1
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Krueger TD, Henderson JN, Breen IL, Zhu L, Wachter RM, Mills JH, Fang C. Capturing excited-state structural snapshots of evolutionary green-to-red photochromic fluorescent proteins. Front Chem 2023; 11:1328081. [PMID: 38144887 PMCID: PMC10748491 DOI: 10.3389/fchem.2023.1328081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 11/24/2023] [Indexed: 12/26/2023] Open
Abstract
Photochromic fluorescent proteins (FPs) have proved to be indispensable luminous probes for sophisticated and advanced bioimaging techniques. Among them, an interplay between photoswitching and photoconversion has only been observed in a limited subset of Kaede-like FPs that show potential for discovering the key mechanistic steps during green-to-red photoconversion. Various spectroscopic techniques including femtosecond stimulated Raman spectroscopy (FSRS), X-ray crystallography, and femtosecond transient absorption were employed on a set of five related FPs with varying photoconversion and photoswitching efficiencies. A 3-methyl-histidine chromophore derivative, incorporated through amber suppression using orthogonal aminoacyl tRNA synthetase/tRNA pairs, displays more dynamic photoswitching but greatly reduced photoconversion versus the least-evolved ancestor (LEA). Excitation-dependent measurements of the green anionic chromophore reveal that the varying photoswitching efficiencies arise from both the initial transient dynamics of the bright cis state and the final trans-like photoswitched off state, with an exocyclic bridge H-rocking motion playing an active role during the excited-state energy dissipation. This investigation establishes a close-knit feedback loop between spectroscopic characterization and protein engineering, which may be especially beneficial to develop more versatile FPs with targeted mutations and enhanced functionalities, such as photoconvertible FPs that also feature photoswitching properties.
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Affiliation(s)
- Taylor D. Krueger
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
| | - J. Nathan Henderson
- Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Isabella L. Breen
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
| | - Rebekka M. Wachter
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
| | - Jeremy H. Mills
- Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
| | - Chong Fang
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
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2
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Krueger TD, Chen C, Fang C. Targeting Ultrafast Spectroscopic Insights into Red Fluorescent Proteins. Chem Asian J 2023; 18:e202300668. [PMID: 37682793 DOI: 10.1002/asia.202300668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/08/2023] [Accepted: 09/08/2023] [Indexed: 09/10/2023]
Abstract
Red fluorescent proteins (RFPs) represent an increasingly popular class of genetically encodable bioprobes and biomarkers that can advance next-generation breakthroughs across the imaging and life sciences. Since the rational design of RFPs with improved functions or enhanced versatility requires a mechanistic understanding of their working mechanisms, while fluorescence is intrinsically an ultrafast event, a suitable toolset involving steady-state and time-resolved spectroscopic techniques has become powerful in delineating key structural features and dynamic steps which govern irreversible photoconverting or reversible photoswitching RFPs, and large Stokes shift (LSS)RFPs. The pertinent cis-trans isomerization and protonation state change of RFP chromophores in their local environments, involving key residues in protein matrices, lead to rich and complicated spectral features across multiple timescales. In particular, ultrafast excited-state proton transfer in various LSSRFPs showcases the resolving power of wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS) in mapping a photocycle with crucial knowledge about the red-emitting species. Moreover, recent progress in noncanonical RFPs with a site-specifically modified chromophore provides an appealing route for efficient engineering of redder and brighter RFPs, highly desirable for bioimaging. Such an effective feedback loop involving physical chemists, protein engineers, and biomedical microscopists will enable future successes to expand fundamental knowledge and improve human health.
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Affiliation(s)
- Taylor D Krueger
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon, 97331-4003, USA
| | - Cheng Chen
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon, 97331-4003, USA
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon, 97331-4003, USA
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3
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Heesink G, Caron C, van Leijenhorst-Groener K, Molenaar R, Gadella TWJ, Claessens MMAE, Blum C. Quantification of Dark Protein Populations in Fluorescent Proteins by Two-Color Coincidence Detection and Nanophotonic Manipulation. J Phys Chem B 2022; 126:7906-7915. [PMID: 36190918 PMCID: PMC9574928 DOI: 10.1021/acs.jpcb.2c04627] [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] [Indexed: 11/28/2022]
Abstract
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Genetically encoded visible fluorescent proteins (VFPs)
are a key
tool used to visualize cellular processes. However, compared to synthetic
fluorophores, VFPs are photophysically complex. This photophysical
complexity includes the presence of non-emitting, dark proteins within
the ensemble of VFPs. Quantitative fluorescence microcopy approaches
that rely on VFPs to obtain molecular insights are hampered by the
presence of these dark proteins. To account for the presence of dark
proteins, it is necessary to know the fraction of dark proteins (fdark) in the ensemble. To date, fdark has rarely been quantified, and different methods
to determine fdark have not been compared.
Here, we use and compare two different methods to determine the fdark of four commonly used VFPs: EGFP, SYFP2,
mStrawberry, and mRFP1. In the first, direct method, we make use of
VFP tandems and single-molecule two-color coincidence detection (TCCD).
The second method relies on comparing the bright state fluorescence
quantum yield obtained by photonic manipulation to the ensemble-averaged
fluorescence quantum yield of the VFP. Our results show that, although
very different in nature, both methods are suitable to obtain fdark. Both methods show that all four VFPs contain
a considerable fraction of dark proteins. We determine fdark values between 30 and 60% for the different VFPs.
The high values for fdark of these commonly
used VFPs highlight that fdark has to
be accounted for in quantitative microscopy and spectroscopy.
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Affiliation(s)
- Gobert Heesink
- Nanobiophysics (NBP), MESA+ Institute for Nanotechnology and Technical Medical Centre, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AEEnschede, The Netherlands
| | - Cécile Caron
- Nanobiophysics (NBP), MESA+ Institute for Nanotechnology and Technical Medical Centre, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AEEnschede, The Netherlands
| | - Kirsten van Leijenhorst-Groener
- Nanobiophysics (NBP), MESA+ Institute for Nanotechnology and Technical Medical Centre, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AEEnschede, The Netherlands
| | - Robert Molenaar
- Nanobiophysics (NBP), MESA+ Institute for Nanotechnology and Technical Medical Centre, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AEEnschede, The Netherlands
| | - Theodorus W J Gadella
- Section of Molecular Cytology, Swammerdam Institute for Life Sciences, University of Amsterdam, P.O. Box 94215, 1090 GEAmsterdam, The Netherlands
| | - Mireille M A E Claessens
- Nanobiophysics (NBP), MESA+ Institute for Nanotechnology and Technical Medical Centre, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AEEnschede, The Netherlands
| | - Christian Blum
- Nanobiophysics (NBP), MESA+ Institute for Nanotechnology and Technical Medical Centre, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AEEnschede, The Netherlands
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4
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Stopel MHW, Blum C, Subramaniam V. Excitation Spectra and Stokes Shift Measurements of Single Organic Dyes at Room Temperature. J Phys Chem Lett 2014; 5:3259-3264. [PMID: 26276342 DOI: 10.1021/jz501536a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report measurements of excitation and emission spectra of single, polymer-embedded, perylene dye molecules at room temperature. From these measurements, we can derive the Stokes shift for each single molecule. We determined the distribution of excitation and emission peak energies and, thus, the distribution of single molecule Stokes shifts. Single molecule Stokes shifts have not been recorded to date, and the Stokes shift has often been assumed to be constant in single molecule studies. Our data show that the observed spectral heterogeneity in single molecule emission originates not only from synchronous energetic shifts of the excitation and the emission spectra but also from variations in the Stokes shift, speaking against the assumption of constant Stokes shift.
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Affiliation(s)
- Martijn H W Stopel
- †Nanobiophysics, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Christian Blum
- †Nanobiophysics, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Vinod Subramaniam
- †Nanobiophysics, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
- ‡Nanobiophysics, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
- §FOM Institute AMOLF, 104 Science Park, 1098 XG Amsterdam, The Netherlands
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5
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Dutschk V, Karapantsios T, Liggieri L, McMillan N, Miller R, Starov V. Smart and green interfaces: from single bubbles/drops to industrial environmental and biomedical applications. Adv Colloid Interface Sci 2014; 209:109-26. [PMID: 24679903 DOI: 10.1016/j.cis.2014.02.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 02/21/2014] [Accepted: 02/26/2014] [Indexed: 01/15/2023]
Abstract
Interfaces can be called Smart and Green (S&G) when tailored such that the required technologies can be implemented with high efficiency, adaptability and selectivity. At the same time they also have to be eco-friendly, i.e. products must be biodegradable, reusable or simply more durable. Bubble and drop interfaces are in many of these smart technologies the fundamental entities and help develop smart products of the everyday life. Significant improvements of these processes and products can be achieved by implementing and manipulating specific properties of these interfaces in a simple and smart way, in order to accomplish specific tasks. The severe environmental issues require in addition attributing eco-friendly features to these interfaces, by incorporating innovative, or, sometimes, recycle materials and conceiving new production processes which minimize the use of natural resources and energy. Such concept can be extended to include important societal challenges related to support a sustainable development and a healthy population. The achievement of such ambitious targets requires the technology research to be supported by a robust development of theoretical and experimental tools, needed to understand in more details the behavior of complex interfaces. A wide but not exhaustive review of recent work concerned with green and smart interfaces is presented, addressing different scientific and technological fields. The presented approaches reveal a huge potential in relation to various technological fields, such as nanotechnologies, biotechnologies, medical diagnostics, and new or improved materials.
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6
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Zhang H, Li F, Dever B, Wang C, Li XF, Le XC. DNA-Assemblierung mittels Affinitätsbindung für die ultraempfindliche Proteindetektion. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201210022] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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7
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Zhang H, Li F, Dever B, Wang C, Li XF, Le XC. Assembling DNA through affinity binding to achieve ultrasensitive protein detection. Angew Chem Int Ed Engl 2013; 52:10698-705. [PMID: 24038633 DOI: 10.1002/anie.201210022] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Revised: 03/17/2013] [Indexed: 11/06/2022]
Abstract
Recent advances in DNA assembly and affinity binding have enabled exciting developments of nanosensors and ultrasensitive assays for specific proteins. These sensors and assays share three main attractive features: 1) the detection of proteins can be accomplished by the detection of amplifiable DNA, thereby dramatically enhancing the sensitivity; 2) assembly of DNA is triggered by affinity binding of two or more probes to a single target molecule, thereby resulting in increased specificity; and 3) the assay is conducted in solution with no need for separation, thus making the assay attractive for potential point-of-care applications. We illustrate here the principle of assembling DNA through affinity binding, and we highlight novel applications to the detection of proteins.
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Affiliation(s)
- Hongquan Zhang
- Department of Laboratory Medicine and Pathology and Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G3 (Canada) http://www.ualberta.ca/∼xcle
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8
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Fron E, Van der Auweraer M, Moeyaert B, Michiels J, Mizuno H, Hofkens J, Adam V. Revealing the excited-state dynamics of the fluorescent protein Dendra2. J Phys Chem B 2013; 117:2300-13. [PMID: 23356883 DOI: 10.1021/jp309219m] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Green-to-red photoconversion is a reaction that occurs in a limited number of fluorescent proteins and that is currently mechanistically debated. In this contribution, we report on our investigation of the photoconvertible fluorescent protein Dendra2 by employing a combination of pump-probe, up-conversion and single photon timing spectroscopic techniques. Our findings indicate that upon excitation of the neutral green state an excited state proton transfer proceeds with a time constant of 3.4 ps between the neutral green and the anionic green states. In concentrated solution we detected resonance energy transfer (25 ps time constant) between green and red monomers. The time-resolved emission spectra suggest also the formation of a super-red species, first observed for DsRed (a red fluorescent protein from the corallimorph species Discosoma) and consistent with peculiar structural details present in both proteins.
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Affiliation(s)
- Eduard Fron
- Division of Molecular Imaging and Photonics, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
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9
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Dedecker P, De Schryver FC, Hofkens J. Fluorescent Proteins: Shine on, You Crazy Diamond. J Am Chem Soc 2013; 135:2387-402. [DOI: 10.1021/ja309768d] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Peter Dedecker
- Department of Chemistry, University of Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
| | - Frans C. De Schryver
- Department of Chemistry, University of Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
| | - Johan Hofkens
- Department of Chemistry, University of Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
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10
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Laufer J, Jathoul A, Pule M, Beard P. In vitro characterization of genetically expressed absorbing proteins using photoacoustic spectroscopy. BIOMEDICAL OPTICS EXPRESS 2013; 4:2477-90. [PMID: 24298408 PMCID: PMC3829541 DOI: 10.1364/boe.4.002477] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 10/01/2013] [Accepted: 10/01/2013] [Indexed: 05/21/2023]
Abstract
Genetically expressed fluorescent proteins have been shown to provide photoacoustic contrast. However, they can be limited by low photoacoustic generation efficiency and low optical absorption at red and near infrared wavelengths, thus limiting their usefulness in mammalian small animal models. In addition, many fluorescent proteins exhibit low photostability due to photobleaching and transient absorption effects. In this study, we explore these issues by synthesizing and characterizing a range of commonly used fluorescent proteins (dsRed, mCherry, mNeptune, mRaspberry, AQ143, E2 Crimson) and novel non-fluorescent chromoproteins (aeCP597 and cjBlue and a non-fluorescent mutant of E2 Crimson). The photoacoustic spectra, photoacoustic generation efficiency and photostability of each fluorescent protein and chromoprotein were measured. Compared to the fluorescent proteins, the chromoproteins were found to exhibit higher photoacoustic generation efficiency due to the absence of radiative relaxation and ground state depopulation, and significantly higher photostability. The feasibility of converting an existing fluorescent protein into a non-fluorescent chromoprotein via mutagenesis was also demonstrated. The chromoprotein mutant exhibited greater photoacoustic signal generation efficiency and better agreement between the photoacoustic and the specific extinction coefficient spectra than the original fluorescent protein. Lastly, the genetic expression of a chromoprotein in mammalian cells was demonstrated. This study suggests that chromoproteins may have potential for providing genetically encoded photoacoustic contrast.
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Affiliation(s)
- Jan Laufer
- Department of Medical Physics and Bioengineering, University College London, Gower Street, London WC1E 6BT, UK
- Julius Wolff Institut, Charité – Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
- Contributed equally to this work
| | - Amit Jathoul
- Department of Haematology, Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
- Centre for Advanced Biomedical Imaging, Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
- Contributed equally to this work
| | - Martin Pule
- Department of Haematology, Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
- Centre for Advanced Biomedical Imaging, Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
- Contributed equally to this work
| | - Paul Beard
- Department of Medical Physics and Bioengineering, University College London, Gower Street, London WC1E 6BT, UK
- Centre for Advanced Biomedical Imaging, Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
- Contributed equally to this work
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11
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Stopel MHW, Prangsma JC, Blum C, Subramaniam V. Blinking statistics of colloidal quantum dots at different excitation wavelengths. RSC Adv 2013. [DOI: 10.1039/c3ra43637c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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12
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Blum C, Schleifenbaum F, Stopel M, Peter S, Sackrow M, Subramaniam V, Meixner AJ. Room temperature excitation spectroscopy of single quantum dots. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2011; 2:516-24. [PMID: 22003458 PMCID: PMC3190622 DOI: 10.3762/bjnano.2.56] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 06/09/2011] [Indexed: 05/23/2023]
Abstract
We report a single molecule detection scheme to investigate excitation spectra of single emitters at room temperature. We demonstrate the potential of single emitter photoluminescence excitation spectroscopy by recording excitation spectra of single CdSe nanocrystals over a wide spectral range of 100 nm. The spectra exhibit emission intermittency, characteristic of single emitters. We observe large variations in the spectra close to the band edge, which represent the individual heterogeneity of the observed quantum dots. We also find specific excitation wavelengths for which the single quantum dots analyzed show an increased propensity for a transition to a long-lived dark state. We expect that the additional capability of recording excitation spectra at room temperature from single emitters will enable insights into the photophysics of emitters that so far have remained inaccessible.
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Affiliation(s)
- Christian Blum
- Nanobiophysics Group and MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Frank Schleifenbaum
- Center for Plant Molecular Biology, Biophysical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Martijn Stopel
- Nanobiophysics Group and MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Sébastien Peter
- Center for Plant Molecular Biology, Biophysical Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
| | - Marcus Sackrow
- Institut für Physikalische und Theoretische Chemie, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
- present address: Picoquant GmbH, Rudower Chaussee 29, 12489 Berlin, Germany
| | - Vinod Subramaniam
- Nanobiophysics Group and MESA+ Institute for Nanotechnology, University of Twente, PO Box 217, 7500 AE Enschede, The Netherlands
| | - Alfred J Meixner
- Institut für Physikalische und Theoretische Chemie, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
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13
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Walther KA, Papke B, Sinn MB, Michel K, Kinkhabwala A. Precise measurement of protein interacting fractions with fluorescence lifetime imaging microscopy. MOLECULAR BIOSYSTEMS 2011; 7:322-36. [PMID: 21221430 DOI: 10.1039/c0mb00132e] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Precise quantification of endogenous protein-protein interactions across live cells would be a major boon to biology. Such precise measurement is theoretically possible with fluorescence lifetime imaging microscopy (FLIM) but requires first properly addressing multiple biological, instrumental, statistical, and photophysical challenges. We present a detailed investigation of the last three FLIM-specific challenges. Using an efficient, highly accurate analysis code for time-domain FLIM data that accounts for all significant instrumental artifacts (in part, through use of a parametrized model for the instrument response function) and is rigorously based on both conventional statistics (full lifetime histogram fitting by χ(2) minimization) and novel statistics (single pixel fitting of lifetime populations using "maximum fidelity"), we address multiple photophysical challenges, including the proper side-by-side statistical comparison of fluorophore monoexponentiality, the precise assessment of fluorophore lifetimes and lifetime photostability, and the determination of acceptor dark state fractions. Finally, we demonstrate the feasibility of precise measurement of the interacting fraction of a protein across live cells with FLIM.
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Affiliation(s)
- Kirstin A Walther
- Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
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14
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Blum C, Meixner AJ, Subramaniam V. Dark proteins disturb multichromophore coupling in tetrameric fluorescent proteins. JOURNAL OF BIOPHOTONICS 2011; 4:114-121. [PMID: 20635430 DOI: 10.1002/jbio.201000075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 06/29/2010] [Accepted: 06/30/2010] [Indexed: 05/29/2023]
Abstract
DsRed is representative of the tetrameric reef coral fluorescent proteins that constitute particularly interesting coupled multichromophoric systems. Either a green emitting or a red emitting chromophore can form within each of the monomers of the protein tetramer. Within the tetramers the chromophores are thought to be efficiently fluorescence resonance energy transfer (FRET) coupled. We have used spectrally resolved room temperature single molecule spectroscopy to address the issue of FRET and the role of dark proteins within single protein tetramers of DsRed and its variants DsRed2, DsRed_N42H and AG4. Our results show that for the majority of the tetramers the different chromophores are indeed effectively coupled. However, in a fraction of the tetramers that is characteristic for each DsRed variant analyzed, we observe a lack of effective FRET coupling. For these tetramers we invoke the existence of dark proteins lacking a functional chromophore that interrupt the energy transfer chain within the multichromophoric system. We show that these species lead to donor dequenching that strongly influences the bulk emission spectra.
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Affiliation(s)
- Christian Blum
- Nanobiophysics, MESA+Institute for Nanotechnology & MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
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15
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Dragan AI, Geddes CD. Excitation volumetric effects (EVE) in metal-enhanced fluorescence. Phys Chem Chem Phys 2011; 13:3831-8. [DOI: 10.1039/c0cp01986k] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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van Thor JJ. Photoconversion of the Green Fluorescent Protein and Related Proteins. SPRINGER SERIES ON FLUORESCENCE 2011. [DOI: 10.1007/4243_2011_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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17
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Chmyrov A, Sandén T, Widengren J. Recovery of Photoinduced Reversible Dark States Utilized for Molecular Diffusion Measurements. Anal Chem 2010; 82:9998-10005. [DOI: 10.1021/ac1014047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Andriy Chmyrov
- Experimental Biomolecular Physics, Department of Applied Physics, Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Tor Sandén
- Experimental Biomolecular Physics, Department of Applied Physics, Royal Institute of Technology, SE-10691 Stockholm, Sweden
| | - Jerker Widengren
- Experimental Biomolecular Physics, Department of Applied Physics, Royal Institute of Technology, SE-10691 Stockholm, Sweden
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18
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Widengren J. Fluorescence-based transient state monitoring for biomolecular spectroscopy and imaging. J R Soc Interface 2010; 7:1135-44. [PMID: 20375039 PMCID: PMC2894879 DOI: 10.1098/rsif.2010.0146] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Accepted: 03/15/2010] [Indexed: 11/12/2022] Open
Abstract
To increase read-out speed, sensitivity or specificity, an often applied strategy in fluorescence-based biomolecular spectroscopy and imaging is to simultaneously record two or more of the fluorescence parameters: intensity, lifetime, polarization or wavelength. This review highlights how additional, to-date largely unexploited, information can be extracted by monitoring long-lived, photo-induced transient states of organic dyes and their dynamics. Two major approaches are presented, where the transient state information is obtained either from fluorescence fluctuation analysis or by recording the time-averaged fluorescence response to a time-modulated excitation. The two approaches combine the detection sensitivity of the fluorescence signal with the environmental sensitivity of the long-lived transient states. For both techniques, proof-of-principle experiments are reviewed, and advantages, limitations and possible applications for biomolecular cellular biology studies are discussed.
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Affiliation(s)
- Jerker Widengren
- Experimental Biomolecular Physics, Department of Applied Physics, Royal Institute of Technology (KTH), Albanova University Center, Stockholm 106 91, Sweden.
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19
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Antoku Y, Hotta JI, Mizuno H, Dickson RM, Hofkens J, Vosch T. Transfection of living HeLa cells with fluorescent poly-cytosine encapsulated Ag nanoclusters. Photochem Photobiol Sci 2010; 9:716-21. [PMID: 20442932 PMCID: PMC2913586 DOI: 10.1039/c0pp00015a] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 03/05/2010] [Indexed: 11/21/2022]
Abstract
The fluorescence of silver clusters encapsulated by single stranded oligo-DNA (24 cytosine base pairs, C(24):Ag(n)) was used to monitor the transfection of this new silver/DNA fluorophore inside living HeLa cells. For this, the C(24):Ag(n) molecules were complexed with a commercially available transfection reagent Lipofectamine and the internalization of C(24):Ag(n) was followed with confocal fluorescence microscopy. Bright near-infrared fluorescence was observed from inside the transfected HeLa cells, when exciting with 633 nm excitation, opening up the possibility for the use of these C(24):Ag(n) clusters for biological labelling and imaging of living cells and for monitoring the transfection process with limited harm to the living cells.
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Affiliation(s)
- Yasuko Antoku
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001, Heverlee, Belgium
| | - Jun-ichi Hotta
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001, Heverlee, Belgium
| | - Hideaki Mizuno
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001, Heverlee, Belgium
| | - Robert M. Dickson
- School of Chemistry and Biochemistry and Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 901 Atlantic Drive, Atlanta, GA, 30332-0400, USA
| | - Johan Hofkens
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001, Heverlee, Belgium
| | - Tom Vosch
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001, Heverlee, Belgium
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van Thor JJ. Photoreactions and dynamics of the green fluorescent protein. Chem Soc Rev 2009; 38:2935-50. [DOI: 10.1039/b820275n] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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