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Park SW, Kim D, Rhee YM. Overcoming the Limitation of Spin Statistics in Organic Light Emitting Diodes (OLEDs): Hot Exciton Mechanism and Its Characterization. Int J Mol Sci 2023; 24:12362. [PMID: 37569740 PMCID: PMC10418923 DOI: 10.3390/ijms241512362] [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: 06/30/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/13/2023] Open
Abstract
Triplet harvesting processes are essential for enhancing efficiencies of fluorescent organic light-emitting diodes. Besides more conventional thermally activated delayed fluorescence and triplet-triplet annihilation, the hot exciton mechanism has been recently noticed because it helps reduce the efficiency roll-off and improve device stability. Hot exciton materials enable the conversion of triplet excitons to singlet ones via reverse inter-system crossing from high-lying triplet states and thereby the depopulation of long-lived triplet excitons that are prone to chemical and/or efficiency degradation. Although their anti-Kasha characteristics have not been clearly explained, numerous molecules with behaviors assigned to the hot exciton mechanism have been reported. Indeed, the related developments appear to have just passed the stage of infancy now, and there will likely be more roles that computational elucidations can play. With this perspective in mind, we review some selected experimental studies on the mechanism and the related designs and then on computational studies. On the computational side, we examine what has been found and what is still missing with regard to properly understanding this interesting mechanism. We further discuss potential future points of computational interests toward aiming for eventually presenting in silico design guides.
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Affiliation(s)
- Soo Wan Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Dongwook Kim
- Department of Chemistry, Kyonggi University, Suwon 16227, Republic of Korea
| | - Young Min Rhee
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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2
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Opioid-Modulated Receptor Localization and Erk1/2 Phosphorylation in Cells Coexpressing μ-Opioid and Nociceptin Receptors. Int J Mol Sci 2023; 24:ijms24021048. [PMID: 36674576 PMCID: PMC9865058 DOI: 10.3390/ijms24021048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/30/2022] [Accepted: 01/03/2023] [Indexed: 01/09/2023] Open
Abstract
We attempted to examine the alterations elicited by opioids via coexpressed μ-opioid (MOP) and nociceptin/orphanin FQ (NOP) receptors for receptor localization and Erk1/2 (p44/42 MAPK) in human embryonic kidney (HEK) 293 cells. Through two-photon microscopy, the proximity of MOP and NOP receptors was verified by fluorescence resonance energy transfer (FRET), and morphine but not buprenorphine facilitated the process of MOP-NOP heterodimerization. Single-particle tracking (SPT) further revealed that morphine or buprenorphine hindered the movement of the MOP-NOP heterodimers. After exposure to morphine or buprenorphine, receptor localization on lipid rafts was detected by immunocytochemistry, and phosphorylation of Erk1/2 was determined by immunoblotting in HEK 293 cells expressing MOP, NOP, or MOP+NOP receptors. Colocalization of MOP and NOP on lipid rafts was enhanced by morphine but not buprenorphine. Morphine stimulated the phosphorylation of Erk1/2 with a similar potency in HEK 293 cells expressing MOP and MOP+NOP receptors, but buprenorphine appeared to activate Erk1/2 solely through NOP receptors. Our results suggest that opioids can fine-tune the cellular localization of opioid receptors and phosphorylation of Erk1/2 in MOP+NOP-expressing cells.
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3
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Tu Y, Cao J, Zhang M, Liu M, Huang C, Li Y, Wang C. Dual Detection of Temperature And Chiral Amino Acid Using Triphenylamine‐Based Fluorescent Probes. ChemistrySelect 2022. [DOI: 10.1002/slct.202203323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yajing Tu
- School of Chemistry and Chemical Engineering Shanghai University of Engineering Science 333 Longteng Road Shanghai 201620 P. R. China
| | - Jian Cao
- School of Chemistry and Chemical Engineering Shanghai University of Engineering Science 333 Longteng Road Shanghai 201620 P. R. China
| | - Meijuan Zhang
- School of Chemistry and Chemical Engineering Shanghai University of Engineering Science 333 Longteng Road Shanghai 201620 P. R. China
| | - Mingming Liu
- School of Chemistry and Chemical Engineering Shanghai University of Engineering Science 333 Longteng Road Shanghai 201620 P. R. China
| | - Cuiping Huang
- School of Chemistry and Chemical Engineering Shanghai University of Engineering Science 333 Longteng Road Shanghai 201620 P. R. China
| | - Yanan Li
- School of Chemistry and Chemical Engineering Shanghai University of Engineering Science 333 Longteng Road Shanghai 201620 P. R. China
| | - Chuanxiao Wang
- School of Chemistry and Chemical Engineering Shanghai University of Engineering Science 333 Longteng Road Shanghai 201620 P. R. China
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4
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Effect of Temperature on Re-entrant Condensation of Globular Protein in Presence of Tri-valent Ions. J Fluoresc 2022; 32:791-797. [DOI: 10.1007/s10895-021-02874-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/17/2021] [Indexed: 11/26/2022]
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5
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Kaur H, Nguyen K, Kumar P. Pressure and temperature dependence of fluorescence anisotropy of green fluorescent protein. RSC Adv 2022; 12:8647-8655. [PMID: 35424839 PMCID: PMC8984833 DOI: 10.1039/d1ra08977c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/11/2022] [Indexed: 11/21/2022] Open
Abstract
We have studied the effect of high hydrostatic pressure and temperature on the steady state fluorescence anisotropy of Green Fluorescent Protein (GFP). We find that the fluorescence anisotropy of GFP at a constant temperature decreases with increasing pressure. At atmospheric pressure, anisotropy decreases with increasing temperature but exhibits a maximum with temperature for pressure larger than 20 MPa. The temperature corresponding to the maximum of anisotropy increases with increasing pressure. By taking into account of the rotational correlation time changes of GFP with the pressure–temperature dependent viscosity of the solvent, we argue that viscosity increase with pressure is not a major contributing factor to the decrease in anisotropy with pressure. The decrease of anisotropy with pressure may result from changes in H-bonding environment around the chromophore. Effect of high hydrostatic pressure and temperature on the steady state fluorescence anisotropy of Green Fluorescent Protein (GFP).![]()
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Affiliation(s)
- Harpreet Kaur
- Department of Physics, University of Arkansas, Fayetteville, AR, USA
| | - Khanh Nguyen
- Department of Physics, University of Arkansas, Fayetteville, AR, USA
| | - Pradeep Kumar
- Department of Physics, University of Arkansas, Fayetteville, AR, USA
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6
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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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7
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Photoactivatable fluorescent probes for spatiotemporal-controlled biosensing and imaging. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2020.115811] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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8
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Zhao CM, Wang KR, Wang C, He X, Li XL. Cooling-Induced NIR Emission Enhancement and Targeting Fluorescence Imaging of Biperylene Monoimide and Glycodendrimer Conjugates. ACS Macro Lett 2019; 8:381-386. [PMID: 35651141 DOI: 10.1021/acsmacrolett.9b00095] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Under high concentrations, strong pressure, and low temperature, fluorophores usually exhibit the fluorescence quenching phenomenon. Of significance, the development of aggregation-induced emission (AIE) and pressure-induced emission (PIE) fluorophores has perfectly prevented fluorescence quenching under high concentrations and strong pressure. However, cooling-induced fluorescence quenching in water is still an urgent problem. In this paper, cooling-induced emission (CIE) enhancement based on a biperylene monoimide (BPMI) derivative, BPMI-18Lac, with a conjugated lactose-based glycodendrimer was developed. BPMI-18Lac, as a non-AIE molecule, exhibited the CIE phenomenon with a fluorescent intensity increasing 7-fold when the temperature decreased from 80 to -40 °C. The mechanism was due to the inhibition of the intramolecular electron interactions between the perylene monoimide moieties linked by the C-C single bond. In addition, BPMI-18Lac, as a multivalent glycodendrimer, showed selective fluorescence imaging for HepG 2 cells through the ASGP receptor on the cell surface. Importantly, this work developed a water-soluble CIE molecule for potential application below freezing temperature.
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Affiliation(s)
- Chun-Miao Zhao
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China
| | - Ke-Rang Wang
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China
| | - Chong Wang
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China
| | - Xu He
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China
| | - Xiao-Liu Li
- Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education, Key Laboratory of Chemical Biology of Hebei Province, College of Chemistry and Environmental Science, Hebei University, Baoding 071002, China
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9
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Augustine G, Raghavan S, NumbiRamudu K, Easwaramoorthi S, Shanmugam G, Seetharani Murugaiyan J, Gunasekaran K, Govind C, Karunakaran V, Ayyadurai N. Excited State Electronic Interconversion and Structural Transformation of Engineered Red-Emitting Green Fluorescent Protein Mutant. J Phys Chem B 2019; 123:2316-2324. [PMID: 30789731 DOI: 10.1021/acs.jpcb.8b10516] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Red fluorescent proteins with a large Stokes shift offer a limited autofluorescence background and are used in deep tissue imaging. Here, by introducing the free amino group in Aequorea victoria, the electrostatic charges of the p-hydroxybenzylidene imidazolinone chromophore of green fluorescent protein (GFP) have been altered resulting in an unusual, 85 nm red-shifted fluorescence. The structural and biophysical analysis suggested that the red shift is due to positional shift occupancy of Glu222 and Arg96, resulting in extended conjugation and a relaxed chromophore. Femtosecond transient absorption spectra exhibited that the excited state relaxation dynamics of red-shifted GFP (rGFP) (τ4 = 234 ps) are faster compared to the A. victoria green fluorescent protein (τ4 = 3.0 ns). The nanosecond time-resolved emission spectra of rGFP reveal the continuous spectral shift during emission by a solvent reorientation in the chromophore. Finally, the molecular dynamics simulations revealed the rearrangement of the hydrogen bond interactions in the chromophore vicinity, reshaping the symmetric distribution of van der Waals space to fine tune the GFP structure resulting from highly red-shifted rGFP.
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Affiliation(s)
- George Augustine
- Department of Biochemistry and Biotechnology , Council of Scientific and Industrial Research-Central Leather Research Institute (CSIR-CLRI) , Chennai 600 020 , India
| | - Sriram Raghavan
- Department of Crystallography and Biophysics , University of Madras , Chennai 600 025 , India
| | - Kamini NumbiRamudu
- Department of Biochemistry and Biotechnology , Council of Scientific and Industrial Research-Central Leather Research Institute (CSIR-CLRI) , Chennai 600 020 , India
| | | | | | | | - Krishnasamy Gunasekaran
- Department of Crystallography and Biophysics , University of Madras , Chennai 600 025 , India
| | - Chinju Govind
- Photosciences and Photonics Section, Chemical Sciences and Technology Division , CSIR-National Institute for Interdisciplinary Science and Technology , Thiruvananthapuram , 695 019 Kerala , India
| | - Venugopal Karunakaran
- Photosciences and Photonics Section, Chemical Sciences and Technology Division , CSIR-National Institute for Interdisciplinary Science and Technology , Thiruvananthapuram , 695 019 Kerala , India
| | - Niraikulam Ayyadurai
- Department of Biochemistry and Biotechnology , Council of Scientific and Industrial Research-Central Leather Research Institute (CSIR-CLRI) , Chennai 600 020 , India
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10
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Non-traditional intrinsic luminescence: inexplicable blue fluorescence observed for dendrimers, macromolecules and small molecular structures lacking traditional/conventional luminophores. Prog Polym Sci 2019. [DOI: 10.1016/j.progpolymsci.2018.09.004] [Citation(s) in RCA: 159] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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11
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Pandit S, Kundu S. Optical responses of BSA protein under re-entrant condensation in presence of trivalent ions. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2018.12.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Simine L, Lammert H, Sun L, Onuchic JN, Rossky PJ. Fluorescent Proteins Detect Host Structural Rearrangements via Electrostatic Mechanism. J Am Chem Soc 2018; 140:1203-1206. [PMID: 29328673 DOI: 10.1021/jacs.7b10851] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The rational design of genetically encoded fluorescent biosensors, which can detect rearrangements of target proteins via interdomain allostery, is hindered by the absence of mechanistic understanding of the underlying photophysics. Here, we focus on the modulation of fluorescence by mechanical perturbation in a popular biological probe: enhanced Green Fluorescent Protein (eGFP). Using a combination of molecular dynamics (MD) simulations and quantum chemistry, and a set of physically motivated assumptions, we construct a map of fluorescence quantum yield as a function of a 2D electric field imposed by the protein environment on the fluorophore. This map is transferable between Tsien's Class 2 GFP's, and it allows one to estimate the shifts in fluorescence intensity due to mechanical perturbations directly from MD simulations. We use it in combination with steered MD simulations to put forward a hypothesis for the mechanism of a genetically encoded voltage probe (ArcLight) whose mechanism is currently under debate.
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Affiliation(s)
- Lena Simine
- Departments of Chemistry, and ‡Physics, and §the Center for Theoretical Biological Physics, Rice University , Houston, Texas 77030, United States
| | - Heiko Lammert
- Departments of Chemistry, and ‡Physics, and §the Center for Theoretical Biological Physics, Rice University , Houston, Texas 77030, United States
| | - Li Sun
- Departments of Chemistry, and ‡Physics, and §the Center for Theoretical Biological Physics, Rice University , Houston, Texas 77030, United States
| | - José N Onuchic
- Departments of Chemistry, and ‡Physics, and §the Center for Theoretical Biological Physics, Rice University , Houston, Texas 77030, United States
| | - Peter J Rossky
- Departments of Chemistry, and ‡Physics, and §the Center for Theoretical Biological Physics, Rice University , Houston, Texas 77030, United States
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13
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Acharya A, Bogdanov AM, Grigorenko BL, Bravaya KB, Nemukhin AV, Lukyanov KA, Krylov AI. Photoinduced Chemistry in Fluorescent Proteins: Curse or Blessing? Chem Rev 2016; 117:758-795. [PMID: 27754659 DOI: 10.1021/acs.chemrev.6b00238] [Citation(s) in RCA: 178] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Photoinduced reactions play an important role in the photocycle of fluorescent proteins from the green fluorescent protein (GFP) family. Among such processes are photoisomerization, photooxidation/photoreduction, breaking and making of covalent bonds, and excited-state proton transfer (ESPT). Many of these transformations are initiated by electron transfer (ET). The quantum yields of these processes vary significantly, from nearly 1 for ESPT to 10-4-10-6 for ET. Importantly, even when quantum yields are relatively small, at the conditions of repeated illumination the overall effect is significant. Depending on the task at hand, fluorescent protein photochemistry is regarded either as an asset facilitating new applications or as a nuisance leading to the loss of optical output. The phenomena arising due to phototransformations include (i) large Stokes shifts, (ii) photoconversions, photoactivation, and photoswitching, (iii) phototoxicity, (iv) blinking, (v) permanent bleaching, and (vi) formation of long-lived intermediates. The focus of this review is on the most recent experimental and theoretical work on photoinduced transformations in fluorescent proteins. We also provide an overview of the photophysics of fluorescent proteins, highlighting the interplay between photochemistry and other channels (fluorescence, radiationless relaxation, and intersystem crossing). The similarities and differences with photochemical processes in other biological systems and in dyes are also discussed.
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Affiliation(s)
- Atanu Acharya
- Department of Chemistry, University of Southern California , Los Angeles, California 90089-0482, United States
| | - Alexey M Bogdanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Moscow, Russia.,Nizhny Novgorod State Medical Academy , Nizhny Novgorod, Russia
| | - Bella L Grigorenko
- Department of Chemistry, Lomonosov Moscow State University , Moscow, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences , Moscow, Russia
| | - Ksenia B Bravaya
- Department of Chemistry, Boston University , Boston, Massachusetts United States
| | - Alexander V Nemukhin
- Department of Chemistry, Lomonosov Moscow State University , Moscow, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences , Moscow, Russia
| | - Konstantin A Lukyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Moscow, Russia.,Nizhny Novgorod State Medical Academy , Nizhny Novgorod, Russia
| | - Anna I Krylov
- Department of Chemistry, University of Southern California , Los Angeles, California 90089-0482, United States
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14
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Design and development of genetically encoded fluorescent sensors to monitor intracellular chemical and physical parameters. Biophys Rev 2016; 8:121-138. [PMID: 28510054 PMCID: PMC4884202 DOI: 10.1007/s12551-016-0195-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 03/09/2016] [Indexed: 01/26/2023] Open
Abstract
Over the past decades many researchers have made major contributions towards the development of genetically encoded (GE) fluorescent sensors derived from fluorescent proteins. GE sensors are now used to study biological phenomena by facilitating the measurement of biochemical behaviors at various scales, ranging from single molecules to single cells or even whole animals. Here, we review the historical development of GE fluorescent sensors and report on their current status. We specifically focus on the development strategies of the GE sensors used for measuring pH, ion concentrations (e.g., chloride and calcium), redox indicators, membrane potential, temperature, pressure, and molecular crowding. We demonstrate that these fluroescent protein-based sensors have a shared history of concepts and development strategies, and we highlight the most original concepts used to date. We believe that the understanding and application of these various concepts will pave the road for the development of future GE sensors and lead to new breakthroughs in bioimaging.
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15
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Jacchetti E, Gabellieri E, Cioni P, Bizzarri R, Nifosì R. Temperature and pressure effects on GFP mutants: explaining spectral changes by molecular dynamics simulations and TD-DFT calculations. Phys Chem Chem Phys 2016; 18:12828-38. [PMID: 27102429 DOI: 10.1039/c6cp01274d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
By combining spectroscopic measurements under high pressure with molecular dynamics simulations and quantum mechanics calculations we investigate how sub-angstrom structural perturbations are able to tune protein function. We monitored the variations in fluorescence output of two green fluorescent protein mutants (termed Mut2 and Mut2Y, the latter containing the key T203Y mutation) subjected to pressures up to 600 MPa, at various temperatures in the 280-320 K range. By performing 150 ns molecular dynamics simulations of the protein structures at various pressures, we evidenced subtle changes in conformation and dynamics around the light-absorbing chromophore. Such changes explain the measured spectral tuning in the case of the sizable 120 cm(-1) red-shift observed for pressurized Mut2Y, but absent in Mut2. Previous work [Barstow et al., Proc. Natl. Acad. Sci. U. S. A., 2008, 105, 13362] on pressure effects on GFP also involved a T203Y mutant. On the basis of cryocooling X-ray crystallography, the pressure-induced fluorescence blue shift at low temperature (77 K) was attributed to key changes in relative conformation of the chromophore and Tyr203 phenol ring. At room temperature, however, a red shift was observed at high pressure, analogous to the one we observe in Mut2Y. Our investigation of structural variations in compressed Mut2Y also explains their result, bridging the gap between low-temperature and room-temperature high-pressure effects.
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16
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Park JW, Rhee YM. Emission shaping in fluorescent proteins: role of electrostatics and π-stacking. Phys Chem Chem Phys 2016; 18:3944-55. [DOI: 10.1039/c5cp07535a] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We obtained the fluorescence spectrum of the GFP with trajectory simulations, and revealed the role of the protein sidechains in emission shifts.
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Affiliation(s)
- Jae Woo Park
- Center for Self-assembly and Complexity
- Institute for Basic Science (IBS)
- Pohang 37673
- Korea
- Department of Chemistry
| | - Young Min Rhee
- Center for Self-assembly and Complexity
- Institute for Basic Science (IBS)
- Pohang 37673
- Korea
- Department of Chemistry
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17
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Brantley JN, Bailey CB, Wiggins KM, Keatinge-Clay AT, Bielawski CW. Mechanobiochemistry: harnessing biomacromolecules for force-responsive materials. Polym Chem 2013. [DOI: 10.1039/c3py00001j] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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18
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Laurent AD, Mironov VA, Chapagain PP, Nemukhin AV, Krylov AI. Exploring structural and optical properties of fluorescent proteins by squeezing: modeling high-pressure effects on the mStrawberry and mCherry red fluorescent proteins. J Phys Chem B 2012; 116:12426-40. [PMID: 22988813 PMCID: PMC3500579 DOI: 10.1021/jp3060944] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Molecular dynamics calculations of pressure effects on mStrawberry and mCherry fluorescent proteins are reported. The simulations reveal that mStrawberry has much floppier structure at atmospheric pressure, as evidenced by larger backbone fluctuations and the coexistence of two conformers that differ by Ser146 orientation. Consequently, pressure increase has a larger effect on mStrawberry, making its structure more rigid and reducing the population of one of the conformers. The most significant effect of pressure increase is in the hydrogen-bonding network between the chromophore and the nearby residues. The quantum-mechanics/molecular mechanics calculations of excitation energies in mStrawberry explain the observed blue shift and identify Lys70 as the residue that has the most pronounced effect on the spectra. The results suggest that pressure increase causes an initial increase of fluorescence yield only for relatively floppy fluorescent proteins, whereas the fluorescent proteins that have more rigid structures have quantum yields close to their maximum. The results suggest that a low quantum yield in fluorescent proteins is dynamic in nature and depends on the range of thermal motions of the chromophore and fluctuations in the H-bonding network rather than on their average structure.
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19
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Park JW, Rhee YM. Interpolated mechanics-molecular mechanics study of internal rotation dynamics of the chromophore unit in blue fluorescent protein and its variants. J Phys Chem B 2012; 116:11137-47. [PMID: 22891786 DOI: 10.1021/jp306257t] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The excited state dynamics of the blue fluorescent protein (BFP) and its variants, azurite, EBFP1.2, and EBFP2.0, are studied using molecular dynamics (MD) simulations on potential energy surfaces (PESs) generated with the interpolated mechanics-molecular mechanics (IM/MM) scheme. This IM/MM strategy adopts the interpolated PES for an important area of the complex and the conventional force field for the remaining part. We focus on the internal rotation dynamics of the chromophore unit, which is directly related to its fluorescence property, and analyze the time evolutions of the nonrotated chromophore fractions based on trajectories over 10 μs of aggregate simulation time. The characteristics obtained from the calculated time progresses of the nonrotated chromophore fractions in BFP and other variants agree well with experimentally observed properties. The results show that the MD simulation with an IM/MM potential is an attractive approach for studying excited state dynamics of fluorescent proteins in consideration of its efficiency and reliability. We also attempt to investigate the detailed roles that the mutated residues play in delaying the excited state chromophore twisting and thus improving the fluorescence property, and discuss the contributions by the Coulombic and the steric interactions between the chromophore and the mutated residues.
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Affiliation(s)
- Jae Woo Park
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea
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Pozzi EA, Schwall LR, Jimenez R, Weber JM. Pressure-induced changes in the fluorescence behavior of red fluorescent proteins. J Phys Chem B 2012; 116:10311-6. [PMID: 22861177 PMCID: PMC4022145 DOI: 10.1021/jp306093h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We present an experimental study on the fluorescence behavior of the red fluorescent proteins TagRFP-S, TagRFP-T, mCherry, mOrange2, mStrawberry, and mKO as a function of pressure up to several GPa. TagRFP-S, TagRFP-T, mOrange2, and mStrawberry show an initial increase in fluorescence intensity upon application of pressure above ambient conditions. At higher pressures, the fluorescence intensity decreases dramatically for all proteins under study, probably due to denaturing of the proteins. Small blue shifts in the fluorescence spectra with increasing pressure were seen in all proteins under study, hinting at increased rigidity of the chromophore environment. In addition, mOrange2 and mStrawberry exhibit strong and abrupt changes in their fluorescence spectra at certain pressures. These changes are likely due to structural modifications of the hydrogen bonding environment of the chromophore. The strong differences in behavior between proteins with identical or very similar chromophores highlight how the chromophore environment contributes to pressure-induced behavior of the fluorescence performance.
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Affiliation(s)
- Eric A. Pozzi
- JILA, NIST and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0440, USA
| | - Linda R. Schwall
- JILA, NIST and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0440, USA
| | - Ralph Jimenez
- JILA, NIST and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0440, USA
| | - J. Mathias Weber
- JILA, NIST and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0440, USA
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21
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Newman RH, Fosbrink MD, Zhang J. Genetically encodable fluorescent biosensors for tracking signaling dynamics in living cells. Chem Rev 2011; 111:3614-66. [PMID: 21456512 PMCID: PMC3092831 DOI: 10.1021/cr100002u] [Citation(s) in RCA: 260] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Robert H. Newman
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Matthew D. Fosbrink
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Jin Zhang
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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22
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Barstow B, Ando N, Kim CU, Gruner SM. Coupling of pressure-induced structural shifts to spectral changes in a yellow fluorescent protein. Biophys J 2009; 97:1719-27. [PMID: 19751677 PMCID: PMC2749779 DOI: 10.1016/j.bpj.2009.06.039] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 06/02/2009] [Accepted: 06/24/2009] [Indexed: 11/19/2022] Open
Abstract
X-ray diffraction analysis of pressure-induced structural changes in the Aequorea yellow fluorescent protein Citrine reveals the structural basis for the continuous fluorescence peak shift from yellow to green that is observed on pressurization. This fluorescence peak shift is caused by a reorientation of the two elements of the Citrine chromophore. This study describes the structural linkages in Citrine that are responsible for the local reorientation of the chromophore. The deformation of the Citrine chromophore is actuated by the differential motion of two clusters of atoms that compose the beta-barrel scaffold of the molecule, resulting in a slight bending of the beta-barrel. The high-pressure structures also show a perturbation of the hydrogen bonding network that stabilizes the excited state of the Citrine chromophore. The perturbation of this network is implicated in the reduction of fluorescence intensity of Citrine. The blue-shift of the Citrine fluorescence spectrum resulting from the bending of the beta-barrel provides structural insight into the transient blue-shifting of isolated yellow fluorescent protein molecules under ambient conditions and suggests mechanisms to alter the time-dependent behavior of Citrine under ambient conditions.
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Affiliation(s)
- Buz Barstow
- School of Applied Physics, Cornell University, Ithaca, New York
| | - Nozomi Ando
- Department of Physics, Cornell University, Ithaca, New York
| | - Chae Un Kim
- Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York
| | - Sol M. Gruner
- Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York
- Department of Physics, Cornell University, Ithaca, New York
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23
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Megley CM, Dickson LA, Maddalo SL, Chandler GJ, Zimmer M. Photophysics and dihedral freedom of the chromophore in yellow, blue, and green fluorescent protein. J Phys Chem B 2009; 113:302-8. [PMID: 19067572 PMCID: PMC2671006 DOI: 10.1021/jp806285s] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 10/28/2008] [Indexed: 11/30/2022]
Abstract
Green fluorescent protein (GFP) and GFP-like fluorescent proteins owe their photophysical properties to an autocatalytically formed intrinsic chromophore. According to quantum mechanical calculations, the excited state of chromophore model systems has significant dihedral freedom, which may lead to fluorescence quenching intersystem crossing. Molecular dynamics simulations with freely rotating chromophoric dihedrals were performed on green, yellow, and blue fluorescent proteins in order to model the dihedral freedom available to the chromophore in the excited state. Most current theories suggest that a restriction in the rotational freedom of the fluorescent protein chromophore will lead to an increase in fluorescence brightness and/or quantum yield. According to our calculations, the dihedral freedom of the systems studied (BFP > A5 > YFP > GFP) increases in the inverse order to the quantum yield. In all simulations, the chromophore undergoes a negatively correlated hula twist (also known as a bottom hula twist mechanism).
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Affiliation(s)
- Colleen M Megley
- Chemistry Department, Connecticut College, New London, Connecticut 06320, USA
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24
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Tkaczyk ER, Mauring K, Tkaczyk AH, Krasnenko V, Ye JY, Baker JR, Norris TB. Control of the blue fluorescent protein with advanced evolutionary pulse shaping. Biochem Biophys Res Commun 2008; 376:733-7. [PMID: 18817751 DOI: 10.1016/j.bbrc.2008.09.075] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Accepted: 09/12/2008] [Indexed: 11/29/2022]
Abstract
We demonstrate optical coherent control of the two-photon fluorescence of the blue fluorescent protein (BFP), which is of interest in investigations of protein-protein interactions. In addition to biological relevance, BFP represents an interesting target for coherent control from a chemical perspective due to its many components of highly nonexponential fluorescence decay and low quantum yield resulting from excited state isomerization. Using a genetic algorithm with a multiplicative (rather than ratiometric) fitness parameter, we are able to control the ratio of BFP fluorescence to second-harmonic generation without a considerable drop in the maximized signal. The importance of linear chirp and power-scaling on the discrimination process is investigated in detail.
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Affiliation(s)
- Eric R Tkaczyk
- Center for Ultrafast Optical Science, University of Michigan, 2200 Bonisteel Boulevard, Ann Arbor, MI 48109-2099, USA.
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25
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Jung G, Werner M, Schneider M. Efficient photoconversion distorts the fluorescence lifetime of GFP in confocal microscopy: a model kinetic study on mutant Thr203Val. Chemphyschem 2008; 9:1867-74. [PMID: 18752240 DOI: 10.1002/cphc.200800276] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Phototransformations of autofluorescent proteins are applied in high-resolution microscopy and in studying cellular transport, but they are detrimental when accidentally occurring in blinking or photobleaching (BL). Here, we investigate the kinetics of phototransformations of a photoactivatable green fluorescent protein (GFP) in confocal microscopy. Photoconversion (PC) is achieved by excitation of the barely present anionic chromophore state R(eq) (-) in the GFP mutant Thr203Val. Besides the shift of the equilibrium between the neutral chromophore state RH and R(eq) (-), the photoconverted anionic chromophore R(PC) (-) exhibits a reduced fluorescence lifetime tau(fl)=2.2 ns. In fluorescence lifetime imaging microscopy, tau(fl) is found to depend, however, on the excitation conditions and history. The underlying photochemistry is described by the kinetic scheme of consecutive reactions, R(eq) (-)-->R(PC) (-)-->P(dark), in which the anionic chromophore species and the dark protein P(dark) are coupled by PC and BL. Time-correlated single-photon-counting detection in a confocal geometry of freely diffusing species is used to compute the quantum yields for PC and BL, Phi(PC) and Phi(BL). The assessed values are Phi(PC)=5.5 x 10(-4) and Phi(BL)>1 x 10(-5). Based on these values, PC provokes misinterpretation in fluorescence resonance energy transfer experiments and is responsible for spectroscopic peculiarities in single-molecule detection.
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Affiliation(s)
- Gregor Jung
- Biophysical Chemistry, Saarland University, Campus, Building B2 2, 66123 Saarbrücken, Germany.
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Krasnenko V, Tkaczyk AH, Tkaczyk ER, Mauring K. Physicochemical properties of blue fluorescent protein determined via molecular dynamics simulation. Biopolymers 2008; 89:1136-43. [DOI: 10.1002/bip.21065] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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27
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Leiderman P, Huppert D, Remington SJ, Tolbert LM, Solntsev KM. The effect of pressure on the excited-state proton transfer in the wild-type green fluorescent protein. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.02.079] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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28
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Abstract
Solvent reorganization around the excited state of a chromophore leads to an emission shift to longer wavelengths during the excited-state lifetime. This solvation response is absent in wild-type green fluorescent protein, and this has been attributed to rigidity in the chromophore's environment necessary to exclude nonradiative transitions to the ground state. The fluorescent protein mPlum was developed via directed evolution by selection for red emission, and we use time-resolved fluorescence to study the dynamic Stokes shift through its evolutionary history. The far-red emission of mPlum is attributed to a picosecond solvation response that is observed at all temperatures above the glass transition. This time-dependent shift in emission is not observed in its evolutionary ancestors, suggesting that selective pressure has produced a chromophore environment that allows solvent reorganization. The evolutionary pathway and structures of related fluorescent proteins suggest the role of a single residue in close proximity to the chromophore as the primary cause of the solvation response.
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Stafforst T, Diederichsen U. Synthesis of Alaninyl andN-(2-Aminoethyl)glycinyl Amino Acid Derivatives Containing the Green Fluorescent Protein Chromophore in Their Side Chains for Incorporation into Peptides and Peptide Nucleic Acids. European J Org Chem 2007. [DOI: 10.1002/ejoc.200600729] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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30
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Mena MA, Treynor TP, Mayo SL, Daugherty PS. Blue fluorescent proteins with enhanced brightness and photostability from a structurally targeted library. Nat Biotechnol 2006; 24:1569-71. [PMID: 17115054 DOI: 10.1038/nbt1264] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Accepted: 10/11/2006] [Indexed: 11/09/2022]
Abstract
The utility of blue fluorescent protein (BFP) has been limited by its low quantum yield and rapid photobleaching. A library targeting residues neighboring the chromophore yielded a variant with enhanced quantum yield (0.55 versus 0.34), reduced pH sensitivity and a 40-fold increase in photobleaching half-life. This BFP, named Azurite, is well expressed in bacterial and mammalian cells and extends the palette of fluorescent proteins that can be used for imaging.
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Affiliation(s)
- Marco A Mena
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA
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