1
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Sarkar B, Ishii K, Tahara T. Pulsed-Interleaved-Excitation Two-Dimensional Fluorescence Lifetime Correlation Spectroscopy. J Phys Chem B 2024; 128:4685-4695. [PMID: 38692581 PMCID: PMC11104349 DOI: 10.1021/acs.jpcb.4c01224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 04/13/2024] [Accepted: 04/17/2024] [Indexed: 05/03/2024]
Abstract
We report on pulsed-interleaved-excitation two-dimensional fluorescence lifetime correlation spectroscopy (PIE 2D FLCS) to study biomolecular structural dynamics with high sensitivity and high time resolution using Förster resonance energy transfer (FRET). PIE 2D FLCS is an extension of 2D FLCS, which is a unique single-molecule fluorescence method that uses fluorescence lifetime information to distinguish different fluorescence species in equilibrium and resolves their interconversion dynamics with a submicrosecond time resolution. Because 2D FLCS has used only a single-color excitation so far, it was difficult to distinguish a very low-FRET (or zero-FRET) species from only donor-labeled species. We overcome this difficulty by implementing the PIE scheme (i.e., alternate excitation of the donor and acceptor dyes using two temporally interleaved excitations with different colors) to 2D FLCS, realizing two-color excitation and two-color fluorescence detection in 2D FLCS. After proof-of-principle PIE 2D FLCS analysis on the photon data synthesized with Monte Carlo simulation, we apply PIE 2D FLCS to a DNA-hairpin sample and show that this method readily distinguishes four fluorescent species, i.e., high-FRET, low-FRET, and two single-dye-labeled species. In addition, we show that PIE 2D FLCS can also quantitatively evaluate the contributions of the donor-acceptor spectral crosstalk, which often appears as artifacts in FRET studies and degrades the information obtained.
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Affiliation(s)
- Bidyut Sarkar
- Molecular
Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan
| | - Kunihiko Ishii
- Molecular
Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan
- Ultrafast
Spectroscopy Research Team, RIKEN Center
for Advanced Photonics (RAP), 2-1 Hirosawa, Wako 351-0198, Japan
| | - Tahei Tahara
- Molecular
Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan
- Ultrafast
Spectroscopy Research Team, RIKEN Center
for Advanced Photonics (RAP), 2-1 Hirosawa, Wako 351-0198, Japan
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2
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Shimizu K, Sakaguchi M, Yamaguchi S, Otosu T. Peripheral adsorption of polylysine on one leaflet of a lipid bilayer reduces the lipid diffusion of both leaflets. Phys Chem Chem Phys 2024; 26:8873-8878. [PMID: 38426343 DOI: 10.1039/d3cp04882a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Understanding polycation-lipid interaction is essential not only in molecular biology but also in the biomedical industry and pharmacology. However, the effect of the polycation-lipid interaction on the molecular properties of lipids in biomembranes remains elusive. Here, two fluorescence correlation spectroscopies (FCSs), pulse-interleaved excitation (PIE) FCS and lifetime-based FCS, were performed to elucidate the change in the lipid diffusion of a model biomembrane induced by polylysine (PLL) adsorption. The results of PIE-FCS showed that the diffusions of both anionic and zwitterionic lipids become slower in the presence of PLL but the mobility of the anionic lipids is much reduced, suggesting the preferential interaction between the PLL and the anionic lipids due to the electrostatic attraction. Furthermore, leaflet-specific lipid diffusion analysis by lifetime-based FCS clearly showed that PLL adsorption on one leaflet of the membrane reduces the lipid diffusion of both leaflets in the same manner. This clearly indicates that the interleaflet coupling is strong in the presence of PLL.
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Affiliation(s)
- Kosei Shimizu
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan.
| | - Miyuki Sakaguchi
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan.
| | - Shoichi Yamaguchi
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan.
| | - Takuhiro Otosu
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan.
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3
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Lecat-Guillet N, Quast RB, Liu H, Bourrier E, Møller TC, Rovira X, Soldevila S, Lamarque L, Trinquet E, Liu J, Pin JP, Rondard P, Margeat E. Concerted conformational changes control metabotropic glutamate receptor activity. SCIENCE ADVANCES 2023; 9:eadf1378. [PMID: 37267369 PMCID: PMC10413646 DOI: 10.1126/sciadv.adf1378] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 04/27/2023] [Indexed: 06/04/2023]
Abstract
Allosteric modulators bear great potential to fine-tune neurotransmitter action. Promising targets are metabotropic glutamate (mGlu) receptors, which are associated with numerous brain diseases. Orthosteric and allosteric ligands act in synergy to control the activity of these multidomain dimeric GPCRs. Here, we analyzed the effect of such molecules on the concerted conformational changes of full-length mGlu2 at the single-molecule level. We first established FRET sensors through genetic code expansion combined with click chemistry to monitor conformational changes on live cells. We then used single-molecule FRET and show that orthosteric agonist binding leads to the stabilization of most of the glutamate binding domains in their closed state, while the reorientation of the dimer into the active state remains partial. Allosteric modulators, interacting with the transmembrane domain, are required to stabilize the fully reoriented active dimer. These results illustrate how concerted conformational changes within multidomain proteins control their activity, and how these are modulated by allosteric ligands.
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Affiliation(s)
- Nathalie Lecat-Guillet
- Institut de Génomique Fonctionnelle, Univ. Montpellier, CNRS, INSERM, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
| | - Robert B. Quast
- Centre de Biologie Structurale (CBS), Univ. Montpellier, CNRS, INSERM, Montpellier, France
| | - Hongkang Liu
- Institut de Génomique Fonctionnelle, Univ. Montpellier, CNRS, INSERM, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
- Key Laboratory of Molecular Biophysics of MOE, International Research Center for Sensory Biology and Technology of MOST, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | | | - Thor C. Møller
- Institut de Génomique Fonctionnelle, Univ. Montpellier, CNRS, INSERM, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
| | - Xavier Rovira
- Institut de Génomique Fonctionnelle, Univ. Montpellier, CNRS, INSERM, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
| | | | | | - Eric Trinquet
- PerkinElmer Cisbio, Parc Marcel Boiteux, 30200 Codolet, France
| | - Jianfeng Liu
- Key Laboratory of Molecular Biophysics of MOE, International Research Center for Sensory Biology and Technology of MOST, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan, 430074, China
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, Univ. Montpellier, CNRS, INSERM, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, Univ. Montpellier, CNRS, INSERM, 141 rue de la Cardonille, 34094, Montpellier Cedex 05, France
| | - Emmanuel Margeat
- Centre de Biologie Structurale (CBS), Univ. Montpellier, CNRS, INSERM, Montpellier, France
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4
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Quast RB, Fatemi F, Kranendonk M, Margeat E, Truan G. Accurate Determination of Human CPR Conformational Equilibrium by smFRET Using Dual Orthogonal Noncanonical Amino Acid Labeling. Chembiochem 2019; 20:659-666. [DOI: 10.1002/cbic.201800607] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Indexed: 12/26/2022]
Affiliation(s)
- Robert B. Quast
- LISBP; Université de Toulouse; CNRS; INRA; INSA; 135 Avenue de Rangueil 31077 Toulouse France
| | - Fataneh Fatemi
- Protein Research Center; Shahid Beheshti University, G.C.; Evin 1983969411 Tehran Iran
| | - Michel Kranendonk
- Center for Toxicogenomics and Human Health (ToxOmics); Genetics, Oncology and Human Toxicology; NOVA Medical School; Faculdade de Ciências Médicas; Universidade Nova de Lisboa; Rua Câmara Pestana, no. 6 1150-082 Lisboa Portugal
| | - Emmanuel Margeat
- BS; CNRS; CINSERM; Université de Montpellier; Montpellier France
| | - Gilles Truan
- LISBP; Université de Toulouse; CNRS; INRA; INSA; 135 Avenue de Rangueil 31077 Toulouse France
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5
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Tora AS, Rovira X, Cao AM, Cabayé A, Olofsson L, Malhaire F, Scholler P, Baik H, Van Eeckhaut A, Smolders I, Rondard P, Margeat E, Acher F, Pin JP, Goudet C. Chloride ions stabilize the glutamate-induced active state of the metabotropic glutamate receptor 3. Neuropharmacology 2018; 140:275-286. [PMID: 30102917 DOI: 10.1016/j.neuropharm.2018.08.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/25/2018] [Accepted: 08/09/2018] [Indexed: 02/06/2023]
Abstract
Due to the essential roles of glutamate, detection and response to a large range of extracellular concentrations of this excitatory amino acid are necessary for the fine-tuning of brain functions. Metabotropic glutamate receptors (mGluRs) are implicated in shaping the activity of many synapses in the central nervous system. Among the eight mGluR subtypes, there is increasing interest in studying the mGlu3 receptor which has recently been linked to various diseases, including psychiatric disorders. This receptor displays striking functional properties, with a high and, often, full basal activity, making its study elusive in heterologous systems. Here, we demonstrate that Cl- ions exert strong positive allosteric modulation of glutamate on the mGlu3 receptor. We have also identified the molecular and structural determinants lying behind this allostery: a unique interactive "chloride-lock" network. Indeed, Cl- ions dramatically stabilize the glutamate-induced active state of the extracellular domain of the mGlu3 receptor. Thus, the mGlu3 receptors' large basal activity does not correspond to a constitutive activity in absence of agonist. Instead, it results mostly from a Cl-mediated amplified response to low ambient glutamate concentrations, such as those measured in cell media. This strong interaction between glutamate and Cl- ions allows the mGlu3 receptor to sense and efficiently react to sub-micromolar concentrations of glutamate, making it the most sensitive member of mGluR family.
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Affiliation(s)
- Amélie S Tora
- IGF, CNRS, INSERM, Univ. de Montpellier, Montpellier, F-34094, Montpellier, France
| | - Xavier Rovira
- IGF, CNRS, INSERM, Univ. de Montpellier, Montpellier, F-34094, Montpellier, France; Present Address: Molecular Photopharmacology Research Group, The Tissue Repair and Regeneration Laboratory, University of Vic - Central University of Catalonia, C. de La Laura,13, 08500, Vic, Spain
| | - Anne-Marinette Cao
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, Université de Montpellier, F-34094, Montpellier, France
| | - Alexandre Cabayé
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, CNRS UMR8601, Université Paris Descartes, Sorbonne Paris Cité, F-75270, Paris Cedex 6, France
| | - Linnéa Olofsson
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, Université de Montpellier, F-34094, Montpellier, France
| | - Fanny Malhaire
- IGF, CNRS, INSERM, Univ. de Montpellier, Montpellier, F-34094, Montpellier, France
| | - Pauline Scholler
- IGF, CNRS, INSERM, Univ. de Montpellier, Montpellier, F-34094, Montpellier, France
| | - Hayeon Baik
- IGF, CNRS, INSERM, Univ. de Montpellier, Montpellier, F-34094, Montpellier, France
| | - Ann Van Eeckhaut
- Research Group Experimental Pharmacology (EFAR/FASC), Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), 1090, Brussel, Belgium
| | - Ilse Smolders
- Research Group Experimental Pharmacology (EFAR/FASC), Center for Neurosciences (C4N), Vrije Universiteit Brussel (VUB), 1090, Brussel, Belgium
| | - Philippe Rondard
- IGF, CNRS, INSERM, Univ. de Montpellier, Montpellier, F-34094, Montpellier, France
| | - Emmanuel Margeat
- Centre de Biochimie Structurale (CBS), INSERM, CNRS, Université de Montpellier, F-34094, Montpellier, France
| | - Francine Acher
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, CNRS UMR8601, Université Paris Descartes, Sorbonne Paris Cité, F-75270, Paris Cedex 6, France.
| | - Jean-Philippe Pin
- IGF, CNRS, INSERM, Univ. de Montpellier, Montpellier, F-34094, Montpellier, France.
| | - Cyril Goudet
- IGF, CNRS, INSERM, Univ. de Montpellier, Montpellier, F-34094, Montpellier, France.
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6
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Otosu T, Yamaguchi S. Total Internal Reflection Two-Dimensional Fluorescence Lifetime Correlation Spectroscopy. J Phys Chem B 2018; 122:5758-5764. [DOI: 10.1021/acs.jpcb.8b01176] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Takuhiro Otosu
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan
| | - Shoichi Yamaguchi
- Department of Applied Chemistry, Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura, Saitama 338-8570, Japan
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7
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Ait-Bara S, Clerté C, Declerck N, Margeat E. Competitive folding of RNA structures at a termination-antitermination site. RNA (NEW YORK, N.Y.) 2017; 23:721-734. [PMID: 28235843 PMCID: PMC5393181 DOI: 10.1261/rna.060178.116] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 02/08/2017] [Indexed: 06/06/2023]
Abstract
Antitermination is a regulatory process based on the competitive folding of terminator-antiterminator structures that can form in the leader region of nascent transcripts. In the case of the Bacillus subtilis licS gene involved in β-glucosides utilization, the binding of the antitermination protein LicT to a short RNA hairpin (RAT) prevents the formation of an overlapping terminator and thereby allows transcription to proceed. Here, we monitored in vitro the competition between termination and antitermination by combining bulk and single-molecule fluorescence-based assays using labeled RNA oligonucleotide constructs of increasing length that mimic the progressive transcription of the terminator invading the antiterminator hairpin. Although high affinity binding is abolished as soon as the antiterminator basal stem is disrupted by the invading terminator, LicT can still bind and promote closing of the partially unfolded RAT hairpin. However, binding no longer occurs once the antiterminator structure has been disrupted by the full-length terminator. Based on these findings, we propose a kinetic competition model for the sequential events taking place at the termination-antitermination site, where LicT needs to capture its RAT target before completion of the terminator to remain tightly bound during RNAP pausing, before finally dissociating irreversibly from the elongated licS transcript.
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Affiliation(s)
- Soraya Ait-Bara
- CNRS UMR5048, Centre de Biochimie Structurale, 34090 Montpellier, France
- INSERM U1054, 34090 Montpellier, France
- Université de Montpellier, 34090 Montpellier, France
| | - Caroline Clerté
- CNRS UMR5048, Centre de Biochimie Structurale, 34090 Montpellier, France
- INSERM U1054, 34090 Montpellier, France
- Université de Montpellier, 34090 Montpellier, France
| | - Nathalie Declerck
- CNRS UMR5048, Centre de Biochimie Structurale, 34090 Montpellier, France
- INSERM U1054, 34090 Montpellier, France
- Université de Montpellier, 34090 Montpellier, France
- INRA, departement MICA, 78352 Jouy-en-Josas, France
| | - Emmanuel Margeat
- CNRS UMR5048, Centre de Biochimie Structurale, 34090 Montpellier, France
- INSERM U1054, 34090 Montpellier, France
- Université de Montpellier, 34090 Montpellier, France
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8
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Konate K, Lindberg MF, Vaissiere A, Jourdan C, Aldrian G, Margeat E, Deshayes S, Boisguerin P. Optimisation of vectorisation property: A comparative study for a secondary amphipathic peptide. Int J Pharm 2016; 509:71-84. [PMID: 27224007 DOI: 10.1016/j.ijpharm.2016.05.030] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/12/2016] [Accepted: 05/13/2016] [Indexed: 02/08/2023]
Abstract
RNA interference provides a powerful technology for specific gene silencing. Therapeutic applications of small interfering RNA (siRNA) however require efficient vehicles for stable complexation and intracellular delivery. In order to enhance their cell delivery, short amphipathic peptides called cell-penetrating peptides (CPPs) have been intensively developed for the last two decades. In this context, the secondary amphipathic peptide CADY has shown to form stable siRNA complexes and to improve their cellular uptake independent of the endosomal pathway. In the present work, we have described the parameters influencing CADY nanoparticle formation (buffers, excipients, presence of serum, etc.), and have followed in details the CPP:siRNA self-assembly. Once optimal conditions were determined, we have compared the ability of seven different CADY analogues to form siRNA-loaded nanoparticles compared to CADY:siRNA. First of all, we were able to show by biophysical methods that structural polymorphism (α-helix) is an important prerequisite for stable nanoparticle formation independently of occurring sequence mutations. Luciferase assays revealed that siRNA complexed to CADY-K (shorter version) shows better knock-down efficiency on Neuro2a-Luc(+) and B16-F10-Luc(+) cells compared to CADY:siRNA. Altogether, CADY-K is an ideal candidate for further application especially with regards to ex vivo or in vivo applications.
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Affiliation(s)
- Karidia Konate
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier CEDEX 5, France
| | - Mattias F Lindberg
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier CEDEX 5, France
| | - Anaïs Vaissiere
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier CEDEX 5, France
| | - Carole Jourdan
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier CEDEX 5, France
| | - Gudrun Aldrian
- Sys2Diag, FRE3690-CNRS/ALCEDIAG, 1682 Rue de la Valsiere, 34184 Montpellier CEDEX 4, France
| | - Emmanuel Margeat
- CNRS UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090 Montpellier, France; INSERM U1054, 34090 Montpellier, France; Université de Montpellier, 34090 Montpellier, France
| | - Sébastien Deshayes
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier CEDEX 5, France.
| | - Prisca Boisguerin
- Centre de Recherche de Biologie cellulaire de Montpellier (CRBM), CNRS UMR 5237, 1919 Route de Mende, 34293 Montpellier CEDEX 5, France.
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9
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Smith AW. Detection of rhodopsin dimerization in situ by PIE-FCCS, a time-resolved fluorescence spectroscopy. Methods Mol Biol 2015; 1271:205-19. [PMID: 25697526 DOI: 10.1007/978-1-4939-2330-4_14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Rhodopsin self-associates in the plasma membrane. At low concentrations, the interactions are consistent with a monomer-dimer equilibrium (Comar et al., J Am Chem Soc 136(23):8342-8349, 2014). At high concentrations in native tissue, higher-order clusters have been observed (Fotiadis et al., Nature 421:127-128, 2003). The physiological role of rhodopsin dimerization is still being investigated, but it is clear that a quantitative assessment is essential to determining the function of rhodopsin clusters in vision. To quantify rhodopsin interactions, I will outline the theory and methodology of a specialized time-resolved fluorescence spectroscopy for measuring membrane protein-protein interactions called pulsed-interleaved excitation fluorescence cross-correlation spectroscopy (PIE-FCCS). The strength of this technique is its ability to quantify rhodopsin interactions in situ (i.e., a live cell plasma membrane). There are two reasons for restricting the scope to live cell membranes. First, the compositional heterogeneity of the plasma membrane creates a complex milieu with thousands of lipid, protein, and carbohydrate species. This makes it difficult to infer quaternary interactions from detergent solubilized samples or construct a model phospholipid bilayer that recapitulates all of the interactions present in native membranes. Second, organizational structure and dynamics is a key feature of the plasma membrane, and fixation techniques like formaldehyde cross-linking and vitrification will modulate the interactions. PIE-FCCS is based on two-color fluorescence imaging with time-correlated single-photon counting (TCSPC) (Becker et al., Rev Sci Instrum 70:1835-1841, 1999). By time-tagging every detected photon, the data can be analyzed as a fluorescence intensity distribution, fluorescence lifetime histogram, or fluorescence (cross-)correlation spectra (FCS/FCCS) (Becker, Advanced time-correlated single-photon counting techniques, Springer, Berlin, 2005). These analysis tools can then be used to quantify protein concentration, mobility, clustering, and Förster resonance energy transfer (FRET). In this paper I will focus on PIE-FCCS, which interleaves two wavelength excitation events in time so that the effects of spectral cross-talk and FRET can be isolated. In this way it is possible to characterize monomer-dimer-oligomer equilibria with high accuracy (Müller et al., Biophys J 89:3508-3522, 2005). Currently, PIE-FCCS requires a customized equipment configuration that will be described below. There is an excellent protocol that outlines traditional FCCS on a commercially available instrument (Bacia and Schwille, Nat Protoc 2:2842-2856, 2007). The PIE-FCCS approach is a relatively recent advance in FCCS that has been used in live cell assays to quantify lipid-anchored protein clustering (Triffo et al., J Am Chem Soc 134:10833-10842, 2012), epidermal growth factor receptor dimerization (Endres et al., Cell 152:543-556, 2013), and recently the dimerization of opsin (Comar et al., J Am Chem Soc 136(23):8342-8349, 2014). This paper will outline the theory and instrumentation requirements for PIE-FCCS, as well as the data collection and analysis process.
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Affiliation(s)
- Adam W Smith
- Department of Chemistry, University of Akron, 190 Buchtel Common, Akron, OH, 44325-3601, USA,
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10
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Wei S, Falk SJ, Black BE, Lee TH. A novel hybrid single molecule approach reveals spontaneous DNA motion in the nucleosome. Nucleic Acids Res 2015; 43:e111. [PMID: 26013809 PMCID: PMC4787812 DOI: 10.1093/nar/gkv549] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 04/22/2015] [Accepted: 05/14/2015] [Indexed: 11/23/2022] Open
Abstract
Structural dynamics of nucleic acid and protein is an important physical basis of their functions. These motions are often very difficult to synchronize and too fast to be clearly resolved with the currently available single molecule methods. Here we demonstrate a novel hybrid single molecule approach combining stochastic data analysis with fluorescence correlation that enables investigations of sub-ms unsynchronized structural dynamics of macromolecules. Based on the method, we report the first direct evidence of spontaneous DNA motions at the nucleosome termini. The nucleosome, comprising DNA and a histone core, is the fundamental packing unit of eukaryotic genes that must be accessed during various genome transactions. Spontaneous DNA opening at the nucleosome termini has long been hypothesized to enable gene access in the nucleosome, but has yet to be directly observed. Our approach reveals that DNA termini in the nucleosome open and close repeatedly at 0.1-1 ms(-1). The kinetics depends on salt concentration and DNA-histone interactions but not much on DNA sequence, suggesting that this dynamics is universal and imposes the kinetic limit to gene access. These results clearly demonstrate that our method provides an efficient and robust means to investigate unsynchronized structural changes of DNA at a sub-ms time resolution.
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Affiliation(s)
- Sijie Wei
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Samantha J Falk
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ben E Black
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tae-Hee Lee
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
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11
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Le Gall A, Valeri A, Nollmann M. Roles of chromatin insulators in the formation of long-range contacts. Nucleus 2015; 6:118-22. [PMID: 25781057 DOI: 10.1080/19491034.2015.1010962] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Chromatin insulators are factors involved in higher-order, genome-wide organization of chromatin, and play key roles in regulating transcriptional programs. In this review, we discuss recent studies on the diverse composition of insulator complexes, and on the mechanism by which they establish long-range DNA interactions. Particularly, we describe new biophysical methods that allow for the study of the composition of large molecular complexes, and for defining the factors potentially required to establish long-range DNA contacts.
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Affiliation(s)
- Antoine Le Gall
- a Centre de Biochimie Structurale ; CNRS UMR5048; INSERM U1054; Université de Montpellier ; Montpellier , France
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12
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Ait-Bara S, Clerté C, Margeat E. Single-molecule FRET characterization of RNA remodeling induced by an antitermination protein. Methods Mol Biol 2015; 1259:349-68. [PMID: 25579596 DOI: 10.1007/978-1-4939-2214-7_21] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Single-molecule Förster Resonance Energy Transfer (smFRET) is a useful technique to probe conformational changes within bio-macromolecules. Here, we introduce how to perform smFRET measurements in solution to investigate RNA remodeling and RNA-protein interactions. In particular, we focus on how the close-to-open transition of an antiterminator hairpin is influenced by the binding of the antitermination protein and the competition by oligonucleotides.
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Affiliation(s)
- Soraya Ait-Bara
- CNRS UMR5048, Centre de Biochimie Structurale, 29 rue de Navacelles, 34090, Montpellier, France
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13
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Fine tuning of sub-millisecond conformational dynamics controls metabotropic glutamate receptors agonist efficacy. Nat Commun 2014; 5:5206. [DOI: 10.1038/ncomms6206] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 09/09/2014] [Indexed: 11/08/2022] Open
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14
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Hohlbein J, Craggs TD, Cordes T. Alternating-laser excitation: single-molecule FRET and beyond. Chem Soc Rev 2014; 43:1156-71. [PMID: 24037326 DOI: 10.1039/c3cs60233h] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The alternating-laser excitation (ALEX) scheme continues to expand the possibilities of fluorescence-based assays to study biological entities and interactions. Especially the combination of ALEX and single-molecule Förster Resonance Energy Transfer (smFRET) has been very successful as ALEX enables the sorting of fluorescently labelled species based on the number and type of fluorophores present. ALEX also provides a convenient way of accessing the correction factors necessary for determining accurate molecular distances. Here, we provide a comprehensive overview of the concept and current applications of ALEX and we explicitly discuss how to obtain fully corrected distance information across the entire FRET range. We also present new ideas for applications of ALEX which will push the limits of smFRET-based experiments in terms of temporal and spatial resolution for the study of complex biological systems.
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Affiliation(s)
- Johannes Hohlbein
- Laboratory of Biophysics, Wageningen UR, Wageningen, The Netherlands.
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15
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Vogelmann J, Le Gall A, Dejardin S, Allemand F, Gamot A, Labesse G, Cuvier O, Nègre N, Cohen-Gonsaud M, Margeat E, Nöllmann M. Chromatin insulator factors involved in long-range DNA interactions and their role in the folding of the Drosophila genome. PLoS Genet 2014; 10:e1004544. [PMID: 25165871 PMCID: PMC4148193 DOI: 10.1371/journal.pgen.1004544] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 06/17/2014] [Indexed: 11/18/2022] Open
Abstract
Chromatin insulators are genetic elements implicated in the organization of chromatin and the regulation of transcription. In Drosophila, different insulator types were characterized by their locus-specific composition of insulator proteins and co-factors. Insulators mediate specific long-range DNA contacts required for the three dimensional organization of the interphase nucleus and for transcription regulation, but the mechanisms underlying the formation of these contacts is currently unknown. Here, we investigate the molecular associations between different components of insulator complexes (BEAF32, CP190 and Chromator) by biochemical and biophysical means, and develop a novel single-molecule assay to determine what factors are necessary and essential for the formation of long-range DNA interactions. We show that BEAF32 is able to bind DNA specifically and with high affinity, but not to bridge long-range interactions (LRI). In contrast, we show that CP190 and Chromator are able to mediate LRI between specifically-bound BEAF32 nucleoprotein complexes in vitro. This ability of CP190 and Chromator to establish LRI requires specific contacts between BEAF32 and their C-terminal domains, and dimerization through their N-terminal domains. In particular, the BTB/POZ domains of CP190 form a strict homodimer, and its C-terminal domain interacts with several insulator binding proteins. We propose a general model for insulator function in which BEAF32/dCTCF/Su(HW) provide DNA specificity (first layer proteins) whereas CP190/Chromator are responsible for the physical interactions required for long-range contacts (second layer). This network of organized, multi-layer interactions could explain the different activities of insulators as chromatin barriers, enhancer blockers, and transcriptional regulators, and suggest a general mechanism for how insulators may shape the organization of higher-order chromatin during cell division.
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Affiliation(s)
- Jutta Vogelmann
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5048, Centre de Biochimie Structurale, Montpellier, France
- Institut National de la Santé et la Recherche Médicale, Unité 1054, Montpellier, France
- Universités Montpellier I et II, Montpellier, France
| | - Antoine Le Gall
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5048, Centre de Biochimie Structurale, Montpellier, France
- Institut National de la Santé et la Recherche Médicale, Unité 1054, Montpellier, France
- Universités Montpellier I et II, Montpellier, France
| | - Stephanie Dejardin
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5048, Centre de Biochimie Structurale, Montpellier, France
- Institut National de la Santé et la Recherche Médicale, Unité 1054, Montpellier, France
- Universités Montpellier I et II, Montpellier, France
| | - Frederic Allemand
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5048, Centre de Biochimie Structurale, Montpellier, France
- Institut National de la Santé et la Recherche Médicale, Unité 1054, Montpellier, France
- Universités Montpellier I et II, Montpellier, France
| | - Adrien Gamot
- Laboratoire de Biologie Moléculaire Eucaryote, CNRS and Université de Toulouse, Toulouse; France
| | - Gilles Labesse
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5048, Centre de Biochimie Structurale, Montpellier, France
- Institut National de la Santé et la Recherche Médicale, Unité 1054, Montpellier, France
- Universités Montpellier I et II, Montpellier, France
| | - Olivier Cuvier
- Laboratoire de Biologie Moléculaire Eucaryote, CNRS and Université de Toulouse, Toulouse; France
| | - Nicolas Nègre
- Laboratoire Diversité, Génomes & Interactions Microorganismes-Insectes, INRA UMR1333, Université de Montpellier 2, Montpellier, France
| | - Martin Cohen-Gonsaud
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5048, Centre de Biochimie Structurale, Montpellier, France
- Institut National de la Santé et la Recherche Médicale, Unité 1054, Montpellier, France
- Universités Montpellier I et II, Montpellier, France
| | - Emmanuel Margeat
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5048, Centre de Biochimie Structurale, Montpellier, France
- Institut National de la Santé et la Recherche Médicale, Unité 1054, Montpellier, France
- Universités Montpellier I et II, Montpellier, France
| | - Marcelo Nöllmann
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5048, Centre de Biochimie Structurale, Montpellier, France
- Institut National de la Santé et la Recherche Médicale, Unité 1054, Montpellier, France
- Universités Montpellier I et II, Montpellier, France
- * E-mail:
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RUEDAS-RAMA MJ, ALVAREZ-PEZ JM, ORTE A. SOLVING SINGLE BIOMOLECULES BY ADVANCED FRET-BASED SINGLE-MOLECULE FLUORESCENCE TECHNIQUES. ACTA ACUST UNITED AC 2014. [DOI: 10.1142/s1793048013300041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The use of Förster resonance energy transfer (FRET) has undergone a renaissance in the last two decades, especially in the study of structure of biomolecules, biomolecular interactions, and dynamics. Thanks to powerful advances in single-molecule fluorescence (SMF) techniques, seeing molecules at work is a reality, which has helped to build up the mindset of molecular machines. In the last few years, many technical developments have broadened the applications of SMF-FRET, expanding the amount of information that can be recovered from individual molecules. Here, we focus on the non-standard SMF-FRET techniques, such as two-color coincidence detection (TCCD), alternating laser excitation (ALEX), multiparameter fluorescence detection (MFD); the addition of fluorescence lifetime as an orthogonal dimension in single-molecule experiments; or the development of novel and improved methods of analysis constituting to a set of advanced methodologies that may become routine tools in a close future. [Formula: see text]Special Issue Comment: This review about advanced single-molecule FRET techniques is specially related to the review by Jørgensen and Hatzakis,6 who detail experimetal strategies to solve the activity of single enzymes. The advanced techniques described in our paper may serve as interesting alternatives when applied to enzyme studies. Our manuscript is also related to the reviews in this Special Issue that deal with model solving.22,130
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Affiliation(s)
- M. J. RUEDAS-RAMA
- Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Cartuja Campus, Granada, 18071, Spain
| | - J. M. ALVAREZ-PEZ
- Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Cartuja Campus, Granada, 18071, Spain
| | - A. ORTE
- Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Cartuja Campus, Granada, 18071, Spain
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MFD-PIE and PIE-FI: Ways to Extract More Information with TCSPC. SPRINGER SERIES ON FLUORESCENCE 2014. [DOI: 10.1007/4243_2014_66] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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