1
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Pati AK, Kilic Z, Martin MI, Terry DS, Borgia A, Bar S, Jockusch S, Kiselev R, Altman RB, Blanchard SC. Recovering true FRET efficiencies from smFRET investigations requires triplet state mitigation. Nat Methods 2024; 21:1222-1230. [PMID: 38877317 PMCID: PMC11239528 DOI: 10.1038/s41592-024-02293-8] [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: 03/29/2023] [Accepted: 04/25/2024] [Indexed: 06/16/2024]
Abstract
Single-molecule fluorescence resonance energy transfer (smFRET) methods employed to quantify time-dependent compositional and conformational changes within biomolecules require elevated illumination intensities to recover robust photon emission streams from individual fluorophores. Here we show that outside the weak-excitation limit, and in regimes where fluorophores must undergo many rapid cycles of excitation and relaxation, non-fluorescing, excitation-induced triplet states with lifetimes orders of magnitude longer lived than photon-emitting singlet states degrade photon emission streams from both donor and acceptor fluorophores resulting in illumination-intensity-dependent changes in FRET efficiency. These changes are not commonly taken into consideration; therefore, robust strategies to suppress excited state accumulations are required to recover accurate and precise FRET efficiency, and thus distance, estimates. We propose both robust triplet state suppression and data correction strategies that enable the recovery of FRET efficiencies more closely approximating true values, thereby extending the spatial and temporal resolution of smFRET.
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Affiliation(s)
- Avik K Pati
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
- Department of Chemistry, Birla Institute of Technology and Science, Pilani, Rajasthan, India
| | - Zeliha Kilic
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Maxwell I Martin
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Daniel S Terry
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Alessandro Borgia
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Sukanta Bar
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Steffen Jockusch
- Center for Photochemical Sciences and Department of Chemistry, Bowling Green State University, Bowling Green, OH, USA
| | - Roman Kiselev
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Roger B Altman
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.
- Department of Chemical Biology & Therapeutics, St. Jude Children's Research Hospital, Memphis, TN, USA.
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2
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Gharbi AM, Biswas DS, Crégut O, Malý P, Didier P, Klymchenko A, Léonard J. Exciton annihilation and diffusion length in disordered multichromophoric nanoparticles. NANOSCALE 2024; 16:11550-11563. [PMID: 38868990 DOI: 10.1039/d4nr00325j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Efficient exciton transport is the essential property of natural and synthetic light-harvesting (LH) devices. Here we investigate exciton transport properties in LH organic polymer nanoparticles (ONPs) of 40 nm diameter. The ONPs are loaded with a rhodamine B dye derivative and bulky counterion, enabling dye loadings as high as 0.3 M, while preserving fluorescence quantum yields larger than 30%. We use time-resolved fluorescence spectroscopy to monitor exciton-exciton annihilation (EEA) kinetics within the ONPs dispersed in water. We demonstrate that unlike the common practice for photoluminescence investigations of EEA, the non-uniform intensity profile of the excitation light pulse must be taken into account to analyse reliably intensity-dependent population dynamics. Alternatively, a simple confocal detection scheme is demonstrated, which enables (i) retrieving the correct value for the bimolecular EEA rate which would otherwise be underestimated by a typical factor of three, and (ii) revealing minor EEA by-products otherwise unnoticed. Considering the ONPs as homogeneous rigid solutions of weakly interacting dyes, we postulate an incoherent exciton hoping mechanism to infer a diffusion constant exceeding 0.003 cm2 s-1 and a diffusion length as large as 70 nm. This work demonstrates the success of the present ONP design strategy at engineering efficient exciton transport in disordered multichromophoric systems.
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Affiliation(s)
| | | | - Olivier Crégut
- IPCMS, Université de Strasbourg - CNRS, Strasbourg, France.
| | - Pavel Malý
- Charles University, Prague, Czech Republic
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3
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Blondot V, Arnold C, Delteil A, Gérard D, Bogicevic A, Pons T, Lequeux N, Hugonin JP, Greffet JJ, Buil S, Hermier JP. Fluorescence decay enhancement and FRET inhibition in self-assembled hybrid gold CdSe/CdS/CdZnS colloidal nanocrystal supraparticles. OPTICS EXPRESS 2023; 31:4454-4464. [PMID: 36785413 DOI: 10.1364/oe.476441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 12/06/2022] [Indexed: 06/18/2023]
Abstract
We report on the synthesis of hybrid light emitting particles with a diameter ranging between 100 and 500 nm, consisting in a compact semiconductor CdSe/CdS/CdZnS nanocrystal aggregate encapsulated by a controlled nanometric size silica and gold layers. We first characterize the Purcell decay rate enhancement corresponding to the addition of the gold nanoshell as a function of the particle size and find a good agreement with the predictions of numerical simulations. Then, we show that the contribution corresponding to Förster resonance energy transfer is inhibited.
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4
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Solvothermally synthesized pyrazoledicarboxylate incorporated Fe(II) MOF: Design, characterization, Hirshfeld studies, and mechanistic insight into fluorescent detection of mutagenic adulterant 2,4,6-trinitrophenol. INORG CHEM COMMUN 2022. [DOI: 10.1016/j.inoche.2022.109810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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5
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Yakimov B, Gayer A, Maksimov E, Mamonov E, Maydykovsky A, Murzina T, Fadeev V, Shirshin E. Fluorescence saturation imaging microscopy: molecular fingerprinting in living cells using two-photon absorption cross section as a contrast mechanism. OPTICS LETTERS 2022; 47:4455-4458. [PMID: 36048677 DOI: 10.1364/ol.465605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 07/30/2022] [Indexed: 06/15/2023]
Abstract
Imaging of molecular-specific photophysical parameters such as fluorescence intensity, emission band shape, or fluorescence decay is widely used in biophysics. Here we propose a method for quantitative mapping of another molecular-specific parameter in living cells, two-photon absorption cross section, based on the fluorescence saturation effect. Using model dye solutions and cell culture, we show that the analysis of the fluorescence signal dependencies on the intensity of two-photon excitation within the range typical for routine two-photon microscopy experiments allows one to reconstruct two-photon absorption cross section maps across the sample. We believe that the absorption cross section contrast visualized by the proposed fluorescence saturation imaging microscopy could be a new tool for studying processes in living cells and tissues.
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6
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Kotulska AM, Pilch-Wróbel A, Lahtinen S, Soukka T, Bednarkiewicz A. Upconversion FRET quantitation: the role of donor photoexcitation mode and compositional architecture on the decay and intensity based responses. LIGHT, SCIENCE & APPLICATIONS 2022; 11:256. [PMID: 35986019 PMCID: PMC9391450 DOI: 10.1038/s41377-022-00946-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 07/03/2022] [Accepted: 07/25/2022] [Indexed: 05/15/2023]
Abstract
Lanthanide-doped colloidal nanoparticles capable of photon upconversion (UC) offer long luminescence lifetimes, narrowband absorption and emission spectra, and efficient anti-Stokes emission. These features are highly advantageous for Förster Resonance Energy Transfer (FRET) based detection. Upconverting nanoparticles (UCNPs) as donors may solve the existing problems of molecular FRET systems, such as photobleaching and limitations in quantitative analysis, but these new labels also bring new challenges. Here we have studied the impact of the core-shell compositional architecture of upconverting nanoparticle donors and the mode of photoexcitation on the performance of UC-FRET from UCNPs to Rose Bengal (RB) molecular acceptor. We have quantitatively compared luminescence rise and decay kinetics of Er3+ emission using core-only NaYF4: 20% Yb, 2% Er and core-shell NaYF4: 20% Yb @ NaYF4: 20% Yb, 5% Er donor UCNPs under three photoexcitation schemes: (1) direct short-pulse photoexcitation of Er3+ at 520 nm; indirect photoexcitation of Er3+ through Yb3+ sensitizer with (2) 980 nm short (5-7 ns) or (3) 980 nm long (4 ms) laser pulses. The donor luminescence kinetics and steady-state emission spectra differed between the UCNP architectures and excitation schemes. Aiming for highly sensitive kinetic upconversion FRET-based biomolecular assays, the experimental results underline the complexity of the excitation and energy-migration mechanisms affecting the Er3+ donor responses and suggest ways to optimize the photoexcitation scheme and the architecture of the UCNPs used as luminescent donors.
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Affiliation(s)
- Agata M Kotulska
- Division of Biomedical Physicochemistry, Institute of Low Temperature and Structure Research, PAN, ul. Okolna 2, Wrocław, 50-422, Poland
| | - Aleksandra Pilch-Wróbel
- Division of Biomedical Physicochemistry, Institute of Low Temperature and Structure Research, PAN, ul. Okolna 2, Wrocław, 50-422, Poland
| | - Satu Lahtinen
- Department of Life Technologies/Biotechnology, University of Turku, Kiinamyllynkatu 10, 20520, Turku, Finland
| | - Tero Soukka
- Department of Life Technologies/Biotechnology, University of Turku, Kiinamyllynkatu 10, 20520, Turku, Finland.
| | - Artur Bednarkiewicz
- Division of Biomedical Physicochemistry, Institute of Low Temperature and Structure Research, PAN, ul. Okolna 2, Wrocław, 50-422, Poland.
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7
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Barth A, Opanasyuk O, Peulen TO, Felekyan S, Kalinin S, Sanabria H, Seidel CAM. Unraveling multi-state molecular dynamics in single-molecule FRET experiments. I. Theory of FRET-lines. J Chem Phys 2022; 156:141501. [PMID: 35428384 PMCID: PMC9014241 DOI: 10.1063/5.0089134] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 02/27/2022] [Indexed: 01/31/2023] Open
Abstract
Conformational dynamics of biomolecules are of fundamental importance for their function. Single-molecule studies of Förster Resonance Energy Transfer (smFRET) between a tethered donor and acceptor dye pair are a powerful tool to investigate the structure and dynamics of labeled molecules. However, capturing and quantifying conformational dynamics in intensity-based smFRET experiments remains challenging when the dynamics occur on the sub-millisecond timescale. The method of multiparameter fluorescence detection addresses this challenge by simultaneously registering fluorescence intensities and lifetimes of the donor and acceptor. Together, two FRET observables, the donor fluorescence lifetime τD and the intensity-based FRET efficiency E, inform on the width of the FRET efficiency distribution as a characteristic fingerprint for conformational dynamics. We present a general framework for analyzing dynamics that relates average fluorescence lifetimes and intensities in two-dimensional burst frequency histograms. We present parametric relations of these observables for interpreting the location of FRET populations in E-τD diagrams, called FRET-lines. To facilitate the analysis of complex exchange equilibria, FRET-lines serve as reference curves for a graphical interpretation of experimental data to (i) identify conformational states, (ii) resolve their dynamic connectivity, (iii) compare different kinetic models, and (iv) infer polymer properties of unfolded or intrinsically disordered proteins. For a simplified graphical analysis of complex kinetic networks, we derive a moment-based representation of the experimental data that decouples the motion of the fluorescence labels from the conformational dynamics of the biomolecule. Importantly, FRET-lines facilitate exploring complex dynamic models via easily computed experimental observables. We provide extensive computational tools to facilitate applying FRET-lines.
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Affiliation(s)
- Anders Barth
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Oleg Opanasyuk
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Thomas-Otavio Peulen
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Suren Felekyan
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Stanislav Kalinin
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Hugo Sanabria
- Department of Physics and Astronomy, Clemson University, Clemson, South Carolina 29631, USA
| | - Claus A. M. Seidel
- Institut für Physikalische Chemie, Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität, Düsseldorf, Germany
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8
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Fanciullo G, Conti I, Didier P, Klymchenko A, Léonard J, Garavelli M, Rivalta I. Modelling quenching mechanisms of disordered molecular systems in the presence of molecular aggregates. Phys Chem Chem Phys 2022; 24:1787-1794. [PMID: 34985481 DOI: 10.1039/d1cp04260b] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Exciton density dynamics recorded in time-resolved spectroscopic measurements is a useful tool to recover information on energy transfer (ET) processes that can occur at different timescales, up to the ultrafast regime. Macroscopic models of exciton density decays, involving both direct Förster-like ET and diffusion mechanisms for exciton-exciton annihilation, are largely used to fit time-resolved experimental data but generally neglect contributions from molecular aggregates that can work as quenching species. In this work, we introduce a macroscopic model that includes contributions from molecular aggregate quenchers in a disordered molecular system. As an exemplifying case, we considered a homogenous distribution of rhodamine B dyes embedded in organic nanoparticles to set the initial parameters of the proposed model. The influence of such model parameters is systematically analysed, showing that the presence of molecular aggregate quenchers can be monitored by evaluating the exciton density long time decays. We showed that the proposed model can be applied to molecular systems with ultrafast decays, and we anticipated that it could be used in future studies for global fitting of experimental data with potential support from first-principles simulations.
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Affiliation(s)
- Giacomo Fanciullo
- Dipartimento di Chimica Industriale "Toso Montanari", ALMA MATER STUDIORUM, Università di Bologna, Viale del Risorgimento 4, 40126 Bologna, Italy.
| | - Irene Conti
- Dipartimento di Chimica Industriale "Toso Montanari", ALMA MATER STUDIORUM, Università di Bologna, Viale del Risorgimento 4, 40126 Bologna, Italy.
| | - Pascal Didier
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, 74 Route du Rhin, 67401 Illkirch, France
| | - Andrey Klymchenko
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, 74 Route du Rhin, 67401 Illkirch, France
| | - Jérémie Léonard
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, F-67000 Strasbourg, France
| | - Marco Garavelli
- Dipartimento di Chimica Industriale "Toso Montanari", ALMA MATER STUDIORUM, Università di Bologna, Viale del Risorgimento 4, 40126 Bologna, Italy.
| | - Ivan Rivalta
- Dipartimento di Chimica Industriale "Toso Montanari", ALMA MATER STUDIORUM, Università di Bologna, Viale del Risorgimento 4, 40126 Bologna, Italy. .,Université de Lyon, École Normale Supérieure de Lyon, Université Lyon 1, CNRS UMR 5182, Laboratoire de Chimie, 46 Allée d'Italie, F69364 Lyon, France
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9
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Gopich IV, Chung HS. Theory and Analysis of Single-Molecule FRET Experiments. Methods Mol Biol 2022; 2376:247-282. [PMID: 34845614 DOI: 10.1007/978-1-0716-1716-8_14] [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: 06/13/2023]
Abstract
Inter-dye distances and conformational dynamics can be studied using single-molecule FRET measurements. We consider two approaches to analyze sequences of photons with recorded photon colors and arrival times. The first approach is based on FRET efficiency histograms obtained from binned photon sequences. The experimental histograms are compared with the theoretical histograms obtained using the joint distribution of acceptor and donor photons or the Gaussian approximation. In the second approach, a photon sequence is analyzed without binning. The parameters of a model describing conformational dynamics are found by maximizing the appropriate likelihood function. The first approach is simpler, while the second one is more accurate, especially when the population of species is small and transition rates are fast. The likelihood-based analysis as well as the recoloring method has the advantage that diffusion of molecules through the laser focus can be rigorously handled.
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Affiliation(s)
- Irina V Gopich
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA.
| | - Hoi Sung Chung
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
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10
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Naudi-Fabra S, Tengo M, Jensen MR, Blackledge M, Milles S. Quantitative Description of Intrinsically Disordered Proteins Using Single-Molecule FRET, NMR, and SAXS. J Am Chem Soc 2021; 143:20109-20121. [PMID: 34817999 PMCID: PMC8662727 DOI: 10.1021/jacs.1c06264] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Indexed: 12/18/2022]
Abstract
Studying the conformational landscape of intrinsically disordered and partially folded proteins is challenging and only accessible to a few solution state techniques, such as nuclear magnetic resonance (NMR), small-angle scattering techniques, and single-molecule Förster resonance energy transfer (smFRET). While each of the techniques is sensitive to different properties of the disordered chain, such as local structural propensities, overall dimension, or intermediate- and long-range contacts, conformational ensembles describing intrinsically disordered proteins (IDPs) accurately should ideally respect all of these properties. Here we develop an integrated approach using a large set of FRET efficiencies and fluorescence lifetimes, NMR chemical shifts, and paramagnetic relaxation enhancements (PREs), as well as small-angle X-ray scattering (SAXS) to derive quantitative conformational ensembles in agreement with all parameters. Our approach is tested using simulated data (five sets of PREs and 15 FRET efficiencies) and validated experimentally on the example of the disordered domain of measles virus phosphoprotein, providing new insights into the conformational landscape of this viral protein that comprises transient structural elements and is more compact than an unfolded chain throughout its length. Rigorous cross-validation using FRET efficiencies, fluorescence lifetimes, and SAXS demonstrates the predictive nature of the calculated conformational ensembles and underlines the potential of this strategy in integrative dynamic structural biology.
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Affiliation(s)
- Samuel Naudi-Fabra
- Institut de Biologie Structurale,
Université Grenoble Alpes-CEA-CNRS, 71, Avenue des Martyrs, 38044 Grenoble, France
| | - Maud Tengo
- Institut de Biologie Structurale,
Université Grenoble Alpes-CEA-CNRS, 71, Avenue des Martyrs, 38044 Grenoble, France
| | - Malene Ringkjøbing Jensen
- Institut de Biologie Structurale,
Université Grenoble Alpes-CEA-CNRS, 71, Avenue des Martyrs, 38044 Grenoble, France
| | - Martin Blackledge
- Institut de Biologie Structurale,
Université Grenoble Alpes-CEA-CNRS, 71, Avenue des Martyrs, 38044 Grenoble, France
| | - Sigrid Milles
- Institut de Biologie Structurale,
Université Grenoble Alpes-CEA-CNRS, 71, Avenue des Martyrs, 38044 Grenoble, France
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11
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Benke S, Holla A, Wunderlich B, Soranno A, Nettels D, Schuler B. Combining Rapid Microfluidic Mixing and Three-Color Single-Molecule FRET for Probing the Kinetics of Protein Conformational Changes. J Phys Chem B 2021; 125:6617-6628. [PMID: 34125545 DOI: 10.1021/acs.jpcb.1c02370] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Single-molecule Förster resonance energy transfer (FRET) is well suited for studying the kinetics of protein conformational changes, owing to its high sensitivity and ability to resolve individual subpopulations in heterogeneous systems. However, the most common approach employing two fluorophores can only monitor one distance at a time, and the use of three fluorophores for simultaneously monitoring multiple distances has largely been limited to equilibrium fluctuations. Here we show that three-color single-molecule FRET can be combined with rapid microfluidic mixing to investigate conformational changes in a protein from milliseconds to minutes. In combination with manual mixing, we extended the kinetics to 1 h, corresponding to a total range of 5 orders of magnitude in time. We studied the monomer-to-protomer conversion of the pore-forming toxin cytolysin A (ClyA), one of the largest protein conformational transitions known. Site-specific labeling of ClyA with three fluorophores enabled us to follow the kinetics of three intramolecular distances at the same time and revealed a previously undetected intermediate. The combination of three-color single-molecule FRET with rapid microfluidic mixing thus provides an approach for probing the mechanisms of complex biomolecular processes with high time resolution.
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Affiliation(s)
- Stephan Benke
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Andrea Holla
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Bengt Wunderlich
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Andrea Soranno
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.,Department of Biochemistry and Molecular Biophysics, Center for Science and Engineering of Living Systems (CSELS), Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Daniel Nettels
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Benjamin Schuler
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.,Department of Physics, University of Zurich, Winterthurerstrasse. 190, 8057 Zurich, Switzerland
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12
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Lerner E, Barth A, Hendrix J, Ambrose B, Birkedal V, Blanchard SC, Börner R, Sung Chung H, Cordes T, Craggs TD, Deniz AA, Diao J, Fei J, Gonzalez RL, Gopich IV, Ha T, Hanke CA, Haran G, Hatzakis NS, Hohng S, Hong SC, Hugel T, Ingargiola A, Joo C, Kapanidis AN, Kim HD, Laurence T, Lee NK, Lee TH, Lemke EA, Margeat E, Michaelis J, Michalet X, Myong S, Nettels D, Peulen TO, Ploetz E, Razvag Y, Robb NC, Schuler B, Soleimaninejad H, Tang C, Vafabakhsh R, Lamb DC, Seidel CAM, Weiss S. FRET-based dynamic structural biology: Challenges, perspectives and an appeal for open-science practices. eLife 2021; 10:e60416. [PMID: 33779550 PMCID: PMC8007216 DOI: 10.7554/elife.60416] [Citation(s) in RCA: 135] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 02/09/2021] [Indexed: 12/18/2022] Open
Abstract
Single-molecule FRET (smFRET) has become a mainstream technique for studying biomolecular structural dynamics. The rapid and wide adoption of smFRET experiments by an ever-increasing number of groups has generated significant progress in sample preparation, measurement procedures, data analysis, algorithms and documentation. Several labs that employ smFRET approaches have joined forces to inform the smFRET community about streamlining how to perform experiments and analyze results for obtaining quantitative information on biomolecular structure and dynamics. The recent efforts include blind tests to assess the accuracy and the precision of smFRET experiments among different labs using various procedures. These multi-lab studies have led to the development of smFRET procedures and documentation, which are important when submitting entries into the archiving system for integrative structure models, PDB-Dev. This position paper describes the current 'state of the art' from different perspectives, points to unresolved methodological issues for quantitative structural studies, provides a set of 'soft recommendations' about which an emerging consensus exists, and lists openly available resources for newcomers and seasoned practitioners. To make further progress, we strongly encourage 'open science' practices.
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Affiliation(s)
- Eitan Lerner
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, and The Center for Nanoscience and Nanotechnology, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of JerusalemJerusalemIsrael
| | - Anders Barth
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-UniversitätDüsseldorfGermany
| | - Jelle Hendrix
- Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre and Biomedical Research Institute (BIOMED), Hasselt UniversityDiepenbeekBelgium
| | - Benjamin Ambrose
- Department of Chemistry, University of SheffieldSheffieldUnited Kingdom
| | - Victoria Birkedal
- Department of Chemistry and iNANO center, Aarhus UniversityAarhusDenmark
| | - Scott C Blanchard
- Department of Structural Biology, St. Jude Children's Research HospitalMemphisUnited States
| | - Richard Börner
- Laserinstitut HS Mittweida, University of Applied Science MittweidaMittweidaGermany
| | - Hoi Sung Chung
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaUnited States
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität MünchenPlanegg-MartinsriedGermany
| | - Timothy D Craggs
- Department of Chemistry, University of SheffieldSheffieldUnited Kingdom
| | - Ashok A Deniz
- Department of Integrative Structural and Computational Biology, The Scripps Research InstituteLa JollaUnited States
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati School of MedicineCincinnatiUnited States
| | - Jingyi Fei
- Department of Biochemistry and Molecular Biology and The Institute for Biophysical Dynamics, University of ChicagoChicagoUnited States
| | - Ruben L Gonzalez
- Department of Chemistry, Columbia UniversityNew YorkUnited States
| | - Irina V Gopich
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesdaUnited States
| | - Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Howard Hughes Medical InstituteBaltimoreUnited States
| | - Christian A Hanke
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-UniversitätDüsseldorfGermany
| | - Gilad Haran
- Department of Chemical and Biological Physics, Weizmann Institute of ScienceRehovotIsrael
| | - Nikos S Hatzakis
- Department of Chemistry & Nanoscience Centre, University of CopenhagenCopenhagenDenmark
- Denmark Novo Nordisk Foundation Centre for Protein Research, Faculty of Health and Medical Sciences, University of CopenhagenCopenhagenDenmark
| | - Sungchul Hohng
- Department of Physics and Astronomy, and Institute of Applied Physics, Seoul National UniversitySeoulRepublic of Korea
| | - Seok-Cheol Hong
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science and Department of Physics, Korea UniversitySeoulRepublic of Korea
| | - Thorsten Hugel
- Institute of Physical Chemistry and Signalling Research Centres BIOSS and CIBSS, University of FreiburgFreiburgGermany
| | - Antonino Ingargiola
- Department of Chemistry and Biochemistry, and Department of Physiology, University of California, Los AngelesLos AngelesUnited States
| | - Chirlmin Joo
- Department of BioNanoScience, Kavli Institute of Nanoscience, Delft University of TechnologyDelftNetherlands
| | - Achillefs N Kapanidis
- Biological Physics Research Group, Clarendon Laboratory, Department of Physics, University of OxfordOxfordUnited Kingdom
| | - Harold D Kim
- School of Physics, Georgia Institute of TechnologyAtlantaUnited States
| | - Ted Laurence
- Physical and Life Sciences Directorate, Lawrence Livermore National LaboratoryLivermoreUnited States
| | - Nam Ki Lee
- School of Chemistry, Seoul National UniversitySeoulRepublic of Korea
| | - Tae-Hee Lee
- Department of Chemistry, Pennsylvania State UniversityUniversity ParkUnited States
| | - Edward A Lemke
- Departments of Biology and Chemistry, Johannes Gutenberg UniversityMainzGermany
- Institute of Molecular Biology (IMB)MainzGermany
| | - Emmanuel Margeat
- Centre de Biologie Structurale (CBS), CNRS, INSERM, Universitié de MontpellierMontpellierFrance
| | | | - Xavier Michalet
- Department of Chemistry and Biochemistry, and Department of Physiology, University of California, Los AngelesLos AngelesUnited States
| | - Sua Myong
- Department of Biophysics, Johns Hopkins UniversityBaltimoreUnited States
| | - Daniel Nettels
- Department of Biochemistry and Department of Physics, University of ZurichZurichSwitzerland
| | - Thomas-Otavio Peulen
- Department of Bioengineering and Therapeutic Sciences, University of California, San FranciscoSan FranciscoUnited States
| | - Evelyn Ploetz
- Physical Chemistry, Department of Chemistry, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-UniversitätMünchenGermany
| | - Yair Razvag
- Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, and The Center for Nanoscience and Nanotechnology, Faculty of Mathematics & Science, The Edmond J. Safra Campus, The Hebrew University of JerusalemJerusalemIsrael
| | - Nicole C Robb
- Warwick Medical School, University of WarwickCoventryUnited Kingdom
| | - Benjamin Schuler
- Department of Biochemistry and Department of Physics, University of ZurichZurichSwitzerland
| | - Hamid Soleimaninejad
- Biological Optical Microscopy Platform (BOMP), University of MelbourneParkvilleAustralia
| | - Chun Tang
- College of Chemistry and Molecular Engineering, PKU-Tsinghua Center for Life Sciences, Beijing National Laboratory for Molecular Sciences, Peking UniversityBeijingChina
| | - Reza Vafabakhsh
- Department of Molecular Biosciences, Northwestern UniversityEvanstonUnited States
| | - Don C Lamb
- Physical Chemistry, Department of Chemistry, Center for Nanoscience (CeNS), Center for Integrated Protein Science Munich (CIPSM) and Nanosystems Initiative Munich (NIM), Ludwig-Maximilians-UniversitätMünchenGermany
| | - Claus AM Seidel
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-UniversitätDüsseldorfGermany
| | - Shimon Weiss
- Department of Chemistry and Biochemistry, and Department of Physiology, University of California, Los AngelesLos AngelesUnited States
- Department of Physiology, CaliforniaNanoSystems Institute, University of California, Los AngelesLos AngelesUnited States
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13
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Lewinson O, Orelle C, Seeger MA. Structures of ABC transporters: handle with care. FEBS Lett 2020; 594:3799-3814. [PMID: 33098660 PMCID: PMC7756565 DOI: 10.1002/1873-3468.13966] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/22/2020] [Accepted: 10/15/2020] [Indexed: 12/11/2022]
Abstract
In the past two decades, the ATP‐binding cassette (ABC) transporters' field has undergone a structural revolution. The importance of structural biology to the development of the field of ABC transporters cannot be overstated, as the ensemble of structures not only revealed the architecture of ABC transporters but also shaped our mechanistic view of these remarkable molecular machines. Nevertheless, we advocate that the mechanistic interpretation of the structures is not trivial and should be carried out with prudence. Herein, we bring several examples of structures of ABC transporters that merit re‐interpretation via careful comparison to experimental data. We propose that it is of the upmost importance to place new structures within the context of the available experimental data.
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Affiliation(s)
- Oded Lewinson
- Department of Molecular Microbiology and the Rappaport Institute for Medical Sciences, Faculty of Medicine, The Technion-Israel Institute of Technology, Haifa, Israel
| | - Cédric Orelle
- CNRS, Molecular Microbiology and Structural Biochemistry (MMSB, UMR 5086), University of Lyon, Lyon, France
| | - Markus A Seeger
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
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14
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Bertolin G, Sizaire F, Déméautis C, Chapuis C, Mérola F, Erard M, Tramier M. Optimized FRET Pairs and Quantification Approaches To Detect the Activation of Aurora Kinase A at Mitosis. ACS Sens 2019; 4:2018-2027. [PMID: 31317736 DOI: 10.1021/acssensors.9b00486] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Genetically encoded Förster's Resonance Energy Transfer (FRET) biosensors are indispensable tools to sense the spatiotemporal dynamics of signal transduction pathways. Investigating the crosstalk between different signaling pathways is becoming increasingly important to follow cell development and fate programs. To this end, FRET biosensors must be optimized to monitor multiple biochemical activities simultaneously and in single cells. In addition, their sensitivity must be increased to follow their activation even when the abundance of the biosensor is low. We describe here the development of a second generation of Aurora kinase A/AURKA biosensors. First, we adapt the original AURKA biosensor-GFP-AURKA-mCherry-to multiplex FRET by using dark acceptors as ShadowG or ShadowY. Then, we use the novel superYFP acceptor protein to measure FRET by 2-color Fluorescence Cross-Correlation Spectroscopy, in cytosolic regions where the abundance of AURKA is extremely low and undetectable with the original AURKA biosensor. These results pave the way to the use of FRET biosensors to follow AURKA activation in conjunction with substrate-based activity biosensors. In addition, they open up the possibility of tracking the activation of small pools of AURKA and its interaction with novel substrates, which would otherwise remain undetectable with classical biochemical approaches.
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Affiliation(s)
- Giulia Bertolin
- Univ Rennes, CNRS, IGDR (Genetics and Development Institute of Rennes), UMR 6290, F-35000 Rennes, France
| | - Florian Sizaire
- Univ Rennes, CNRS, IGDR (Genetics and Development Institute of Rennes), UMR 6290, F-35000 Rennes, France
| | - Claire Déméautis
- Univ Rennes, CNRS, IGDR (Genetics and Development Institute of Rennes), UMR 6290, F-35000 Rennes, France
| | - Catherine Chapuis
- Univ Rennes, CNRS, IGDR (Genetics and Development Institute of Rennes), UMR 6290, F-35000 Rennes, France
| | - Fabienne Mérola
- Univ Paris Sud, CNRS, LCP (Laboratoire de Chimie Physique), UMR 800, F-91400 Orsay, France
| | - Marie Erard
- Univ Paris Sud, CNRS, LCP (Laboratoire de Chimie Physique), UMR 800, F-91400 Orsay, France
| | - Marc Tramier
- Univ Rennes, CNRS, IGDR (Genetics and Development Institute of Rennes), UMR 6290, F-35000 Rennes, France
- Univ Rennes, BIOSIT, UMS CNRS 3480, US INSERM
018, F-35000 Rennes, France
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15
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Szendi-Szatmári T, Szabó Á, Szöllősi J, Nagy P. Reducing the Detrimental Effects of Saturation Phenomena in FRET Microscopy. Anal Chem 2019; 91:6378-6382. [DOI: 10.1021/acs.analchem.9b01504] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tímea Szendi-Szatmári
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem Square 1, 4032 Debrecen, Hungary
| | - Ágnes Szabó
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem Square 1, 4032 Debrecen, Hungary
- MTA-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - János Szöllősi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem Square 1, 4032 Debrecen, Hungary
- MTA-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Peter Nagy
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem Square 1, 4032 Debrecen, Hungary
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16
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Vandenberk N, Barth A, Borrenberghs D, Hofkens J, Hendrix J. Evaluation of Blue and Far-Red Dye Pairs in Single-Molecule Förster Resonance Energy Transfer Experiments. J Phys Chem B 2018. [DOI: 10.1021/acs.jpcb.8b00108] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Niels Vandenberk
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Anders Barth
- Physical Chemistry, Department of Chemistry, Munich Center for Integrated Protein Science, Nanosystems Initiative Munich and Centre for Nanoscience, Ludwig-Maximilians-Universität München, 80539 Munich, Germany
| | - Doortje Borrenberghs
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Johan Hofkens
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Jelle Hendrix
- Laboratory for Photochemistry and Spectroscopy, Division for Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
- Dynamic Bioimaging Lab, Advanced Optical Microscopy Centre and Biomedical Research Institute, Hasselt University, Agoralaan C (BIOMED), Diepenbeek, B-3590, Belgium
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17
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Zosel F, Haenni D, Soranno A, Nettels D, Schuler B. Combining short- and long-range fluorescence reporters with simulations to explore the intramolecular dynamics of an intrinsically disordered protein. J Chem Phys 2017; 147:152708. [DOI: 10.1063/1.4992800] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
- Franziska Zosel
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Dominik Haenni
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Center for Microscopy and Image Analysis, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Andrea Soranno
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA
| | - Daniel Nettels
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Benjamin Schuler
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Department of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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18
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Abstract
Electronic energy pooling via excited state (exciton) annihilation, primarily in organic systems, is reviewed in tutorial form. Cross-disciplinary terminologies and references are used and reference is made to the historical origins of the phenomena. Applications in organic photovoltaic and electroluminescent devices are addressed. Particular attention is paid to the kinetics of the processes involved; a standard format for all systems is developed. Within the organic materials framework, all triplet–triplet, triplet–singlet, and singlet–singlet annihilation processes are discussed. Examples from gas, liquid, and solid phase systems, including both homo- and hetero-species interactions, are employed. Particular attention is given to triplet–triplet annihilation processes in which product states other than the lowest excited singlet state are formed.
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Affiliation(s)
- Ronald P. Steer
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada
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19
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Peulen TO, Opanasyuk O, Seidel CAM. Combining Graphical and Analytical Methods with Molecular Simulations To Analyze Time-Resolved FRET Measurements of Labeled Macromolecules Accurately. J Phys Chem B 2017; 121:8211-8241. [PMID: 28709377 PMCID: PMC5592652 DOI: 10.1021/acs.jpcb.7b03441] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
Förster resonance energy transfer
(FRET) measurements from
a donor, D, to an acceptor, A, fluorophore are frequently used in vitro and in live cells to reveal information on the
structure and dynamics of DA labeled macromolecules. Accurate descriptions
of FRET measurements by molecular models are complicated because the
fluorophores are usually coupled to the macromolecule via flexible
long linkers allowing for diffusional exchange between multiple states
with different fluorescence properties caused by distinct environmental
quenching, dye mobilities, and variable DA distances. It is often
assumed for the analysis of fluorescence intensity decays that DA
distances and D quenching are uncorrelated (homogeneous quenching
by FRET) and that the exchange between distinct fluorophore states
is slow (quasistatic). This allows us to introduce the FRET-induced
donor decay, εD(t), a function solely
depending on the species fraction distribution of the rate constants
of energy transfer by FRET, for a convenient joint analysis of fluorescence
decays of FRET and reference samples by integrated graphical and analytical
procedures. Additionally, we developed a simulation toolkit to model
dye diffusion, fluorescence quenching by the protein surface, and
FRET. A benchmark study with simulated fluorescence decays of 500
protein structures demonstrates that the quasistatic homogeneous model
works very well and recovers for single conformations the average
DA distances with an accuracy of < 2%. For more complex
cases, where proteins adopt multiple conformations with significantly
different dye environments (heterogeneous case), we introduce a general
analysis framework and evaluate its power in resolving heterogeneities
in DA distances. The developed fast simulation methods, relying on
Brownian dynamics of a coarse-grained dye in its sterically accessible
volume, allow us to incorporate structural information in the decay
analysis for heterogeneous cases by relating dye states with protein
conformations to pave the way for fluorescence and FRET-based dynamic
structural biology. Finally, we present theories and simulations to
assess the accuracy and precision of steady-state and time-resolved
FRET measurements in resolving DA distances on the single-molecule
and ensemble level and provide a rigorous framework for estimating
approximation, systematic, and statistical errors.
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Affiliation(s)
- Thomas-Otavio Peulen
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität , Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Oleg Opanasyuk
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität , Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Claus A M Seidel
- Lehrstuhl für Molekulare Physikalische Chemie, Heinrich-Heine-Universität , Universitätsstraße 1, 40225 Düsseldorf, Germany
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20
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Würsch D, May R, Wiederer G, Jester SS, Höger S, Vogelsang J, Lupton JM. Interactions between π-conjugated chromophores in a giant molecular spoked wheel. Chem Commun (Camb) 2017; 53:352-355. [PMID: 27929148 DOI: 10.1039/c6cc08396j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We discuss the intriguing photophysics of a giant molecular spoked wheel of π-conjugated arylene-alkynylene chromophores on the single-molecule level. This "molecular mesoscopic" structure, C1878H2682, shows fast switching between the 12 identical chromophores since the fluorescence is unpolarised but only one chromophore emits at a time.
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Affiliation(s)
- D Würsch
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.
| | - R May
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.
| | - G Wiederer
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.
| | - S-S Jester
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - S Höger
- Kekulé-Institut für Organische Chemie und Biochemie, Universität Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - J Vogelsang
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.
| | - J M Lupton
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany.
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21
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Chung HS, Louis JM, Gopich IV. Analysis of Fluorescence Lifetime and Energy Transfer Efficiency in Single-Molecule Photon Trajectories of Fast-Folding Proteins. J Phys Chem B 2016; 120:680-99. [PMID: 26812046 DOI: 10.1021/acs.jpcb.5b11351] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In single-molecule Förster resonance energy transfer (FRET) spectroscopy, the dynamics of molecular processes are usually determined by analyzing the fluorescence intensity of donor and acceptor dyes. Since FRET efficiency is related to fluorescence lifetimes, additional information can be extracted by analyzing fluorescence intensity and lifetime together. For fast processes where individual states are not well separated in a trajectory, it is not easy to obtain the lifetime information. Here, we present analysis methods to utilize fluorescence lifetime information from single-molecule FRET experiments, and apply these methods to three fast-folding, two-state proteins. By constructing 2D FRET efficiency-lifetime histograms, the correlation can be visualized between the FRET efficiency and fluorescence lifetimes in the presence of the submicrosecond to millisecond dynamics. We extend the previously developed method for analyzing delay times of donor photons to include acceptor delay times. To determine the kinetics and lifetime parameters accurately, we used a maximum likelihood method. We found that acceptor blinking can lead to inaccurate parameters in the donor delay time analysis. This problem can be solved by incorporating acceptor blinking into a model. While the analysis of acceptor delay times is not affected by acceptor blinking, it is more sensitive to the shape of the delay time distribution resulting from a broad conformational distribution in the unfolded state.
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Affiliation(s)
- Hoi Sung Chung
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
| | - John M Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
| | - Irina V Gopich
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, Maryland 20892-0520, United States
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