussen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Ricky Teiwes
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Pavel A Kusochek
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | | | - Lars H Andersen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
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3
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Rasmussen AP, Gruber E, Teiwes R, Sheves M, Andersen LH. Spectroscopy and photoisomerization of protonated Schiff-base retinal derivatives in vacuo. Phys Chem Chem Phys 2021; 23:27227-27233. [PMID: 34853839 DOI: 10.1039/d1cp04501f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The protonated Schiff-base retinal acts as the chromophore in bacteriorhodopsin as well as in rhodopsin. In both cases, photoexcitation initializes fast isomerization which eventually results in storage of chemical energy or signaling. The details of the photophysics for this important chromophore is still not fully understood. In this study, action-absorption spectra and photoisomerization dynamics of three retinal derivatives are measured in the gas phase and compared to that of the protonated Schiff-base retinal. The retinal derivatives include C9C10trans-locked, C13C14trans-locked and a retinal derivative without the β-ionone ring. The spectroscopy as well as the isomerization speed of the chromophores are altered significantly as a consequence of the steric constraints.
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Affiliation(s)
- Anne P Rasmussen
- Department of Physics and Astronomy, Aarhus University, Denmark.
| | - Elisabeth Gruber
- Department of Physics and Astronomy, Aarhus University, Denmark.
| | - Ricky Teiwes
- Department of Physics and Astronomy, Aarhus University, Denmark.
| | - Mordechai Sheves
- Department of Organic Chemistry, Weizmann Institute of Science, Israel
| | - Lars H Andersen
- Department of Physics and Astronomy, Aarhus University, Denmark.
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4
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Liu Y, Zhu C. Trajectory surface hopping molecular dynamics simulations for retinal protonated Schiff-base photoisomerization. Phys Chem Chem Phys 2021; 23:23861-23874. [PMID: 34651159 DOI: 10.1039/d1cp03401d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Global switching trajectory surface hopping molecular dynamics simulations are performed using accurate on-the-fly (TD)CAM-B3LYP/6-31G potential energy surfaces to study retinal protonated Schiff-base photoisomerization up to S1 excitation. The simulations detected two-layer conical intersection networks: one is at an energy as high as 8 eV and the other is in the energy range around 3-4 eV. Six conical intersections within the low-layer energy region that correspond to active conical intersections under experimental conditions are found via the use of pairwise isomers, within which nonadiabatic molecular dynamics simulations are performed. Eight isomer products are populated with simulated sampling trajectories from which the simulated quantum yield in the gas phase is estimated to be 0.11 (0.08) moving from the all-trans isomer to the 11-cis (11-cis to all-trans) isomer in comparison with an experimental value of 0.09 (0.2) in the solution phase. Each conical intersection is related to one specific twist angle accompanying a related CC double bond motion during photoisomerization. Nonplanar distortion of the entire dynamic process has a significant role in the formation of the relevant photoisomerization products. The present simulation indicates that all hopping points show well-behaved potential energy surface topology, as calculated via the conventional TDDFT method, at conical intersections between S1 and S0 states. Therefore, the present nonadiabatic dynamics simulations with the TDDFT method are very encouraging for simulating various large systems related to retinal Schiff-base photoisomerization in the real world.
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Affiliation(s)
- Yuxiu Liu
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao-Tung University, Hsinchu 30010, Taiwan.
| | - Chaoyuan Zhu
- Department of Applied Chemistry and Institute of Molecular Science, National Chiao-Tung University, Hsinchu 30010, Taiwan. .,Department of Applied Chemistry and Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
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5
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Intrinsic photoisomerization dynamics of protonated Schiff-base retinal. Nat Commun 2019; 10:1210. [PMID: 30872581 PMCID: PMC6418104 DOI: 10.1038/s41467-019-09225-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 02/27/2019] [Indexed: 11/24/2022] Open
Abstract
The retinal protonated Schiff-base (RPSB) in its all-trans form is found in bacterial rhodopsins, whereas visual rhodopsin proteins host 11-cis RPSB. In both cases, photoexcitation initiates fast isomerization of the retinal chromophore, leading to proton transport, storage of chemical energy or signaling. It is an unsolved problem, to which degree this is due to protein interactions or intrinsic RPSB quantum properties. Here, we report on time-resolved action-spectroscopy studies, which show, that upon photoexcitation, cis isomers of RPSB have an almost barrierless fast 400 fs decay, whereas all-trans isomers exhibit a barrier-controlled slow 3 ps decay. Moreover, formation of the 11-cis isomer is greatly favored for all-trans RPSB when isolated. The very fast photoresponse of visual photoreceptors is thus directly related to intrinsic retinal properties, whereas bacterial rhodopsins tune the excited state potential-energy surface to lower the barrier for particular double-bond isomerization, thus changing both the timescale and specificity of the photoisomerization. The primary photoresponse of protonated Schiff-base retinal in visual and bacterial rhodopsins is fast sub-ps isomerisation. Here, the authors show that the fast photoisomerization of rhodopsin is related to an intrinsic retinal property, whereas bacterial rhodopsins tune the excited-state potential-energy surface and improve the isomerization timescale and specificity.
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6
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Ma F, Yartsev A. Ultrafast photoisomerization of pinacyanol: watching an excited state reaction transiting from barrier to barrierless forms. RSC Adv 2016. [DOI: 10.1039/c6ra03299k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Photoisomerization of 1,1′-diethyl-2,2′-carbocyanine iodide (pinacyanol) in alcohols was investigated by means of femtosecond time-resolved absorption spectroscopy.
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Affiliation(s)
- Fei Ma
- Chemical Physics
- Department of Chemistry
- Lund University
- Lund
- Sweden
| | - Arkady Yartsev
- Chemical Physics
- Department of Chemistry
- Lund University
- Lund
- Sweden
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7
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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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8
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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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9
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Prokhorenko VI, Halpin A, Johnson PJM, Miller RJD, Brown LS. Coherent control of the isomerization of retinal in bacteriorhodopsin in the high intensity regime. J Chem Phys 2011; 134:085105. [DOI: 10.1063/1.3554743] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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10
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Loevsky B, Wand A, Bismuth O, Friedman N, Sheves M, Ruhman S. A New Spectral Window on Retinal Protein Photochemistry. J Am Chem Soc 2011; 133:1626-9. [DOI: 10.1021/ja1087387] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Boris Loevsky
- Institute of Chemistry and the Farkas Center for Light-Induced Processes, The Hebrew University, Jerusalem 91904, Israel
| | - Amir Wand
- Institute of Chemistry and the Farkas Center for Light-Induced Processes, The Hebrew University, Jerusalem 91904, Israel
| | - Oshrat Bismuth
- Institute of Chemistry and the Farkas Center for Light-Induced Processes, The Hebrew University, 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, Jerusalem 91904, Israel
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11
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Methodology of pulsed photoacoustics and its application to probe photosystems and receptors. SENSORS 2010; 10:5642-67. [PMID: 22219680 PMCID: PMC3247725 DOI: 10.3390/s100605642] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Revised: 05/27/2010] [Accepted: 05/27/2010] [Indexed: 11/16/2022]
Abstract
We review recent advances in the methodology of pulsed time-resolved photoacoustics and its application to studies of photosynthetic reaction centers and membrane receptors such as the G protein-coupled receptor rhodopsin. The experimental parameters accessible to photoacoustics include molecular volume change and photoreaction enthalpy change. Light-driven volume change secondary to protein conformational changes or electrostriction is directly related to the photoreaction and thus can be a useful measurement of activity and function. The enthalpy changes of the photochemical reactions observed can be measured directly by photoacoustics. With the measurement of enthalpy change, the reaction entropy can also be calculated when free energy is known. Dissecting the free energy of a photoreaction into enthalpic and entropic components may provide critical information about photoactivation mechanisms of photosystems and photoreceptors. The potential limitations and future applications of time-resolved photoacoustics are also discussed.
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12
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Gross R, Wolf MMN, Schumann C, Friedman N, Sheves M, Li L, Engelhard M, Trentmann O, Neuhaus HE, Diller R. Primary photoinduced protein response in bacteriorhodopsin and sensory rhodopsin II. J Am Chem Soc 2010; 131:14868-78. [PMID: 19778046 DOI: 10.1021/ja904218n] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Essential for the biological function of the light-driven proton pump, bacteriorhodopsin (BR), and the light sensor, sensory rhodopsin II (SRII), is the coupling of the activated retinal chromophore to the hosting protein moiety. In order to explore the dynamics of this process we have performed ultrafast transient mid-infrared spectroscopy on isotopically labeled BR and SRII samples. These include SRII in D(2)O buffer, BR in H(2)(18)O medium, SRII with (15)N-labeled protein, and BR with (13)C(14)(13)C(15)-labeled retinal chromophore. Via observed shifts of infrared difference bands after photoexcitation and their kinetics we provide evidence for nonchromophore bands in the amide I and the amide II region of BR and SRII. A band around 1550 cm(-1) is very likely due to an amide II vibration. In the amide I region, contributions of modes involving exchangeable protons and modes not involving exchangeable protons can be discerned. Observed bands in the amide I region of BR are not due to bending vibrations of protein-bound water molecules. The observed protein bands appear in the amide I region within the system response of ca. 0.3 ps and in the amide II region within 3 ps, and decay partially in both regions on a slower time scale of 9-18 ps. Similar observations have been presented earlier for BR5.12, containing a nonisomerizable chromophore (R. Gross et al. J. Phys. Chem. B 2009, 113, 7851-7860). Thus, the results suggest a common mechanism for ultrafast protein response in the artificial and the native system besides isomerization, which could be induced by initial chromophore polarization.
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Affiliation(s)
- Ruth Gross
- University of Kaiserslautern, Department of Physics, Erwin-Schrodinger-Strasse, 67663 Kaiserslautern, Germany
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13
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Gross R, Schumann C, Wolf MMN, Herbst J, Diller R, Friedman N, Sheves M. Ultrafast Protein Conformational Alterations in Bacteriorhodopsin and Its Locked Analogue BR5.12. J Phys Chem B 2009; 113:7851-60. [PMID: 19422251 DOI: 10.1021/jp810042f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ruth Gross
- Department of Physics, University of Kaiserslautern, D-67663 Kaiserslautern, Germany, and Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Christian Schumann
- Department of Physics, University of Kaiserslautern, D-67663 Kaiserslautern, Germany, and Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Matthias M. N. Wolf
- Department of Physics, University of Kaiserslautern, D-67663 Kaiserslautern, Germany, and Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Johannes Herbst
- Department of Physics, University of Kaiserslautern, D-67663 Kaiserslautern, Germany, and Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Rolf Diller
- Department of Physics, University of Kaiserslautern, D-67663 Kaiserslautern, Germany, and Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Noga Friedman
- Department of Physics, University of Kaiserslautern, D-67663 Kaiserslautern, Germany, and Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Mordechai Sheves
- Department of Physics, University of Kaiserslautern, D-67663 Kaiserslautern, Germany, and Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
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14
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Wang J, El-Sayed MA. Rapid Thermal Tuning of Chromophore Structure in Membrane Protein. J Phys Chem B 2009; 113:4184-6. [DOI: 10.1021/jp901560m] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jianping Wang
- Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, and Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
| | - Mostafa A. El-Sayed
- Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China, and Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
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15
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Liu Y, Edens GJ, Grzymski J, Mauzerall D. Volume and enthalpy changes of proton transfers in the bacteriorhodopsin photocycle studied by millisecond time-resolved photopressure measurements. Biochemistry 2008; 47:7752-61. [PMID: 18578542 DOI: 10.1021/bi800158x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The volume and enthalpy changes associated with proton translocation steps during the bacteriorhodopsin (BR) photocycle were determined by time-resolved photopressure measurements. The data at 25 degrees C show a prompt increase in volume followed by two further increases and one decrease to the original state to complete the cycle. These volume changes are decomposed into enthalpy and inherent volume changes. The positive enthalpy changes support the argument for inherent entropy-driven late steps in the BR photocycle [Ort, D. R., and Parson, W. M. (1979) Enthalpy changes during the photochemical cycle of bacteriorhodopsin. Biophys. J. 25, 355-364]. The volume change data can be interpreted by the electrostriction effect as charges are canceled and formed during the proton transfers. A simple glutamic acid-glutamate ion model or a diglutamate-arginine-protonated water charge-delocalized model for the proton-release complex (PRC) fit the data. A conformational change with a large positive volume change is required in the slower rise (M --> N of the optical cycle) step and is reversed in the decay (N --> O --> BR) steps. The large variation in the published values for both the volume and enthalpy changes is greatly ameliorated if the values are presented per absorbed photon instead of per mole of BR. Thus, it is the highly differing assumptions about the quantum or reaction yields that cause the variations in the published results.
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Affiliation(s)
- Yan Liu
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, USA.
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16
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Prokhorenko VI, Nagy AM, Waschuk SA, Brown LS, Birge RR, Miller RJD. Coherent Control of Retinal Isomerization in Bacteriorhodopsin. Science 2006; 313:1257-61. [PMID: 16946063 DOI: 10.1126/science.1130747] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Optical control of the primary step of photoisomerization of the retinal molecule in bacteriorhodopsin from the all-trans to the 13-cis state was demonstrated under weak field conditions (where only 1 of 300 retinal molecules absorbs a photon during the excitation cycle) that are relevant to understanding biological processes. By modulating the phases and amplitudes of the spectral components in the photoexcitation pulse, we showed that the absolute quantity of 13-cis retinal formed upon excitation can be enhanced or suppressed by +/-20% of the yield observed using a short transform-limited pulse having the same actinic energy. The shaped pulses were shown to be phase-sensitive at intensities too low to access different higher electronic states, and so these pulses apparently steer the isomerization through constructive and destructive interference effects, a mechanism supported by observed signatures of vibrational coherence. These results show that the wave properties of matter can be observed and even manipulated in a system as large and complex as a protein.
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Affiliation(s)
- Valentyn I Prokhorenko
- Institute for Optical Sciences, Departments of Chemistry and Physics, University of Toronto, 80 St. George Street, M5S3H6, Toronto, Ontario, Canada
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17
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Gensch T, Viappiani C. Time-resolved photothermal methods: accessing time-resolved thermodynamics of photoinduced processes in chemistry and biology. Photochem Photobiol Sci 2003; 2:699-721. [PMID: 12911218 DOI: 10.1039/b303177b] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photothermal methods are currently being employed in a variety of research areas, ranging from materials science to environmental monitoring. Despite the common term which they are collected under, the implementations of these techniques are as diverse as the fields of application. In this review, we concentrate on the recent applications of time-resolved methods in photochemistry and photobiology.
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Affiliation(s)
- Thomas Gensch
- Forschungszentrum Jülich, Institut für Biologische Informationsverarbeitung 1, 52425 Jülich, Germany.
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18
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Mauzerall D, Liu Y, Edens GJ, Grzymski J. Measurement of enthalpy and volume changes in photoinitiated reactions on the ms timescale with a novel pressure cell. Photochem Photobiol Sci 2003; 2:788-90. [PMID: 12911228 DOI: 10.1039/b301448g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-resolved photoacoustics is an excellent method with which to measure enthalpy and volume changes of photochemical and photobiological reactions. However, it fails at times longer than approximately 10 micros. The design principles of a pressure or volume cell covering the time range of 20 micros to several seconds is presented. The sensitivity of the cell has been verified and its application to the photocycle of bacteriorhodopsin is presented. Because of the similar cell structure and data analysis it is now possible to determine enthalpy and volume changes in photo-initiated reactions over the timescale of nanoseconds to seconds with the same solution.
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Affiliation(s)
- David Mauzerall
- The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
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Birge RR, Vought BW. Energetics of rhodopsin photobleaching: photocalorimetric studies of energy storage in early and later intermediates. Methods Enzymol 2000; 315:143-63. [PMID: 10736700 DOI: 10.1016/s0076-6879(00)15841-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Affiliation(s)
- R R Birge
- Department of Chemistry, Syracuse University, New York 13244-4100, USA
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20
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Abstract
The atomic structure of bacteriorhodopsin and the outlines of its proton transport mechanism are now available. Photoisomerization of the retinal in the chromophore creates a steric and electrostatic conflict at the retinal binding site. The free energy gain sets off a sequence of reactions in which directed proton transfers take place between the protonated retinal Schiff base, Asp-85, and Asp-96. These internal steps, and other proton transfers at and near the two aqueous interfaces, add up to the translocation of a proton from the cytoplasmic to the extracellular side of the membrane. Bound water plays a crucial role in proton conduction in both extracellular and cytoplasmic regions, but the means by which the protons move from site to site differ. Proton release to the extracellular surface is through interaction of a hydrogen-bonded chain of identified aspartic acid, arginine, water, and glutamic acid residues with Asp-85, while proton uptake from the cytoplasmic surface utilizes a single aspartic acid, Asp-96, whose protonation state appears to be regulated by the protein conformation dependent hydration of this region. The directionality of the translocation is ensured by the accessibility of the Schiff base to the extracellular and cytoplasmic directions after the retinal is photoisomerized, as well as the changing proton affinities of the acceptor Asp-85 and donor Asp-96.
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Affiliation(s)
- J K Lanyi
- Department of Physiology and Biophysics, University of California, Irvine, California, 92697, USA.
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Oesterhelt D. The structure and mechanism of the family of retinal proteins from halophilic archaea. Curr Opin Struct Biol 1998; 8:489-500. [PMID: 9729742 DOI: 10.1016/s0959-440x(98)80128-0] [Citation(s) in RCA: 177] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Retinal proteins from halophilic archaea provide a unique opportunity to analyze vectorial ion translocation. Studies on its structure, conformational changes, proton conduction and electrogenic steps have helped to elucidate the catalytic cycle of bacteriorhodopsin in increasing detail. Experimental modulation of the vectoriality and ion specificity by altering the substrate availability, point mutations and light conditions for the different retinal proteins allows the proposal of a general model of ion transport for this protein family.
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Affiliation(s)
- D Oesterhelt
- Max-Planck-Institut für Biochemie, Martinsried, Germany.
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Gai F, Hasson KC, McDonald JC, Anfinrud PA. Chemical dynamics in proteins: the photoisomerization of retinal in bacteriorhodopsin. Science 1998; 279:1886-91. [PMID: 9506931 DOI: 10.1126/science.279.5358.1886] [Citation(s) in RCA: 173] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Chemical dynamics in proteins are discussed, with bacteriorhodopsin serving as a model system. Ultrafast time-resolved methods used to probe the chemical dynamics of retinal photoisomerization in bacteriorhodopsin are discussed, along with future prospects for ultrafast time-resolved crystallography. The photoisomerization of retinal in bacteriorhodopsin is far more selective and efficient than in solution, the origins of which are discussed in the context of a three-state model for the photoisomerization reaction coordinate. The chemical dynamics are complex, with the excited-state relaxation exhibiting a multiexponential decay with well-defined rate constants. Possible origins for the two major components are also discussed.
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Affiliation(s)
- F Gai
- Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA
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