1
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Gavshina AV, Solovyev ID, Khrenova MG, Boyko KM, Varfolomeeva LA, Minyaev ME, Popov VO, Savitsky AP. The role of the correlated motion(s) of the chromophore in photoswitching of green and red forms of the photoconvertible fluorescent protein mSAASoti. Sci Rep 2024; 14:8754. [PMID: 38627478 PMCID: PMC11021400 DOI: 10.1038/s41598-024-59364-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 04/09/2024] [Indexed: 04/19/2024] Open
Abstract
Wild-type SAASoti and its monomeric variant mSAASoti can undergo phototransformations, including reversible photoswitching of the green form to a nonfluorescent state and irreversible green-to-red photoconversion. In this study, we extend the photochemistry of mSAASoti variants to enable reversible photoswitching of the red form. This result is achieved by rational and site-saturated mutagenesis of the M163 and F177 residues. In the case of mSAASoti it is M163T substitution that leads to the fastest switching and the most photostable variant, and reversible photoswitching can be observed for both green and red forms when expressed in eukaryotic cells. We obtained a 13-fold increase in the switching efficiency with the maximum switching contrast of the green form and the appearance of comparable switching of the red form for the C21N/M163T mSAASoti variant. The crystal structure of the C21N mSAASoti in its green on-state was obtained for the first time at 3.0 Å resolution, and it is in good agreement with previously calculated 3D-model. Dynamic network analysis reveals that efficient photoswitching occurs if motions of the 66H residue and phenyl fragment of chromophore are correlated and these moieties belong to the same community.
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Affiliation(s)
- Alexandra V Gavshina
- A.N. Bach Institute of Biochemistry, Federal Research Centre 'Fundamentals of Biotechnology' of the Russian Academy of Sciences, Moscow, Russia
| | - Ilya D Solovyev
- A.N. Bach Institute of Biochemistry, Federal Research Centre 'Fundamentals of Biotechnology' of the Russian Academy of Sciences, Moscow, Russia
| | - Maria G Khrenova
- A.N. Bach Institute of Biochemistry, Federal Research Centre 'Fundamentals of Biotechnology' of the Russian Academy of Sciences, Moscow, Russia
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia
- Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - Konstantin M Boyko
- A.N. Bach Institute of Biochemistry, Federal Research Centre 'Fundamentals of Biotechnology' of the Russian Academy of Sciences, Moscow, Russia
| | - Larisa A Varfolomeeva
- A.N. Bach Institute of Biochemistry, Federal Research Centre 'Fundamentals of Biotechnology' of the Russian Academy of Sciences, Moscow, Russia
| | - Mikhail E Minyaev
- N.D. Zelinsky Institute of Organic Chemistry Russian Academy of Sciences, Moscow, Russia
| | - Vladimir O Popov
- A.N. Bach Institute of Biochemistry, Federal Research Centre 'Fundamentals of Biotechnology' of the Russian Academy of Sciences, Moscow, Russia
| | - Alexander P Savitsky
- A.N. Bach Institute of Biochemistry, Federal Research Centre 'Fundamentals of Biotechnology' of the Russian Academy of Sciences, Moscow, Russia.
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2
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Zhu YH, Liu XX, Fang Q, Liu XY, Fang WH, Cui G. Multiple Photoisomerization Pathways of the Green Fluorescent Protein Chromophore in a Reversibly Photoswitchable Fluorescent Protein: Insights from Quantum Mechanics/Molecular Mechanics Simulations. J Phys Chem Lett 2023; 14:2588-2598. [PMID: 36881005 DOI: 10.1021/acs.jpclett.3c00165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Herein, we have employed a combined CASPT2//CASSCF approach within the quantum mechanics/molecular mechanics (QM/MM) framework to explore the early time photoisomerization of rsEGFP2 starting from its two OFF trans states, i.e., Trans1 and Trans2. The results show similar vertical excitation energies to the S1 state in their Franck-Condon regions. Considering the clockwise and counterclockwise rotations of the C11-C9 bond, four pairs of the S1 excited-state minima and low-lying S1/S0 conical intersections were optimized, based on which we determined four S1 photoisomerization paths that are essentially barrierless to the relevant S1/S0 conical intersections leading to efficient excited-state deactivation to the S0 state. Most importantly, our work first identified multiple photoisomerization and excited-state decay paths, which must be seriously considered in the future. This work not only sheds significant light on the primary trans-cis photoisomerization of rsEGFP2 but also aids in the understanding of the microscopic mechanism of GFP-like RSFPs and the design of novel GFP-like fluorescent proteins.
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Affiliation(s)
- Yun-Hua Zhu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xin-Xin Liu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Qiu Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xiang-Yang Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China
| | - Wei-Hai Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
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3
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Krueger TD, Tang L, Chen C, Zhu L, Breen IL, Wachter RM, Fang C. To twist or not to twist: From chromophore structure to dynamics inside engineered photoconvertible and photoswitchable fluorescent proteins. Protein Sci 2023; 32:e4517. [PMID: 36403093 PMCID: PMC9793981 DOI: 10.1002/pro.4517] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/31/2022] [Accepted: 11/15/2022] [Indexed: 11/21/2022]
Abstract
Green-to-red photoconvertible fluorescent proteins (FPs) are vital biomimetic tools for powerful techniques such as super-resolution imaging. A unique Kaede-type FP named the least evolved ancestor (LEA) enables delineation of the evolutionary step to acquire photoconversion capability from the ancestral green fluorescent protein (GFP). A key residue, Ala69, was identified through several steady-state and time-resolved spectroscopic techniques that allows LEA to effectively photoswitch and enhance the green-to-red photoconversion. However, the inner workings of this functional protein have remained elusive due to practical challenges of capturing the photoexcited chromophore motions in real time. Here, we implemented femtosecond stimulated Raman spectroscopy and transient absorption on LEA-A69T, aided by relevant crystal structures and control FPs, revealing that Thr69 promotes a stronger π-π stacking interaction between the chromophore phenolate (P-)ring and His193 in FP mutants that cannot photoconvert or photoswitch. Characteristic time constants of ~60-67 ps are attributed to P-ring twist as the onset for photoswitching in LEA (major) and LEA-A69T (minor) with photoconversion capability, different from ~16/29 ps in correlation with the Gln62/His62 side-chain twist in ALL-GFP/ALL-Q62H, indicative of the light-induced conformational relaxation preferences in various local environments. A minor subpopulation of LEA-A69T capable of positive photoswitching was revealed by time-resolved electronic spectroscopies with targeted light irradiation wavelengths. The unveiled chromophore structure and dynamics inside engineered FPs in an aqueous buffer solution can be generalized to improve other green-to-red photoconvertible FPs from the bottom up for deeper biophysics with molecular biology insights and powerful bioimaging advances.
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Affiliation(s)
| | - Longteng Tang
- Department of ChemistryOregon State UniversityCorvallisOregonUSA
| | - Cheng Chen
- Department of ChemistryOregon State UniversityCorvallisOregonUSA
| | - Liangdong Zhu
- Department of ChemistryOregon State UniversityCorvallisOregonUSA
| | - Isabella L. Breen
- School of Molecular Sciences, Center for Bioenergy and Photosynthesis, Biodesign Center for Applied Structural DiscoveryArizona State UniversityTempeArizonaUSA
| | - Rebekka M. Wachter
- School of Molecular Sciences, Center for Bioenergy and Photosynthesis, Biodesign Center for Applied Structural DiscoveryArizona State UniversityTempeArizonaUSA
| | - Chong Fang
- Department of ChemistryOregon State UniversityCorvallisOregonUSA
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4
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Gavshina AV, Solovyev ID, Savitsky AP. The Role of the 145 Residue in Photochemical Properties of the Biphotochromic Protein mSAASoti: Brightness versus Photoconversion. Int J Mol Sci 2022; 23:ijms232416058. [PMID: 36555699 PMCID: PMC9787662 DOI: 10.3390/ijms232416058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/06/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Photoswitchable fluorescent proteins (FPs) have become indispensable tools for studying life sciences. mSAASoti FP, a biphotochromic FP, is an important representative of this protein family. We created a series of mSAASoti mutants in order to obtain fast photoswitchable variants with high brightness. K145P mSAASoti has the highest molar extinction coefficient of all SAASoti mutants studied; C21N/K145P/M163A switches to the dark state 36 times faster than mSAASoti, but it lost its ability to undergo green-to-red photoconversion. Finally, the C21N/K145P/F177S and C21N/K145P/M163A/F177S variants demonstrated a high photoswitching rate between both green and red forms.
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5
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De Zitter E, Hugelier S, Duwé S, Vandenberg W, Tebo AG, Van Meervelt L, Dedecker P. Structure-Function Dataset Reveals Environment Effects within a Fluorescent Protein Model System*. Angew Chem Int Ed Engl 2021; 60:10073-10081. [PMID: 33543524 DOI: 10.1002/anie.202015201] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Indexed: 11/05/2022]
Abstract
Anisotropic environments can drastically alter the spectroscopy and photochemistry of molecules, leading to complex structure-function relationships. We examined this using fluorescent proteins as easy-to-modify model systems. Starting from a single scaffold, we have developed a range of 27 photochromic fluorescent proteins that cover a broad range of spectroscopic properties, including the determination of 43 crystal structures. Correlation and principal component analysis confirmed the complex relationship between structure and spectroscopy, but also allowed us to identify consistent trends and to relate these to the spatial organization. We find that changes in spectroscopic properties can come about through multiple underlying mechanisms, of which polarity, hydrogen bonding and presence of water molecules are key modulators. We anticipate that our findings and rich structure/spectroscopy dataset can open opportunities for the development and evaluation of new and existing protein engineering methods.
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Affiliation(s)
- Elke De Zitter
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G - box 2403, 3001, Leuven, Belgium.,Present address: University Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des Martyrs, 38000, Grenoble, France
| | - Siewert Hugelier
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G - box 2403, 3001, Leuven, Belgium
| | - Sam Duwé
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G - box 2403, 3001, Leuven, Belgium.,Present address: Advanced Optical Microscopy Centre, Hasselt University, Agoralaan building C, 3590, Diepenbeek, Belgium
| | - Wim Vandenberg
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G - box 2403, 3001, Leuven, Belgium
| | - Alison G Tebo
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia, 20147, USA
| | - Luc Van Meervelt
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G - box 2403, 3001, Leuven, Belgium
| | - Peter Dedecker
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G - box 2403, 3001, Leuven, Belgium
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6
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De Zitter E, Hugelier S, Duwé S, Vandenberg W, Tebo AG, Van Meervelt L, Dedecker P. Structure–Function Dataset Reveals Environment Effects within a Fluorescent Protein Model System**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202015201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Elke De Zitter
- Department of Chemistry KU Leuven Celestijnenlaan 200G – box 2403 3001 Leuven Belgium
- Present address: University Grenoble Alpes CEA CNRS IBS 71 Avenue des Martyrs 38000 Grenoble France
| | - Siewert Hugelier
- Department of Chemistry KU Leuven Celestijnenlaan 200G – box 2403 3001 Leuven Belgium
| | - Sam Duwé
- Department of Chemistry KU Leuven Celestijnenlaan 200G – box 2403 3001 Leuven Belgium
- Present address: Advanced Optical Microscopy Centre Hasselt University Agoralaan building C 3590 Diepenbeek Belgium
| | - Wim Vandenberg
- Department of Chemistry KU Leuven Celestijnenlaan 200G – box 2403 3001 Leuven Belgium
| | - Alison G. Tebo
- Janelia Research Campus Howard Hughes Medical Institute 19700 Helix Drive Ashburn Virginia 20147 USA
| | - Luc Van Meervelt
- Department of Chemistry KU Leuven Celestijnenlaan 200G – box 2403 3001 Leuven Belgium
| | - Peter Dedecker
- Department of Chemistry KU Leuven Celestijnenlaan 200G – box 2403 3001 Leuven Belgium
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7
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Smyrnova D, Marín MDC, Olivucci M, Ceulemans A. Systematic Excited State Studies of Reversibly Switchable Fluorescent Proteins. J Chem Theory Comput 2018; 14:3163-3172. [PMID: 29772175 DOI: 10.1021/acs.jctc.8b00050] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The reversibly switchable fluorescent proteins Dronpa, rsFastLime, rsKame, Padron, and bsDronpa feature the same chromophore but display a 40 nm variation in absorption maxima and an only 18 nm variation in emission maxima. In the present contribution, we employ QM/MM models to investigate the mechanism of such remarkably different spectral variations, which are caused by just a few amino acid replacements. We show that the models, which are based on CASPT2//CASSCF level of QM theory, reproduce the observed trends in absorption maxima, with only a 3.5 kcal/mol blue-shift, and in emission maxima, with an even smaller 1.5 kcal/mol blue-shift with respect to the observed quantities. In order to explain the variations across the series, we look at the chromophore's electronic structure change during absorption and emission. Such analysis indicates that a change in charge-transfer character, which is more pronounced during absorption, triggers a cascade of hydrogen-bond-network rearrangements, suggesting preparation to an isomerization event. We also show how the contribution of Arg 89 and Arg 64 residues to the chromophore conformational changes correlate with the spectral variations in absorption and emission. Furthermore, we describe how the conical intersection stability is related to the protein's photophysical properties. While for the Dronpa, rsFastLime, and rsKame triad, the stability correlates with the photoswitching speed, this does not happen for bsDronpa and Padron, suggesting a less obvious photoisomerization mechanism.
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Affiliation(s)
- Daryna Smyrnova
- Quantum Chemistry and Physical Chemistry Division, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B-3001 Heverlee , Belgium
| | - María Del Carmen Marín
- Department of Biotechnology, Chemistry, and Pharmacy , Universitá di Siena , via A. Moro 2 , I-53100 Siena , Italy.,Department of Chemistry , Bowling Green State University , Bowling Green , Ohio 43403 , United States
| | - Massimo Olivucci
- Department of Biotechnology, Chemistry, and Pharmacy , Universitá di Siena , via A. Moro 2 , I-53100 Siena , Italy.,Department of Chemistry , Bowling Green State University , Bowling Green , Ohio 43403 , United States
| | - Arnout Ceulemans
- Quantum Chemistry and Physical Chemistry Division, Department of Chemistry , KU Leuven , Celestijnenlaan 200F , B-3001 Heverlee , Belgium
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8
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Roebroek T, Duwé S, Vandenberg W, Dedecker P. Reduced Fluorescent Protein Switching Fatigue by Binding-Induced Emissive State Stabilization. Int J Mol Sci 2017; 18:ijms18092015. [PMID: 28930199 PMCID: PMC5618663 DOI: 10.3390/ijms18092015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 01/12/2023] Open
Abstract
Reversibly switchable fluorescent proteins (RSFPs) enable advanced fluorescence imaging, though the performance of this imaging crucially depends on the properties of the labels. We report on the use of an existing small binding peptide, named Enhancer, to modulate the spectroscopic properties of the recently developed rsGreen series of RSFPs. Fusion constructs of Enhancer with rsGreen1 and rsGreenF revealed an increased molecular brightness and pH stability, although expression in living E. coli or HeLa cells resulted in a decrease of the overall emission. Surprisingly, Enhancer binding also increased off-switching speed and resistance to switching fatigue. Further investigation suggested that the RSFPs can interconvert between fast- and slow-switching emissive states, with the overall protein population gradually converting to the slow-switching state through irradiation. The Enhancer modulates the spectroscopic properties of both states, but also preferentially stabilizes the fast-switching state, supporting the increased fatigue resistance. This work demonstrates how the photo-physical properties of RSFPs can be influenced by their binding to other small proteins, which opens up new horizons for applications that may require such modulation. Furthermore, we provide new insights into the photoswitching kinetics that should be of general consideration when developing new RSFPs with improved or different photochromic properties.
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Affiliation(s)
- Thijs Roebroek
- Laboratory for Nanobiology, Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.
| | - Sam Duwé
- Laboratory for Nanobiology, Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.
| | - Wim Vandenberg
- Laboratory for Nanobiology, Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.
| | - Peter Dedecker
- Laboratory for Nanobiology, Department of Chemistry, KU Leuven, Celestijnenlaan 200G, 3001 Leuven, Belgium.
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9
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Lin CY, Both J, Do K, Boxer SG. Mechanism and bottlenecks in strand photodissociation of split green fluorescent proteins (GFPs). Proc Natl Acad Sci U S A 2017; 114:E2146-E2155. [PMID: 28242710 PMCID: PMC5358378 DOI: 10.1073/pnas.1618087114] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Split GFPs have been widely applied for monitoring protein-protein interactions by expressing GFPs as two or more constituent parts linked to separate proteins that only fluoresce on complementing with one another. Although this complementation is typically irreversible, it has been shown previously that light accelerates dissociation of a noncovalently attached β-strand from a circularly permuted split GFP, allowing the interaction to be reversible. Reversible complementation is desirable, but photodissociation has too low of an efficiency (quantum yield <1%) to be useful as an optogenetic tool. Understanding the physical origins of this low efficiency can provide strategies to improve it. We elucidated the mechanism of strand photodissociation by measuring the dependence of its rate on light intensity and point mutations. The results show that strand photodissociation is a two-step process involving light-activated cis-trans isomerization of the chromophore followed by light-independent strand dissociation. The dependence of the rate on temperature was then used to establish a potential energy surface (PES) diagram along the photodissociation reaction coordinate. The resulting energetics-function model reveals the rate-limiting process to be the transition from the electronic excited-state to the ground-state PES accompanying cis-trans isomerization. Comparisons between split GFPs and other photosensory proteins, like photoactive yellow protein and rhodopsin, provide potential strategies for improving the photodissociation quantum yield.
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Affiliation(s)
- Chi-Yun Lin
- Department of Chemistry, Stanford University, Stanford, CA 94305-5012
| | - Johan Both
- Department of Chemistry, Stanford University, Stanford, CA 94305-5012
| | - Keunbong Do
- Department of Chemistry, Stanford University, Stanford, CA 94305-5012
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, CA 94305-5012
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10
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Smyrnova D, Zinovjev K, Tuñón I, Ceulemans A. Thermal Isomerization Mechanism in Dronpa and Its Mutants. J Phys Chem B 2016; 120:12820-12825. [PMID: 28002952 DOI: 10.1021/acs.jpcb.6b10859] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photoswitching speed of the reversibly switchable fluorescent proteins (RSFPs) from the family of green fluorescent proteins (GFPs) changes upon mutation which is of direct importance for various high-resolution techniques. Dronpa is one of the most used RSFPs. Its point mutants rsFastLime (Dronpa V157G) and rsKame (Dronpa V157L) exhibit a striking difference in their photoswitching speed. Here the QM/MM on-the-fly string method is used in order to explore the details of the thermal isomerization mechanism. The four principal ways in which isomerization may occur have been scrutinized for each of the three proteins. It has been shown that thermal isomerization occurs via a one-bond-flip mechanism in all three proteins, although, in rsKame, where the chromophore is constrained more, the activation free energy difference between hula-twist and one-bond-flip is significantly smaller. Functional mode analysis has been applied to examine the motions of the amino acids during the isomerization. It clearly identifies the importance of Val/Leu 157 as well as the amino acids in the α-helix during the isomerization.
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Affiliation(s)
- Daryna Smyrnova
- Quantum Chemistry and Physical Chemistry Division, Department of Chemistry, KU Leuven , Celestijnenlaan 200F, 3001 Heverlee, Belgium
| | - Kirill Zinovjev
- Departament de Química Física, Universitat de València , 46100 Burjassot, Spain
| | - Iñaki Tuñón
- Departament de Química Física, Universitat de València , 46100 Burjassot, Spain
| | - Arnout Ceulemans
- Quantum Chemistry and Physical Chemistry Division, Department of Chemistry, KU Leuven , Celestijnenlaan 200F, 3001 Heverlee, Belgium
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11
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Acharya A, Bogdanov AM, Grigorenko BL, Bravaya KB, Nemukhin AV, Lukyanov KA, Krylov AI. Photoinduced Chemistry in Fluorescent Proteins: Curse or Blessing? Chem Rev 2016; 117:758-795. [PMID: 27754659 DOI: 10.1021/acs.chemrev.6b00238] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Photoinduced reactions play an important role in the photocycle of fluorescent proteins from the green fluorescent protein (GFP) family. Among such processes are photoisomerization, photooxidation/photoreduction, breaking and making of covalent bonds, and excited-state proton transfer (ESPT). Many of these transformations are initiated by electron transfer (ET). The quantum yields of these processes vary significantly, from nearly 1 for ESPT to 10-4-10-6 for ET. Importantly, even when quantum yields are relatively small, at the conditions of repeated illumination the overall effect is significant. Depending on the task at hand, fluorescent protein photochemistry is regarded either as an asset facilitating new applications or as a nuisance leading to the loss of optical output. The phenomena arising due to phototransformations include (i) large Stokes shifts, (ii) photoconversions, photoactivation, and photoswitching, (iii) phototoxicity, (iv) blinking, (v) permanent bleaching, and (vi) formation of long-lived intermediates. The focus of this review is on the most recent experimental and theoretical work on photoinduced transformations in fluorescent proteins. We also provide an overview of the photophysics of fluorescent proteins, highlighting the interplay between photochemistry and other channels (fluorescence, radiationless relaxation, and intersystem crossing). The similarities and differences with photochemical processes in other biological systems and in dyes are also discussed.
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Affiliation(s)
- Atanu Acharya
- Department of Chemistry, University of Southern California , Los Angeles, California 90089-0482, United States
| | - Alexey M Bogdanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Moscow, Russia.,Nizhny Novgorod State Medical Academy , Nizhny Novgorod, Russia
| | - Bella L Grigorenko
- Department of Chemistry, Lomonosov Moscow State University , Moscow, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences , Moscow, Russia
| | - Ksenia B Bravaya
- Department of Chemistry, Boston University , Boston, Massachusetts United States
| | - Alexander V Nemukhin
- Department of Chemistry, Lomonosov Moscow State University , Moscow, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences , Moscow, Russia
| | - Konstantin A Lukyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Moscow, Russia.,Nizhny Novgorod State Medical Academy , Nizhny Novgorod, Russia
| | - Anna I Krylov
- Department of Chemistry, University of Southern California , Los Angeles, California 90089-0482, United States
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