1
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Rajbongshi BK, Abdullah S, Lama B, Bhattacharyya HP, Sarma M. Regioselective and solvent-dependent photoisomerization induced internal conversion in red fluorescent protein chromophore analogues. RSC Adv 2024; 14:18373-18384. [PMID: 38860252 PMCID: PMC11163268 DOI: 10.1039/d4ra00988f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 05/23/2024] [Indexed: 06/12/2024] Open
Abstract
Photophysical properties of three red fluorescent protein (RFP) chromophore analogues are reported here. The three RFP chromophore analogues differ in the additional conjugation present in the RFP chromophore. The three chromophores do not exhibit any solvent effect in both absorption and fluorescence spectra. The photoirradiation experiments and recording of 1H NMR before and after irradiation on one of the three RFP model chromophores show isomerization of the (Z,E) diastereomer to the (E,E) diastereomer. Calculation of S0 and S1 potential energy curves shows the preference for isomerization through the exocyclic C[double bond, length as m-dash]C bond with Z-stereochemistry, thus corroborating the experimental results. The computational studies also suggest that torsional motion along the exocyclic C[double bond, length as m-dash]C bond pushes the molecules to a conical intersection, thus paving the pathway for radiationless deactivation.
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Affiliation(s)
| | - Sheikh Abdullah
- Department of Chemistry, Cotton University Panbazar Guwahati Assam 781001 India
| | - Bittu Lama
- Department of Chemistry, Indian Institute of Technology Guwahati Assam 781039 India
| | | | - Manabendra Sarma
- Department of Chemistry, Indian Institute of Technology Guwahati Assam 781039 India
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2
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Ikejiri M, Yoshimizu A, Shiota F, Nagayama A, Fujisaka A, Kuboki Y, Miyashita K. Viscosity-Induced Emission of 5-(Diarylmethylene)imidazolone with Extended Conjugation via Attachment of N-Methylpyrrole at the 2-Position. Chem Pharm Bull (Tokyo) 2024; 72:518-523. [PMID: 38825446 DOI: 10.1248/cpb.c24-00143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
We have developed a series of 2-monoaryl-5-diarylmethylene analogs of the green fluorescent protein chromophore to study their viscosity-induced emission (VIE) properties. The analogs were synthesized by a condensation with methyl imidate and N-(diarylmethylene)glycinate. Among the analogs, the N-methylpyrrol-2-yl-substituted analog 1h induced the most remarkable VIE behavior in triglyceride and lipid bilayers probably due to the high π-electron-rich property of the pyrrole ring. The pyrrole substituent in imidazolone analogs can be expected to become a common template for introducing VIE behavior.
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Affiliation(s)
| | | | | | - Ai Nagayama
- Faculty of Pharmacy, Osaka Ohtani University
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3
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Joron K, Viegas JO, Haas-Neill L, Bier S, Drori P, Dvir S, Lim PSL, Rauscher S, Meshorer E, Lerner E. Fluorescent protein lifetimes report densities and phases of nuclear condensates during embryonic stem-cell differentiation. Nat Commun 2023; 14:4885. [PMID: 37573411 PMCID: PMC10423231 DOI: 10.1038/s41467-023-40647-6] [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: 01/19/2023] [Accepted: 08/03/2023] [Indexed: 08/14/2023] Open
Abstract
Fluorescent proteins (FP) are frequently used for studying proteins inside cells. In advanced fluorescence microscopy, FPs can report on additional intracellular variables. One variable is the local density near FPs, which can be useful in studying densities within cellular bio-condensates. Here, we show that a reduction in fluorescence lifetimes of common monomeric FPs reports increased levels of local densities. We demonstrate the use of this fluorescence-based variable to report the distribution of local densities within heterochromatin protein 1α (HP1α) in mouse embryonic stem cells (ESCs), before and after early differentiation. We find that local densities within HP1α condensates in pluripotent ESCs are heterogeneous and cannot be explained by a single liquid phase. Early differentiation, however, induces a change towards a more homogeneous distribution of local densities, which can be explained as a liquid-like phase. In conclusion, we provide a fluorescence-based method to report increased local densities and apply it to distinguish between homogeneous and heterogeneous local densities within bio-condensates.
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Affiliation(s)
- Khalil Joron
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Juliane Oliveira Viegas
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 91904, Israel
| | - Liam Haas-Neill
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
- Department of Physics, University of Toronto, Toronto, ON, M5S 1A7, Canada
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Sariel Bier
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 91904, Israel
| | - Paz Drori
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Shani Dvir
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
| | - Patrick Siang Lin Lim
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 91904, Israel
| | - Sarah Rauscher
- Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada
- Department of Physics, University of Toronto, Toronto, ON, M5S 1A7, Canada
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Eran Meshorer
- Department of Genetics, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Givat Ram, Jerusalem, 91904, Israel.
- Edmond and Lily Center for Brain Sciences (ELSC), The Hebrew University of Jerusalem, Jerusalem, 91904, Israel.
| | - Eitan Lerner
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel.
- The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem, 9190401, Israel.
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4
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Chen C, Henderson JN, Ruchkin DA, Kirsh JM, Baranov MS, Bogdanov AM, Mills JH, Boxer SG, Fang C. Structural Characterization of Fluorescent Proteins Using Tunable Femtosecond Stimulated Raman Spectroscopy. Int J Mol Sci 2023; 24:11991. [PMID: 37569365 PMCID: PMC10418586 DOI: 10.3390/ijms241511991] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 07/19/2023] [Accepted: 07/24/2023] [Indexed: 08/13/2023] Open
Abstract
The versatile functions of fluorescent proteins (FPs) as fluorescence biomarkers depend on their intrinsic chromophores interacting with the protein environment. Besides X-ray crystallography, vibrational spectroscopy represents a highly valuable tool for characterizing the chromophore structure and revealing the roles of chromophore-environment interactions. In this work, we aim to benchmark the ground-state vibrational signatures of a series of FPs with emission colors spanning from green, yellow, orange, to red, as well as the solvated model chromophores for some of these FPs, using wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS) in conjunction with quantum calculations. We systematically analyzed and discussed four factors underlying the vibrational properties of FP chromophores: sidechain structure, conjugation structure, chromophore conformation, and the protein environment. A prominent bond-stretching mode characteristic of the quinoidal resonance structure is found to be conserved in most FPs and model chromophores investigated, which can be used as a vibrational marker to interpret chromophore-environment interactions and structural effects on the electronic properties of the chromophore. The fundamental insights gained for these light-sensing units (e.g., protein active sites) substantiate the unique and powerful capability of wavelength-tunable FSRS in delineating FP chromophore properties with high sensitivity and resolution in solution and protein matrices. The comprehensive characterization for various FPs across a colorful palette could also serve as a solid foundation for future spectroscopic studies and the rational engineering of FPs with diverse and improved functions.
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Affiliation(s)
- Cheng Chen
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331, USA;
| | - J. Nathan Henderson
- Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; (J.N.H.); (J.H.M.)
| | - Dmitry A. Ruchkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ulitsa Miklukho-Maklaya, 16/10, 117997 Moscow, Russia; (D.A.R.); (M.S.B.); (A.M.B.)
| | - Jacob M. Kirsh
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA; (J.M.K.); (S.G.B.)
| | - Mikhail S. Baranov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ulitsa Miklukho-Maklaya, 16/10, 117997 Moscow, Russia; (D.A.R.); (M.S.B.); (A.M.B.)
- Laboratory of Medicinal Substances Chemistry, Institute of Translational Medicine, Pirogov Russian National Research Medical University, Ostrovitianov 1, 117997 Moscow, Russia
| | - Alexey M. Bogdanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Ulitsa Miklukho-Maklaya, 16/10, 117997 Moscow, Russia; (D.A.R.); (M.S.B.); (A.M.B.)
| | - Jeremy H. Mills
- Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA; (J.N.H.); (J.H.M.)
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Steven G. Boxer
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA; (J.M.K.); (S.G.B.)
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331, USA;
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5
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Ashworth EK, Dezalay J, Ryan CRM, Ieritano C, Hopkins WS, Chambrier I, Cammidge AN, Stockett MH, Noble JA, Bull JN. Protomers of the green and cyan fluorescent protein chromophores investigated using action spectroscopy. Phys Chem Chem Phys 2023. [PMID: 37465988 DOI: 10.1039/d3cp02661b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Abstract
The photophysics of biochromophore ions often depends on the isomeric or protomeric distribution, yet this distribution, and the individual isomer contributions to an action spectrum, can be difficult to quantify. Here, we use two separate photodissociation action spectroscopy instruments to record electronic spectra for protonated forms of the green (pHBDI+) and cyan (Cyan+) fluorescent protein chromophores. One instrument allows for cryogenic (T = 40 ± 10 K) cooling of the ions, while the other offers the ability to perform protomer-selective photodissociation spectroscopy. We show that both chromophores are generated as two protomers when using electrospray ionisation, and that the protomers have partially overlapping absorption profiles associated with the S1 ← S0 transition. The action spectra for both species span the 340-460 nm range, although the spectral onset for the pHBDI+ protomer with the proton residing on the carbonyl oxygen is red-shifted by ≈40 nm relative to the lower-energy imine protomer. Similarly, the imine and carbonyl protomers are the lowest energy forms of Cyan+, with the main band for the carbonyl protomer red-shifted by ≈60 nm relative to the lower-energy imine protomer. The present strategy for investigating protomers can be applied to a wide range of other biochromophore ions.
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Affiliation(s)
- Eleanor K Ashworth
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Jordan Dezalay
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | - Christian Ieritano
- Department of Chemistry, University of Waterloo, Waterloo N2L 3G1, Canada
| | - W Scott Hopkins
- Department of Chemistry, University of Waterloo, Waterloo N2L 3G1, Canada
| | - Isabelle Chambrier
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Andrew N Cammidge
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Mark H Stockett
- Department of Physics, Stockholm University, SE-10691 Stockholm, Sweden
| | | | - James N Bull
- School of Chemistry, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK.
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6
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Lossouarn A, Puteaux C, Bailly L, Tognetti V, Joubert L, Renard P, Sabot C. Metalloenzyme‐Mediated Thiol‐Yne Addition Towards Photoisomerizable Fluorescent Dyes. Chemistry 2022; 28:e202202180. [DOI: 10.1002/chem.202202180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Alexis Lossouarn
- Normandie Univ, CNRS, UNIROUEN, INSA Rouen, COBRA (UMR 6014) Rouen 76000 France
| | - Chloé Puteaux
- Normandie Univ, CNRS, UNIROUEN, INSA Rouen, COBRA (UMR 6014) Rouen 76000 France
| | - Laetitia Bailly
- Normandie Univ, CNRS, UNIROUEN, INSA Rouen, COBRA (UMR 6014) Rouen 76000 France
| | - Vincent Tognetti
- Normandie Univ, CNRS, UNIROUEN, INSA Rouen, COBRA (UMR 6014) Rouen 76000 France
| | - Laurent Joubert
- Normandie Univ, CNRS, UNIROUEN, INSA Rouen, COBRA (UMR 6014) Rouen 76000 France
| | - Pierre‐Yves Renard
- Normandie Univ, CNRS, UNIROUEN, INSA Rouen, COBRA (UMR 6014) Rouen 76000 France
| | - Cyrille Sabot
- Normandie Univ, CNRS, UNIROUEN, INSA Rouen, COBRA (UMR 6014) Rouen 76000 France
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7
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Jones CM, List NH, Martínez TJ. Resolving the ultrafast dynamics of the anionic green fluorescent protein chromophore in water. Chem Sci 2021; 12:11347-11363. [PMID: 34667545 PMCID: PMC8447926 DOI: 10.1039/d1sc02508b] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 07/13/2021] [Indexed: 11/21/2022] Open
Abstract
The chromophore of the green fluorescent protein (GFP) is critical for probing environmental influences on fluorescent protein behavior. Using the aqueous system as a bridge between the unconfined vacuum system and a constricting protein scaffold, we investigate the steric and electronic effects of the environment on the photodynamical behavior of the chromophore. Specifically, we apply ab initio multiple spawning to simulate five picoseconds of nonadiabatic dynamics after photoexcitation, resolving the excited-state pathways responsible for internal conversion in the aqueous chromophore. We identify an ultrafast pathway that proceeds through a short-lived (sub-picosecond) imidazolinone-twisted (I-twisted) species and a slower (several picoseconds) channel that proceeds through a long-lived phenolate-twisted (P-twisted) intermediate. The molecule navigates the non-equilibrium energy landscape via an aborted hula-twist-like motion toward the one-bond-flip dominated conical intersection seams, as opposed to following the pure one-bond-flip paths proposed by the excited-state equilibrium picture. We interpret our simulations in the context of time-resolved fluorescence experiments, which use short- and long-time components to describe the fluorescence decay of the aqueous GFP chromophore. Our results suggest that the longer time component is caused by an energetically uphill approach to the P-twisted intersection seam rather than an excited-state barrier to reach the twisted intramolecular charge-transfer species. Irrespective of the location of the nonadiabatic population events, the twisted intersection seams are inefficient at facilitating isomerization in aqueous solution. The disordered and homogeneous nature of the aqueous solvent environment facilitates non-selective stabilization with respect to I- and P-twisted species, offering an important foundation for understanding the consequences of selective stabilization in heterogeneous and rigid protein environments.
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Affiliation(s)
- Chey M Jones
- Department of Chemistry and the PULSE Institute, Stanford University Stanford CA 94305 USA
- SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
| | - Nanna H List
- Department of Chemistry and the PULSE Institute, Stanford University Stanford CA 94305 USA
- SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
| | - Todd J Martínez
- Department of Chemistry and the PULSE Institute, Stanford University Stanford CA 94305 USA
- SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
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8
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Peng B, Dikdan R, Hill SE, Patterson-Orazem AC, Lieberman RL, Fahrni CJ, Dickson RM. Optically Modulated and Optically Activated Delayed Fluorescent Proteins through Dark State Engineering. J Phys Chem B 2021; 125:5200-5209. [PMID: 33978414 DOI: 10.1021/acs.jpcb.1c00649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Modulating fluorescent protein emission holds great potential for increasing readout sensitivity for applications in biological imaging and detection. Here, we identify and engineer optically modulated yellow fluorescent proteins (EYFP, originally 10C, but renamed EYFP later, and mVenus) to yield new emitters with distinct modulation profiles and unique, optically gated, delayed fluorescence. The parent YFPs are individually modulatable through secondary illumination, depopulating a long-lived dark state to dynamically increase fluorescence. A single point mutation introduced near the chromophore in each of these YFPs provides access to a second, even longer-lived modulatable dark state, while a different double mutant renders EYFP unmodulatable. The naturally occurring dark state in the parent YFPs yields strong fluorescence modulation upon long-wavelength-induced dark state depopulation, allowing selective detection at the frequency at which the long wavelength secondary laser is intensity modulated. Distinct from photoswitches, however, this near IR secondary coexcitation repumps the emissive S1 level from the long-lived triplet state, resulting in optically activated delayed fluorescence (OADF). This OADF results from secondary laser-induced, reverse intersystem crossing (RISC), producing additional nanosecond-lived, visible fluorescence that is delayed by many microseconds after the primary excitation has turned off. Mutation of the parent chromophore environment opens an additional modulation pathway that avoids the OADF-producing triplet state, resulting in a second, much longer-lived, modulatable dark state. These Optically Modulated and Optically Activated Delayed Fluorescent Proteins (OMFPs and OADFPs) are thus excellent for background- and reference-free, high sensitivity cellular imaging, but time-gated OADF offers a second modality for true background-free detection. Our combined structural and spectroscopic data not only gives additional mechanistic details for designing optically modulated fluorescent proteins but also provides the opportunity to distinguish similarly emitting OMFPs through OADF and through their unique modulation spectra.
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Affiliation(s)
- Baijie Peng
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Ryan Dikdan
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Shannon E Hill
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Athéna C Patterson-Orazem
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Raquel L Lieberman
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Christoph J Fahrni
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Robert M Dickson
- School of Chemistry & Biochemistry and Petit Institute for Biosciences and Bioengineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
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9
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Morikawa TJ, Nishiyama M, Yoshizawa K, Fujita H, Watanabe TM. Glycine insertion modulates the fluorescence properties of Aequorea victoria green fluorescent protein and its variants in their ambient environment. Biophys Physicobiol 2021; 18:145-158. [PMID: 34178565 PMCID: PMC8214926 DOI: 10.2142/biophysico.bppb-v18.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/27/2021] [Indexed: 12/04/2022] Open
Abstract
The green fluorescent protein (GFP) derived from Pacific Ocean jellyfish is an essential tool in biology. GFP-solvent interactions can modulate the fluorescent property of GFP. We previously reported that glycine insertion is an effective mutation in the yellow variant of GFP, yellow fluorescent protein (YFP). Glycine insertion into one of the β-strands comprising the barrel structure distorts its structure, allowing water molecules to invade near the chromophore, enhancing hydrostatic pressure or solution hydrophobicity sensitivity. However, the underlying mechanism of how glycine insertion imparts environmental sensitivity to YFP has not been elucidated yet. To unveil the relationship between fluorescence and β-strand distortion, we investigated the effects of glycine insertion on the dependence of the optical properties of GFP variants named enhanced-GFP (eGFP) and its yellow (eYFP) and cyan (eCFP) variants with respect to pH, temperature, pressure, and hydrophobicity. Our results showed that the quantum yield decreased depending on the number of inserted glycines in all variants, and the dependence on pH, temperature, pressure, and hydrophobicity was altered, indicating the invasion of water molecules into the β-barrel. Peak shifts in the emission spectrum were observed in glycine-inserted eGFP, suggesting a change of the electric state in the excited chromophore. A comparative investigation of the spectral shift among variants under different conditions demonstrated that glycine insertion rearranged the hydrogen bond network between His148 and the chromophore. The present results provide important insights for further understanding the fluorescence mechanism in GFPs and suggest that glycine insertion could be a potent approach for investigating the relationship between water molecules and the intra-protein chromophore.
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Affiliation(s)
- Takamitsu J Morikawa
- Laboratory for Comprehensive Bioimaging, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Hyogo 650-0047, Japan.,Graduate School of Frontier Bioscience, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masayoshi Nishiyama
- Department of Physics, Kindai University, Higashiosaka, Osaka 577-8502, Japan
| | - Keiko Yoshizawa
- Laboratory for Comprehensive Bioimaging, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Hyogo 650-0047, Japan
| | - Hideaki Fujita
- Laboratory for Comprehensive Bioimaging, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Hyogo 650-0047, Japan.,Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553, Japan
| | - Tomonobu M Watanabe
- Laboratory for Comprehensive Bioimaging, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Hyogo 650-0047, Japan.,Department of Stem Cell Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553, Japan
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10
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Christou NE, Giandoreggio-Barranco K, Ayala I, Glushonkov O, Adam V, Bourgeois D, Brutscher B. Disentangling Chromophore States in a Reversibly Switchable Green Fluorescent Protein: Mechanistic Insights from NMR Spectroscopy. J Am Chem Soc 2021; 143:7521-7530. [PMID: 33966387 DOI: 10.1021/jacs.1c02442] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The photophysical properties of fluorescent proteins, including phototransformable variants used in advanced microscopy applications, are influenced by the environmental conditions in which they are expressed and used. Rational design of improved fluorescent protein markers requires a better understanding of these environmental effects. We demonstrate here that solution NMR spectroscopy can detect subtle changes in the chemical structure, conformation, and dynamics of the photoactive chromophore moiety with atomic resolution, providing such mechanistic information. Studying rsFolder, a reversibly switchable green fluorescent protein, we have identified four distinct configurations of its p-HBI chromophore, corresponding to the cis and trans isomers, with each one either protonated (neutral) or deprotonated (anionic) at the benzylidene ring. The relative populations and interconversion kinetics of these chromophore species depend on sample pH and buffer composition that alter in a complex way the strength of H-bonds that contribute in stabilizing the chromophore within the protein scaffold. We show in particular the important role of histidine-149 in stabilizing the neutral trans chromophore at intermediate pH values, leading to ground-state cis-trans isomerization with a peculiar pH dependence. We discuss the potential implications of our findings on the pH dependence of the photoswitching contrast, a critical parameter in nanoscopy applications.
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Affiliation(s)
- Nina Eleni Christou
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
| | | | - Isabel Ayala
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
| | - Oleksandr Glushonkov
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
| | - Virgile Adam
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
| | - Dominique Bourgeois
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
| | - Bernhard Brutscher
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale (IBS), 38000 Grenoble, France
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11
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Fluorescent Orthopalladated Complexes of 4-Aryliden-5(4 H)-oxazolones from the Kaede Protein: Synthesis and Characterization. Molecules 2021; 26:molecules26051238. [PMID: 33669118 PMCID: PMC7956804 DOI: 10.3390/molecules26051238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/22/2021] [Accepted: 02/22/2021] [Indexed: 11/18/2022] Open
Abstract
The goal of the work reported here was to amplify the fluorescent properties of 4-aryliden-5(4H)-oxazolones by suppression of the hula-twist non-radiative deactivation pathway. This aim was achieved by simultaneous bonding of a Pd center to the N atom of the heterocycle and the ortho carbon of the arylidene ring. Two different 4-((Z)-arylidene)-2-((E)-styryl)-5(4H)-oxazolones, the structures of which are closely related to the chromophore of the Kaede protein and substituted at the 2- and 4-positions of the arylidene ring (1a OMe; 1b F), were used as starting materials. Oxazolones 1a and 1b were reacted with Pd(OAc)2 to give the corresponding dinuclear orthometalated palladium derivates 2a and 2b by regioselective C–H activation of the ortho-position of the arylidene ring. Reaction of 2a (2b) with LiCl promoted the metathesis of the bridging carboxylate by chloride ligands to afford dinuclear 3a (3b). Mononuclear complexes containing the orthopalladated oxazolone and a variety of ancillary ligands (acetylacetonate (4a, 4b), hydroxyquinolinate (5a), aminoquinoline (6a), bipyridine (7a), phenanthroline (8a)) were prepared from 3a or 3b through metathesis of anionic ligands or substitution of neutral weakly bonded ligands. All species were fully characterized and the X-ray determination of the molecular structure of 7a was carried out. This structure has strongly distorted ligands due to intramolecular interactions. Fluorescence measurements showed an increase in the quantum yield (QY) by up to one order of magnitude on comparing the free oxazolone (QY < 1%) with the palladated oxazolone (QY = 12% for 6a). This fact shows that the coordination of the oxazolone to the palladium efficiently suppresses the hula-twist deactivation pathway.
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Zagorec-Marks W, Foreman MM, Weber JM. Tag-Free, Temperature Dependent Infrared Spectra of the GFP Chromophore: Revisiting the Question of Isomerism. J Phys Chem A 2020; 124:7827-7831. [PMID: 32866387 DOI: 10.1021/acs.jpca.0c07172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report infrared spectra of a model chromophore of green fluorescent protein, prepared in an ion trap at temperatures ranging from 30 K to room temperature. We compare the changes in the infrared spectrum with predicted infrared spectra for the Z and E isomers of this molecule, and we confirm that the molecule exists as the Z isomer at low temperatures. We revisit the question whether or not it can thermally isomerize in the temperature range of this experiment, and we find no evidence for isomerization.
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Affiliation(s)
- Wyatt Zagorec-Marks
- JILA and Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Madison M Foreman
- JILA and Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - J Mathias Weber
- JILA and Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
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Lin CY, Boxer SG. Mechanism of Color and Photoacidity Tuning for the Protonated Green Fluorescent Protein Chromophore. J Am Chem Soc 2020; 142:11032-11041. [PMID: 32453950 DOI: 10.1021/jacs.0c02796] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The neutral or A state of the green fluorescent protein (GFP) chromophore is a remarkable example of a photoacid naturally embedded in the protein environment and accounts for the large Stokes shift of GFP in response to near UV excitation. Its color tuning mechanism has been largely overlooked, as it is less preferred for imaging applications than the redder anionic or B state. Past studies, based on site-directed mutagenesis or solvatochromism of the isolated chromophore, have concluded that its color tuning range is much narrower than its anionic counterpart. However, as we performed extensive investigation on more GFP mutants, we found that the color of the neutral chromophore can be more sensitive to protein electrostatics than can the anionic counterpart. Electronic Stark spectroscopy reveals a fundamentally different electrostatic color tuning mechanism for the neutral state of the chromophore that demands a three-form model as compared to that of the anionic state, which requires only two forms ( J. Am. Chem. Soc. 2019, 141, 15250-15265). Specifically, an underlying zwitterionic charge-transfer state is required to explain its sensitivity to electrostatics. As the Stokes shift is tightly linked to excited-state proton transfer (ESPT) of the protonated chromophore, we infer design principles of the GFP chromophore as a photoacid through the color tuning mechanisms of both protonation states. The three-form model could also be applied to similar biological and nonbiological dyes and complements the failure of the two-form model for donor-acceptor systems with localized ground-state electronic distributions.
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Affiliation(s)
- Chi-Yun Lin
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Steven G Boxer
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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14
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Kim S, Le TH, Choi Y, Lee H, Heo E, Lee U, Kim S, Chae S, Kim YA, Yoon H. Electrical monitoring of photoisomerization of block copolymers intercalated into graphene sheets. Nat Commun 2020; 11:1324. [PMID: 32165623 PMCID: PMC7067762 DOI: 10.1038/s41467-020-15132-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 02/19/2020] [Indexed: 12/01/2022] Open
Abstract
Insulating polymers have received little attention in electronic applications. Here, we synthesize a photoresponsive, amphiphilic block copolymer (PEO-b-PVBO) and further control the chain growth of the block segment (PVBO) to obtain different degrees of polymerization (DPs). The benzylidene oxazolone moiety in PEO-b-PVBO facilitated chain-conformational changes due to photoisomerization under visible/ultraviolet (UV) light illumination. Intercalation of the photoresponsive but electrically insulating PEO-b-PVBO into graphene sheets enabled electrical monitoring of the conformational change of the block copolymer at the molecular level. The current change at the microampere level was proportional to the DP of PVBO, demonstrating that the PEO-b-PVBO-intercalated graphene nanohybrid (PGNH) can be used in UV sensors. Additionally, discrete signals at the nanoampere level were separated from the first derivative of the time-dependent current using the fast Fourier transform (FFT). Analysis of the harmonic frequencies using the FFT revealed that the PGNH afforded sawtooth-type current flow mediated by Coulomb blockade oscillation. Block copolymers are electrically insulating and therefore characterization with electrical or electrochemical methods is not possible. Here, the authors demonstrate electrical monitoring of the photoisomerization transition in a benzylidene oxazolone block co-polymer intercalated into graphene sheets.
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Affiliation(s)
- Semin Kim
- Department of Polymer Engineering, Graduate School, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea
| | - Thanh-Hai Le
- Department of Polymer Engineering, Graduate School, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea
| | - Yunseok Choi
- Department of Polymer Engineering, Graduate School, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea
| | - Haney Lee
- Alan G. MacDiarmid Energy Research Institute & School of Polymer Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea
| | - Eunseo Heo
- Department of Polymer Engineering, Graduate School, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea
| | - Unhan Lee
- Department of Polymer Engineering, Graduate School, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea
| | - Saerona Kim
- Department of Polymer Engineering, Graduate School, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea
| | - Subin Chae
- Department of Polymer Engineering, Graduate School, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea
| | - Yoong Ahm Kim
- Department of Polymer Engineering, Graduate School, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea.,Alan G. MacDiarmid Energy Research Institute & School of Polymer Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea
| | - Hyeonseok Yoon
- Department of Polymer Engineering, Graduate School, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea. .,Alan G. MacDiarmid Energy Research Institute & School of Polymer Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186, South Korea.
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15
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Zagorec-Marks W, Foreman MM, Verlet JRR, Weber JM. Probing the Microsolvation Environment of the Green Fluorescent Protein Chromophore In Vacuo. J Phys Chem Lett 2020; 11:1940-1946. [PMID: 32073271 DOI: 10.1021/acs.jpclett.0c00105] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We present vibrational and electronic photodissociation spectra of a model chromophore of the green fluorescent protein in complexes with up to two water molecules, prepared in a cryogenic ion trap at 160-180 K. We find the band origin of the singly hydrated chromophore at 20 985 cm-1 (476.5 nm) and observe partially resolved vibrational signatures. While a single water molecule induces only a small shift of the S1 electronic band of the chromophore, without significant change of the Franck-Condon envelope, the spectrum of the dihydrate shows significant broadening and a greater blue shift of the band edge. Comparison of the vibrational spectra with predicted infrared spectra from density functional theory indicates that water molecules can interact with the oxygen atom on the phenolate group or on the imidazole moiety, respectively.
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Affiliation(s)
- Wyatt Zagorec-Marks
- JILA and Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Madison M Foreman
- JILA and Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham DH1 3LE, U.K
| | - J Mathias Weber
- JILA and Department of Chemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
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16
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Hally C, Delcanale P, Nonell S, Viappiani C, Abbruzzetti S. Photosensitizing proteins for antibacterial photodynamic inactivation. TRANSLATIONAL BIOPHOTONICS 2020. [DOI: 10.1002/tbio.201900031] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Affiliation(s)
- Cormac Hally
- Institut Quimic de Sarrià, Universitat Ramon Llull Barcelona Spain
- Dipartimento di Scienze Matematiche, Fisiche e InformaticheUniversità di Parma Parma Italy
| | - Pietro Delcanale
- Institute for Bioengineering of Catalonia (IBEC), the Barcelona Institute of Science and Technology (BIST) Barcelona Spain
| | - Santi Nonell
- Institut Quimic de Sarrià, Universitat Ramon Llull Barcelona Spain
| | - Cristiano Viappiani
- Dipartimento di Scienze Matematiche, Fisiche e InformaticheUniversità di Parma Parma Italy
| | - Stefania Abbruzzetti
- Dipartimento di Scienze Matematiche, Fisiche e InformaticheUniversità di Parma Parma Italy
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17
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Chatterjee S, Ahire K, Karuso P. Room-Temperature Dual Fluorescence of a Locked Green Fluorescent Protein Chromophore Analogue. J Am Chem Soc 2019; 142:738-749. [PMID: 31846319 DOI: 10.1021/jacs.9b05096] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A structurally locked green fluorescent protein (GFP) chromophore with a phenyl group at C(2) of the imidazolone has been synthesized. Rotation around the exocyclic double bond is hindered, resulting in room-temperature fluorescence. The quantum yield in water is 500 times greater than that of unlocked analogues. Unlike the methyl-substituted analogue, the phenyl analogue exhibits a dual emission (cyan and red) that can be used for ultrasensitive ratiometric measurements and fluorescence microscopy. To explain this dual emission, DFT calculations were carried out along with fluorescence upconversion experiments. The Z-isomer was found to be emissive, while the origin of the dual emission was dependent on the phenyl group in the Z-isomer, which stabilizes the Franck-Condon state, resulting in a cyan fluorescence, while the zwitterionic tautomer fluoresces red. These results bring important new insights into the photophysics of the GFP chromophore and provide a new scaffold capable of dual emission with utility in biotechnology.
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Affiliation(s)
- Soumit Chatterjee
- Department of Molecular Sciences , Macquarie University , Sydney , NSW 2109 , Australia
| | - Ketan Ahire
- Department of Molecular Sciences , Macquarie University , Sydney , NSW 2109 , Australia
| | - Peter Karuso
- Department of Molecular Sciences , Macquarie University , Sydney , NSW 2109 , Australia
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18
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Zagorec-Marks W, Foreman MM, Verlet JRR, Weber JM. Cryogenic Ion Spectroscopy of the Green Fluorescent Protein Chromophore in Vacuo. J Phys Chem Lett 2019; 10:7817-7822. [PMID: 31682445 DOI: 10.1021/acs.jpclett.9b02916] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We present the spectrum of the S1 ← S0 transition of an anionic model for the chromophore of the green fluorescent protein in vacuo at cryogenic temperatures, showing previously unresolved vibrational features, and resolving the band origin at 20 930 cm-1 (477.8 nm) with unprecedented accuracy. The vibrational spectrum establishes that the molecule is in the Z isomer at low temperature. At increased temperature, the S1 ← S0 band shifts to the red, which we tentatively attribute to emergent population of the E isomer.
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Affiliation(s)
- Wyatt Zagorec-Marks
- JILA and Department of Chemistry , University of Colorado , Boulder , Colorado 80309-0440 , United States
| | - Madison M Foreman
- JILA and Department of Chemistry , University of Colorado , Boulder , Colorado 80309-0440 , United States
| | - Jan R R Verlet
- Department of Chemistry , Durham University , Durham , DH1 3LE , U.K
| | - J Mathias Weber
- JILA and Department of Chemistry , University of Colorado , Boulder , Colorado 80309-0440 , United States
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19
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Karlsson JKG, Laude A, Hall MJ, Harriman A. Photo-isomerization of the Cyanine Dye Alexa-Fluor 647 (AF-647) in the Context of dSTORM Super-Resolution Microscopy. Chemistry 2019; 25:14983-14998. [PMID: 31515919 DOI: 10.1002/chem.201904117] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Indexed: 02/06/2023]
Abstract
Cyanine dyes, as used in super-resolution fluorescence microscopy, undergo light-induced "blinking", enabling localization of fluorophores with spatial resolution beyond the optical diffraction limit. Despite a plethora of studies, the molecular origins of this blinking are not well understood. Here, we examine the photophysical properties of a bio-conjugate cyanine dye (AF-647), used extensively in dSTORM imaging. In the absence of a potent sacrificial reductant, light-induced electron transfer and intermediates formed via the metastable, triplet excited state are considered unlikely to play a significant role in the blinking events. Instead, it is found that, under conditions appropriate to dSTORM microscopy, AF-647 undergoes reversible photo-induced isomerization to at least two long-lived dark species. These photo-isomers are characterized spectroscopically and their interconversion probed by computational means. The first-formed isomer is light sensitive and transforms to a longer-lived species in modest yield that could be involved in dSTORM related blinking. Permanent photobleaching of AF-647 occurs with very low quantum yield and is partially suppressed by the anaerobic redox buffer.
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Affiliation(s)
- Joshua K G Karlsson
- Molecular Photonics Laboratory, SNES, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Alex Laude
- Bio-Imaging Unit, Medical School, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Michael J Hall
- School of Natural and Environmental Sciences, Bedson Building, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
| | - Anthony Harriman
- Molecular Photonics Laboratory, SNES, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
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20
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Shinoda H, Lu K, Nakashima R, Wazawa T, Noguchi K, Matsuda T, Nagai T. Acid-Tolerant Reversibly Switchable Green Fluorescent Protein for Super-resolution Imaging under Acidic Conditions. Cell Chem Biol 2019; 26:1469-1479.e6. [DOI: 10.1016/j.chembiol.2019.07.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 06/13/2019] [Accepted: 07/23/2019] [Indexed: 02/08/2023]
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21
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Novel Phototransformable Fluorescent Protein SAASoti with Unique Photochemical Properties. Int J Mol Sci 2019; 20:ijms20143399. [PMID: 31373280 PMCID: PMC6678895 DOI: 10.3390/ijms20143399] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/04/2019] [Accepted: 07/08/2019] [Indexed: 12/27/2022] Open
Abstract
SAASoti is a unique fluorescent protein (FP) that combines properties of green-to-red photoconversion and reversible photoswitching (in its green state), without any amino acid substitutions in the wild type gene. In the present work, we investigated its ability to photoswitch between fluorescent red (‘on’) and dark (‘off’) states. Surprisingly, generated by 400 nm exposure, the red form of SAASoti (R1) does not exhibit any reversible photoswitching behavior under 550 nm illumination, while a combination of prior 470 nm and subsequent 400 nm irradiation led to the appearance of another—R2—form that can be partially photoswitched (550 nm) to the dark state, with a very fast recovery time. The phenomenon might be explained by chemical modification in the chromophore microenvironment during prior 470 nm exposure, and the resulting R2 SAASoti differs chemically from the R1 form. The suggestion is supported by the mass spectrometry analysis of the tryptic peptides before and after 470 nm light exposure, that revealed Met164 oxidation, as proceeds in another dual phototransformable FP, IrisFP.
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22
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Povarova NV, Zaitseva SO, Baleeva NS, Smirnov AY, Myasnyanko IN, Zagudaylova MB, Bozhanova NG, Gorbachev DA, Malyshevskaya KK, Gavrikov AS, Mishin AS, Baranov MS. Red-Shifted Substrates for FAST Fluorogen-Activating Protein Based on the GFP-Like Chromophores. Chemistry 2019; 25:9592-9596. [PMID: 31111975 DOI: 10.1002/chem.201901151] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/14/2019] [Indexed: 11/10/2022]
Abstract
A genetically encoded fluorescent tag for live cell microscopy is presented. This tag is composed of previously published fluorogen-activating protein FAST and a novel fluorogenic derivative of green fluorescent protein (GFP)-like chromophore with red fluorescence. The reversible binding of the novel fluorogen and FAST is accompanied by three orders of magnitude increase in red fluorescence (580-650 nm). The proposed dye instantly stains target cellular proteins fused with FAST, washes out in a minute timescale, and exhibits higher photostability of the fluorescence signal in confocal and widefield microscopy, in contrast with previously published fluorogen:FAST complexes.
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Affiliation(s)
- Natalia V Povarova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Snizhana O Zaitseva
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Nadezhda S Baleeva
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Alexander Yu Smirnov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Ivan N Myasnyanko
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Marina B Zagudaylova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Nina G Bozhanova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Dmitriy A Gorbachev
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia.,Center of Life Sciences, Skolkovo Institute of Science and Technology, Bolshoy Blvd 30, Moscow, 121205, Russia
| | - Kseniya K Malyshevskaya
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia.,Center of Life Sciences, Skolkovo Institute of Science and Technology, Bolshoy Blvd 30, Moscow, 121205, Russia
| | - Alexey S Gavrikov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Alexander S Mishin
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia
| | - Mikhail S Baranov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia.,Pirogov Russian National Research Medical University, Ostrovitianov 1, Moscow, 117997, Russia
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Santra K, Geraskin I, Nilsen-Hamilton M, Kraus GA, Petrich JW. Characterization of the Photophysical Behavior of DFHBI Derivatives: Fluorogenic Molecules that Illuminate the Spinach RNA Aptamer. J Phys Chem B 2019; 123:2536-2545. [PMID: 30807171 DOI: 10.1021/acs.jpcb.8b11166] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
( Z)-5-(3,5-Difluoro-4-hydroxybenzylidene)-2,3-dimethyl-3,5-dihydro-4 H-imidazol-4-one (DFHBI) and its analogues are fluorogenic molecules that bind the Spinach aptamer (a small RNA molecule), which was selected for imaging RNA. They are extremely weakly fluorescent in liquid solvents. It had been hypothesized that photoisomerization is a very efficient nonradiative process of deactivation. We show, consistent with the results of other studies, that if the isomerization is impeded, the fluorescence signal is enhanced significantly. In addition, we provide a thorough characterization of the photophysical behavior of DFHBI and its derivatives, notably that of ( Z)-5-(3,5-difluoro-4-hydroxybenzylidene)-2-methyl-3-((perfluorophenyl)methyl)-3,5-dihydro-4 H-imidazol-4-one (PFP-DFHBI) in various solvent environments. Solvent-dependent studies were performed with various mixtures of solvents. The results suggest that hydrogen bonding or strong interactions of the solvents with the phenolic-OH group change the absorption band near 420-460 nm and the nature of emission near 430 and 500 nm through various degrees of stabilization and the transformation between the neutral and the anionic species at both ground and excited states. These observations are confirmed by using a methoxy-substituted molecule (( Z)-5-(4-methoxybenzylidene)-2,3-dimethyl-3,5-dihydro-4 H-imidazol-4-one), where the 420-460 nm band is absent in the presence of methanol and the spectra are similar to those of PFP-DFHBI in noninteracting solvents, such as acetonitrile and dichloromethane. Thus, in addition to the major role of photoisomerization as a nonradiative process of deactivation of the excited state, the fluorescence of DFHBI-type molecules is very sensitively dependent upon the pH of the medium as well as upon solvent-specific interactions, such as hydrogen-bonding ability and polarity.
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25
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Storti B, Margheritis E, Abbandonato G, Domenichini G, Dreier J, Testa I, Garau G, Nifosì R, Bizzarri R. Role of Gln222 in Photoswitching of Aequorea Fluorescent Proteins: A Twisting and H-Bonding Affair? ACS Chem Biol 2018; 13:2082-2093. [PMID: 29878744 DOI: 10.1021/acschembio.8b00267] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Reversibly photoswitchable fluorescent proteins (RSFPs) admirably combine the genetic encoding of fluorescence with the ability to repeatedly toggle between a bright and dark state, adding a new temporal dimension to the fluorescence signal. Accordingly, in recent years RSFPs have paved the way to novel applications in cell imaging that rely on their reversible photoswitching, including many super-resolution techniques such as F-PALM, RESOLFT, and SOFI that provide nanoscale pictures of the living matter. Yet many RSFPs have been engineered by a rational approach only to a limited extent, in the absence of clear structure-property relationships that in most cases make anecdotic the emergence of the photoswitching. We reported [ Bizzarri et al. J. Am Chem Soc. 2010 , 102 , 85 ] how the E222Q replacement is a single photoswitching mutation, since it restores the intrinsic cis-trans photoisomerization properties of the chromophore in otherwise nonswitchable Aequorea proteins of different color and mutation pattern (Q-RSFPs). We here investigate the subtle role of Q222 on the excited-state photophysics of the two simplest Q-RSFPs by a combined experimental and theoretical approach, using their nonswitchable anacestor EGFP as benchmark. Our findings link indissolubly photoswitching and Q222 presence, by a simple yet elegant scenario: largely twisted chromophore structures around the double bond (including hula-twist configurations) are uniquely stabilized by Q222 via H-bonds. Likely, these H-bonds subtly modulate the electronic properties of the chromophore, enabling the conical intersection that connects the excited cis to ground trans chromophore. Thus, Q222 belongs to a restricted family of single mutations that change dramatically the functional phenotype of a protein. The capability to distinguish quantitatively T65S/E222Q EGFP ("WildQ", wQ) from the spectrally identical EGFP by quantitative Optical Lock-In Detection (qOLID) witnesses the relevance of this mutation for cell imaging.
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Affiliation(s)
- Barbara Storti
- NEST, Scuola Normale Superiore and NANO-CNR, 56127 Pisa, Italy
| | - Eleonora Margheritis
- Center for Nanotechnology Innovation @ NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy
| | | | | | - Jes Dreier
- Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, Tomtebodavägen 23A, 171 65 Stockholm, Sweden
| | - Ilaria Testa
- Department of Applied Physics and Science for Life Laboratory, KTH Royal Institute of Technology, Tomtebodavägen 23A, 171 65 Stockholm, Sweden
| | - Gianpiero Garau
- Center for Nanotechnology Innovation @ NEST, Istituto Italiano di Tecnologia, 56127 Pisa, Italy
| | - Riccardo Nifosì
- NEST, Scuola Normale Superiore and NANO-CNR, 56127 Pisa, Italy
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26
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Zaitseva SO, Golodukhina SV, Baleeva NS, Levina EA, Smirnov AY, Zagudaylova MB, Baranov MS. Azidoacetic Acid Amides in the Synthesis of Substituted Arylidene‐1‐
H
‐imidazol‐5‐(4
H
)‐ones. ChemistrySelect 2018. [DOI: 10.1002/slct.201801349] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Snizhana O. Zaitseva
- Institute of Bioorganic ChemistryRussian Academy of Sciences, Miklukho-Maklaya 16/10 117997 Moscow Russia
| | - Svetlana V. Golodukhina
- Institute of Bioorganic ChemistryRussian Academy of Sciences, Miklukho-Maklaya 16/10 117997 Moscow Russia
| | - Nadezhda S. Baleeva
- Institute of Bioorganic ChemistryRussian Academy of Sciences, Miklukho-Maklaya 16/10 117997 Moscow Russia
| | - Evgenia A. Levina
- Institute of Bioorganic ChemistryRussian Academy of Sciences, Miklukho-Maklaya 16/10 117997 Moscow Russia
| | - Alexander Yu. Smirnov
- Institute of Bioorganic ChemistryRussian Academy of Sciences, Miklukho-Maklaya 16/10 117997 Moscow Russia
| | - Marina B. Zagudaylova
- Institute of Bioorganic ChemistryRussian Academy of Sciences, Miklukho-Maklaya 16/10 117997 Moscow Russia
| | - Mikhail S. Baranov
- Institute of Bioorganic ChemistryRussian Academy of Sciences, Miklukho-Maklaya 16/10 117997 Moscow Russia
- Pirogov Russian National Research Medical University, Ostrovitianov 1 117997 Moscow Russia
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27
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Laptenok SP, Gil AA, Hall CR, Lukacs A, Iuliano JN, Jones GA, Greetham GM, Donaldson P, Miyawaki A, Tonge PJ, Meech SR. Infrared spectroscopy reveals multi-step multi-timescale photoactivation in the photoconvertible protein archetype dronpa. Nat Chem 2018; 10:845-852. [PMID: 29892029 DOI: 10.1038/s41557-018-0073-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 04/27/2018] [Indexed: 01/13/2023]
Abstract
Photochromic fluorescent proteins play key roles in super-resolution microscopy and optogenetics. The light-driven structural changes that modulate the fluorescence involve both trans-to-cis isomerization and proton transfer. The mechanism, timescale and relative contribution of chromophore and protein dynamics are currently not well understood. Here, the mechanism of off-to-on-state switching in dronpa is studied using femtosecond-to-millisecond time-resolved infrared spectroscopy and isotope labelling. Chromophore and protein dynamics are shown to occur on multiple timescales, from picoseconds to hundreds of microseconds. Following excitation of the trans chromophore, a ground-state primary product is formed within picoseconds. Surprisingly, the characteristic vibrational spectrum of the neutral cis isomer appears only after several tens of nanoseconds. Further fluctuations in protein structure around the neutral cis chromophore are required to form a new intermediate, which promotes the final proton-transfer reaction. These data illustrate the interplay between chromophore dynamics and the protein environment underlying fluorescent protein photochromism.
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Affiliation(s)
- Sergey P Laptenok
- School of Chemistry, University of East Anglia, Norwich, UK.,Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Agnieszka A Gil
- Department of Chemistry, Stony Brook University, Stony Brook, NY, USA.,Department of Molecular Biology, Princeton University, Princeton, NJ, USA
| | - Christopher R Hall
- School of Chemistry, University of East Anglia, Norwich, UK.,ARC Centre of Excellence in Exciton Science, School of Chemistry, The University of Melbourne, Parkville, Victoria, Australia
| | - Andras Lukacs
- Department of Biophysics, Medical School, University of Pecs, Pecs, Hungary
| | - James N Iuliano
- Department of Chemistry, Stony Brook University, Stony Brook, NY, USA
| | - Garth A Jones
- School of Chemistry, University of East Anglia, Norwich, UK
| | - Gregory M Greetham
- Central Laser Facility, Harwell Science and Innovation Campus, Didcot, Oxfordshire, UK
| | - Paul Donaldson
- Central Laser Facility, Harwell Science and Innovation Campus, Didcot, Oxfordshire, UK
| | - Atsushi Miyawaki
- Laboratory for Cell Function Dynamics, RIKEN Center for Brain Science, Wako, Saitama, Japan
| | - Peter J Tonge
- Department of Chemistry, Stony Brook University, Stony Brook, NY, USA.
| | - Stephen R Meech
- School of Chemistry, University of East Anglia, Norwich, UK.
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28
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Carrascosa E, Bull JN, Scholz MS, Coughlan NJA, Olsen S, Wille U, Bieske EJ. Reversible Photoisomerization of the Isolated Green Fluorescent Protein Chromophore. J Phys Chem Lett 2018; 9:2647-2651. [PMID: 29724104 DOI: 10.1021/acs.jpclett.8b01201] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Fluorescent proteins have revolutionized the visualization of biological processes, prompting efforts to understand and control their intrinsic photophysics. Here we investigate the photoisomerization of deprotonated p-hydroxybenzylidene-2,3-dimethylimidazolinone anion (HBDI-), the chromophore in green fluorescent protein and in Dronpa protein, where it plays a role in switching between fluorescent and nonfluorescent states. In the present work, isolated HBDI- molecules are switched between the Z and E forms in the gas phase in a tandem ion mobility mass spectrometer outfitted for selecting the initial and final isomers. Excitation of the S1 ← S0 transition provokes both Z → E and E → Z photoisomerization, with a maximum response for both processes at 480 nm. Photodetachment is a minor channel at low light intensity. At higher light intensities, absorption of several photons in the drift region drives photofragmentation, through channels involving CH3 loss and concerted CO and CH3CN loss, although isomerization remains the dominant process.
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Affiliation(s)
- Eduardo Carrascosa
- School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - James N Bull
- School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Michael S Scholz
- School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Neville J A Coughlan
- School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Seth Olsen
- School of Chemistry , Monash University , Clayton , Victoria 3800 , Australia
| | - Uta Wille
- School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
| | - Evan J Bieske
- School of Chemistry , The University of Melbourne , Parkville , Victoria 3010 , Australia
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29
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Glazachev YI, Orlova DY, Řezníčková P, Bártová E. Effective scheme of photolysis of GFP in live cell as revealed with confocal fluorescence microscopy. Phys Biol 2018; 15:036008. [PMID: 29493532 DOI: 10.1088/1478-3975/aab31e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We proposed an effective kinetics scheme of photolysis of green fluorescent protein (GFP) observed in live cells with a commercial confocal fluorescence microscope. We investigated the photolysis of GFP-tagged heterochromatin protein, HP1β-GFP, in live nucleus with the pulse position modulation approach, which has several advantages over the classical pump-and-probe method. At the basis of the proposed scheme lies a process of photoswitching from the native fluorescence state to the intermediate fluorescence state, which has a lower fluorescence yield and recovers back to native state in the dark. This kinetics scheme includes four effective parameters (photoswitching, reverse switching, photodegradation rate constants, and relative brightness of the intermediate state) and covers the time scale from dozens of milliseconds to minutes of the experimental fluorescence kinetics. Additionally, the applicability of the scheme was demonstrated in the cases of continuous irradiation and the classical pump-and-probe approach using numerical calculations and analytical solutions. An interesting finding of experimental data analysis was that the overall photodegradation of GFP proceeds dominantly from the intermediate state, and demonstrated approximately the second-order reaction versus irradiation power. As a practical example, the proposed scheme elucidates the artifacts of fluorescence recovery after the photobleaching method, and allows us to propose some suggestions on how to diminish them.
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Affiliation(s)
- Yu I Glazachev
- Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian academy of Science, Novosibirsk 630090, Russia. Author to whom any correspondence should be addressed
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30
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Conyard J, Heisler IA, Chan Y, Bulman Page PC, Meech SR, Blancafort L. A new twist in the photophysics of the GFP chromophore: a volume-conserving molecular torsion couple. Chem Sci 2018; 9:1803-1812. [PMID: 29675225 PMCID: PMC5892128 DOI: 10.1039/c7sc04091a] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/30/2017] [Indexed: 01/19/2023] Open
Abstract
Dynamics of a nonplanar GFP chromophore are studied experimentally and theoretically. Coupled torsional motion is responsible for the ultrafast decay.
The simple structure of the chromophore of the green fluorescent protein (GFP), a phenol and an imidazolone ring linked by a methyne bridge, supports an exceptionally diverse range of excited state phenomena. Here we describe experimentally and theoretically the photochemistry of a novel sterically crowded nonplanar derivative of the GFP chromophore. It undergoes an excited state isomerization reaction accompanied by an exceptionally fast (sub 100 fs) excited state decay. The decay dynamics are essentially independent of solvent polarity and viscosity. Excited state structural dynamics are probed by high level quantum chemical calculations revealing that the fast decay is due to a conical intersection characterized by a twist of the rings and pyramidalization of the methyne bridge carbon. The intersection can be accessed without a barrier from the pre-twisted Franck–Condon structure, and the lack of viscosity dependence is due to the fact that the rings twist in the same direction, giving rise to a volume-conserving decay coordinate. Moreover, the rotation of the phenyl, methyl and imidazolone groups is coupled in the sterically crowded structure, with the methyl group translating the rotation of one ring to the next. As a consequence, the excited state dynamics can be viewed as a torsional couple, where the absorbed photon energy leads to conversion of the out-of-plane orientation from one ring to the other in a volume conserving fashion. A similar modification of the range of methyne dyes may provide a new family of devices for molecular machines, specifically torsional couples.
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Affiliation(s)
- Jamie Conyard
- School of Chemistry , University of East Anglia , Norwich Research Park , Norwich NR4 7TJ , UK .
| | - Ismael A Heisler
- School of Chemistry , University of East Anglia , Norwich Research Park , Norwich NR4 7TJ , UK .
| | - Yohan Chan
- School of Chemistry , University of East Anglia , Norwich Research Park , Norwich NR4 7TJ , UK .
| | - Philip C Bulman Page
- School of Chemistry , University of East Anglia , Norwich Research Park , Norwich NR4 7TJ , UK .
| | - Stephen R Meech
- School of Chemistry , University of East Anglia , Norwich Research Park , Norwich NR4 7TJ , UK .
| | - Lluís Blancafort
- Institut de Química Computacional i Catàlisi , Departament de Química , Facultat de Ciències , Universitat de Girona , C/ M. A. Capmany 69 , 17003 Girona , Spain .
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31
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Gotthard G, von Stetten D, Clavel D, Noirclerc-Savoye M, Royant A. Chromophore Isomer Stabilization Is Critical to the Efficient Fluorescence of Cyan Fluorescent Proteins. Biochemistry 2017; 56:6418-6422. [PMID: 29148725 DOI: 10.1021/acs.biochem.7b01088] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
ECFP, the first usable cyan fluorescent protein (CFP), was obtained by adapting the tyrosine-based chromophore environment in green fluorescent protein to that of a tryptophan-based one. This first-generation CFP was superseded by the popular Cerulean, CyPet, and SCFP3A that were engineered by rational and random mutagenesis, yet the latter CFPs still exhibit suboptimal properties of pH sensitivity and reversible photobleaching behavior. These flaws were serendipitously corrected in the third-generation CFP mTurquoise and its successors without an obvious rationale. We show here that the evolution process had unexpectedly remodeled the chromophore environment in second-generation CFPs so they would accommodate a different isomer, whose formation is favored by acidic pH or light irradiation and which emits fluorescence much less efficiently. Our results illustrate how fluorescent protein engineering based solely on fluorescence efficiency optimization may affect other photophysical or physicochemical parameters and provide novel insights into the rational evolution of fluorescent proteins with a tryptophan-based chromophore.
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Affiliation(s)
| | | | - Damien Clavel
- Univ. Grenoble Alpes, CNRS, CEA, IBS (Institut de Biologie Structurale), F-38000 Grenoble, France
| | | | - Antoine Royant
- European Synchrotron Radiation Facility , F-38043 Grenoble, France.,Univ. Grenoble Alpes, CNRS, CEA, IBS (Institut de Biologie Structurale), F-38000 Grenoble, France
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32
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Bozhanova NG, Baranov MS, Sarkisyan KS, Gritcenko R, Mineev KS, Golodukhina SV, Baleeva NS, Lukyanov KA, Mishin AS. Yellow and Orange Fluorescent Proteins with Tryptophan-based Chromophores. ACS Chem Biol 2017; 12:1867-1873. [PMID: 28525263 DOI: 10.1021/acschembio.7b00337] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rapid development of new microscopy techniques exposed the need for genetically encoded fluorescent tags with special properties. Recent works demonstrated the potential of fluorescent proteins with tryptophan-based chromophores. We applied rational design and random mutagenesis to the monomeric red fluorescent protein FusionRed and found two groups of mutants carrying a tryptophan-based chromophore: with yellow (535 nm) or orange (565 nm) emission. On the basis of the properties of proteins, a model synthetic chromophore, and a computational modeling, we concluded that the presence of a ketone-containing chromophore in different isomeric forms can explain the observed yellow and orange phenotypes.
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Affiliation(s)
- Nina G Bozhanova
- Institute of Bioorganic Chemistry, Russian Academy of Sciences , Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Mikhail S Baranov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences , Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Pirogov Russian National Research Medical University , Ostrovitianov 1, 117997 Moscow, Russia
| | - Karen S Sarkisyan
- Institute of Bioorganic Chemistry, Russian Academy of Sciences , Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Roman Gritcenko
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University , 22100 Lund, Sweden
| | - Konstantin S Mineev
- Institute of Bioorganic Chemistry, Russian Academy of Sciences , Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Moscow Institute of Physics and Technology , Institutsky per., 9, 141701 Dolgoprudny, Russia
| | - Svetlana V Golodukhina
- Institute of Bioorganic Chemistry, Russian Academy of Sciences , Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Nadezhda S Baleeva
- Institute of Bioorganic Chemistry, Russian Academy of Sciences , Miklukho-Maklaya 16/10, 117997 Moscow, Russia
- Pirogov Russian National Research Medical University , Ostrovitianov 1, 117997 Moscow, Russia
| | - Konstantin A Lukyanov
- Institute of Bioorganic Chemistry, Russian Academy of Sciences , Miklukho-Maklaya 16/10, 117997 Moscow, Russia
| | - Alexander S Mishin
- Institute of Bioorganic Chemistry, Russian Academy of Sciences , Miklukho-Maklaya 16/10, 117997 Moscow, Russia
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33
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Tsai MS, Ou CL, Tsai CJ, Huang YC, Cheng YC, Sun SS, Yang JS. Fluorescence Enhancement of Unconstrained GFP Chromophore Analogues Based on the Push–Pull Substituent Effect. J Org Chem 2017; 82:8031-8039. [DOI: 10.1021/acs.joc.7b01260] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Meng-Shiue Tsai
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan
- Institute
of Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Chun-Lin Ou
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Chi-Jui Tsai
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yen-Chin Huang
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Yuan-Chung Cheng
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan
| | - Shih-Sheng Sun
- Institute
of Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Jye-Shane Yang
- Department
of Chemistry, National Taiwan University, Taipei 10617, Taiwan
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34
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Bose S, Chakrabarty S, Ghosh D. Electrostatic Origin of the Red Solvatochromic Shift of DFHBDI in RNA Spinach. J Phys Chem B 2017; 121:4790-4798. [DOI: 10.1021/acs.jpcb.7b02445] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Samik Bose
- Physical and Materials
Chemistry
Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Suman Chakrabarty
- Physical and Materials
Chemistry
Division, CSIR-National Chemical Laboratory, Pune 411008, India
| | - Debashree Ghosh
- Physical and Materials
Chemistry
Division, CSIR-National Chemical Laboratory, Pune 411008, India
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35
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Zutterman F, Liégeois V, Champagne B. Simulation of the UV/Visible Absorption Spectra of Fluorescent Protein Chromophore Models. CHEMPHOTOCHEM 2017. [DOI: 10.1002/cptc.201700002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Freddy Zutterman
- Laboratoire de Chimie Théorique, Unité de Chimie-Physique Théorique et Structurale; Université de Namur; rue de Bruxelles, 61 B-5000 Namur Belgium
| | - Vincent Liégeois
- Laboratoire de Chimie Théorique, Unité de Chimie-Physique Théorique et Structurale; Université de Namur; rue de Bruxelles, 61 B-5000 Namur Belgium
| | - Benoît Champagne
- Laboratoire de Chimie Théorique, Unité de Chimie-Physique Théorique et Structurale; Université de Namur; rue de Bruxelles, 61 B-5000 Namur Belgium
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36
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Saito R, Hoshi M, Kato A, Ishikawa C, Komatsu T. Green fluorescent protein chromophore derivatives as a new class of aldose reductase inhibitors. Eur J Med Chem 2017; 125:965-974. [DOI: 10.1016/j.ejmech.2016.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 09/14/2016] [Accepted: 10/07/2016] [Indexed: 10/20/2022]
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37
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Nienhaus K, Nienhaus GU. Chromophore photophysics and dynamics in fluorescent proteins of the GFP family. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:443001. [PMID: 27604321 DOI: 10.1088/0953-8984/28/44/443001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Proteins of the green fluorescent protein (GFP) family are indispensable for fluorescence imaging experiments in the life sciences, particularly of living specimens. Their essential role as genetically encoded fluorescence markers has motivated many researchers over the last 20 years to further advance and optimize these proteins by using protein engineering. Amino acids can be exchanged by site-specific mutagenesis, starting with naturally occurring proteins as templates. Optical properties of the fluorescent chromophore are strongly tuned by the surrounding protein environment, and a targeted modification of chromophore-protein interactions requires a profound knowledge of the underlying photophysics and photochemistry, which has by now been well established from a large number of structural and spectroscopic experiments and molecular-mechanical and quantum-mechanical computations on many variants of fluorescent proteins. Nevertheless, such rational engineering often does not meet with success and thus is complemented by random mutagenesis and selection based on the optical properties. In this topical review, we present an overview of the key structural and spectroscopic properties of fluorescent proteins. We address protein-chromophore interactions that govern ground state optical properties as well as processes occurring in the electronically excited state. Special emphasis is placed on photoactivation of fluorescent proteins. These light-induced reactions result in large structural changes that drastically alter the fluorescence properties of the protein, which enables some of the most exciting applications, including single particle tracking, pulse chase imaging and super-resolution imaging. We also present a few examples of fluorescent protein application in live-cell imaging experiments.
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Affiliation(s)
- Karin Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), Wolfgang Gaede-Straße 1, 76131 Karlsruhe, Germany
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38
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Bhaskaran-Nair K, Valiev M, Deng SHM, Shelton WA, Kowalski K, Wang XB. Probing microhydration effect on the electronic structure of the GFP chromophore anion: Photoelectron spectroscopy and theoretical investigations. J Chem Phys 2016; 143:224301. [PMID: 26671369 DOI: 10.1063/1.4936252] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The photophysics of the Green Fluorescent Protein (GFP) chromophore is critically dependent on its local structure and on its environment. Despite extensive experimental and computational studies, there remain many open questions regarding the key fundamental variables that govern this process. One outstanding problem is the role of autoionization as a possible relaxation pathway of the excited state under different environmental conditions. This issue is considered in our work through combined experimental and theoretical studies of microsolvated clusters of the deprotonated p-hydroxybenzylidene-2,3-dimethylimidazolinone anion (HBDI(-)), an analog of the GFP chromophore. Through selective generation of microsolvated structures of predetermined size and subsequent analysis of experimental photoelectron spectra by high level ab initio methods, we are able to precisely identify the structure of the system, establish the accuracy of theoretical data, and provide reliable description of auto-ionization process as a function of hydrogen-bonding environment. Our study clearly illustrates the first few water molecules progressively stabilize the excited state of the chromophore anion against the autodetached neutral state, which should be an important trait for crystallographic water molecules in GFPs that has not been fully explored to date.
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Affiliation(s)
- Kiran Bhaskaran-Nair
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Marat Valiev
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, K8-91, P.O. Box 999, Richland, Washington 99352, USA
| | - S H M Deng
- Physical Sciences Division, Pacific Northwest National Laboratory, K8-88, P.O. Box 999, Richland, Washington 99352, USA
| | - William A Shelton
- Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Karol Kowalski
- William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, K8-91, P.O. Box 999, Richland, Washington 99352, USA
| | - Xue-Bin Wang
- Physical Sciences Division, Pacific Northwest National Laboratory, K8-88, P.O. Box 999, Richland, Washington 99352, USA
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39
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Chatterjee T, Lacombat F, Yadav D, Mandal M, Plaza P, Espagne A, Mandal PK. Ultrafast Dynamics of a Green Fluorescent Protein Chromophore Analogue: Competition between Excited-State Proton Transfer and Torsional Relaxation. J Phys Chem B 2016; 120:9716-22. [DOI: 10.1021/acs.jpcb.6b05795] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tanmay Chatterjee
- Department
of Chemical Sciences, Indian Institute of Science Education and Research (IISER) - Kolkata, Mohanpur, West-Bengal 741246, India
| | - Fabien Lacombat
- Ecole Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005 Paris, France
- Sorbonne Universités, UPMC Univ Paris 06,
ENS, CNRS, PASTEUR, 75005 Paris, France
| | - Dheerendra Yadav
- Ecole Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005 Paris, France
- Sorbonne Universités, UPMC Univ Paris 06,
ENS, CNRS, PASTEUR, 75005 Paris, France
| | - Mrinal Mandal
- Department
of Chemical Sciences, Indian Institute of Science Education and Research (IISER) - Kolkata, Mohanpur, West-Bengal 741246, India
| | - Pascal Plaza
- Ecole Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005 Paris, France
- Sorbonne Universités, UPMC Univ Paris 06,
ENS, CNRS, PASTEUR, 75005 Paris, France
| | - Agathe Espagne
- Ecole Normale Supérieure, PSL Research University, UPMC Univ Paris 06, CNRS, Département de Chimie, PASTEUR, 24, rue Lhomond, 75005 Paris, France
- Sorbonne Universités, UPMC Univ Paris 06,
ENS, CNRS, PASTEUR, 75005 Paris, France
| | - Prasun K. Mandal
- Department
of Chemical Sciences, Indian Institute of Science Education and Research (IISER) - Kolkata, Mohanpur, West-Bengal 741246, India
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40
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Abbandonato G, Storti B, Signore G, Beltram F, Bizzarri R. Quantitative optical lock-in detection for quantitative imaging of switchable and non-switchable components. Microsc Res Tech 2016; 79:929-937. [PMID: 27447845 DOI: 10.1002/jemt.22724] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 06/24/2016] [Accepted: 06/28/2016] [Indexed: 11/08/2022]
Abstract
Reversible photoswitching has been proposed as a way to identify molecules that are present in small numbers over a large, non-switching, background. This approach, called optical-lock-in-detection (OLID) requires the deterministic control of the fluorescence of a photochromic emitter through optical modulation between a bright (on) and a dark state (off). OLID yields a high-contrast map where the switching molecules are pinpointed, but the fractional intensities of the emitters are not returned. The present work presents a modified OLID approach (quantitative OLID or qOLID) that yields quantitative information of the switching (fSW ) and non-switching (fNS ) components. After the validation of the method with a sample dataset and image sequence, we apply qOLID to measurements in cells that transiently express the photochromic protein EYQ1. We show that qOLID is efficient in separating the modulated from the non-modulated signal, the latter deriving from background/autofluorescence or fluorophores emitting in the same spectral region. Finally, we apply qOLID to Förster (Fluorescence) Resonance Energy Transfer (FRET) imaging. We here demonstrate that qOLID is able to highlight the distribution of FRET intensity in a sample by using a photochromic donor and a non-photochromic acceptor.
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Affiliation(s)
- Gerardo Abbandonato
- NEST, Scuola Normale Superiore and Istituto Nanoscienze, piazza San Silvestro 12, I-56127, Italy
| | - Barbara Storti
- NEST, Scuola Normale Superiore and Istituto Nanoscienze, piazza San Silvestro 12, I-56127, Italy
| | - Giovanni Signore
- Center for Nanotechnology Innovation @ NEST, Istituto Italiano di Tecnologia, piazza San Silvestro 12, I-56127, Italy
| | - Fabio Beltram
- NEST, Scuola Normale Superiore and Istituto Nanoscienze, piazza San Silvestro 12, I-56127, Italy
| | - Ranieri Bizzarri
- NEST, Scuola Normale Superiore and Istituto Nanoscienze, piazza San Silvestro 12, I-56127, Italy.
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41
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Chatterjee T, Mandal M, Das A, Bhattacharyya K, Datta A, Mandal PK. Dual Fluorescence in GFP Chromophore Analogues: Chemical Modulation of Charge Transfer and Proton Transfer Bands. J Phys Chem B 2016; 120:3503-10. [PMID: 26998908 DOI: 10.1021/acs.jpcb.6b01993] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Tanmay Chatterjee
- Department
of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, West-Bengal 741246, India
| | - Mrinal Mandal
- Department
of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, West-Bengal 741246, India
| | - Ananya Das
- Department
of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, West-Bengal 741246, India
| | - Kalishankar Bhattacharyya
- Department
of Spectroscopy, Indian Association for the Cultivation of Science, 2A and 2B Raja S. C. Mullick Road, Kolkata, West Bengal 700032, India
| | - Ayan Datta
- Department
of Spectroscopy, Indian Association for the Cultivation of Science, 2A and 2B Raja S. C. Mullick Road, Kolkata, West Bengal 700032, India
| | - Prasun K. Mandal
- Department
of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, West-Bengal 741246, India
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42
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Ikejiri M, Matsumoto K, Hasegawa H, Yamaguchi D, Tsuchino M, Chihara Y, Yamaguchi T, Mori K, Imanishi T, Obika S, Miyashita K. Synthesis and fluorescence properties of 4-diarylmethylene analogues of the green fluorescent protein chromophore. Tetrahedron 2015. [DOI: 10.1016/j.tet.2015.05.073] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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43
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Hosoi H, Tayama R, Takeuchi S, Tahara T. Solvent dependence of two-photon absorption spectra of the enhanced green fluorescent protein (eGFP) chromophore. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.04.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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44
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Manna P, Jimenez R. Time and frequency-domain measurement of ground-state recovery times in red fluorescent proteins. J Phys Chem B 2015; 119:4944-54. [PMID: 25781915 DOI: 10.1021/acs.jpcb.5b00950] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The field of bioimaging and biosensors has been revolutionized by the discovery of fluorescent proteins (FPs) and their use in live cells. FPs are characterized with rich photodynamics due to the presence of nonfluorescent or dark states which are responsible for fluorescence intermittency or "blinking", which has been exploited in several localization-based super-resolution techniques that surpass the diffraction-limited resolution of conventional microscopy. Molecules that convert to these dark states recover to the ground states either spontaneously or upon absorption of another photon, depending on the particular FP and the structural transition that is involved. In this work, we demonstrate time- and frequency-domain methods for the measurement of the ground-state recovery (GSR) times of FPs both in live cells and in solutions. In the time-domain method, we excited the sample with millisecond pulses at varying dark times to obtain percent-recovery. In the frequency-domain method, dark-state hysteresis was employed to obtain the positive phase shift or "phase advance". We extracted the GSR time constants from our measurements using calculations and simulations based on a three-state model system. The GSR time constants of the red FPs studied in these experiments fall in the range from μs to msec time-scales. We find that the time- and frequency-domain techniques are complementary to each other. While accurate GSR times can be extracted from the time-domain technique, frequency-domain measurements are primarily sensitive to the rates of dark-state conversion (DSC) processes. A correlation between GSR times, DSC, and photobleaching rates for the red FPs mCherry, TagRFP-T, and Kriek were observed. These time- and frequency-domain methods can be used in high-throughput screening and sorting of FPs clones based on GSR time constant and photostability and will therefore be valuable for the development of new photoswitchable or photoactivatable FPs.
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Affiliation(s)
- Premashis Manna
- †Department of Chemistry and Biochemistry, University of Colorado at Boulder, 215 UCB, Boulder, Colorado 80309, United States
- ‡JILA, University of Colorado at Boulder and National Institute of Standards and Technology, 440 UCB, Boulder, Colorado 80309, United States
| | - Ralph Jimenez
- †Department of Chemistry and Biochemistry, University of Colorado at Boulder, 215 UCB, Boulder, Colorado 80309, United States
- ‡JILA, University of Colorado at Boulder and National Institute of Standards and Technology, 440 UCB, Boulder, Colorado 80309, United States
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45
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Pennacchietti F, Losi A, Xu XL, Zhao KH, Gärtner W, Viappiani C, Cella F, Diaspro A, Abbruzzetti S. Photochromic conversion in a red/green cyanobacteriochrome from Synechocystis PCC6803: quantum yields in solution and photoswitching dynamics in living E. coli cells. Photochem Photobiol Sci 2015; 14:229-37. [DOI: 10.1039/c4pp00337c] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photochromic conversion in GAF3 has been followed in solution and in E. coli cells.
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Affiliation(s)
| | - Aba Losi
- Dipartimento di Fisica e Scienze della Terra “Macedonio Melloni”
- Università di Parma
- Parma
- Italy
| | - Xiu-ling Xu
- Max-Planck-Institute for Chemical Energy Conversion
- D-45470 Mülheim
- Germany
| | - Kai-hong Zhao
- State Key Laboratory of Agricultural Microbiology
- Huazhong Agricultural University
- Wuhan 430070
- PR China
| | - Wolfgang Gärtner
- Max-Planck-Institute for Chemical Energy Conversion
- D-45470 Mülheim
- Germany
| | - Cristiano Viappiani
- Dipartimento di Fisica e Scienze della Terra “Macedonio Melloni”
- Università di Parma
- Parma
- Italy
- NEST
| | | | - Alberto Diaspro
- Fondazione Istituto Italiano di Tecnologia
- 16163 Genova
- Italy
- Nikon Imaging Center
- Fondazione Istituto Italiano di Tecnologia
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46
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Huang GJ, Lin CJ, Liu YH, Peng SM, Yang JS. o-Amino Analogs of Green Fluorescence Protein Chromophore: Photoisomerization, Photodimerization and Aggregation-induced Emission. Photochem Photobiol 2014; 91:714-22. [DOI: 10.1111/php.12373] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 10/20/2014] [Indexed: 01/26/2023]
Affiliation(s)
- Guan-Jhih Huang
- Department of Chemistry; National Taiwan University; Taipei Taiwan
| | - Che-Jen Lin
- Department of Chemistry; National Taiwan University; Taipei Taiwan
| | - Yi-Hung Liu
- Department of Chemistry; National Taiwan University; Taipei Taiwan
| | - Shie-Ming Peng
- Department of Chemistry; National Taiwan University; Taipei Taiwan
| | - Jye-Shane Yang
- Department of Chemistry; National Taiwan University; Taipei Taiwan
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47
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Yadav D, Lacombat F, Dozova N, Rappaport F, Plaza P, Espagne A. Real-time monitoring of chromophore isomerization and deprotonation during the photoactivation of the fluorescent protein Dronpa. J Phys Chem B 2014; 119:2404-14. [PMID: 25325882 DOI: 10.1021/jp507094f] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dronpa is a photochromic green fluorescent protein (GFP) homologue used as a probe in super-resolution microscopy. It is known that the photochromic reaction involves cis/trans isomerization of the chromophore and protonation/deprotonation of its phenol group, but the sequence in time of the two steps and their characteristic time scales are still the subject of much debate. We report here a comprehensive UV-visible transient absorption spectroscopy study of the photoactivation mechanism of Dronpa, covering all relevant time scales from ∼100 fs to milliseconds. The Dronpa-2 variant was also studied and showed the same behavior. By carefully controlling the excitation energy to avoid multiphoton processes, we could measure both the spectrum and the anisotropy of the first photoactivation intermediate. We show that the observed few nanometer blue-shift of this intermediate is characteristic for a neutral cis chromophore, and that its anisotropy of ∼0.2 is in good agreement with the reorientation of the transition dipole moment expected upon isomerization. These data constitute the first clear evidence that trans → cis isomerization of the chromophore precedes its deprotonation and occurs on the picosecond time scale, concomitantly to the excited-state decay. We found the deprotonation step to follow in ∼10 μs and lead directly from the neutral cis intermediate to the final state.
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Affiliation(s)
- Dheerendra Yadav
- Ecole Normale Supérieure-PSL Research University , Département de Chimie, 24 rue Lhomond, 75005 Paris, France
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48
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Nienhaus K, Nienhaus GU. Fluorescent proteins for live-cell imaging with super-resolution. Chem Soc Rev 2014; 43:1088-106. [PMID: 24056711 DOI: 10.1039/c3cs60171d] [Citation(s) in RCA: 259] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fluorescent proteins (FPs) from the GFP family have become indispensable as marker tools for imaging live cells, tissues and entire organisms. A wide variety of these proteins have been isolated from natural sources and engineered to optimize their properties as genetically encoded markers. Here we review recent developments in this field. A special focus is placed on photoactivatable FPs, for which the fluorescence emission can be controlled by light irradiation at specific wavelengths. They enable regional optical marking in pulse-chase experiments on live cells and tissues, and they are essential marker tools for live-cell optical imaging with super-resolution. Photoconvertible FPs, which can be activated irreversibly via a photo-induced chemical reaction that either turns on their emission or changes their emission wavelength, are excellent markers for localization-based super-resolution microscopy (e.g., PALM). Patterned illumination microscopy (e.g., RESOLFT), however, requires markers that can be reversibly photoactivated many times. Photoswitchable FPs can be toggled repeatedly between a fluorescent and a non-fluorescent state by means of a light-induced chromophore isomerization coupled to a protonation reaction. We discuss the mechanistic origins of the effect and illustrate how photoswitchable FPs are employed in RESOLFT imaging. For this purpose, special FP variants with low switching fatigue have been introduced in recent years. Despite nearly two decades of FP engineering by many laboratories, there is still room for further improvement of these important markers for live cell imaging.
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Affiliation(s)
- Karin Nienhaus
- Institute of Applied Physics and Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straβe 1, 76131 Karlsruhe, Germany
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49
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Runčevski T, Blanco-Lomas M, Marazzi M, Cejuela M, Sampedro D, Dinnebier RE. Following a Photoinduced Reconstructive Phase Transformation and its Influence on the Crystal Integrity: Powder Diffraction and Theoretical Study. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201402515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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50
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Deng SHM, Kong XY, Zhang G, Yang Y, Zheng WJ, Sun ZR, Zhang DQ, Wang XB. Vibrationally Resolved Photoelectron Spectroscopy of the Model GFP Chromophore Anion Revealing the Photoexcited S1 State Being Both Vertically and Adiabatically Bound against the Photodetached D0 Continuum. J Phys Chem Lett 2014; 5:2155-2159. [PMID: 26270508 DOI: 10.1021/jz500869b] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The first excited state of the model green fluorescence protein (GFP) chromophore anion (S1) and its energy level against the electron-detached neutral radical D0 state are crucial in determining the photophysics and the photoinduced dynamics of GFP. Extensive experimental and theoretical studies, particularly several very recent gas-phase investigations, concluded that S1 is a bound state in the Franck-Condon vertical region with respect to D0. However, what remains unknown and challenging is if S1 is bound adiabatically, primarily due to lack of accurate experimental measurements as well as due to the close proximity in energy for these two states that even sophisticated high-level ab initio calculations cannot reliably predict. Here, we report a negative ion photoelectron spectroscopy study on the model GFP chromophore anion, the deprotonated p-hydroxybenzylidene-2,3-dimethylimidazolinone anion (HBDI(-)) taken under low-temperature conditions with improved energy resolution. Despite the considerable size and low symmetry of the molecule, resolved vibrational structures were obtained with the 0-0 transition being the most intense peak. The adiabatic (ADE) and vertical detachment (VDE) energies therefore are determined both to be 2.73 ± 0.01 eV, indicating that the detached D0 state is 0.16 eV higher in energy than the photon excited S1 state. The accurate ADE and VDE values and the well-resolved photoelectron spectra reported here provide much needed robust benchmarks for future theoretical investigations.
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Affiliation(s)
- S H M Deng
- †Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K8-88, Richland, Washington 99352, United States
| | - Xiang-Yu Kong
- †Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K8-88, Richland, Washington 99352, United States
| | | | - Yan Yang
- †Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K8-88, Richland, Washington 99352, United States
- ∥State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
- ⊥State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
| | | | - Zhen-Rong Sun
- ∥State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | | | - Xue-Bin Wang
- †Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K8-88, Richland, Washington 99352, United States
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