1
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Doszyn O, Dulski T, Zmorzynska J. Diving into the zebrafish brain: exploring neuroscience frontiers with genetic tools, imaging techniques, and behavioral insights. Front Mol Neurosci 2024; 17:1358844. [PMID: 38533456 PMCID: PMC10963419 DOI: 10.3389/fnmol.2024.1358844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 02/27/2024] [Indexed: 03/28/2024] Open
Abstract
The zebrafish (Danio rerio) is increasingly used in neuroscience research. Zebrafish are relatively easy to maintain, and their high fecundity makes them suitable for high-throughput experiments. Their small, transparent embryos and larvae allow for easy microscopic imaging of the developing brain. Zebrafish also share a high degree of genetic similarity with humans, and are amenable to genetic manipulation techniques, such as gene knockdown, knockout, or knock-in, which allows researchers to study the role of specific genes relevant to human brain development, function, and disease. Zebrafish can also serve as a model for behavioral studies, including locomotion, learning, and social interactions. In this review, we present state-of-the-art methods to study the brain function in zebrafish, including genetic tools for labeling single neurons and neuronal circuits, live imaging of neural activity, synaptic dynamics and protein interactions in the zebrafish brain, optogenetic manipulation, and the use of virtual reality technology for behavioral testing. We highlight the potential of zebrafish for neuroscience research, especially regarding brain development, neuronal circuits, and genetic-based disorders and discuss its certain limitations as a model.
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Affiliation(s)
| | | | - J. Zmorzynska
- Laboratory of Molecular and Cellular Neurobiology, International Institute of Molecular and Cell Biology in Warsaw (IIMCB), Warsaw, Poland
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2
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Torii K, Benson S, Hori Y, Vendrell M, Kikuchi K. No-wash fluorogenic labeling of proteins for reversible photoswitching in live cells. Chem Sci 2024; 15:1393-1401. [PMID: 38274070 PMCID: PMC10806661 DOI: 10.1039/d3sc04953a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 12/16/2023] [Indexed: 01/27/2024] Open
Abstract
Photoswitchable fluorescent molecules (PSFMs) are positioned as valuable tools for biomolecule localization tracking and super-resolution imaging technologies due to their unique ability to reversibly control fluorescence intensity upon light irradiation. Despite the high demand for PSFMs that are suitable for live-cell imaging, no general method has been reported that enables reversible fluorescence control on proteins of interest in living cells. Herein, we have established a platform to realize reversible fluorescence switching in living cells by adapting a protein labeling system. We have developed a new PSFM, named HTL-Trp-BODIPY-FF, which exhibits strong fluorogenicity upon recognition of Halo-tag protein and reversible fluorescence photoswitching in living cells. This is the first example of a PSFM that can be applicable to a general-purpose Halo-tag protein labeling system for no-wash live-cell imaging.
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Affiliation(s)
- Kenji Torii
- Graduate School of Engineering, Osaka University Suita Osaka 565-0871 Japan
| | - Sam Benson
- Centre for Inflammation Research, The University of Edinburgh Edinburgh EH16 4UU UK
- IRR Chemistry Hub, Institute for Regeneration and Repair, The University of Edinburgh Edinburgh EH16 4UU UK
| | - Yuichiro Hori
- Faculty of Science, Kyushu University Fukuoka Fukuoka 819-0395 Japan
| | - Marc Vendrell
- Centre for Inflammation Research, The University of Edinburgh Edinburgh EH16 4UU UK
- IRR Chemistry Hub, Institute for Regeneration and Repair, The University of Edinburgh Edinburgh EH16 4UU UK
| | - Kazuya Kikuchi
- Graduate School of Engineering, Osaka University Suita Osaka 565-0871 Japan
- Immunology Frontier Research Center, Osaka University Suita Osaka 565-0871 Japan
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3
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Jimbo M, Otake M, Amano H, Yasumoto K, Watabe S, Okada D, Kumagai H. Characterization of recombinant photoconverting green fluorescent Akanes. J Biochem 2023; 175:25-34. [PMID: 37812399 DOI: 10.1093/jb/mvad078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 09/13/2023] [Accepted: 09/19/2023] [Indexed: 10/10/2023] Open
Abstract
Akanes are fluorescent proteins that have several fluorescence maxima. In this report, Akane1 and Akane3 from Scleronephthya gracillima were selected, successfully overexpressed in Escherichia coli and purified by affinity chromatography. Fluorescence spectra of the recombinant Akanes matured in darkness, or ambient light were found to have several fluorescence peaks. SDS-PAGE analysis revealed that Akanes matured in ambient light have two fragments. MS/MS analysis of Akanes digested with trypsin showed that the cleavage site is the same as observed for the photoconvertible fluorescent protein Kaede. The differences between the calculated masses from the amino acid sequence of Akane1 and the measured masses of Akane1 fragments obtained under ambient light coincided with those of Kaede. In contrast, a mass difference between the measured N-terminal Akane3 fragment and the calculated mass indicated that Akane3 is modified in the N-terminal region. These results indicate that numerous peaks in the fluorescent spectra of Akanes partly arise from isoproteins of Akanes and photoconversion. Photoconversion of Akane1 caused a fluorescence change from green to red, which was also observed for Akane3; however, the fluorescent intensity decreased dramatically when compared with that of Akane3.
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Affiliation(s)
- Mitsuru Jimbo
- School of Marine Biosciences, Kitasato University. 1-15-1, Kitasato, Sagamihara, Kanagawa 252-0373, Japan
| | - Mayumi Otake
- School of Marine Biosciences, Kitasato University. 1-15-1, Kitasato, Sagamihara, Kanagawa 252-0373, Japan
| | - Haruna Amano
- School of Marine Biosciences, Kitasato University. 1-15-1, Kitasato, Sagamihara, Kanagawa 252-0373, Japan
| | - Ko Yasumoto
- School of Marine Biosciences, Kitasato University. 1-15-1, Kitasato, Sagamihara, Kanagawa 252-0373, Japan
| | - Shugo Watabe
- School of Marine Biosciences, Kitasato University. 1-15-1, Kitasato, Sagamihara, Kanagawa 252-0373, Japan
| | - Daisuke Okada
- School of Medicine, Kitasato University. 1-15-1, Kitasato, Sagamihara, Kanagawa 252-0373, Japan
| | - Hiroshi Kumagai
- School of Allied Health Sciences, Kitasato University. 1-15-1, Kitasato, Sagamihara, Kanagawa 252-0373, Japan
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4
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Krueger TD, Henderson JN, Breen IL, Zhu L, Wachter RM, Mills JH, Fang C. Capturing excited-state structural snapshots of evolutionary green-to-red photochromic fluorescent proteins. Front Chem 2023; 11:1328081. [PMID: 38144887 PMCID: PMC10748491 DOI: 10.3389/fchem.2023.1328081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 11/24/2023] [Indexed: 12/26/2023] Open
Abstract
Photochromic fluorescent proteins (FPs) have proved to be indispensable luminous probes for sophisticated and advanced bioimaging techniques. Among them, an interplay between photoswitching and photoconversion has only been observed in a limited subset of Kaede-like FPs that show potential for discovering the key mechanistic steps during green-to-red photoconversion. Various spectroscopic techniques including femtosecond stimulated Raman spectroscopy (FSRS), X-ray crystallography, and femtosecond transient absorption were employed on a set of five related FPs with varying photoconversion and photoswitching efficiencies. A 3-methyl-histidine chromophore derivative, incorporated through amber suppression using orthogonal aminoacyl tRNA synthetase/tRNA pairs, displays more dynamic photoswitching but greatly reduced photoconversion versus the least-evolved ancestor (LEA). Excitation-dependent measurements of the green anionic chromophore reveal that the varying photoswitching efficiencies arise from both the initial transient dynamics of the bright cis state and the final trans-like photoswitched off state, with an exocyclic bridge H-rocking motion playing an active role during the excited-state energy dissipation. This investigation establishes a close-knit feedback loop between spectroscopic characterization and protein engineering, which may be especially beneficial to develop more versatile FPs with targeted mutations and enhanced functionalities, such as photoconvertible FPs that also feature photoswitching properties.
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Affiliation(s)
- Taylor D. Krueger
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
| | - J. Nathan Henderson
- Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
| | - Isabella L. Breen
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
| | - Liangdong Zhu
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
| | - Rebekka M. Wachter
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
| | - Jeremy H. Mills
- Center for Molecular Design and Biomimetics, The Biodesign Institute, Arizona State University, Tempe, AZ, United States
- School of Molecular Sciences, Arizona State University, Tempe, AZ, United States
| | - Chong Fang
- Department of Chemistry, Oregon State University, Corvallis, OR, United States
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5
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McCulley CH, Walker AR. Dimer Interface Destabilization of Photodissociative Dronpa Driven by Asymmetric Monomer Dynamics. J Phys Chem B 2023; 127:9248-9257. [PMID: 37871275 DOI: 10.1021/acs.jpcb.3c03798] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Photoswitchable Dronpa (psDronpa) is a unique member of the fluorescent protein family that can undergo reversible photoinduced switching between fluorescent and dark states and has recently been engineered into a dimer (pdDronpaV) that can dissociate and reassociate as part of its photoswitchable pathway. However, the specific details of the protein structure-function relationship of the dimer interface along with how the dimer proteins interact with each other upon chromophore isomerization are not yet clear. Classical molecular dynamics simulations were performed on psDronpa as monomers and dimers as well as the pdDronpaV dimer and with cis/trans chromophore structures. Analysis of the cis and trans isomers of the chromophore illustrated key differences between their interactions with residues in the protein in both the monomer and dimer forms of psDronpa. Examination of the psDronpa dimer showed nonidentical chromophore interactions between the domains, indicating domain directional favoring. Examination of the trans form of pdDronpaV illuminated the importance of hydrogen bonding between the monomeric domains in maintaining their association, as well as illustrating the motion of dissociation of the domains. This discovery offers important information for possible future mutations of pdDronpaV that might be made to accelerate dissociation.
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Affiliation(s)
- Christina H McCulley
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Alice R Walker
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
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6
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Krueger TD, Chen C, Fang C. Targeting Ultrafast Spectroscopic Insights into Red Fluorescent Proteins. Chem Asian J 2023; 18:e202300668. [PMID: 37682793 DOI: 10.1002/asia.202300668] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/08/2023] [Accepted: 09/08/2023] [Indexed: 09/10/2023]
Abstract
Red fluorescent proteins (RFPs) represent an increasingly popular class of genetically encodable bioprobes and biomarkers that can advance next-generation breakthroughs across the imaging and life sciences. Since the rational design of RFPs with improved functions or enhanced versatility requires a mechanistic understanding of their working mechanisms, while fluorescence is intrinsically an ultrafast event, a suitable toolset involving steady-state and time-resolved spectroscopic techniques has become powerful in delineating key structural features and dynamic steps which govern irreversible photoconverting or reversible photoswitching RFPs, and large Stokes shift (LSS)RFPs. The pertinent cis-trans isomerization and protonation state change of RFP chromophores in their local environments, involving key residues in protein matrices, lead to rich and complicated spectral features across multiple timescales. In particular, ultrafast excited-state proton transfer in various LSSRFPs showcases the resolving power of wavelength-tunable femtosecond stimulated Raman spectroscopy (FSRS) in mapping a photocycle with crucial knowledge about the red-emitting species. Moreover, recent progress in noncanonical RFPs with a site-specifically modified chromophore provides an appealing route for efficient engineering of redder and brighter RFPs, highly desirable for bioimaging. Such an effective feedback loop involving physical chemists, protein engineers, and biomedical microscopists will enable future successes to expand fundamental knowledge and improve human health.
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Affiliation(s)
- Taylor D Krueger
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon, 97331-4003, USA
| | - Cheng Chen
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon, 97331-4003, USA
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon, 97331-4003, USA
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7
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Yang Y, Fan S, Webb JA, Ma Y, Goyette J, Chen X, Gaus K, Tilley RD, Gooding JJ. Electrochemical fluorescence switching of enhanced green fluorescent protein. Biosens Bioelectron 2023; 237:115467. [PMID: 37437456 DOI: 10.1016/j.bios.2023.115467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 07/14/2023]
Abstract
Switchable fluorescent proteins, for which fluorescence can be switched ON and OFF, are widely used for molecule tracking and super resolution imaging. However, the robust use of the switchable fluorescent proteins is still limited as either the switching is not repeatable, or such switching requires irradiation with coupled lasers of different wavelengths. Herein, we report an electrochemical approach to reversible fluorescence switching for enhanced green fluorescent proteins (EGFP) on indium tin oxide coated glass. Our results demonstrate that negative and positive electrochemical potentials can efficiently switch the fluorescent proteins between the dim (OFF) and bright (ON) states at the single molecule level. The electrochemical fluorescence switching is fast, reversible, and may be performed up to hundreds of cycles before photobleaching occurs. These findings highlight that this method of electrochemical fluorescence switching can be incorporated into advanced fluorescence microscopy.
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Affiliation(s)
- Ying Yang
- School of Chemistry and Australian Centre for NanoMedicine, University of New South Wales, Sydney, 2052, Australia
| | - Sanjun Fan
- School of Chemistry and Australian Centre for NanoMedicine, University of New South Wales, Sydney, 2052, Australia
| | - James A Webb
- School of Chemistry and Australian Centre for NanoMedicine, University of New South Wales, Sydney, 2052, Australia
| | - Yuanqing Ma
- School of Chemistry and Australian Centre for NanoMedicine, University of New South Wales, Sydney, 2052, Australia
| | - Jesse Goyette
- EMBL Australia Node in Single Molecule Science, The University of New South Wales, 2052, Sydney, Australia
| | - Xueqian Chen
- School of Chemistry and Australian Centre for NanoMedicine, University of New South Wales, Sydney, 2052, Australia
| | - Katharina Gaus
- EMBL Australia Node in Single Molecule Science, The University of New South Wales, 2052, Sydney, Australia
| | - Richard D Tilley
- School of Chemistry and Australian Centre for NanoMedicine, University of New South Wales, Sydney, 2052, Australia; Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, 2052, Australia
| | - J Justin Gooding
- School of Chemistry and Australian Centre for NanoMedicine, University of New South Wales, Sydney, 2052, Australia.
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8
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Hargreaves R, Duwé S, Rozario AM, Funston AM, Tabor RF, Dedecker P, Whelan DR, Bell TDM. Live-Cell SOFI Correlation with SMLM and AFM Imaging. ACS BIO & MED CHEM AU 2023; 3:261-269. [PMID: 37363082 PMCID: PMC10288496 DOI: 10.1021/acsbiomedchemau.2c00086] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/09/2023] [Accepted: 03/10/2023] [Indexed: 06/28/2023]
Abstract
Standard optical imaging is diffraction-limited and lacks the resolving power to visualize many of the organelles and proteins found within the cell. The advent of super-resolution techniques overcame this barrier, enabling observation of subcellular structures down to tens of nanometers in size; however these techniques require or are typically applied to fixed samples. This raises the question of how well a fixed-cell image represents the system prior to fixation. Here we present the addition of live-cell Super-Resolution Optical Fluctuation Imaging (SOFI) to a previously reported correlative process using Single Molecule Localization Microscopy (SMLM) and Atomic Force Microscopy (AFM). SOFI was used with fluorescent proteins and low laser power to observe cellular ultrastructure in live COS-7 cells. SOFI-SMLM-AFM of microtubules showed minimal changes to the microtubule network in the 20 min between live-cell SOFI and fixation. Microtubule diameters were also analyzed through all microscopies; SOFI found diameters of 249 ± 68 nm and SMLM was 71 ± 33 nm. AFM height measurements found microtubules to protrude 26 ± 13 nm above the surrounding cellular material. The correlation of SMLM and AFM was extended to two-color SMLM to image both microtubules and actin. Two target SOFI was performed with various fluorescent protein combinations. rsGreen1-rsKAME, rsGreen1-Dronpa, and ffDronpaF-rsKAME fluorescent protein combinations were determined to be suitable for two target SOFI imaging. This correlative application of super-resolution live-cell and fixed-cell imaging revealed minimal artifacts created for the imaged target structures through the sample preparation procedure and emphasizes the power of correlative microscopy.
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Affiliation(s)
| | - Sam Duwé
- Advanced
Optical Microscopy Centre, Hasselt University, Diepenbeek 3590, Belgium
| | - Ashley M. Rozario
- Department
of Rural Clinical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Bendigo 3552, Victoria, Australia
| | - Alison M. Funston
- School
of Chemistry, Monash University, Melbourne, Victoria 3800, Australia
- ARC
Centre of Excellence in Exciton Science, Monash University, Clayton, Victoria 3800, Australia
| | - Rico F. Tabor
- School
of Chemistry, Monash University, Melbourne, Victoria 3800, Australia
| | - Peter Dedecker
- Department
of Chemistry, KU Leuven, Leuven 3001, Belgium
| | - Donna R. Whelan
- Department
of Rural Clinical Sciences, La Trobe Institute for Molecular Science, La Trobe University, Bendigo 3552, Victoria, Australia
| | - Toby D. M. Bell
- School
of Chemistry, Monash University, Melbourne, Victoria 3800, Australia
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9
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Ke HW, Sung K. 7-membered-ring effect on fluorescence quantum yield: does metal-complexation-induced twisting-inhibition of an amino GFP chromophore derivative enhance fluorescence? Phys Chem Chem Phys 2023; 25:14627-14634. [PMID: 37194347 DOI: 10.1039/d3cp00467h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
To investigate two aspects, namely, (1) the 7-membered-ring effect on fluorescence quantum yield and (2) whether metal-complexation-induced twisting-inhibition of an amino green fluorescent protein (GFP) chromophore derivative is bound to enhance fluorescence, a novel GFP-chromophore-based triamine ligand, (Z)-o-PABDI, is designed and synthesized. Before complexation with metal ions, the S1 excited state of (Z)-o-PABDI undergoes τ-torsion relaxation (Z/E photoisomerization) with a Z/E photoisomerization quantum yield of 0.28, forming both ground-state (Z)- and (E)-o-PABDI isomers. Since (E)-o-PABDI is less stable than (Z)-o-PABDI, it is thermo-isomerized back to (Z)-o-PABDI at room temperature in acetonitrile with a first-order rate constant of (1.366 ± 0.082) × 10-6 s-1. After complexation with a Zn2+ ion, (Z)-o-PABDI as a tridentate ligand forms a 1 : 1 complex with the Zn2+ ion in acetonitrile and in the solid state, resulting in complete inhibition of the φ-torsion and τ-torsion relaxations, which does not enhance fluorescence but causes fluorescence quenching. (Z)-o-PABDI also forms complexes with other first-row transition metal ions Mn2+, Fe3+, Co2+, Ni2+ and Cu2+, generating almost the same fluorescence quenching effect. By comparison with the 2/Zn2+ complex, in which a 6-membered ring of Zn2+-complexation enhances fluorescence significantly (a positive 6-membered-ring effect on fluorescence quantum yield), we find that the flexible 7-membered rings of the (Z)-o-PABDI/Mn+ complexes trigger their S1 excited states to relax through internal conversion at a rate much faster than fluorescence (a negative 7-membered-ring effect on fluorescence quantum yield), leading to fluorescence quenching regardless of the type of transition metal that complexes with (Z)-o-PABDI.
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Affiliation(s)
- Hao-Wei Ke
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
| | - Kuangsen Sung
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
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10
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Clark MG, Ma S, Mahapatra S, Mohn KJ, Zhang C. Chemical-imaging-guided optical manipulation of biomolecules. Front Chem 2023; 11:1198670. [PMID: 37214479 PMCID: PMC10196011 DOI: 10.3389/fchem.2023.1198670] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 04/20/2023] [Indexed: 05/24/2023] Open
Abstract
Chemical imaging via advanced optical microscopy technologies has revealed remarkable details of biomolecules in living specimens. However, the ways to control chemical processes in biological samples remain preliminary. The lack of appropriate methods to spatially regulate chemical reactions in live cells in real-time prevents investigation of site-specific molecular behaviors and biological functions. Chemical- and site-specific control of biomolecules requires the detection of chemicals with high specificity and spatially precise modulation of chemical reactions. Laser-scanning optical microscopes offer great platforms for high-speed chemical detection. A closed-loop feedback control system, when paired with a laser scanning microscope, allows real-time precision opto-control (RPOC) of chemical processes for dynamic molecular targets in live cells. In this perspective, we briefly review recent advancements in chemical imaging based on laser scanning microscopy, summarize methods developed for precise optical manipulation, and highlight a recently developed RPOC technology. Furthermore, we discuss future directions of precision opto-control of biomolecules.
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Affiliation(s)
| | - Seohee Ma
- Department of Chemistry, West Lafayette, IN, United States
| | | | | | - Chi Zhang
- Department of Chemistry, West Lafayette, IN, United States
- Purdue Center for Cancer Research, West Lafayette, IN, United States
- Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN, United States
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11
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Zhu YH, Liu XX, Fang Q, Liu XY, Fang WH, Cui G. Multiple Photoisomerization Pathways of the Green Fluorescent Protein Chromophore in a Reversibly Photoswitchable Fluorescent Protein: Insights from Quantum Mechanics/Molecular Mechanics Simulations. J Phys Chem Lett 2023; 14:2588-2598. [PMID: 36881005 DOI: 10.1021/acs.jpclett.3c00165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Herein, we have employed a combined CASPT2//CASSCF approach within the quantum mechanics/molecular mechanics (QM/MM) framework to explore the early time photoisomerization of rsEGFP2 starting from its two OFF trans states, i.e., Trans1 and Trans2. The results show similar vertical excitation energies to the S1 state in their Franck-Condon regions. Considering the clockwise and counterclockwise rotations of the C11-C9 bond, four pairs of the S1 excited-state minima and low-lying S1/S0 conical intersections were optimized, based on which we determined four S1 photoisomerization paths that are essentially barrierless to the relevant S1/S0 conical intersections leading to efficient excited-state deactivation to the S0 state. Most importantly, our work first identified multiple photoisomerization and excited-state decay paths, which must be seriously considered in the future. This work not only sheds significant light on the primary trans-cis photoisomerization of rsEGFP2 but also aids in the understanding of the microscopic mechanism of GFP-like RSFPs and the design of novel GFP-like fluorescent proteins.
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Affiliation(s)
- Yun-Hua Zhu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xin-Xin Liu
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Qiu Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Xiang-Yang Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China
| | - Wei-Hai Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
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12
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Bracamonte AG. Current Advances in Nanotechnology for the Next Generation of Sequencing (NGS). BIOSENSORS 2023; 13:260. [PMID: 36832027 PMCID: PMC9954403 DOI: 10.3390/bios13020260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/03/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
This communication aims at discussing strategies based on developments from nanotechnology focused on the next generation of sequencing (NGS). In this regard, it should be noted that even in the advanced current situation of many techniques and methods accompanied with developments of technology, there are still existing challenges and needs focused on real samples and low concentrations of genomic materials. The approaches discussed/described adopt spectroscopical techniques and new optical setups. PCR bases are introduced to understand the role of non-covalent interactions by discussing about Nobel prizes related to genomic material detection. The review also discusses colorimetric methods, polymeric transducers, fluorescence detection methods, enhanced plasmonic techniques such as metal-enhanced fluorescence (MEF), semiconductors, and developments in metamaterials. In addition, nano-optics, challenges linked to signal transductions, and how the limitations reported in each technique could be overcome are considered in real samples. Accordingly, this study shows developments where optical active nanoplatforms generate signal detection and transduction with enhanced performances and, in many cases, enhanced signaling from single double-stranded deoxyribonucleic acid (DNA) interactions. Future perspectives on miniaturized instrumentation, chips, and devices aimed at detecting genomic material are analyzed. However, the main concept in this report derives from gained insights into nanochemistry and nano-optics. Such concepts could be incorporated into other higher-sized substrates and experimental and optical setups.
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Affiliation(s)
- Angel Guillermo Bracamonte
- Instituto de Investigaciones en Físicoquímica de Córdoba (INFIQC), Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina; or
- Departement de Chimie et Centre d’Optique, Photonique et Laser (COPL), Université Laval, Québec, QC G1V 0A6, Canada
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13
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Anderson M, Padgett CM, Dargatz CJ, Nichols CR, Vittalam KR, DeVore NM. Engineering a Yellow Thermostable Fluorescent Protein by Rational Design. ACS OMEGA 2023; 8:436-443. [PMID: 36643458 PMCID: PMC9835079 DOI: 10.1021/acsomega.2c05005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/29/2022] [Indexed: 06/17/2023]
Abstract
Thermal green protein (TGP) is an extremely stable, highly soluble synthetic green fluorescent protein. The quantum yield of TGP is lower than the closest related natural fluorescent protein, monomeric Azami-Green. We improved the thermal recovery of TGP through the introduction of a chromophore mutation, Q66E. Furthermore, we developed a yellow thermal protein (YTP) via mutation of histidine 193 to tyrosine. Incorporation of Q66E into YTP (YTP-E) improved chemostability and pH stability. Both YTP and YTP-E have superior thermostability compared to TGP or TGP-E. These proteins offer a new option for green or yellow fluorescence under harsh chemical or thermal conditions.
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Affiliation(s)
- Matthew
R. Anderson
- Department
of Chemistry and Biochemistry, Missouri
State University, 901 South National Ave, Springfield, Missouri65897, United States
| | - Caitlin M. Padgett
- Department
of Chemistry and Biochemistry, Missouri
State University, 901 South National Ave, Springfield, Missouri65897, United States
| | - Cammi J. Dargatz
- Department
of Chemistry and Biochemistry, Missouri
State University, 901 South National Ave, Springfield, Missouri65897, United States
| | - Calysta R. Nichols
- Department
of Chemistry and Biochemistry, Missouri
State University, 901 South National Ave, Springfield, Missouri65897, United States
| | - Keerti R. Vittalam
- Department
of Chemistry and Biochemistry, Missouri
State University, 901 South National Ave, Springfield, Missouri65897, United States
- Greenwood
Laboratory School, 1024
E. Harrison, Springfield, Missouri65897, United
States
| | - Natasha M. DeVore
- Department
of Chemistry and Biochemistry, Missouri
State University, 901 South National Ave, Springfield, Missouri65897, United States
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14
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Addison K, Roy P, Bressan G, Skudaite K, Robb J, Bulman Page PC, Ashworth EK, Bull JN, Meech SR. Photophysics of the red-form Kaede chromophore. Chem Sci 2023; 14:3763-3775. [PMID: 37035701 PMCID: PMC10074405 DOI: 10.1039/d3sc00368j] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/08/2023] [Indexed: 03/18/2023] Open
Abstract
The chromophore responsible for colour switching in the optical highlighting protein Kaede has unexpectedly complicated excited state dynamics, which are measured and analysed here. This will inform the development of new imaging proteins.
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Affiliation(s)
- Kiri Addison
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Palas Roy
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Giovanni Bressan
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Karolina Skudaite
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Josh Robb
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | | | - Eleanor K. Ashworth
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - James N. Bull
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
| | - Stephen R. Meech
- School of Chemistry, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK
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15
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Krueger TD, Tang L, Chen C, Zhu L, Breen IL, Wachter RM, Fang C. To twist or not to twist: From chromophore structure to dynamics inside engineered photoconvertible and photoswitchable fluorescent proteins. Protein Sci 2023; 32:e4517. [PMID: 36403093 PMCID: PMC9793981 DOI: 10.1002/pro.4517] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/31/2022] [Accepted: 11/15/2022] [Indexed: 11/21/2022]
Abstract
Green-to-red photoconvertible fluorescent proteins (FPs) are vital biomimetic tools for powerful techniques such as super-resolution imaging. A unique Kaede-type FP named the least evolved ancestor (LEA) enables delineation of the evolutionary step to acquire photoconversion capability from the ancestral green fluorescent protein (GFP). A key residue, Ala69, was identified through several steady-state and time-resolved spectroscopic techniques that allows LEA to effectively photoswitch and enhance the green-to-red photoconversion. However, the inner workings of this functional protein have remained elusive due to practical challenges of capturing the photoexcited chromophore motions in real time. Here, we implemented femtosecond stimulated Raman spectroscopy and transient absorption on LEA-A69T, aided by relevant crystal structures and control FPs, revealing that Thr69 promotes a stronger π-π stacking interaction between the chromophore phenolate (P-)ring and His193 in FP mutants that cannot photoconvert or photoswitch. Characteristic time constants of ~60-67 ps are attributed to P-ring twist as the onset for photoswitching in LEA (major) and LEA-A69T (minor) with photoconversion capability, different from ~16/29 ps in correlation with the Gln62/His62 side-chain twist in ALL-GFP/ALL-Q62H, indicative of the light-induced conformational relaxation preferences in various local environments. A minor subpopulation of LEA-A69T capable of positive photoswitching was revealed by time-resolved electronic spectroscopies with targeted light irradiation wavelengths. The unveiled chromophore structure and dynamics inside engineered FPs in an aqueous buffer solution can be generalized to improve other green-to-red photoconvertible FPs from the bottom up for deeper biophysics with molecular biology insights and powerful bioimaging advances.
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Affiliation(s)
| | - Longteng Tang
- Department of ChemistryOregon State UniversityCorvallisOregonUSA
| | - Cheng Chen
- Department of ChemistryOregon State UniversityCorvallisOregonUSA
| | - Liangdong Zhu
- Department of ChemistryOregon State UniversityCorvallisOregonUSA
| | - Isabella L. Breen
- School of Molecular Sciences, Center for Bioenergy and Photosynthesis, Biodesign Center for Applied Structural DiscoveryArizona State UniversityTempeArizonaUSA
| | - Rebekka M. Wachter
- School of Molecular Sciences, Center for Bioenergy and Photosynthesis, Biodesign Center for Applied Structural DiscoveryArizona State UniversityTempeArizonaUSA
| | - Chong Fang
- Department of ChemistryOregon State UniversityCorvallisOregonUSA
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16
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Baxter J, Hutchison CD, Maghlaoui K, Cordon-Preciado V, Morgan RML, Aller P, Butryn A, Axford D, Horrell S, Owen RL, Storm SLS, Devenish NE, van Thor JJ. Observation of Cation Chromophore Photoisomerization of a Fluorescent Protein Using Millisecond Synchrotron Serial Crystallography and Infrared Vibrational and Visible Spectroscopy. J Phys Chem B 2022; 126:9288-9296. [PMID: 36326150 PMCID: PMC9677427 DOI: 10.1021/acs.jpcb.2c06780] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The chromophores of reversibly switchable fluorescent proteins (rsFPs) undergo photoisomerization of both the trans and cis forms. Concurrent with cis/trans photoisomerisation, rsFPs typically become protonated on the phenolic oxygen resulting in a blue shift of the absorption. A synthetic rsFP referred to as rsEospa, derived from EosFP family, displays the same spectroscopic behavior as the GFP-like rsFP Dronpa at pH 8.4 and involves the photoconversion between nonfluorescent neutral and fluorescent anionic chromophore states. Millisecond time-resolved synchrotron serial crystallography of rsEospa at pH 8.4 shows that photoisomerization is accompanied by rearrangements of the same three residues as seen in Dronpa. However, at pH 5.5 we observe that the OFF state is identified as the cationic chromophore with additional protonation of the imidazolinone nitrogen which is concurrent with a newly formed hydrogen bond with the Glu212 carboxylate side chain. FTIR spectroscopy resolves the characteristic up-shifted carbonyl stretching frequency at 1713 cm-1 for the cationic species. Electronic spectroscopy furthermore distinguishes the cationic absorption band at 397 nm from the neutral species at pH 8.4 seen at 387 nm. The observation of photoisomerization of the cationic chromophore state demonstrates the conical intersection for the electronic configuration, where previously fluorescence was proposed to be the main decay route for states containing imidazolinone nitrogen protonation. We present the full time-resolved room-temperature X-ray crystallographic, FTIR, and UV/vis assignment and photoconversion modeling of rsEospa.
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Affiliation(s)
- James
M. Baxter
- Department
of Life Sciences, Imperial College London, LondonSW7 2AZ, United Kingdom
| | | | - Karim Maghlaoui
- Department
of Life Sciences, Imperial College London, LondonSW7 2AZ, United Kingdom
| | | | - R. Marc L. Morgan
- Department
of Life Sciences, Imperial College London, LondonSW7 2AZ, United Kingdom
| | - Pierre Aller
- Research
Complex at Harwell, Rutherford Appleton
Laboratory, DidcotOX11 0FAUnited Kingdom,Diamond
Light Source, Harwell Science and Innovation
Campus, DidcotOX11 0DE, United Kingdom
| | - Agata Butryn
- Research
Complex at Harwell, Rutherford Appleton
Laboratory, DidcotOX11 0FAUnited Kingdom,Diamond
Light Source, Harwell Science and Innovation
Campus, DidcotOX11 0DE, United Kingdom
| | - Danny Axford
- Diamond
Light Source, Harwell Science and Innovation
Campus, DidcotOX11 0DE, United Kingdom
| | - Sam Horrell
- Diamond
Light Source, Harwell Science and Innovation
Campus, DidcotOX11 0DE, United Kingdom
| | - Robin L. Owen
- Diamond
Light Source, Harwell Science and Innovation
Campus, DidcotOX11 0DE, United Kingdom
| | - Selina L. S. Storm
- Diamond
Light Source, Harwell Science and Innovation
Campus, DidcotOX11 0DE, United Kingdom
| | - Nicholas E. Devenish
- Diamond
Light Source, Harwell Science and Innovation
Campus, DidcotOX11 0DE, United Kingdom
| | - Jasper J. van Thor
- Department
of Life Sciences, Imperial College London, LondonSW7 2AZ, United Kingdom,
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17
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Schelski M, Bradke F. Microtubule retrograde flow retains neuronal polarization in a fluctuating state. SCIENCE ADVANCES 2022; 8:eabo2336. [PMID: 36332023 PMCID: PMC9635824 DOI: 10.1126/sciadv.abo2336] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
In developing vertebrate neurons, a neurite is formed by more than a hundred microtubules. While individual microtubules are dynamic, the microtubule array has been regarded as stationary. Using live-cell imaging of neurons in culture or in brain slices, combined with photoconversion techniques and pharmacological manipulations, we uncovered that the microtubule array flows retrogradely within neurites to the soma. This flow drives cycles of microtubule density, a hallmark of the fluctuating state before axon formation, thereby inhibiting neurite growth. The motor protein dynein fuels this process. Shortly after axon formation, microtubule retrograde flow slows down in the axon, reducing microtubule density cycles and enabling axon extension. Thus, keeping neurites short is an active process. Microtubule retrograde flow is a previously unknown type of cytoskeletal dynamics, which changes the hitherto axon-centric view of neuronal polarization.
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Affiliation(s)
- Max Schelski
- Axon Growth and Regeneration Group, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, Building 99, 53127 Bonn, Germany
- International Max Planck Research School for Brain and Behavior, University of Bonn, Bonn, Germany
| | - Frank Bradke
- Axon Growth and Regeneration Group, German Center for Neurodegenerative Diseases (DZNE), Venusberg-Campus 1, Building 99, 53127 Bonn, Germany
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18
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Aparin IO, Yan R, Pelletier R, Choi AA, Danylchuk DI, Xu K, Klymchenko AS. Fluorogenic Dimers as Bright Switchable Probes for Enhanced Super-Resolution Imaging of Cell Membranes. J Am Chem Soc 2022; 144:18043-18053. [PMID: 36153973 DOI: 10.1021/jacs.2c07542] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Super-resolution fluorescence imaging based on single-molecule localization microscopy (SMLM) enables visualizing cellular structures with nanometric precision. However, its spatial and temporal resolution largely relies on the brightness of ON/OFF switchable fluorescent dyes. Moreover, in cell plasma membranes, the single-molecule localization is hampered by the fast lateral diffusion of membrane probes. Here, to address these two fundamental problems, we propose a concept of ON/OFF switchable probes for SMLM (points accumulation for imaging in nanoscale topography, PAINT) based on fluorogenic dimers of bright cyanine dyes. In these probes, the two cyanine units connected with a linker were modified at their extremities with low-affinity membrane anchors. Being self-quenched in water due to intramolecular dye H-aggregation, they displayed light up on reversible binding to lipid membranes. The charged group in the linker further decreased the probe affinity to the lipid membranes, thus accelerating its dynamic reversible ON/OFF switching. The concept was validated on cyanines 3 and 5. SMLM of live cells revealed that the new probes provided higher brightness and ∼10-fold slower diffusion at the cell surface, compared to reference probes Nile Red and DiD, which boosted axial localization precision >3-fold down to 31 nm. The new probe allowed unprecedented observation of nanoscale fibrous protrusions on plasma membranes of live cells with 40 s time resolution, revealing their fast dynamics. Thus, going beyond the brightness limit of single switchable dyes by cooperative dequenching in fluorogenic dimers and slowing down probe diffusion in biomembranes open the route to significant enhancement of super-resolution fluorescence microscopy of live cells.
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Affiliation(s)
- Ilya O Aparin
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, 74 Route du Rhin, 67401 Illkirch, France
| | - Rui Yan
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States.,Chan Zuckerberg Biohub, San Francisco, California 94158, United States
| | - Rémi Pelletier
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, 74 Route du Rhin, 67401 Illkirch, France
| | - Alexander A Choi
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States.,Chan Zuckerberg Biohub, San Francisco, California 94158, United States
| | - Dmytro I Danylchuk
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, 74 Route du Rhin, 67401 Illkirch, France
| | - Ke Xu
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States.,Chan Zuckerberg Biohub, San Francisco, California 94158, United States
| | - Andrey S Klymchenko
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, 74 Route du Rhin, 67401 Illkirch, France
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19
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Clark MG, Gonzalez GA, Luo Y, Aldana-Mendoza JA, Carlsen MS, Eakins G, Dai M, Zhang C. Real-time precision opto-control of chemical processes in live cells. Nat Commun 2022; 13:4343. [PMID: 35896556 PMCID: PMC9329476 DOI: 10.1038/s41467-022-32071-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 07/15/2022] [Indexed: 11/29/2022] Open
Abstract
Precision control of molecular activities and chemical reactions in live cells is a long-sought capability by life scientists. No existing technology can probe molecular targets in cells and simultaneously control the activities of only these targets at high spatial precision. We develop a real-time precision opto-control (RPOC) technology that detects a chemical-specific optical response from molecular targets during laser scanning and uses the optical signal to couple a separate laser to only interact with these molecules without affecting other sample locations. We demonstrate precision control of molecular states of a photochromic molecule in different regions of the cells. We also synthesize a photoswitchable compound and use it with RPOC to achieve site-specific inhibition of microtubule polymerization and control of organelle dynamics in live cells. RPOC can automatically detect and control biomolecular activities and chemical processes in dynamic living samples with submicron spatial accuracy, fast response time, and high chemical specificity. There is a need to control molecular activities at high spatial precision. Here the authors report a real-time precision opto-control technology that detects a chemical-specific optical response from molecular targets, and precisely control photoswitchable microtubule polymerization inhibitors in cells.
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Affiliation(s)
- Matthew G Clark
- Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN, 47907, USA
| | - Gil A Gonzalez
- Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN, 47907, USA
| | - Yiyang Luo
- Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN, 47907, USA
| | - Jesus A Aldana-Mendoza
- Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN, 47907, USA
| | - Mark S Carlsen
- Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN, 47907, USA
| | - Gregory Eakins
- Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN, 47907, USA
| | - Mingji Dai
- Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN, 47907, USA.,Purdue Center for Cancer Research, 201 S. University St., West Lafayette, IN, 47907, USA
| | - Chi Zhang
- Department of Chemistry, Purdue University, 560 Oval Dr., West Lafayette, IN, 47907, USA. .,Purdue Center for Cancer Research, 201 S. University St., West Lafayette, IN, 47907, USA. .,Purdue Institute of Inflammation, Immunology, and Infectious Disease, 207 S. Martin Jischke Dr., West Lafayette, IN, 47907, USA.
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20
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Tang L, Fang C. Photoswitchable Fluorescent Proteins: Mechanisms on Ultrafast Timescales. Int J Mol Sci 2022; 23:6459. [PMID: 35742900 PMCID: PMC9223536 DOI: 10.3390/ijms23126459] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 12/15/2022] Open
Abstract
The advancement of super-resolution imaging (SRI) relies on fluorescent proteins with novel photochromic properties. Using light, the reversibly switchable fluorescent proteins (RSFPs) can be converted between bright and dark states for many photocycles and their emergence has inspired the invention of advanced SRI techniques. The general photoswitching mechanism involves the chromophore cis-trans isomerization and proton transfer for negative and positive RSFPs and hydration-dehydration for decoupled RSFPs. However, a detailed understanding of these processes on ultrafast timescales (femtosecond to millisecond) is lacking, which fundamentally hinders the further development of RSFPs. In this review, we summarize the current progress of utilizing various ultrafast electronic and vibrational spectroscopies, and time-resolved crystallography in investigating the on/off photoswitching pathways of RSFPs. We show that significant insights have been gained for some well-studied proteins, but the real-time "action" details regarding the bidirectional cis-trans isomerization, proton transfer, and intermediate states remain unclear for most systems, and many other relevant proteins have not been studied yet. We expect this review to lay the foundation and inspire more ultrafast studies on existing and future engineered RSFPs. The gained mechanistic insights will accelerate the rational development of RSFPs with enhanced two-way switching rate and efficiency, better photostability, higher brightness, and redder emission colors.
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Affiliation(s)
- Longteng Tang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331-4003, USA
| | - Chong Fang
- Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331-4003, USA
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21
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Absolute measurement of cellular activities using photochromic single-fluorophore biosensors and intermittent quantification. Nat Commun 2022; 13:1850. [PMID: 35387971 PMCID: PMC8986857 DOI: 10.1038/s41467-022-29508-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 03/18/2022] [Indexed: 11/20/2022] Open
Abstract
Genetically-encoded biosensors based on a single fluorescent protein are widely used to visualize analyte levels or enzymatic activities in cells, though usually to monitor relative changes rather than absolute values. We report photochromism-enabled absolute quantification (PEAQ) biosensing, a method that leverages the photochromic properties of biosensors to provide an absolute measure of the analyte concentration or activity. We develop proof-of-concept photochromic variants of the popular GCaMP family of Ca2+ biosensors, and show that these can be used to resolve dynamic changes in the absolute Ca2+ concentration in live cells. We also develop intermittent quantification, a technique that combines absolute aquisitions with fast fluorescence acquisitions to deliver fast but fully quantitative measurements. We also show how the photochromism-based measurements can be expanded to situations where the absolute illumination intensities are unknown. In principle, PEAQ biosensing can be applied to other biosensors with photochromic properties, thereby expanding the possibilities for fully quantitative measurements in complex and dynamic systems. Biosensors often report relative rather than absolute values. Here the authors report a method that utilises the photochromic properties of biosensors to provide an absolute measure of the analyte concentration or activity: photochromism-enabled absolute quantification (PEAQ) biosensing.
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22
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Ferree PL, Xing M, Zhang JQ, Di Talia S. Structure-function analysis of Cdc25 Twine degradation at the Drosophila maternal-to-zygotic transition. Fly (Austin) 2022; 16:111-117. [PMID: 35227166 PMCID: PMC8890428 DOI: 10.1080/19336934.2022.2043095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Downregulation of protein phosphatase Cdc25Twine activity is linked to remodelling of the cell cycle during the Drosophila maternal-to-zygotic transition (MZT). Here, we present a structure-function analysis of Cdc25Twine. We use chimeras to show that the N-terminus regions of Cdc25Twine and Cdc25String control their differential degradation dynamics. Deletion of different regions of Cdc25Twine reveals a putative domain involved in and required for its rapid degradation during the MZT. Notably, a very similar domain is present in Cdc25String and deletion of the DNA replication checkpoint results in similar dynamics of degradation of both Cdc25String and Cdc25Twine. Finally, we show that Cdc25Twine degradation is delayed in embryos lacking the left arm of chromosome III. Thus, we propose a model for the differential regulation of Cdc25 at the Drosophila MZT.
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Affiliation(s)
- Patrick L Ferree
- Department of Cell Biology, Duke University Medical Center, Durham, NC, USA
| | - Maggie Xing
- Department of Cell Biology, Duke University Medical Center, Durham, NC, USA
| | - Jenny Q Zhang
- Department of Surgery, Alpert Medical School, Brown University, Providence, RI, USA
| | - Stefano Di Talia
- Department of Cell Biology, Duke University Medical Center, Durham, NC, USA
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23
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Steindel M, Orsine de Almeida I, Strawbridge S, Chernova V, Holcman D, Ponjavic A, Basu S. Studying the Dynamics of Chromatin-Binding Proteins in Mammalian Cells Using Single-Molecule Localization Microscopy. Methods Mol Biol 2022; 2476:209-247. [PMID: 35635707 DOI: 10.1007/978-1-0716-2221-6_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Single-molecule localization microscopy (SMLM) allows the super-resolved imaging of proteins within mammalian nuclei at spatial resolutions comparable to that of a nucleosome itself (~20 nm). The technique is therefore well suited to the study of chromatin structure. Fixed-cell SMLM has already allowed temporal "snapshots" of how proteins are arranged on chromatin within mammalian nuclei. In this chapter, we focus on how recent developments, for example in selective plane illumination, 3D SMLM, and protein labeling, have led to a range of live-cell SMLM studies. We describe how to carry out single-particle tracking (SPT) of single proteins and, by analyzing their diffusion parameters, how to determine whether proteins interact with chromatin, diffuse freely, or do both. We can study the numbers of proteins that interact with chromatin and also determine their residence time on chromatin. We can determine whether these proteins form functional clusters within the nucleus as well as whether they form specific nuclear structures.
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Affiliation(s)
- Maike Steindel
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | | | - Stanley Strawbridge
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - Valentyna Chernova
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK
| | - David Holcman
- Group of Computational Biology and Applied Mathematics, Institute of Biology, Ecole Normale Supérieure, Paris, France
| | - Aleks Ponjavic
- School of Physics and Astronomy and School of Food Science and Nutrition, University of Leeds, Leeds, UK.
| | - Srinjan Basu
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, UK.
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24
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Liao JW, Sung R, Sung K. Against the NEER principle: the third type of photochromism for GFP chromophore derivatives. Phys Chem Chem Phys 2021; 24:295-304. [PMID: 34889318 DOI: 10.1039/d1cp03581a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photochromism is the heart of photochromic fluorescent proteins. Excited-state proton transfer (ESPT) is the major cause of photochromism for the green fluorescent protein (GFP) and Z-E photoisomerization through τ-torsion is the major cause of photochromism for Dronpa (a GFP mutant). In this article, s-E-1 opens a third type of photochromism for GFP chromophore derivatives, which involves light-driven φ-torsion with no τ-torsion, followed by excited-state intramolecular proton transfer (ESIPT), and is gated by environmental polarity. Since s-E-1 does not follow Z-E photoisomerization through τ-torsion but undergoes light-driven φ-torsion, which involves equilibration of the excited-state rotamers, it is clearly against the NEER (Non-Equilibration of Excited-state Rotamers) principle.
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Affiliation(s)
- Jun-Wei Liao
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
| | - Robert Sung
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
| | - Kuangsen Sung
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan.
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25
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Rozario AM, Duwé S, Elliott C, Hargreaves RB, Moseley GW, Dedecker P, Whelan DR, Bell TDM. Nanoscale characterization of drug-induced microtubule filament dysfunction using super-resolution microscopy. BMC Biol 2021; 19:260. [PMID: 34895240 PMCID: PMC8665533 DOI: 10.1186/s12915-021-01164-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 10/11/2021] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The integrity of microtubule filament networks is essential for the roles in diverse cellular functions, and disruption of its structure or dynamics has been explored as a therapeutic approach to tackle diseases such as cancer. Microtubule-interacting drugs, sometimes referred to as antimitotics, are used in cancer therapy to target and disrupt microtubules. However, due to associated side effects on healthy cells, there is a need to develop safer drug regimens that still retain clinical efficacy. Currently, many questions remain open regarding the extent of effects on cellular physiology of microtubule-interacting drugs at clinically relevant and low doses. Here, we use super-resolution microscopies (single-molecule localization and optical fluctuation based) to reveal the initial microtubule dysfunctions caused by nanomolar concentrations of colcemid. RESULTS We identify previously undetected microtubule (MT) damage caused by clinically relevant doses of colcemid. Short exposure to 30-80 nM colcemid results in aberrant microtubule curvature, with a trend of increased curvature associated to increased doses, and curvatures greater than 2 rad/μm, a value associated with MT breakage. Microtubule fragmentation was detected upon treatment with ≥ 100 nM colcemid. Remarkably, lower doses (< 20 nM after 5 h) led to subtle but significant microtubule architecture remodelling characterized by increased curvature and suppression of microtubule dynamics. CONCLUSIONS Our results support the emerging hypothesis that microtubule-interacting drugs induce non-mitotic effects in cells, and establish a multi-modal imaging assay for detecting and measuring nanoscale microtubule dysfunction. The sub-diffraction visualization of these less severe precursor perturbations compared to the established antimitotic effects of microtubule-interacting drugs offers potential for improved understanding and design of anticancer agents.
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Affiliation(s)
- Ashley M Rozario
- School of Chemistry, Monash University, Clayton, 3800, Australia
| | - Sam Duwé
- Biomedical Research Institute, Hasselt University, 3590, Diepenbeek, Belgium
| | - Cade Elliott
- School of Chemistry, Monash University, Clayton, 3800, Australia
| | | | - Gregory W Moseley
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton, 3800, Australia
| | - Peter Dedecker
- Department of Chemistry, KU Leuven, 3001, Leuven, Belgium
| | - Donna R Whelan
- La Trobe Institute for Molecular Science, La Trobe University, Bendigo, 3552, Australia.
| | - Toby D M Bell
- School of Chemistry, Monash University, Clayton, 3800, Australia.
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26
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Rapid ensemble measurement of protein diffusion and probe blinking dynamics in cells. BIOPHYSICAL REPORTS 2021; 1:100015. [PMID: 36425455 PMCID: PMC9680803 DOI: 10.1016/j.bpr.2021.100015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/30/2021] [Indexed: 12/25/2022]
Abstract
We present a fluorescence fluctuation image correlation analysis method that can rapidly and simultaneously measure the diffusion coefficient, photoblinking rates, and fraction of diffusing particles of fluorescent molecules in cells. Unlike other image correlation techniques, we demonstrated that our method could be applied irrespective of a nonuniformly distributed, immobile blinking fluorophore population. This allows us to measure blinking and transport dynamics in complex cell morphologies, a benefit for a range of super-resolution fluorescence imaging approaches that rely on probe emission blinking. Furthermore, we showed that our technique could be applied without directly accounting for photobleaching. We successfully employed our technique on several simulations with realistic EMCCD noise and photobleaching models, as well as on Dronpa-C12-labeled β-actin in living NIH/3T3 and HeLa cells. We found that the diffusion coefficients measured using our method were consistent with previous literature values. We further found that photoblinking rates measured in the live HeLa cells varied as expected with changing excitation power.
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27
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Osuga M, Nishimura T, Suetsugu S. Development of a green reversibly photoswitchable variant of Eos fluorescent protein with fixation resistance. Mol Biol Cell 2021; 32:br7. [PMID: 34495704 PMCID: PMC8693962 DOI: 10.1091/mbc.e21-01-0044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 08/23/2021] [Accepted: 09/01/2021] [Indexed: 11/11/2022] Open
Abstract
Superresolution microscopy determines the localization of fluorescent proteins with high precision, beyond the diffraction limit of light. Superresolution microscopic techniques include photoactivated localization microscopy (PALM), which can localize a single protein by the stochastic activation of its fluorescence. In the determination of single-molecule localization by PALM, the number of molecules that can be analyzed per image is limited. Thus, many images are required to reconstruct the localization of numerous molecules in the cell. However, most fluorescent proteins lose their fluorescence upon fixation. Here, we combined the amino acid substitutions of two Eos protein derivatives, Skylan-S and mEos4b, which are a green reversibly photoswitchable fluorescent protein (RSFP) and a fixation-resistant green-to-red photoconvertible fluorescent protein, respectively, resulting in the fixation-resistant Skylan-S (frSkylan-S), a green RSFP. The frSkylan-S protein is inactivated by excitation light and reactivated by irradiation with violet light, and retained more fluorescence after aldehyde fixation than Skylan-S. The qualities of the frSkylan-S fusion proteins were sufficiently high in PALM observations, as examined using α-tubulin and clathrin light chain. Furthermore, frSkylan-S can be combined with antibody staining for multicolor imaging. Therefore, frSkylan-S is a green fluorescent protein suitable for PALM imaging under aldehyde-fixation conditions.
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Affiliation(s)
- Mitsuo Osuga
- Nara Institute of Science and Technology, Ikoma 630-0192, Japan
| | | | - Shiro Suetsugu
- Nara Institute of Science and Technology, Ikoma 630-0192, Japan
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28
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Srivastava I, Moitra P, Sar D, Wang K, Alafeef M, Scott J, Pan D. Luminescence switching in polymerically confined carbon nanoparticles triggered by UV-light. NANOSCALE 2021; 13:16288-16295. [PMID: 34558578 DOI: 10.1039/d1nr02786g] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Photo-caged carbon nanoparticles (CNPs) that are non-luminescent under typical microscopic illumination but can be activated by UV light have been synthesized in this work. Negatively charged "bare" CNPs with high luminescence can lose their photoluminescence (PL) when they are chemically crosslinked to a monomer and subsequently polymerized to form an intra-particulate "caged" network at the nanoscale surface. These caged particles could regain their PL emission upon UV irradiation for a sustained period (∼24 h) resulting in the photolytic cleavage of the polymer network, thus, freeing the nanoscale surface of CNPs, ultimately resulting in six-fold emission enhancement. This reversible "on-off-on" PL switching process was verified by spectroscopic techniques. We successfully demonstrated in this work that CNPs can be switched reversibly between fluorescent and non-fluorescent states by irradiation with light. These results further substantiate that the origin of PL in CNPs is a surface phenomenon and highly dependent on their nanoscale coverage.
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Affiliation(s)
- Indrajit Srivastava
- Departments of Bioengineering, Materials Science & Engineering, Beckman Institute for Advanced Science & Technology, and Carle Cancer Centre at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Mills Breast Cancer Institute, Carle Foundation Hospital, Urbana, IL, 61801, USA
| | - Parikshit Moitra
- Departments of Diagnostic Radiology and Nuclear Medicine and Pediatrics, University of Maryland Baltimore, Health Sciences Facility III, 670 W Baltimore St., Baltimore, Maryland, 21201, USA
| | - Dinabandhu Sar
- Departments of Bioengineering, Materials Science & Engineering, Beckman Institute for Advanced Science & Technology, and Carle Cancer Centre at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Mills Breast Cancer Institute, Carle Foundation Hospital, Urbana, IL, 61801, USA
| | - Kevin Wang
- Departments of Bioengineering, Materials Science & Engineering, Beckman Institute for Advanced Science & Technology, and Carle Cancer Centre at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Mills Breast Cancer Institute, Carle Foundation Hospital, Urbana, IL, 61801, USA
| | - Maha Alafeef
- Departments of Bioengineering, Materials Science & Engineering, Beckman Institute for Advanced Science & Technology, and Carle Cancer Centre at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Mills Breast Cancer Institute, Carle Foundation Hospital, Urbana, IL, 61801, USA
- Departments of Diagnostic Radiology and Nuclear Medicine and Pediatrics, University of Maryland Baltimore, Health Sciences Facility III, 670 W Baltimore St., Baltimore, Maryland, 21201, USA
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Interdisciplinary Health Sciences Facility, 1000 Hilltop Circle, Baltimore, Maryland, 21250, USA
- Department of Biomedical Engineering, Faculty of Engineering, Jordan University of Science and Technology, Irbid, Jordan
| | - John Scott
- Illinois Sustainable Technology Centre, University of Illinois at Urbana-Champaign, Champaign, IL, 61820, USA
| | - Dipanjan Pan
- Departments of Bioengineering, Materials Science & Engineering, Beckman Institute for Advanced Science & Technology, and Carle Cancer Centre at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Mills Breast Cancer Institute, Carle Foundation Hospital, Urbana, IL, 61801, USA
- Illinois Sustainable Technology Centre, University of Illinois at Urbana-Champaign, Champaign, IL, 61820, USA
- Departments of Diagnostic Radiology and Nuclear Medicine and Pediatrics, University of Maryland Baltimore, Health Sciences Facility III, 670 W Baltimore St., Baltimore, Maryland, 21201, USA
- Department of Chemical, Biochemical and Environmental Engineering, University of Maryland Baltimore County, Interdisciplinary Health Sciences Facility, 1000 Hilltop Circle, Baltimore, Maryland, 21250, USA
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29
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Out-of-Phase Imaging after Optical Modulation (OPIOM) for Multiplexed Fluorescence Imaging Under Adverse Optical Conditions. Methods Mol Biol 2021; 2350:191-227. [PMID: 34331287 DOI: 10.1007/978-1-0716-1593-5_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Fluorescence imaging has become a powerful tool for observations in biology. Yet it has also encountered limitations to overcome optical interferences of ambient light, autofluorescence, and spectrally interfering fluorophores. In this account, we first examine the current approaches which address these limitations. Then we more specifically report on Out-of-Phase Imaging after Optical Modulation (OPIOM), which has proved attractive for highly selective multiplexed fluorescence imaging even under adverse optical conditions. After exposing the OPIOM principle, we detail the protocols for successful OPIOM implementation.
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30
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Bohrer CH, Yang X, Thakur S, Weng X, Tenner B, McQuillen R, Ross B, Wooten M, Chen X, Zhang J, Roberts E, Lakadamyali M, Xiao J. A pairwise distance distribution correction (DDC) algorithm to eliminate blinking-caused artifacts in SMLM. Nat Methods 2021; 18:669-677. [PMID: 34059826 PMCID: PMC9040192 DOI: 10.1038/s41592-021-01154-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 04/12/2021] [Indexed: 02/04/2023]
Abstract
Single-molecule localization microscopy (SMLM) relies on the blinking behavior of a fluorophore, which is the stochastic switching between fluorescent and dark states. Blinking creates multiple localizations belonging to the same fluorophore, confounding quantitative analyses and interpretations. Here we present a method, termed distance distribution correction (DDC), to eliminate blinking-caused repeat localizations without any additional calibrations. The approach relies on obtaining the true pairwise distance distribution of different fluorophores naturally from the imaging sequence by using distances between localizations separated by a time much longer than the average fluorescence survival time. We show that, using the true pairwise distribution, we can define and maximize the likelihood, obtaining a set of localizations void of blinking artifacts. DDC results in drastic improvements in obtaining the closest estimate of the true spatial organization and number of fluorescent emitters in a wide range of applications, enabling accurate reconstruction and quantification of SMLM images.
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Affiliation(s)
- Christopher H. Bohrer
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA.,Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | - Xinxing Yang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Shreyasi Thakur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Xiaoli Weng
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Brian Tenner
- Department of Pharmacology, University of California San Diego, San Diego, CA, USA
| | - Ryan McQuillen
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Brian Ross
- Department of Pharmacology, University of California San Diego, San Diego, CA, USA
| | - Matthew Wooten
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Xin Chen
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Jin Zhang
- Department of Pharmacology, University of California San Diego, San Diego, CA, USA
| | - Elijah Roberts
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | - Melike Lakadamyali
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jie Xiao
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA
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31
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Bohrer CH, Yang X, Thakur S, Weng X, Tenner B, McQuillen R, Ross B, Wooten M, Chen X, Zhang J, Roberts E, Lakadamyali M, Xiao J. A pairwise distance distribution correction (DDC) algorithm to eliminate blinking-caused artifacts in SMLM. Nat Methods 2021. [PMID: 34059826 DOI: 10.1101/768051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Single-molecule localization microscopy (SMLM) relies on the blinking behavior of a fluorophore, which is the stochastic switching between fluorescent and dark states. Blinking creates multiple localizations belonging to the same fluorophore, confounding quantitative analyses and interpretations. Here we present a method, termed distance distribution correction (DDC), to eliminate blinking-caused repeat localizations without any additional calibrations. The approach relies on obtaining the true pairwise distance distribution of different fluorophores naturally from the imaging sequence by using distances between localizations separated by a time much longer than the average fluorescence survival time. We show that, using the true pairwise distribution, we can define and maximize the likelihood, obtaining a set of localizations void of blinking artifacts. DDC results in drastic improvements in obtaining the closest estimate of the true spatial organization and number of fluorescent emitters in a wide range of applications, enabling accurate reconstruction and quantification of SMLM images.
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Affiliation(s)
- Christopher H Bohrer
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | - Xinxing Yang
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Shreyasi Thakur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Xiaoli Weng
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Brian Tenner
- Department of Pharmacology, University of California San Diego, San Diego, CA, USA
| | - Ryan McQuillen
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Brian Ross
- Department of Pharmacology, University of California San Diego, San Diego, CA, USA
| | - Matthew Wooten
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Xin Chen
- Department of Biology, Johns Hopkins University, Baltimore, MD, USA
| | - Jin Zhang
- Department of Pharmacology, University of California San Diego, San Diego, CA, USA
| | - Elijah Roberts
- Department of Biophysics, Johns Hopkins University, Baltimore, MD, USA
| | - Melike Lakadamyali
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jie Xiao
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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32
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Li MJ, Lin YH, Sung R, Sung K. E- Z Isomerization Mechanism of the Green Fluorescent Protein Chromophore: Remote Regulation by Proton Dissociation of the Phenol Group. J Phys Chem A 2021; 125:3614-3621. [PMID: 33885302 DOI: 10.1021/acs.jpca.1c01371] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dronpa, a GFP (green fluorescent protein)-like fluorescent protein, allows its fluorescent and nonfluorescent states to be switched to each other reversibly by light or heat through E-Z isomerization of the GFP chromophore. In this article, a GFP chromophore (p-HBDI) in water is used as a model to explore this E-Z isomerization mechanism. Based on the experimental solvent isotope effect (kH2O/kD2O = 2.30), the E-Z isomerization of p-HBDI in water is suggested to go through the remote-proton-dissociation-regulated direct mechanism with a proton transfer in the rate-determining step. The fractionation factor (ϕ) of the water-associated phenol proton of p-HBDI in the transition state is found to be 0.43, which is exactly in the range of 0.1-0.6 for the fractionation factor (ϕ) of the transferring proton in the transition state of R2O···H···O+H2 in water. This means that the phenol proton of E-p-HBDI in the transition state is on the way to the associated water oxygen during the E-Z isomerization. The proton dissociation from the phenol group of p-HBDI remotely regulates its E-Z isomerization. Less proton dissociation from the phenol group (pKa = 8.0) at pH = 1-4 results in a modest reduction in the E-Z isomerization rate of p-HBDI, while complete proton dissociation from the phenol group at pH = 11-12 also reduces its E-Z isomerization rate by one order of magnitude because of the larger charge separation in the transition state of the p-HBDI anion. All of these results are consistent with the remote-proton-dissociation-regulated direct mechanism but against the water-assisted addition/elimination mechanism.
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Affiliation(s)
- Ming-Ju Li
- Department of Chemistry, National Cheng Kung University, Tainan 701401, Taiwan
| | - Yen-Hsun Lin
- Department of Chemistry, National Cheng Kung University, Tainan 701401, Taiwan
| | - Robert Sung
- Faculty of Family Medicine, Northern Ontario School of Medicine, Sudbury, Ontario P3E 2C6, Canada
| | - Kuangsen Sung
- Department of Chemistry, National Cheng Kung University, Tainan 701401, Taiwan
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33
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De Zitter E, Hugelier S, Duwé S, Vandenberg W, Tebo AG, Van Meervelt L, Dedecker P. Structure-Function Dataset Reveals Environment Effects within a Fluorescent Protein Model System*. Angew Chem Int Ed Engl 2021; 60:10073-10081. [PMID: 33543524 DOI: 10.1002/anie.202015201] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Indexed: 11/05/2022]
Abstract
Anisotropic environments can drastically alter the spectroscopy and photochemistry of molecules, leading to complex structure-function relationships. We examined this using fluorescent proteins as easy-to-modify model systems. Starting from a single scaffold, we have developed a range of 27 photochromic fluorescent proteins that cover a broad range of spectroscopic properties, including the determination of 43 crystal structures. Correlation and principal component analysis confirmed the complex relationship between structure and spectroscopy, but also allowed us to identify consistent trends and to relate these to the spatial organization. We find that changes in spectroscopic properties can come about through multiple underlying mechanisms, of which polarity, hydrogen bonding and presence of water molecules are key modulators. We anticipate that our findings and rich structure/spectroscopy dataset can open opportunities for the development and evaluation of new and existing protein engineering methods.
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Affiliation(s)
- Elke De Zitter
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G - box 2403, 3001, Leuven, Belgium.,Present address: University Grenoble Alpes, CEA, CNRS, IBS, 71 Avenue des Martyrs, 38000, Grenoble, France
| | - Siewert Hugelier
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G - box 2403, 3001, Leuven, Belgium
| | - Sam Duwé
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G - box 2403, 3001, Leuven, Belgium.,Present address: Advanced Optical Microscopy Centre, Hasselt University, Agoralaan building C, 3590, Diepenbeek, Belgium
| | - Wim Vandenberg
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G - box 2403, 3001, Leuven, Belgium
| | - Alison G Tebo
- Janelia Research Campus, Howard Hughes Medical Institute, 19700 Helix Drive, Ashburn, Virginia, 20147, USA
| | - Luc Van Meervelt
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G - box 2403, 3001, Leuven, Belgium
| | - Peter Dedecker
- Department of Chemistry, KU Leuven, Celestijnenlaan 200G - box 2403, 3001, Leuven, Belgium
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34
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De Zitter E, Hugelier S, Duwé S, Vandenberg W, Tebo AG, Van Meervelt L, Dedecker P. Structure–Function Dataset Reveals Environment Effects within a Fluorescent Protein Model System**. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202015201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Elke De Zitter
- Department of Chemistry KU Leuven Celestijnenlaan 200G – box 2403 3001 Leuven Belgium
- Present address: University Grenoble Alpes CEA CNRS IBS 71 Avenue des Martyrs 38000 Grenoble France
| | - Siewert Hugelier
- Department of Chemistry KU Leuven Celestijnenlaan 200G – box 2403 3001 Leuven Belgium
| | - Sam Duwé
- Department of Chemistry KU Leuven Celestijnenlaan 200G – box 2403 3001 Leuven Belgium
- Present address: Advanced Optical Microscopy Centre Hasselt University Agoralaan building C 3590 Diepenbeek Belgium
| | - Wim Vandenberg
- Department of Chemistry KU Leuven Celestijnenlaan 200G – box 2403 3001 Leuven Belgium
| | - Alison G. Tebo
- Janelia Research Campus Howard Hughes Medical Institute 19700 Helix Drive Ashburn Virginia 20147 USA
| | - Luc Van Meervelt
- Department of Chemistry KU Leuven Celestijnenlaan 200G – box 2403 3001 Leuven Belgium
| | - Peter Dedecker
- Department of Chemistry KU Leuven Celestijnenlaan 200G – box 2403 3001 Leuven Belgium
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35
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Van Genechten W, Demuyser L, Duwé S, Vandenberg W, Van Dijck P, Dedecker P. Photochromic Fluorophores Enable Imaging of Lowly Expressed Proteins in the Autofluorescent Fungus Candida albicans. mSphere 2021; 6:e00146-21. [PMID: 33731469 PMCID: PMC8546692 DOI: 10.1128/msphere.00146-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 02/27/2021] [Indexed: 11/20/2022] Open
Abstract
Fluorescence microscopy is a standard research tool in many fields, although collecting reliable images can be difficult in systems characterized by low expression levels and/or high background fluorescence. We present the combination of a photochromic fluorescent protein and stochastic optical fluctuation imaging (SOFI) to deliver suppression of the background fluorescence. This strategy makes it possible to resolve lowly or endogenously expressed proteins, as we demonstrate for Gcn5, a histone acetyltransferase required for complete virulence, and Erg11, the target of the azole antifungal agents in the fungal pathogen Candida albicans We expect that our method can be readily used for sensitive fluorescence measurements in systems characterized by high background fluorescence.IMPORTANCE Understanding the spatial and temporal organization of proteins of interest is key to unraveling cellular processes and identifying novel possible antifungal targets. Only a few therapeutic targets have been discovered in Candida albicans, and resistance mechanisms against these therapeutic agents are rapidly acquired. Fluorescence microscopy is a valuable tool to investigate molecular processes and assess the localization of possible antifungal targets. Unfortunately, fluorescence microscopy of C. albicans suffers from extensive autofluorescence. In this work, we present the use of a photochromic fluorescent protein and stochastic optical fluctuation imaging to enable the imaging of lowly expressed proteins in C. albicans through the suppression of autofluorescence. This method can be applied in C. albicans research or adapted for other fungal systems, allowing the visualization of intricate processes.
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Affiliation(s)
- Wouter Van Genechten
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, KU Leuven, Leuven, Belgium
- Advanced Optical Microscopy Centre, Biomedical Research Institute (BIOMED), Hasselt University, Hasselt, Belgium
| | - Liesbeth Demuyser
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, KU Leuven, Leuven, Belgium
| | - Sam Duwé
- Advanced Optical Microscopy Centre, Biomedical Research Institute (BIOMED), Hasselt University, Hasselt, Belgium
| | - Wim Vandenberg
- Lab for Nanobiology, Department of Chemistry, KU Leuven, Leuven, Belgium
| | - Patrick Van Dijck
- Laboratory of Molecular Cell Biology, Institute of Botany and Microbiology, KU Leuven, Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, KU Leuven, Leuven, Belgium
| | - Peter Dedecker
- Lab for Nanobiology, Department of Chemistry, KU Leuven, Leuven, Belgium
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36
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Cambré A, Aertsen A. Bacterial Vivisection: How Fluorescence-Based Imaging Techniques Shed a Light on the Inner Workings of Bacteria. Microbiol Mol Biol Rev 2020; 84:e00008-20. [PMID: 33115939 PMCID: PMC7599038 DOI: 10.1128/mmbr.00008-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The rise in fluorescence-based imaging techniques over the past 3 decades has improved the ability of researchers to scrutinize live cell biology at increased spatial and temporal resolution. In microbiology, these real-time vivisections structurally changed the view on the bacterial cell away from the "watery bag of enzymes" paradigm toward the perspective that these organisms are as complex as their eukaryotic counterparts. Capitalizing on the enormous potential of (time-lapse) fluorescence microscopy and the ever-extending pallet of corresponding probes, initial breakthroughs were made in unraveling the localization of proteins and monitoring real-time gene expression. However, later it became clear that the potential of this technique extends much further, paving the way for a focus-shift from observing single events within bacterial cells or populations to obtaining a more global picture at the intra- and intercellular level. In this review, we outline the current state of the art in fluorescence-based vivisection of bacteria and provide an overview of important case studies to exemplify how to use or combine different strategies to gain detailed information on the cell's physiology. The manuscript therefore consists of two separate (but interconnected) parts that can be read and consulted individually. The first part focuses on the fluorescent probe pallet and provides a perspective on modern methodologies for microscopy using these tools. The second section of the review takes the reader on a tour through the bacterial cell from cytoplasm to outer shell, describing strategies and methods to highlight architectural features and overall dynamics within cells.
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Affiliation(s)
- Alexander Cambré
- KU Leuven, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, Leuven, Belgium
| | - Abram Aertsen
- KU Leuven, Department of Microbial and Molecular Systems, Faculty of Bioscience Engineering, Leuven, Belgium
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37
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Kichuk TC, Carrasco-López C, Avalos JL. Lights up on organelles: Optogenetic tools to control subcellular structure and organization. WIREs Mech Dis 2020; 13:e1500. [PMID: 32715616 DOI: 10.1002/wsbm.1500] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 05/26/2020] [Accepted: 05/31/2020] [Indexed: 12/21/2022]
Abstract
Since the neurobiological inception of optogenetics, light-controlled molecular perturbations have been applied in many scientific disciplines to both manipulate and observe cellular function. Proteins exhibiting light-sensitive conformational changes provide researchers with avenues for spatiotemporal control over the cellular environment and serve as valuable alternatives to chemically inducible systems. Optogenetic approaches have been developed to target proteins to specific subcellular compartments, allowing for the manipulation of nuclear translocation and plasma membrane morphology. Additionally, these tools have been harnessed for molecular interrogation of organelle function, location, and dynamics. Optogenetic approaches offer novel ways to answer fundamental biological questions and to improve the efficiency of bioengineered cell factories by controlling the assembly of synthetic organelles. This review first provides a summary of available optogenetic systems with an emphasis on their organelle-specific utility. It then explores the strategies employed for organelle targeting and concludes by discussing our perspective on the future of optogenetics to control subcellular structure and organization. This article is categorized under: Metabolic Diseases > Molecular and Cellular Physiology.
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Affiliation(s)
- Therese C Kichuk
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, USA
| | - César Carrasco-López
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, USA
| | - José L Avalos
- Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey, USA.,Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey, USA
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38
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Kollenz P, Herten DP, Buckup T. Unravelling the Kinetic Model of Photochemical Reactions via Deep Learning. J Phys Chem B 2020; 124:6358-6368. [PMID: 32589422 DOI: 10.1021/acs.jpcb.0c04299] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Time-resolved spectroscopies have been playing an essential role in the elucidation of the fundamental mechanisms of light-driven processes, particularly in exploring relaxation models for electronically excited molecules. However, the determination of such models from experimentally obtained time-resolved and spectrally resolved data still demands a high degree of intuition, frequently poses numerical challenges, and is often not free from ambiguities. Here, we demonstrate the analysis of time-resolved laser spectroscopy data via a deep learning network to obtain the correct relaxation kinetic model. In its current design, the presented Deep Spectroscopy Kinetic Analysis Network (DeepSKAN) can predict kinetic models (involved states and relaxation pathways) consisting of up to five states, which results in 103 possible different classes, by estimating the probability of occurrence of a given kinetic model class. DeepSKAN was trained with synthetic time-resolved spectra spanning over 4 orders of magnitude in time with a unitless time axis, thereby demonstrating its potential as a universal approach for analyzing data from various time-resolved spectroscopy techniques in different time ranges. By adding the probabilities of each pathway of the top-k models normalized by the total probability, we can determine the relaxation pathways for a given data set with high certainty (up to 99%). Due to its architecture and training, DeepSKAN is robust against experimental noise and typical preanalysis errors like time-zero corrections. Application of DeepSKAN to experimental data is successfully demonstrated for three different photoinduced processes: transient absorption of the retinal isomerization, transient IR spectroscopy of the relaxation of the photoactivated DRONPA, and transient absorption of the dynamics in lycopene. This approach delivers kinetic models and could be a unifying asset in several areas of spectroscopy.
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Affiliation(s)
- Philipp Kollenz
- Physikalisch Chemisches Institut, Ruprecht-Karls University, D-69120 Heidelberg, Germany
| | - Dirk-Peter Herten
- Physikalisch Chemisches Institut, Ruprecht-Karls University, D-69120 Heidelberg, Germany.,Institute of Cardiovascular Sciences & School of Chemistry, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, B152TT, Birmingham, United Kingdom.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, United Kingdom
| | - Tiago Buckup
- Physikalisch Chemisches Institut, Ruprecht-Karls University, D-69120 Heidelberg, Germany
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Berckmans B, Kirschner G, Gerlitz N, Stadler R, Simon R. CLE40 Signaling Regulates Root Stem Cell Fate. PLANT PHYSIOLOGY 2020; 182:1776-1792. [PMID: 31806736 PMCID: PMC7140941 DOI: 10.1104/pp.19.00914] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 11/20/2019] [Indexed: 05/02/2023]
Abstract
The quiescent center (QC) of the Arabidopsis (Arabidopsis thaliana) root meristem acts as an organizer that promotes stem cell fate in adjacent cells and patterns the surrounding stem cell niche. The stem cells distal from the QC, the columella stem cells (CSCs), are maintained in an undifferentiated state by the QC-expressed transcription factor WUSCHEL RELATED HOMEOBOX5 (WOX5) and give rise to the columella cells. Differentiated columella cells provide a feedback signal via secretion of the peptide CLAVATA3/ESR-RELATED40 (CLE40), which acts through the receptor kinases ARABIDOPSIS CRINKLY4 (ACR4) and CLAVATA1 (CLV1) to control WOX5 expression. Previously, it was proposed that WOX5 protein movement from the QC into CSCs is required for CSC maintenance, and that the CLE40/CLV1/ACR4 signaling module restricts WOX5 mobility or function. Here, these assumptions were tested by exploring the function of CLE40/CLV1/ACR4 in CSC maintenance. However, no role for CLE40/CLV1/ACR4 in constricting the mobility of WOX5 or other fluorescent test proteins was identified. Furthermore, in contrast to previous observations, WOX5 mobility was not required to inhibit CSC differentiation. We propose that WOX5 acts mainly in the QC, where other short-range signals are generated that not only inhibit differentiation but also promote stem cell division in adjacent cells. Therefore, the main function of columella-derived CLE40 signal is to position the QC at a defined distance from the root tip by repressing QC-specific gene expression via the ACR4/CLV1 receptors in the distal domain and promoting WOX5 expression via the CLV2 receptor in the proximal meristem.
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Affiliation(s)
- Barbara Berckmans
- Institute for Developmental Genetics, Heinrich-Heine University, D-40225 Düsseldorf, Germany
| | - Gwendolyn Kirschner
- Institute for Developmental Genetics, Heinrich-Heine University, D-40225 Düsseldorf, Germany
| | - Nadja Gerlitz
- Molecular Plant Physiology, University of Erlangen, Staudtstrasse 5, 91058 Erlangen, Germany
| | - Ruth Stadler
- Molecular Plant Physiology, University of Erlangen, Staudtstrasse 5, 91058 Erlangen, Germany
| | - Rüdiger Simon
- Institute for Developmental Genetics, Heinrich-Heine University, D-40225 Düsseldorf, Germany
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40
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Boeri L, Jacchetti E, Soncini M, Negro A, Albani D, Raimondi MT. Advantages and limitations of a supernegative GFP in facilitating MyoD intracellular tracking. Methods Appl Fluoresc 2020; 8:025007. [PMID: 32092706 DOI: 10.1088/2050-6120/ab797c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Despite intracellular molecular dynamics being fundamental to understand pathological, biomechanical or biochemical events, several processes are still not clear because of the difficulty of monitoring and measuring these phenomena. To engineer an effective fluorescent tool useful to improve protein intracellular tracking studies, we fused a supernegative green fluorescent protein, (-30)GFP, to a myogenic transcription factor, MyoD. The (-30)GFP-MyoD was able to pass the plasma membrane when complexed with cationic lipids. Fluorescence confocal microscopy showed the protein delivery in just 3 hours with high levels of protein transduction efficiency. Confocal acquisitions also confirmed the maintenance of the MyoD nuclear localization. To examine how the supernegative GFP influenced MyoD activity, we did gene expression analyses, which showed an inhibitory effect of (-30)GFP on transcription factor function. This negative effect was possibly due to a charge-driven interference mechanism, as suggested by further investigations by molecular dynamics simulations. Summarizing these results, despite the functional limitations related to the charge structural characteristics that specifically affected MyoD function, we found (-30)GFP is a suitable fluorescent label for improving protein intracellular tracking studies, such as nucleocytoplasmic transport in mechanotransduction.
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Affiliation(s)
- Lucia Boeri
- Department of Chemistry, Materials and Chemical Engineering 'Giulio Natta', Politecnico di Milano, Milan, Italy
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41
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Woodhouse J, Nass Kovacs G, Coquelle N, Uriarte LM, Adam V, Barends TRM, Byrdin M, de la Mora E, Bruce Doak R, Feliks M, Field M, Fieschi F, Guillon V, Jakobs S, Joti Y, Macheboeuf P, Motomura K, Nass K, Owada S, Roome CM, Ruckebusch C, Schirò G, Shoeman RL, Thepaut M, Togashi T, Tono K, Yabashi M, Cammarata M, Foucar L, Bourgeois D, Sliwa M, Colletier JP, Schlichting I, Weik M. Photoswitching mechanism of a fluorescent protein revealed by time-resolved crystallography and transient absorption spectroscopy. Nat Commun 2020; 11:741. [PMID: 32029745 PMCID: PMC7005145 DOI: 10.1038/s41467-020-14537-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 01/06/2020] [Indexed: 02/08/2023] Open
Abstract
Reversibly switchable fluorescent proteins (RSFPs) serve as markers in advanced fluorescence imaging. Photoswitching from a non-fluorescent off-state to a fluorescent on-state involves trans-to-cis chromophore isomerization and proton transfer. Whereas excited-state events on the ps timescale have been structurally characterized, conformational changes on slower timescales remain elusive. Here we describe the off-to-on photoswitching mechanism in the RSFP rsEGFP2 by using a combination of time-resolved serial crystallography at an X-ray free-electron laser and ns-resolved pump–probe UV-visible spectroscopy. Ten ns after photoexcitation, the crystal structure features a chromophore that isomerized from trans to cis but the surrounding pocket features conformational differences compared to the final on-state. Spectroscopy identifies the chromophore in this ground-state photo-intermediate as being protonated. Deprotonation then occurs on the μs timescale and correlates with a conformational change of the conserved neighbouring histidine. Together with a previous excited-state study, our data allow establishing a detailed mechanism of off-to-on photoswitching in rsEGFP2. rsEGFP2 is a reversibly photoswitchable fluorescent protein used in super-resolution light microscopy. Here the authors present the structure of an rsEGFP2 ground-state intermediate after excited state-decay that was obtained by nanosecond time-resolved serial femtosecond crystallography at an X-ray free electron laser, and time-resolved absorption spectroscopy measurements complement their structural analysis.
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Affiliation(s)
- Joyce Woodhouse
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France
| | - Gabriela Nass Kovacs
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Nicolas Coquelle
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France.,Large-Scale Structures Group, Institut Laue Langevin, 71, avenue des Martyrs, 38042, Grenoble, cedex 9, France
| | - Lucas M Uriarte
- Univ. Lille, CNRS, UMR 8516, LASIR, Laboratoire de Spectrochimie Infrarouge et Raman, F59 000, Lille, France
| | - Virgile Adam
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France
| | - Thomas R M Barends
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Martin Byrdin
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France
| | - Eugenio de la Mora
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France
| | - R Bruce Doak
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Mikolaj Feliks
- Department of Chemistry, University of Southern California, Los Angeles, USA
| | - Martin Field
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France.,Laboratoire Chimie et Biologie des Métaux, BIG, CEA-Grenoble, Grenoble, France
| | - Franck Fieschi
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France
| | - Virginia Guillon
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France
| | - Stefan Jakobs
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Yasumasa Joti
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | - Pauline Macheboeuf
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France
| | - Koji Motomura
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, 980-8577, Japan
| | - Karol Nass
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | | | - Christopher M Roome
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Cyril Ruckebusch
- Univ. Lille, CNRS, UMR 8516, LASIR, Laboratoire de Spectrochimie Infrarouge et Raman, F59 000, Lille, France
| | - Giorgio Schirò
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France
| | - Robert L Shoeman
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Michel Thepaut
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France
| | - Tadashi Togashi
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | - Kensuke Tono
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5198, Japan
| | | | - Marco Cammarata
- Department of Physics, UMR UR1-CNRS 6251, University of Rennes 1, Rennes, France
| | - Lutz Foucar
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany
| | - Dominique Bourgeois
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France
| | - Michel Sliwa
- Univ. Lille, CNRS, UMR 8516, LASIR, Laboratoire de Spectrochimie Infrarouge et Raman, F59 000, Lille, France.
| | | | - Ilme Schlichting
- Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, 69120, Heidelberg, Germany.
| | - Martin Weik
- Univ. Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, F-38000, Grenoble, France.
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42
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Chen YC, Sood C, Francis AC, Melikyan GB, Dickson RM. Facile autofluorescence suppression enabling tracking of single viruses in live cells. J Biol Chem 2019; 294:19111-19118. [PMID: 31694918 DOI: 10.1074/jbc.ra119.010268] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 11/01/2019] [Indexed: 11/06/2022] Open
Abstract
Live cell fluorescence imaging is the method of choice for studying dynamic processes, such as nuclear transport, vesicular trafficking, and virus entry and egress. However, endogenous cellular autofluorescence masks a useful fluorescence signal, limiting the ability to reliably visualize low-abundance fluorescent proteins. Here, we employed synchronously amplified fluorescence image recovery (SAFIRe), which optically alters ground versus photophysical dark state populations within fluorescent proteins to modulate and selectively detect their background-free emission. Using a photoswitchable rsFastLime fluorescent protein combined with a simple illumination and image-processing scheme, we demonstrate the utility of this approach for suppressing undesirable, unmodulatable fluorescence background. Significantly, we adapted this technique to different commercial wide-field and spinning-disk confocal microscopes, obtaining >10-fold improvements in signal to background. SAFIRe allowed visualization of rsFastLime targeted to mitochondria by efficiently suppressing endogenous autofluorescence or overexpressed cytosolic unmodulatable EGFP. Suppression of the overlapping EGFP signal provided a means to perform multiplexed imaging of rsFastLime and spectrally overlapping fluorophores. Importantly, we used SAFIRe to reliably visualize and track single rsFastLime-labeled HIV-1 particles in living cells exhibiting high and uneven autofluorescence signals. Time-lapse SAFIRe imaging can be performed for an extended period of time to visualize HIV-1 entry into cells. SAFIRe should be broadly applicable for imaging live cell dynamics with commercial microscopes, even in strongly autofluorescent cells or cells expressing spectrally overlapping fluorescent proteins.
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Affiliation(s)
- Yen-Cheng Chen
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400.,Department of Pediatrics, Emory School of Medicine, Atlanta, Georgia 30322
| | - Chetan Sood
- Department of Pediatrics, Emory School of Medicine, Atlanta, Georgia 30322
| | - Ashwanth C Francis
- Department of Pediatrics, Emory School of Medicine, Atlanta, Georgia 30322
| | - Gregory B Melikyan
- Department of Pediatrics, Emory School of Medicine, Atlanta, Georgia 30322 .,Children's Healthcare of Atlanta, Atlanta, Georgia 30332
| | - Robert M Dickson
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400
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43
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Tinoco A, Antunes E, Martins M, Gonçalves F, Gomes AC, Silva C, Cavaco-Paulo A, Ribeiro A. Fusion proteins with chromogenic and keratin binding modules. Sci Rep 2019; 9:14044. [PMID: 31575960 PMCID: PMC6773707 DOI: 10.1038/s41598-019-50283-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 09/02/2019] [Indexed: 01/30/2023] Open
Abstract
The present research relates to a fusion protein comprising a chromogenic blue ultramarine protein (UM) bound to a keratin-based peptide (KP). The KP-UM fusion protein explores UM chromogenic nature together with KP affinity towards hair. For the first time a fusion protein with a chromogenic nature is explored as a hair coloring agent. The KP-UM protein colored overbleached hair, being the color dependent on the formulation polarity. The protein was able to bind to the hair cuticle and even to penetrate throughout the hair fibre. Molecular dynamics studies demonstrated that the interaction between the KP-UM protein and the hair was mediated by the KP sequence. All the formulations recovered the mechanical properties of overbleached hair and KP-UM proved to be safe when tested in human keratinocytes. Although based on a chromogenic non-fluorescent protein, the KP-UM protein presented a photoswitch phenomenon, changing from chromogenic to fluorescent depending on the wavelength selected for excitation. KP-UM protein shows the potential to be incorporated in new eco-friendly cosmetic formulations for hair coloration, decreasing the use of traditional dyes and reducing its environmental impact.
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Affiliation(s)
- Ana Tinoco
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Egipto Antunes
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Madalena Martins
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Filipa Gonçalves
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Andreia C Gomes
- Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus of Gualtar, 4710-057, Braga, Portugal
| | - Carla Silva
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Artur Cavaco-Paulo
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
| | - Artur Ribeiro
- CEB - Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
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44
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Shinoda H, Lu K, Nakashima R, Wazawa T, Noguchi K, Matsuda T, Nagai T. Acid-Tolerant Reversibly Switchable Green Fluorescent Protein for Super-resolution Imaging under Acidic Conditions. Cell Chem Biol 2019; 26:1469-1479.e6. [DOI: 10.1016/j.chembiol.2019.07.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 06/13/2019] [Accepted: 07/23/2019] [Indexed: 02/08/2023]
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45
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Fan S, Webb JEA, Yang Y, Nieves DJ, Gonçales VR, Tran J, Hilzenrat G, Kahram M, Tilley RD, Gaus K, Gooding JJ. Observing the Reversible Single Molecule Electrochemistry of Alexa Fluor 647 Dyes by Total Internal Reflection Fluorescence Microscopy. Angew Chem Int Ed Engl 2019; 58:14495-14498. [DOI: 10.1002/anie.201907298] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/08/2019] [Indexed: 01/04/2023]
Affiliation(s)
- Sanjun Fan
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
| | - James E. A. Webb
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
| | - Ying Yang
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
| | - Daniel J. Nieves
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging University of New South Wales Sydney NSW 2052 Australia
| | - Vinicius R. Gonçales
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
| | - Jason Tran
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging University of New South Wales Sydney NSW 2052 Australia
| | - Geva Hilzenrat
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging University of New South Wales Sydney NSW 2052 Australia
| | - Mohaddeseh Kahram
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
| | - Richard D. Tilley
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
| | - Katharina Gaus
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging University of New South Wales Sydney NSW 2052 Australia
| | - J. Justin Gooding
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
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46
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Fan S, Webb JEA, Yang Y, Nieves DJ, Gonçales VR, Tran J, Hilzenrat G, Kahram M, Tilley RD, Gaus K, Gooding JJ. Observing the Reversible Single Molecule Electrochemistry of Alexa Fluor 647 Dyes by Total Internal Reflection Fluorescence Microscopy. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201907298] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Sanjun Fan
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
| | - James E. A. Webb
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
| | - Ying Yang
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
| | - Daniel J. Nieves
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging University of New South Wales Sydney NSW 2052 Australia
| | - Vinicius R. Gonçales
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
| | - Jason Tran
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging University of New South Wales Sydney NSW 2052 Australia
| | - Geva Hilzenrat
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging University of New South Wales Sydney NSW 2052 Australia
| | - Mohaddeseh Kahram
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
| | - Richard D. Tilley
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
| | - Katharina Gaus
- EMBL Australia Node in Single Molecule Science and ARC Centre of Excellence in Advanced Molecular Imaging University of New South Wales Sydney NSW 2052 Australia
| | - J. Justin Gooding
- School of Chemistry Australian Centre for NanoMedicine and The ARC Centre of Excellence in Convergent Bio-Nano Science and Technology University of New South Wales Sydney NSW 2052 Australia
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47
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Danylchuk DI, Moon S, Xu K, Klymchenko AS. Switchable Solvatochromic Probes for Live-Cell Super-resolution Imaging of Plasma Membrane Organization. Angew Chem Int Ed Engl 2019; 58:14920-14924. [PMID: 31392763 DOI: 10.1002/anie.201907690] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 08/01/2019] [Indexed: 12/25/2022]
Abstract
Visualization of the nanoscale organization of cell membranes remains challenging because of the lack of appropriate fluorescent probes. Herein, we introduce a new design concept for super-resolution microscopy probes that combines specific membrane targeting, on/off switching, and environment sensing functions. A functionalization strategy for solvatochromic dye Nile Red that improves its photostability is presented. The dye is grafted to a newly developed membrane-targeting moiety composed of a sulfonate group and an alkyl chain of varied lengths. While the long-chain probe with strong membrane binding, NR12A, is suitable for conventional microscopy, the short-chain probe NR4A, owing to the reversible binding, enables first nanoscale cartography of the lipid order exclusively at the surface of live cells. The latter probe reveals the presence of nanoscopic protrusions and invaginations of lower lipid order in plasma membranes, suggesting a subtle connection between membrane morphology and lipid organization.
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Affiliation(s)
- Dmytro I Danylchuk
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, 74 route du Rhin, 67401, Illkirch, France
| | - Seonah Moon
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA.,Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA
| | - Ke Xu
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, 94720, USA.,Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA
| | - Andrey S Klymchenko
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Université de Strasbourg, 74 route du Rhin, 67401, Illkirch, France
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48
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Switchable Solvatochromic Probes for Live‐Cell Super‐resolution Imaging of Plasma Membrane Organization. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201907690] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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49
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Dajnowicz S, Langan PS, Weiss KL, Ivanov IN, Kovalevsky A. Room-temperature photo-induced martensitic transformation in a protein crystal. IUCRJ 2019; 6:619-629. [PMID: 31316806 PMCID: PMC6608640 DOI: 10.1107/s2052252519005761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 04/26/2019] [Indexed: 06/10/2023]
Abstract
Martensitic transformations are the first-order crystal-to-crystal phase transitions that occur mostly in materials such as steel, alloys and ceramics, thus having many technological applications. These phase transitions are rarely observed in molecular crystals and have not been detected in protein crystals. Reversibly switchable fluorescent proteins are widely used in biotechnology, including super-resolution molecular imaging, and hold promise as candidate biomaterials for future high-tech applications. Here, we report on a reversibly switchable fluorescent protein, Tetdron, whose crystals undergo a photo-induced martensitic transformation at room temperature. Room-temperature X-ray crystallography demonstrates that at equilibrium Tetdron chromophores are all in the trans configuration, with an ∼1:1 mixture of their protonated and deprotonated forms. Irradiation of a Tetdron crystal with 400 nm light induces a martensitic transformation, which results in Tetdron tetramerization at room temperature revealed by X-ray photocrystallography. Crystal and solution spectroscopic measurements provide evidence that the photo-induced martensitic phase transition is coupled with the chromophore deprotonation, but no trans-cis isomerization is detected in the structure of an irradiated crystal. It is hypothesized that protein dynamics assists in the light-induced proton transfer from the chromophore to the bulk solvent and in the ensuing martensitic phase transition. The unique properties of Tetdron may be useful in developing novel biomaterials for optogenetics, data storage and nanotechnology.
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Affiliation(s)
- Steven Dajnowicz
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio 43606, USA
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Patricia S. Langan
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Kevin L. Weiss
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Ilia N. Ivanov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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Jöhr R, Bauer MS, Schendel LC, Kluger C, Gaub HE. Dronpa: A Light-Switchable Fluorescent Protein for Opto-Biomechanics. NANO LETTERS 2019; 19:3176-3181. [PMID: 30912662 DOI: 10.1021/acs.nanolett.9b00639] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Since the development of the green fluorescent protein, fluorescent proteins (FP) are indispensable tools in molecular biology. Some FPs change their structure under illumination, which affects their interaction with other biomolecules or proteins. In particular, FPs that are able to form switchable dimers became an important tool in the field of optogenetics. They are widely used for the investigation of signaling pathways, the control of surface recruitment, as well as enzyme and gene regulation. However, optogenetics did not yet develop tools for the investigation of biomechanical processes. This could be leveraged if one could find a light-switchable FP dimer that is able to withstand sufficiently high forces. In this work, we measure the rupture force of the switchable interface in pdDronpa1.2 dimers using atomic force microscopy-based single molecule force spectroscopy. The most probable dimer rupture force amounts to around 80 pN at a pulling speed of 1600 nm/s. After switching of the dimer using illumination at 488 nm, there are hardly any measurable interface interactions, which indicates the successful dissociation of the dimers. Hence this Dronpa dimer could expand the current toolbox in optogenetics with new opto-biomechanical applications like the control of tension in adhesion processes.
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Affiliation(s)
- Res Jöhr
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , Munich 80799 , Germany
| | - Magnus S Bauer
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , Munich 80799 , Germany
| | - Leonard C Schendel
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , Munich 80799 , Germany
| | - Carleen Kluger
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , Munich 80799 , Germany
| | - Hermann E Gaub
- Lehrstuhl für Angewandte Physik and Center for Nanoscience , Ludwig-Maximilians-Universität , Munich 80799 , Germany
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