1
|
Rudat B, Birtalan E, Thomé I, Kölmel DK, Horhoiu VL, Wissert MD, Lemmer U, Eisler HJ, Balaban TS, Bräse S. Novel pyridinium dyes that enable investigations of peptoids at the single-molecule level. J Phys Chem B 2011; 114:13473-80. [PMID: 20923224 DOI: 10.1021/jp103308s] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Single-molecule microscopy is a powerful tool for investigating various uptake mechanisms of cell-penetrating biomolecules. A particularly interesting class of potential transporter molecules are peptoids. Fluorescence labels for such experiments need to comply with several physical, chemical, and biological requirements. Herein, we report the synthesis and photophysical investigation of new fluorescent pyridinium derived dyes. These fluorescent labels have advantageous structural variations and spacer units in order to avoid undesirable interactions with the labeled molecule and are able to easily functionalize biomolecules. In our case, cell-penetrating peptoids are successfully labeled on solid supports, and in ensemble measurements the photophysical properties of the dyes and the fluorescently labeled peptoids are investigated. Both fluorophores and peptoids are imaged at the single-molecule level in thin polymer gels. With respect to bleaching times and fluorescence lifetimes the dye molecules and the peptoids show only slightly perturbed optical behaviors. These investigations indicate that the new fluorophores fulfill well single-molecule microscopy and solid-phase synthesis requirements.
Collapse
Affiliation(s)
- Birgit Rudat
- Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, D-76131, Karlsruhe, Germany
| | | | | | | | | | | | | | | | | | | |
Collapse
|
2
|
Mudalige K, Habuchi S, Goodwin PM, Pai RK, De Schryver F, Cotlet M. Photophysics of the Red Chromophore of HcRed: Evidence for Cis−Trans Isomerization and Protonation-State Changes. J Phys Chem B 2010; 114:4678-85. [DOI: 10.1021/jp9102146] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Kumara Mudalige
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Mail Stop 735, Upton New York 11973, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Heverlee Leuven B-3001, Belgium, and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Mail Stop K771, Los Alamos, New Mexico 87545
| | - Satoshi Habuchi
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Mail Stop 735, Upton New York 11973, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Heverlee Leuven B-3001, Belgium, and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Mail Stop K771, Los Alamos, New Mexico 87545
| | - Peter M. Goodwin
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Mail Stop 735, Upton New York 11973, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Heverlee Leuven B-3001, Belgium, and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Mail Stop K771, Los Alamos, New Mexico 87545
| | - Ranjith K. Pai
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Mail Stop 735, Upton New York 11973, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Heverlee Leuven B-3001, Belgium, and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Mail Stop K771, Los Alamos, New Mexico 87545
| | - Frans De Schryver
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Mail Stop 735, Upton New York 11973, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Heverlee Leuven B-3001, Belgium, and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Mail Stop K771, Los Alamos, New Mexico 87545
| | - Mircea Cotlet
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Mail Stop 735, Upton New York 11973, Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Heverlee Leuven B-3001, Belgium, and Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Mail Stop K771, Los Alamos, New Mexico 87545
| |
Collapse
|
3
|
Schleifenbaum F, Peter S, Meixner AJ. Detecting the Same Individual Protein and Its Photoproducts via Fluorescence and Surface-Enhanced Raman Spectroscopic Imaging. J Phys Chem A 2009; 114:143-50. [DOI: 10.1021/jp907431r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Frank Schleifenbaum
- Institute of Physical and Theoretical Chemistry, University of Tuebingen, Tuebingen, Germany
| | - Sébastien Peter
- Institute of Physical and Theoretical Chemistry, University of Tuebingen, Tuebingen, Germany
| | - Alfred J. Meixner
- Institute of Physical and Theoretical Chemistry, University of Tuebingen, Tuebingen, Germany
| |
Collapse
|
4
|
Schleifenbaum F, Blum C, Subramaniam V, Meixner AJ. Single-molecule spectral dynamics at room temperature. Mol Phys 2009. [DOI: 10.1080/00268970802635004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
5
|
Habuchi S, Tsutsui H, Kochaniak AB, Miyawaki A, van Oijen AM. mKikGR, a monomeric photoswitchable fluorescent protein. PLoS One 2008; 3:e3944. [PMID: 19079591 PMCID: PMC2592542 DOI: 10.1371/journal.pone.0003944] [Citation(s) in RCA: 150] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Accepted: 11/12/2008] [Indexed: 11/18/2022] Open
Abstract
The recent demonstration and utilization of fluorescent proteins whose fluorescence can be switched on and off has greatly expanded the toolkit of molecular and cell biology. These photoswitchable proteins have facilitated the characterization of specifically tagged molecular species in the cell and have enabled fluorescence imaging of intracellular structures with a resolution far below the classical diffraction limit of light. Applications are limited, however, by the fast photobleaching, slow photoswitching, and oligomerization typical for photoswitchable proteins currently available. Here, we report the molecular cloning and spectroscopic characterization of mKikGR, a monomeric version of the previously reported KikGR that displays high photostability and switching rates. Furthermore, we present single-molecule imaging experiments that demonstrate that individual mKikGR proteins can be localized with a precision of better than 10 nanometers, suggesting their suitability for super-resolution imaging.
Collapse
Affiliation(s)
- Satoshi Habuchi
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Graduate School of Science and Engineering, Tokyo Institute of Technology, Tokyo, Japan
| | - Hidekazu Tsutsui
- Laboratory for Cell Function Dynamics, Brain Science Institute, RIKEN, Wako, Saitama, Japan
| | - Anna B. Kochaniak
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- Graduate Program in Biophysics, Harvard University, Cambridge, Massachusetts, United States of America
| | - Atsushi Miyawaki
- Laboratory for Cell Function Dynamics, Brain Science Institute, RIKEN, Wako, Saitama, Japan
- * E-mail: (AM); (AMvO)
| | - Antoine M. van Oijen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (AM); (AMvO)
| |
Collapse
|
6
|
Blum C, Subramaniam V. Single-molecule spectroscopy of fluorescent proteins. Anal Bioanal Chem 2008; 393:527-41. [DOI: 10.1007/s00216-008-2425-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 09/15/2008] [Accepted: 09/18/2008] [Indexed: 11/28/2022]
|
7
|
Schleifenbaum F, Blum C, Elgass K, Subramaniam V, Meixner AJ. New insights into the photophysics of DsRed by multiparameter spectroscopy on single proteins. J Phys Chem B 2008; 112:7669-74. [PMID: 18528973 DOI: 10.1021/jp7114753] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The red fluorescent protein from DsRed from Discosoma reef coral exhibits complex photophysics. One key reason for this is that DsRed forms obligate tetrameric units containing green and red emitting monomers in random composition. Experimental investigations have proven that these different chromophores within one tetramer are coupled by fluorescence resonance energy transfer (FRET) and that the observed strong red emission is due to a nonradiative energy transfer from the green to the red chromophore when the green chromophore is exclusively excited. Ensemble studies can only provide averaged data on statistical mixtures of tetramers with different compositions, since it is impossible to separate the tetramers into functional monomers containing only red or green emitting chromophores. We present here the results of DsRed multiparameter single molecule spectroscopy. By combination of spectral and time domain spectroscopy, we were able to isolate single tetramers containing only green chromophores and thus record the fluorescence lifetime of the green emitting species without interference from FRET to the red chromophore for the first time. The fluorescence lifetime for the green chromophore of DsRed is remarkably longer than for the green fluorescent protein, which is a chemical analogue to the green chromophore in DsRed. On the basis of our single protein experiments, we can derive a complete set of spectroscopic parameters to describe Forster energy transfer in the DsRed system without any further assumptions. Hence in combination with X-ray studies our data allow for an accurate quantitative description of the radiative and nonradiative relaxation processes in DsRed proteins.
Collapse
Affiliation(s)
- Frank Schleifenbaum
- Institute of Physical and Theoretical Chemistry, University of Tuebingen, Tuebingen, Germany
| | | | | | | | | |
Collapse
|
8
|
Hendrix J, Flors C, Dedecker P, Hofkens J, Engelborghs Y. Dark states in monomeric red fluorescent proteins studied by fluorescence correlation and single molecule spectroscopy. Biophys J 2008; 94:4103-13. [PMID: 18234806 PMCID: PMC2367191 DOI: 10.1529/biophysj.107.123596] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Accepted: 12/21/2007] [Indexed: 11/18/2022] Open
Abstract
Monomeric red fluorescent proteins (mRFPs) have become indispensable tools for studying protein dynamics, interactions and functions in the cellular environment. Their emission spectrum can be well separated from other fluorescent proteins, and their monomeric structure preserves the natural function of fusion proteins. However, previous photophysical studies of some RFPs have shown the presence of light-induced dark states that can complicate the interpretation of cellular experiments. In this article, we extend these studies to mRFP1, mCherry, and mStrawberry by means of fluorescence correlation spectroscopy and prove that this light-driven intensity flickering also occurs in these proteins. Furthermore, we show that the flickering in these proteins is pH-dependent. Single molecule spectroscopy revealed reversible transitions from a bright to a dark state in several timescales, even up to seconds. Time-resolved fluorescence spectroscopy showed multiexponential decays, consistent with a "loose" conformation. We offer a structural basis for the fluorescence flickering using known crystal structures and point out that the environment of Glu-215 is critical for the pH dependence of the flickering in RFPs. We apply dual-color fluorescence correlation spectroscopy inside live cells to prove that this flickering can seriously hamper cellular measurements if the timescales of the flickering and diffusion are not well separated.
Collapse
Affiliation(s)
- Jelle Hendrix
- Laboratory of Biomolecular Dynamics, Department of Chemistry, Katholieke Universiteit Leuven, 3001 Heverlee, Belgium
| | | | | | | | | |
Collapse
|
9
|
Lessard GA, Habuchi S, Werner JH, Goodwin PM, De Schryver F, Hofkens J, Cotlet M. Probing dimerization and intraprotein fluorescence resonance energy transfer in a far-red fluorescent protein from the sea anemone Heteractis crispa. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:031212. [PMID: 18601536 DOI: 10.1117/1.2937477] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Proteins from Anthozoa species are homologous to the green fluorescent protein (GFP) from Aequorea victoria but with absorption/emission properties extended to longer wavelengths. HcRed is a far-red fluorescent protein originating from the sea anemone Heteractis crispa with absorption and emission maxima at 590 and 650 nm, respectively. We use ultrasensitive fluorescence spectroscopic methods to demonstrate that HcRed occurs as a dimer in solution and to explore the interaction between chromophores within such a dimer. We show that red chromophores within a dimer interact through a Forster-type fluorescence resonance energy transfer (FRET) mechanism. We present spectroscopic evidence for the presence of a yellow chromophore, an immature form of HcRed. This yellow chromophore is involved in directional FRET with the red chromophore when both types of chromophores are part of one dimer. We show that by combining ensemble and single molecule methods in the investigation of HcRed, we are able to sort out subpopulations of chromophores with different photophysical properties and to understand the mechanism of interaction between such chromophores. This study will help in future quantitative microscopy investigations that use HcRed as a fluorescent marker.
Collapse
Affiliation(s)
- Guillaume A Lessard
- Los Alamos National Laboratory, Mail Stop J567, Los Alamos, New Mexico 87545, USA
| | | | | | | | | | | | | |
Collapse
|
10
|
Jiménez-Banzo A, Nonell S, Hofkens J, Flors C. Singlet oxygen photosensitization by EGFP and its chromophore HBDI. Biophys J 2007; 94:168-72. [PMID: 17766345 PMCID: PMC2134865 DOI: 10.1529/biophysj.107.107128] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The photosensitization of reactive oxygen species and, in particular, singlet oxygen by proteins from the green fluorescent protein (GFP) family influences important processes such as photobleaching and genetically targeted chromophore-assisted light inactivation. In this article, we report an investigation of singlet oxygen photoproduction by GFPs using time-resolved detection of the NIR phosphorescence of singlet oxygen at 1275 nm. We have detected singlet oxygen generated by enhanced (E)GFP, and measured a lifetime of 4 micros in deuterated solution. By comparison with the model compound of the EGFP fluorophore 4-hydroxybenzylidene-1,2-dimethylimidazoline (HBDI), our results confirm that the beta-can of EGFP provides shielding of the fluorophore and reduces the production of this reactive oxygen species. In addition, our results yield new information about the triplet state of these proteins. The quantum yield for singlet oxygen photosensitization by the model chromophore HBDI is 0.004.
Collapse
Affiliation(s)
- Ana Jiménez-Banzo
- Grup d'Enginyeria Molecular, Institut Químic de Sarrià, Barcelona, Spain
| | | | | | | |
Collapse
|
11
|
Cotlet M, Goodwin PM, Waldo GS, Werner JH. A comparison of the fluorescence dynamics of single molecules of a green fluorescent protein: one- versus two-photon excitation. Chemphyschem 2007; 7:250-60. [PMID: 16353266 DOI: 10.1002/cphc.200500247] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We report on the dynamics of fluorescence from individual molecules of a mutant of the wild-type green fluorescent protein (GFP) from Aequorea victoria, super folder GFP (SFGFP). SFGFP is a novel and robust variant designed for in vivo high-throughput screening of protein expression levels. It shows increased thermal stability and is able to retain its fluorescence when fused to poorly folding proteins. We use a recently developed single-molecule technique which combines fluorescence-fluctuation spectroscopy and time-correlated single photon counting in order to characterize the photophysical properties of SFGFP under one- (OPE) and two- (TPE) photon excitation conditions. We use Rhodamine 110 as a model chromophore to validate the methodology and to explain the single-molecule results of SFGFP. Under OPE, single SFGFP molecules undergo fluorescence flickering on the time scale of micros and tens of micros due to triplet formation and ground-state protonation-deprotonation, respectively, as demonstrated by excitation intensity- and pH-dependent experiments. OPE single-molecule fluorescence lifetimes indicate heterogeneity in the population of SFGFP, indicating the presence of the deprotonated I and B forms of the SFGFP chromophore. TPE of single SFGFP molecules results in the photoconversion of the chromophore. TPE of single SFGFP molecules show fluorescence flickering on the time scale of micros due to triplet formation. A flicker connected with protonation-deprotonation of the SFGFP chromophore is detected only at low pH. Our results show that SFGFP is a promising fusion reporter for intracellular applications using OPE and TPE microscopy.
Collapse
Affiliation(s)
- Mircea Cotlet
- Los Alamos National Laboratory, Material Science and Technology Division, Center for Integrated Nanotechnologies, Mail Stop J586, Los Alamos NM 87545, USA.
| | | | | | | |
Collapse
|
12
|
Huang QL, Chen C, Chen YZ, Gong CG, Wang J, Hua ZC. Fusion protein between protein ZZ and red fluorescent protein DsRed and its application to immunoassays. Biotechnol Appl Biochem 2006; 43:121-7. [PMID: 16218907 DOI: 10.1042/ba20050136] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In the present study, a red fluorescent protein (DsRed) from the coral Discosoma was fused to the C-terminus of protein ZZ, a synthetic artificial IgG-Fc-fragment-binding protein derived from the B-domain of staphylococcal Protein A. The chimaeric protein, tagged with six histidine residues at the N-terminus, was expressed in Escherichia coli and easily purified by one-step Ni2+-chelating affinity chromatography. Its fluorescence and IgG-binding activities were validated using fluorescence-spectrum analysis, ELISA and dot-blot analysis. Furthermore, in subsequent dot-blotting immunoanalysis of glutathione S-transferase and tumour necrosis factor-alpha, and immunofluorescent microscopy assay of interferon regulatory factor 3, the chimaeric protein enabled effective detection of target molecules. Compared with fluorescence-conjugated antibodies, ZZ-DsRed is less susceptible to photobleaching and easy to produce. In addition, unlike HRP (horseradish peroxidase)-conjugated antibodies, using ZZ-DsRed needs no addition of a chromogenic reagent. Our results indicate that ZZ-DsRed shows a wide and promising application potential in immunological detection as a substitute for fluorescent or HRP-conjugated anti-IgGs.
Collapse
Affiliation(s)
- Qi-Lai Huang
- The State Key Laboratory of Pharmaceutical Biotechnology and Department of Biochemistry, College of Life Sciences, Nanjing University, Nanjing 210093, People's Republic of China
| | | | | | | | | | | |
Collapse
|
13
|
Habuchi S, Dedecker P, Hotta JI, Flors C, Ando R, Mizuno H, Miyawaki A, Hofkens J. Photo-induced protonation/deprotonation in the GFP-like fluorescent protein Dronpa: mechanism responsible for the reversible photoswitching. Photochem Photobiol Sci 2006; 5:567-76. [PMID: 16761085 DOI: 10.1039/b516339k] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recently, reversible photoswitching in bulk samples or in individual molecules of Dronpa, a mutant of a green fluorescent protein (GFP)-like fluorescent protein, has been demonstrated. Intense irradiation at 488 nm changed Dronpa in a dim protonated form, and weak irradiation at 405 nm restored it to the bright deprotonated form. Here, we report on the mechanism of photoswitching of Dronpa by means of ensemble and single-molecule spectroscopy. Ensemble spectroscopy shows that the photoswitching can be described, in first approximation, by a three-state model including a deprotonated (B), a protonated (A1), and a photoswitched protonated (A2) forms of the chromophore. While the B and the A1 forms are in a ground state acid-base equilibrium, the B and the A2 forms are reversibly photoswitched upon irradiation with 488 and 405 nm light. At the single-molecule level, the on-times in fluorescence intensity trajectories excited at 488 nm decrease with increasing the excitation power, consistent with the photoswitching from the B to A2 form. The on-times agree well with expected values, which are calculated based on the ensemble spectroscopic properties of Dronpa. The fluorescence trajectory obtained with simultaneous dual-color excitation at 488 and 405 nm demonstrates reversible photoswitching between the B and the A2 forms at the single-molecule level. The efficiency of the photoswitching from the A2 to B form increased with increasing the excitation power of the 405 nm light. Our results demonstrate that Dronpa holds its outstanding photoswitching properties, based on a photo-induced protonation/deprotonation process, even at the single-molecule level.
Collapse
Affiliation(s)
- Satoshi Habuchi
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium.
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Habuchi S, Ando R, Dedecker P, Verheijen W, Mizuno H, Miyawaki A, Hofkens J. Reversible single-molecule photoswitching in the GFP-like fluorescent protein Dronpa. Proc Natl Acad Sci U S A 2005; 102:9511-6. [PMID: 15972810 PMCID: PMC1157093 DOI: 10.1073/pnas.0500489102] [Citation(s) in RCA: 344] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Reversible photoswitching of individual molecules has been demonstrated for a number of mutants of the green fluorescent protein (GFP). To date, however, a limited number of switching events with slow response to light have been achieved at the single-molecule level. Here, we report reversible photoswitching characteristics observed in individual molecules of Dronpa, a mutant of a GFP-like fluorescent protein that was cloned from a coral Pectiniidae. Ensemble spectroscopy shows that intense irradiation at 488 nm changes Dronpa to a dim protonated form, but even weak irradiation at 405 nm restores it to the bright deprotonated form. Although Dronpa exists in an acid-base equilibrium, only the photoinduced protonated form shows the switching behavior. At the single-molecule level, 488- and 405-nm lights can be used to drive the molecule back and forth between the bright and dim states. Such reversible photoswitching could be repeated >100 times. The response speed to irradiation depends almost linearly on the irradiation power, with the response time being in the order of milliseconds. The perfect reversibility of the Dronpa photoswitching allows us to propose a detailed model, which quantitatively describes interconversion among the various states. The fast response of Dronpa to light holds great promise for following fast diffusion or transport of signaling molecules in live cells.
Collapse
Affiliation(s)
- Satoshi Habuchi
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
| | | | | | | | | | | | | |
Collapse
|
15
|
Habuchi S, Cotlet M, Gensch T, Bednarz T, Haber-Pohlmeier S, Rozenski J, Dirix G, Michiels J, Vanderleyden J, Heberle J, De Schryver FC, Hofkens J. Evidence for the Isomerization and Decarboxylation in the Photoconversion of the Red Fluorescent Protein DsRed. J Am Chem Soc 2005; 127:8977-84. [PMID: 15969574 DOI: 10.1021/ja047023o] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recently, it has been shown that the red fluorescent protein DsRed undergoes photoconversion on intense irradiation, but the mechanism of the conversion has not yet been elucidated. Upon irradiation with a nanosecond-pulsed laser at 532 nm, the chromophore of DsRed absorbing at 559 nm and emitting at 583 nm (R form) converts into a super red (SR) form absorbing at 574 nm and emitting at 595 nm. This conversion leads to a significant change in the fluorescence quantum yield from 0.7 to 0.01. Here we demonstrate that the photoconversion is the result of structural changes of the chromophore and one amino acid. Absorption, fluorescence, and vibrational spectroscopy as well as mass spectrometry suggest that a cis-to-trans isomerization of the chromophore and decarboxylation of a glutamate (E215) take place upon irradiation to form SR. At the same time, another photoproduct (B) with an absorption maximum at 386 nm appears upon irradiation. This species is assigned as a protonated form of the DsRed chromophore. It might be a mixture of several protonated DsRed forms as there is at least two ways of formation. Furthermore, the photoconversion of DsRed is proven to occur through a consecutive two-photon absorption process. Our results demonstrate the importance of the chromophore conformation in the ground state on the brightness of the protein as well as the importance of the photon flux to control/avoid the photoconversion process.
Collapse
Affiliation(s)
- Satoshi Habuchi
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Loos D, Cotlet M, De Schryver F, Habuchi S, Hofkens J. Single-molecule spectroscopy selectively probes donor and acceptor chromophores in the phycobiliprotein allophycocyanin. Biophys J 2005; 87:2598-608. [PMID: 15454454 PMCID: PMC1304678 DOI: 10.1529/biophysj.104.046219] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We report on single-molecule fluorescence measurements performed on the phycobiliprotein allophycocyanin (APC). Our data support the presence of a unidirectional Förster-type energy transfer process involving spectrally different chromophores, alpha84 (donor) and beta84 (acceptor), as well as of energy hopping amongst beta84 chromophores. Single-molecule fluorescence spectra recorded from individual immobilized APC proteins indicate the presence of a red-emitting chromophore with emission peaking at 660 nm, which we connect with beta84, and a species with the emission peak blue shifted at 630 nm, which we attribute to alpha84. Polarization data from single APC trimers point to the presence of three consecutive red emitters, suggesting energy hopping amongst beta84 chromophores. Based on the single-molecule fluorescence spectra and assuming that emission at the ensemble level in solution comes mainly from the acceptor chromophore, we were able to resolve the individual absorption and emission spectra of the alpha84 and beta84 chromophores in APC.
Collapse
Affiliation(s)
- Davey Loos
- Laboratory of Photochemistry and Spectroscopy, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium
| | | | | | | | | |
Collapse
|
17
|
Margineanu A, Hofkens J, Cotlet M, Habuchi S, Stefan A, Qu J, Kohl C, Müllen K, Vercammen J, Engelborghs Y, Gensch T, De Schryver FC. Photophysics of a Water−Soluble Rylene Dye: Comparison with Other Fluorescent Molecules for Biological Applications. J Phys Chem B 2004. [DOI: 10.1021/jp048051w] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anca Margineanu
- Lab. Photochemistry and Spectroscopy, Department Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128, Mainz, Germany, Lab. Biomolecular Dynamics, Department Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium, and Institut für Biologische Informationverarbeitung 1, Forschungszentrum Jülich, D-52425, Jülich, Germany
| | - Johan Hofkens
- Lab. Photochemistry and Spectroscopy, Department Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128, Mainz, Germany, Lab. Biomolecular Dynamics, Department Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium, and Institut für Biologische Informationverarbeitung 1, Forschungszentrum Jülich, D-52425, Jülich, Germany
| | - Mircea Cotlet
- Lab. Photochemistry and Spectroscopy, Department Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128, Mainz, Germany, Lab. Biomolecular Dynamics, Department Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium, and Institut für Biologische Informationverarbeitung 1, Forschungszentrum Jülich, D-52425, Jülich, Germany
| | - Satoshi Habuchi
- Lab. Photochemistry and Spectroscopy, Department Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128, Mainz, Germany, Lab. Biomolecular Dynamics, Department Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium, and Institut für Biologische Informationverarbeitung 1, Forschungszentrum Jülich, D-52425, Jülich, Germany
| | - Alina Stefan
- Lab. Photochemistry and Spectroscopy, Department Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128, Mainz, Germany, Lab. Biomolecular Dynamics, Department Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium, and Institut für Biologische Informationverarbeitung 1, Forschungszentrum Jülich, D-52425, Jülich, Germany
| | - Jianqiang Qu
- Lab. Photochemistry and Spectroscopy, Department Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128, Mainz, Germany, Lab. Biomolecular Dynamics, Department Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium, and Institut für Biologische Informationverarbeitung 1, Forschungszentrum Jülich, D-52425, Jülich, Germany
| | - Christopher Kohl
- Lab. Photochemistry and Spectroscopy, Department Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128, Mainz, Germany, Lab. Biomolecular Dynamics, Department Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium, and Institut für Biologische Informationverarbeitung 1, Forschungszentrum Jülich, D-52425, Jülich, Germany
| | - Klaus Müllen
- Lab. Photochemistry and Spectroscopy, Department Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128, Mainz, Germany, Lab. Biomolecular Dynamics, Department Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium, and Institut für Biologische Informationverarbeitung 1, Forschungszentrum Jülich, D-52425, Jülich, Germany
| | - Jo Vercammen
- Lab. Photochemistry and Spectroscopy, Department Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128, Mainz, Germany, Lab. Biomolecular Dynamics, Department Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium, and Institut für Biologische Informationverarbeitung 1, Forschungszentrum Jülich, D-52425, Jülich, Germany
| | - Yves Engelborghs
- Lab. Photochemistry and Spectroscopy, Department Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128, Mainz, Germany, Lab. Biomolecular Dynamics, Department Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium, and Institut für Biologische Informationverarbeitung 1, Forschungszentrum Jülich, D-52425, Jülich, Germany
| | - Thomas Gensch
- Lab. Photochemistry and Spectroscopy, Department Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128, Mainz, Germany, Lab. Biomolecular Dynamics, Department Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium, and Institut für Biologische Informationverarbeitung 1, Forschungszentrum Jülich, D-52425, Jülich, Germany
| | - Frans C. De Schryver
- Lab. Photochemistry and Spectroscopy, Department Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001, Leuven, Belgium, Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128, Mainz, Germany, Lab. Biomolecular Dynamics, Department Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001, Leuven, Belgium, and Institut für Biologische Informationverarbeitung 1, Forschungszentrum Jülich, D-52425, Jülich, Germany
| |
Collapse
|
18
|
Hess ST, Sheets ED, Wagenknecht-Wiesner A, Heikal AA. Quantitative analysis of the fluorescence properties of intrinsically fluorescent proteins in living cells. Biophys J 2004; 85:2566-80. [PMID: 14507719 PMCID: PMC1303480 DOI: 10.1016/s0006-3495(03)74679-7] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The main potential of intrinsically fluorescent proteins (IFPs), as noninvasive and site-specific markers, lies in biological applications such as intracellular visualization and molecular genetics. However, photophysical studies of IFPs have been carried out mainly in aqueous solution. Here, we provide a comprehensive analysis of the intracellular environmental effects on the steady-state spectroscopy and excited-state dynamics of green (EGFP) and red (DsRed) fluorescent proteins, using both one- and two-photon excitation. EGFP and DsRed are expressed either in the cytoplasm of rat basophilic leukemia (RBL-2H3) mucosal mast cells or anchored (via LynB protein) to the inner leaflet of the plasma membrane. The fluorescence lifetimes (within approximately 10%) and spectra in live cells are basically the same as in aqueous solution, which indicate the absence of both IFP aggregation and cellular environmental effects on the protein folding under our experimental conditions. However, comparative time-resolved anisotropy measurements of EGFP reveal a cytoplasmic viscosity 2.5 +/- 0.3 times larger than that of aqueous solution at room temperature, and also provide some insights into the LynB-EGFP structure and the heterogeneity of the cytoplasmic viscosity. Further, the oligomer configuration and internal depolarization of DsRed, previously observed in solution, persists upon expression in these cells. DsRed also undergoes an instantaneous three-photon induced color change under 740-nm excitation, with efficiently nonradiative green species. These results confirm the implicit assumption that in vitro fluorescence properties of IFPs are essentially valid for in vivo applications, presumably due to the beta-barrel protection of the embodied chromophore. We also discuss the relevance of LynB-EGFP anisotropy for specialized domains studies in plasma membranes.
Collapse
Affiliation(s)
- Samuel T Hess
- School of Applied and Engineering Physics, Nanobiotechnology Center, Cornell University, Ithaca, New York 14853, USA
| | | | | | | |
Collapse
|
19
|
Bowen BP, Scruggs A, Enderlein J, Sauer M, Woodbury N. Implementation of Neural Networks for the Identification of Single Molecules. J Phys Chem A 2004. [DOI: 10.1021/jp036456v] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Benjamin P. Bowen
- Department of Chemical and Materials Engineering, Arizona State University, Tempe, Arizona 85287, Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, Institute for Biological Information Processing, Forschungszentrum Jülich, D-52425 Jülich, Germany, and Applied Laserphysics and Laserspectroscopy, University of Bielefeld, 33615 Bielefeld, Germany
| | - Allan Scruggs
- Department of Chemical and Materials Engineering, Arizona State University, Tempe, Arizona 85287, Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, Institute for Biological Information Processing, Forschungszentrum Jülich, D-52425 Jülich, Germany, and Applied Laserphysics and Laserspectroscopy, University of Bielefeld, 33615 Bielefeld, Germany
| | - Jörg Enderlein
- Department of Chemical and Materials Engineering, Arizona State University, Tempe, Arizona 85287, Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, Institute for Biological Information Processing, Forschungszentrum Jülich, D-52425 Jülich, Germany, and Applied Laserphysics and Laserspectroscopy, University of Bielefeld, 33615 Bielefeld, Germany
| | - Markus Sauer
- Department of Chemical and Materials Engineering, Arizona State University, Tempe, Arizona 85287, Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, Institute for Biological Information Processing, Forschungszentrum Jülich, D-52425 Jülich, Germany, and Applied Laserphysics and Laserspectroscopy, University of Bielefeld, 33615 Bielefeld, Germany
| | - Neal Woodbury
- Department of Chemical and Materials Engineering, Arizona State University, Tempe, Arizona 85287, Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287, Institute for Biological Information Processing, Forschungszentrum Jülich, D-52425 Jülich, Germany, and Applied Laserphysics and Laserspectroscopy, University of Bielefeld, 33615 Bielefeld, Germany
| |
Collapse
|
20
|
Andersen LH, Bluhme H, Boyé S, Jørgensen TJD, Krogh H, Nielsen IB, Brøndsted Nielsen S, Svendsen A. Experimental studies of the photophysics of gas-phase fluorescent protein chromophores. Phys Chem Chem Phys 2004. [DOI: 10.1039/b315763f] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
21
|
|
22
|
Hernando J, van der Schaaf M, van Dijk EMHP, Sauer M, García-Parajó MF, van Hulst NF. Excitonic Behavior of Rhodamine Dimers: A Single-Molecule Study. J Phys Chem A 2002. [DOI: 10.1021/jp0218995] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jordi Hernando
- Applied Optics Group, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, and Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Martijn van der Schaaf
- Applied Optics Group, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, and Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Erik M. H. P. van Dijk
- Applied Optics Group, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, and Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Markus Sauer
- Applied Optics Group, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, and Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - María F. García-Parajó
- Applied Optics Group, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, and Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| | - Niek F. van Hulst
- Applied Optics Group, Department of Applied Physics and MESA+ Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, and Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
| |
Collapse
|
23
|
Habuchi S, Cotlet M, Hofkens J, Dirix G, Michiels J, Vanderleyden J, Subramaniam V, De Schryver FC. Resonance energy transfer in a calcium concentration-dependent cameleon protein. Biophys J 2002; 83:3499-506. [PMID: 12496116 PMCID: PMC1302424 DOI: 10.1016/s0006-3495(02)75349-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
We report investigations of resonance energy transfer in the green fluorescent protein and calmodulin-based fluorescent indicator constructs for Ca(2+) called cameleons using steady-state and time-resolved spectroscopy of the full construct and of the component green fluorescent protein mutants, namely ECFP (donor) and EYFP (acceptor). EYFP displays a complicated photophysical behavior including protonated and deprotonated species involved in an excited-state proton transfer. When EYFP is excited in the absorption band of the protonated species, a fast nonradiative deactivation occurs involving almost 97% of the excited protonated population and leading to a low efficiency of excited-state proton transfer to the deprotonated species. ECFP displays a multiexponential fluorescence decay with a major contributing component of 3.2 ns. The time-resolved fluorescence data obtained upon excitation at 420 nm of Ca(2+)-free and Ca(2+)-bound YC3.1 cameleon constructs point to the existence of different conformations of calmodulin dependent on Ca(2+) binding. Whereas steady-state data show only an increase in the efficiency of energy transfer upon Ca(2+) binding, the time-resolved data demonstrate the existence of three distinct conformations/populations within the investigated sample. Although the mechanism of the interconversion between the different conformations and the extent of interconversion are still unclear, the time-resolved fluorescence data offer an estimation of the rate constants, of the efficiency of the energy transfer, and of the donor-acceptor distances in the Ca(2+)-free and Ca(2+)-bound YC3.1 samples.
Collapse
Affiliation(s)
- Satoshi Habuchi
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Sacchetti A, Subramaniam V, Jovin TM, Alberti S. Oligomerization of DsRed is required for the generation of a functional red fluorescent chromophore. FEBS Lett 2002; 525:13-9. [PMID: 12163153 DOI: 10.1016/s0014-5793(02)02874-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The coral red fluorescent protein (DsRed) absorbs and emits light at much higher wavelengths than the structurally homologous green fluorescent protein, raising questions about the properties of its chromophore. We have analyzed the relationship between the aggregation state and fluorescence of native, 6-histidine-tagged, or maltose-binding protein-fused DsRed. In all cases, newly synthesized DsRed molecules were largely monomeric and devoid of covalently closed chromophores. Maturation in vitro induces the expression of red fluorescent chromophores but only in oligomeric forms of the protein, whereas monomers are essentially devoid of fluorescence. NaOH-denatured samples demonstrated a generalized breakdown of the DsRed oligomers to monomers, which refolded after neutralization into weakly green fluorescent and still monomeric species. Red fluorescent chromophores were regenerated only upon oligomerization. These findings demonstrate that 'red' chromophores form and are functional only as oligomers, and suggest that the smallest red fluorescent functional unit is a dimer. A comparison of alkali-, acid- and guanidinium-denatured DsRed indicates that stabilization of the DsRed chromophore by concerted steps of folding and oligomerization may play a critical role in its maturation process.
Collapse
Affiliation(s)
- Andrea Sacchetti
- Laboratory of Experimental Oncology, Department of Cell Biology and Oncology, Istituto di Ricerche Farmacologiche Mario Negri-Consorzio Mario Negri Sud, 66030, Chieti, Santa Maria Imbaro, Italy
| | | | | | | |
Collapse
|
25
|
Blum C, Subramaniam V, Schleifenbaum F, Stracke F, Angres B, Terskikh A, Meixner A. Single molecule fluorescence spectroscopy of mutants of the Discosoma red fluorescent protein DsRed. Chem Phys Lett 2002. [DOI: 10.1016/s0009-2614(02)01014-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
26
|
Garcia-Parajo MF, Koopman M, van Dijk EM, Subramaniam V, van Hulst NF. The nature of fluorescence emission in the red fluorescent protein DsRed, revealed by single-molecule detection. Proc Natl Acad Sci U S A 2001; 98:14392-7. [PMID: 11724943 PMCID: PMC64692 DOI: 10.1073/pnas.251525598] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recent studies on the newly cloned red fluorescence protein DsRed from the Discosoma genus have shown its tremendous advantages: bright red fluorescence and high resistance against photobleaching. However, it has also become clear that the protein forms closely packed tetramers, and there is indication for incomplete protein maturation with unknown proportion of immature green species. We have applied single-molecule methodology to elucidate the nature of the fluorescence emission in the DsRed. Real-time fluorescence trajectories have been acquired with polarization sensitive detection. Our results indicate that energy transfer between identical monomers occurs efficiently with red emission arising equally likely from any of the chromophoric units. Photodissociation of one of the chromophores weakly quenches the emission of adjacent ones. Dual color excitation (at 488 and 568 nm) single-molecule microscopy has been performed to reveal the number and distribution of red vs. green species within each tetramer. We find that 86% of the DsRed contain at least one green species with a red-to-green ratio of 1.2-1.5. On the basis of our findings, oligomer suppression would not only be advantageous for protein fusion but will also increase the fluorescence emission of individual monomers.
Collapse
Affiliation(s)
- M F Garcia-Parajo
- Applied Optics Group, Department of Applied Physics and MESA(+) Research Institute, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
| | | | | | | | | |
Collapse
|
27
|
Cotlet M, Hofkens J, Habuchi S, Dirix G, Van Guyse M, Michiels J, Vanderleyden J, De Schryver FC. Identification of different emitting species in the red fluorescent protein DsRed by means of ensemble and single-molecule spectroscopy. Proc Natl Acad Sci U S A 2001; 98:14398-403. [PMID: 11724946 PMCID: PMC64693 DOI: 10.1073/pnas.251532698] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2001] [Accepted: 10/08/2001] [Indexed: 11/18/2022] Open
Abstract
The photophysics and photochemistry taking place in the DsRed protein, a recently cloned red fluorescent protein from a coral of the Discosoma genus, are investigated here by means of ensemble and single-molecule time-resolved detection and spectroscopic measurements. Ensemble time-resolved data reveal that 25% of the immature green chromophores are present in tetramers containing only this immature form. They are responsible for the weak fluorescence emitted at 500 nm. The remaining 75% of the immature green chromophores are involved in a fluorescence resonance energy transfer process to the red species. The combination of time-resolved detection with spectroscopy at the single-molecule level reveals, on 543-nm excitation of individual DsRed tetramers, the existence of a photoconversion of the red chromophore emitting at 583 nm and decaying with a 3.2-ns time constant into a super red one emitting at 595 nm and for which the decay time constant ranges between 2.7 and 1.5 ns. The phenomenon is further corroborated at the ensemble level by the observation of the creation of a super red form and a blue absorbing species on irradiation with 532-nm pulsed light at high excitation power. Furthermore, single-molecule experiments suggest that a similar photoconversion process might occur in the immature green species on 488-nm excitation.
Collapse
Affiliation(s)
- M Cotlet
- Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200 F, 3001 Heverlee, Belgium
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Paige MF, Bjerneld EJ, Moerner WE. A Comparison of Through-the-Objective Total Internal Reflection Microscopy and Epifluorescence Microscopy for Single-Molecule Fluorescence Imaging. ACTA ACUST UNITED AC 2001. [DOI: 10.1002/1438-5171(200110)2:3<191::aid-simo191>3.0.co;2-k] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
29
|
Malvezzi-Campeggi F, Jahnz M, Heinze KG, Dittrich P, Schwille P. Light-induced flickering of DsRed provides evidence for distinct and interconvertible fluorescent states. Biophys J 2001; 81:1776-85. [PMID: 11509387 PMCID: PMC1301652 DOI: 10.1016/s0006-3495(01)75828-6] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Green fluorescent protein (GFP) from jellyfish Aequorea victoria, the powerful genetically encoded tag presently available in a variety of mutants featuring blue to yellow emission, has found a red-emitting counterpart. The recently cloned red fluorescent protein DsRed, isolated from Discosoma corals (), with its emission maximum at 583 nm, appears to be the long awaited tool for multi-color applications in fluorescence-based biological research. Studying the emission dynamics of DsRed by fluorescence correlation spectroscopy (FCS), it can be verified that this protein exhibits strong light-dependent flickering similar to what is observed in several yellow-shifted mutants of GFP. FCS data recorded at different intensities and excitation wavelengths suggest that DsRed appears under equilibrated conditions in at minimum three interconvertible states, apparently fluorescent with different excitation and emission properties. Light absorption induces transitions and/or cycling between these states on time scales of several tens to several hundreds of microseconds, dependent on excitation intensity. With increasing intensity, the emission maximum of the static fluorescence continuously shifts to the red, implying that at least one state emitting at longer wavelength is preferably populated at higher light levels. In close resemblance to GFP, this light-induced dynamic behavior implies that the chromophore is subject to conformational rearrangements upon population of the excited state.
Collapse
Affiliation(s)
- F Malvezzi-Campeggi
- Experimental Biophysics Group, Max-Planck-Institute for Biophysical Chemistry, D-37077 Göttingen, Germany
| | | | | | | | | |
Collapse
|