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Wills MF, Alejo CB, Hundt N, Hudson AJ, Eperon IC. FluoroTensor: Identification and tracking of colocalised molecules and their stoichiometries in multi-colour single molecule imaging via deep learning. Comput Struct Biotechnol J 2024; 23:918-928. [PMID: 38375530 PMCID: PMC10875188 DOI: 10.1016/j.csbj.2024.02.004] [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: 11/17/2023] [Revised: 02/06/2024] [Accepted: 02/06/2024] [Indexed: 02/21/2024] Open
Abstract
The identification of photobleaching steps in single molecule fluorescence imaging is a well-established procedure for analysing the stoichiometries of molecular complexes. Nonetheless, the method is challenging with protein fluorophores because of the high levels of noise, rapid bleaching and highly variable signal intensities, all of which complicate methods based on statistical analyses of intensities to identify bleaching steps. It has recently been shown that deep learning by convolutional neural networks can yield an accurate analysis with a relatively short computational time. We describe here an improved use of such an approach that detects bleaching events even in the first time point of observation, and we have included this within an integrated software package incorporating fluorescence spot detection, colocalisation, tracking, FRET and photobleaching step analyses of single molecules or complexes. This package, known as FluoroTensor, is written in Python with a self-explanatory user interface.
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Affiliation(s)
- Max F.K. Wills
- Institute for Structural and Chemical Biology, University of Leicester, UK
- Department of Molecular and Cell Biology, University of Leicester, UK
| | - Carlos Bueno Alejo
- Institute for Structural and Chemical Biology, University of Leicester, UK
- Department of Chemistry, University of Leicester, UK
| | - Nikolas Hundt
- Department of Cellular Physiology, Ludwig-Maximilians-Universität München, Germany
| | - Andrew J. Hudson
- Institute for Structural and Chemical Biology, University of Leicester, UK
- Department of Chemistry, University of Leicester, UK
| | - Ian C. Eperon
- Institute for Structural and Chemical Biology, University of Leicester, UK
- Department of Molecular and Cell Biology, University of Leicester, UK
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2
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Liu L, Zhang X, Fedeli S, Cicek YA, Ndugire W, Rotello VM. Controlled Bio-Orthogonal Catalysis Using Nanozyme-Protein Complexes via Modulation of Electrostatic Interactions. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1507. [PMID: 38612022 PMCID: PMC11012815 DOI: 10.3390/ma17071507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 03/15/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024]
Abstract
Bio-orthogonal chemistry provides a powerful tool for drug delivery systems due to its ability to generate therapeutic agents in situ, minimizing off-target effects. Bio-orthogonal transition metal catalysts (TMCs) with stimuli-responsive properties offer possibilities for controllable catalysis due to their spatial-, temporal-, and dosage-controllable properties. In this paper, we fabricated a stimuli-responsive bio-orthogonal catalysis system based on an enhanced green fluorescent protein (EGFP)-nanozyme (NZ) complex (EGFP-NZ). Regulation of the catalytic properties of the EGFP-NZ complex was directly achieved by modulating the ionic strength of the solution. The dielectric screening introduced by salt ions allows the dissociation of the EGFP-NZ complex, increasing the access of substrate to the active site of the NZs and concomitantly increasing nanozyme activity. The change in catalytic rate of the NZ/EGFP = 1:1 complex was positively correlated with salt concentration from 0 mM to 150 mM.
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Affiliation(s)
| | | | | | | | | | - Vincent M. Rotello
- Department of Chemistry, University of Massachusetts Amherst, 710 N. Pleasant St., Amherst, MA 01003, USA; (L.L.); (X.Z.); (S.F.); (Y.A.C.)
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3
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Chandler T, Guo M, Su Y, Chen J, Wu Y, Liu J, Agashe A, Fischer RS, Mehta SB, Kumar A, Baskin TI, Jamouillé V, Liu H, Swaminathan V, Nain A, Oldenbourg R, Riviére PL, Shroff H. Three-dimensional spatio-angular fluorescence microscopy with a polarized dual-view inverted selective-plane illumination microscope (pol-diSPIM). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.09.584243. [PMID: 38712306 PMCID: PMC11071302 DOI: 10.1101/2024.03.09.584243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Polarized fluorescence microscopy is a valuable tool for measuring molecular orientations, but techniques for recovering three-dimensional orientations and positions of fluorescent ensembles are limited. We report a polarized dual-view light-sheet system for determining the three-dimensional orientations and diffraction-limited positions of ensembles of fluorescent dipoles that label biological structures, and we share a set of visualization, histogram, and profiling tools for interpreting these positions and orientations. We model our samples, their excitation, and their detection using coarse-grained representations we call orientation distribution functions (ODFs). We apply ODFs to create physics-informed models of image formation with spatio-angular point-spread and transfer functions. We use theory and experiment to conclude that light-sheet tilting is a necessary part of our design for recovering all three-dimensional orientations. We use our system to extend known two-dimensional results to three dimensions in FM1-43-labelled giant unilamellar vesicles, fast-scarlet-labelled cellulose in xylem cells, and phalloidin-labelled actin in U2OS cells. Additionally, we observe phalloidin-labelled actin in mouse fibroblasts grown on grids of labelled nanowires and identify correlations between local actin alignment and global cell-scale orientation, indicating cellular coordination across length scales.
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Affiliation(s)
- Talon Chandler
- CZ Biohub SF, San Francisco, 94158, California, USA
- Department of Radiology, University of Chicago, Chicago, 60637, Illinois, USA
| | - Min Guo
- State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310027, Zhejiang, China
- Laboratory of High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, 20892, Maryland, USA
| | - Yijun Su
- Laboratory of High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, 20892, Maryland, USA
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, 20892, Maryland, USA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, 20147, Virginia, USA
| | - Jiji Chen
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, 20892, Maryland, USA
| | - Yicong Wu
- Laboratory of High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, 20892, Maryland, USA
| | - Junyu Liu
- State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310027, Zhejiang, China
| | - Atharva Agashe
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, 24061, Virginia, USA
| | - Robert S. Fischer
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, 20892, Maryland, USA
| | - Shalin B. Mehta
- CZ Biohub SF, San Francisco, 94158, California, USA
- Department of Radiology, University of Chicago, Chicago, 60637, Illinois, USA
- Bell Center, Marine Biological Laboratory, Woods Hole, 02543, Massachusetts, USA
| | - Abhishek Kumar
- Bell Center, Marine Biological Laboratory, Woods Hole, 02543, Massachusetts, USA
| | - Tobias I. Baskin
- Biology Department, University of Massachusetts, Amherst, 01003, Maryland, USA
- Whitman Center, Marine Biological Laboratory, Woods Hole, 02543, Massachusetts, USA
| | - Valentin Jamouillé
- Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, 20892, Maryland, USA
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, V5A 1S6, British Columbia, Canada
| | - Huafeng Liu
- State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310027, Zhejiang, China
| | - Vinay Swaminathan
- Department of Clinical Sciences, Lund University, Lund, SE-221 00, Scania, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, SE-221 00, Scania, Sweden
| | - Amrinder Nain
- Department of Mechanical Engineering, Virginia Tech, Blacksburg, 24061, Virginia, USA
- Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, 24061, Virginia, USA
| | - Rudolf Oldenbourg
- Bell Center, Marine Biological Laboratory, Woods Hole, 02543, Massachusetts, USA
| | - Patrick La Riviére
- Department of Radiology, University of Chicago, Chicago, 60637, Illinois, USA
- Whitman Center, Marine Biological Laboratory, Woods Hole, 02543, Massachusetts, USA
| | - Hari Shroff
- Laboratory of High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, 20892, Maryland, USA
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, 20892, Maryland, USA
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, 20147, Virginia, USA
- Whitman Center, Marine Biological Laboratory, Woods Hole, 02543, Massachusetts, USA
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4
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Fessl T, Majellaro M, Bondar A. Microscopy and spectroscopy approaches to study GPCR structure and function. Br J Pharmacol 2023. [PMID: 38087925 DOI: 10.1111/bph.16297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 11/03/2023] [Accepted: 11/30/2023] [Indexed: 01/05/2024] Open
Abstract
The GPCR signalling cascade is a key pathway responsible for the signal transduction of a multitude of physical and chemical stimuli, including light, odorants, neurotransmitters and hormones. Understanding the structural and functional properties of the GPCR cascade requires direct observation of signalling processes in high spatial and temporal resolution, with minimal perturbation to endogenous systems. Optical microscopy and spectroscopy techniques are uniquely suited to this purpose because they excel at multiple spatial and temporal scales and can be used in living objects. Here, we review recent developments in microscopy and spectroscopy technologies which enable new insights into GPCR signalling. We focus on advanced techniques with high spatial and temporal resolution, single-molecule methods, labelling strategies and approaches suitable for endogenous systems and large living objects. This review aims to assist researchers in choosing appropriate microscopy and spectroscopy approaches for a variety of applications in the study of cellular signalling.
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Affiliation(s)
- Tomáš Fessl
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | | | - Alexey Bondar
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Laboratory of Microscopy and Histology, Institute of Entomology, Biology Centre of the Czech Academy of Sciences, České Budějovice, Czech Republic
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5
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Khoroshyy P, Martinez-Seara H, Myšková J, Lazar J. Dynamics of transition dipole moment orientation in representative fluorescent proteins. Phys Chem Chem Phys 2023; 25:22117-22123. [PMID: 37560975 DOI: 10.1039/d3cp01242e] [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: 08/11/2023]
Abstract
Molecules of fluorescent proteins (FPs) exhibit distinct optical directionality. This optical directionality is characterized by transition dipole moments (TDMs), and their orientation with respect to the molecular structures. Although our recent observations of FP crystals allowed us to determine the mean TDM directions with respect to the framework of representative FP molecules, the dynamics of TDM orientations within FP molecules remain to be ascertained. Here we describe the results of our investigations of the dynamics of TDM directions in the fluorescent proteins eGFP, mTurquoise2 and mCherry, through time-resolved fluorescence polarization measurements and microsecond time scale all-atom molecular dynamics (MD) simulations. The investigated FPs exhibit initial fluorescence anisotropies (r0) consistent with significant differences in the orientation of the excitation and emission TDMs. However, based on MD data, we largely attribute this observation to rapid (sub-nanosecond) fluorophore motions within the FP molecular framework. Our results allow improved determinations of orientational distributions of FP molecules by polarization microscopy, as well as more accurate interpretations of fluorescence resonance energy transfer (FRET) observations.
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Affiliation(s)
- Petro Khoroshyy
- Inst. of Organic Chemistry and Biochemistry CAS, Flemingovo nám. 2, 160 00, Prague 6, Czech Republic
- 1st Faculty of Medicine, Charles University, Albertov 4, 128 00, Prague 2, Czech Republic.
| | - Hector Martinez-Seara
- Inst. of Organic Chemistry and Biochemistry CAS, Flemingovo nám. 2, 160 00, Prague 6, Czech Republic
| | - Jitka Myšková
- 1st Faculty of Medicine, Charles University, Albertov 4, 128 00, Prague 2, Czech Republic.
| | - Josef Lazar
- Inst. of Organic Chemistry and Biochemistry CAS, Flemingovo nám. 2, 160 00, Prague 6, Czech Republic
- 1st Faculty of Medicine, Charles University, Albertov 4, 128 00, Prague 2, Czech Republic.
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6
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van Zanten TS, S GP, Mayor S. Quantitative fluorescence emission anisotropy microscopy for implementing homo-fluorescence resonance energy transfer measurements in living cells. Mol Biol Cell 2023; 34:tp1. [PMID: 37144969 DOI: 10.1091/mbc.e22-09-0446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023] Open
Abstract
Quantitative fluorescence emission anisotropy microscopy reveals the organization of fluorescently labeled cellular components and allows their characterization in terms of changes in either rotational diffusion or homo-Förster's energy transfer characteristics in living cells. These properties provide insights into molecular organization, such as orientation, confinement, and oligomerization in situ. Here we elucidate how quantitative measurements of anisotropy using multiple microscope systems may be made by bringing out the main parameters that influence the quantification of fluorescence emission anisotropy. We focus on a variety of parameters that contribute to errors associated with the measurement of emission anisotropy in a microscope. These include the requirement for adequate photon counts for the necessary discrimination of anisotropy values, the influence of extinction ratios of the illumination source, the detector system, the role of numerical aperture, and excitation wavelength. All these parameters also affect the ability to capture the dynamic range of emission anisotropy necessary for quantifying its reduction due to homo-FRET and other processes. Finally, we provide easily implementable tests to assess whether homo-FRET is a cause for the observed emission depolarization.
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Affiliation(s)
- Thomas S van Zanten
- Cell Biology Group, National Centre for Biological Sciences, UAS-GKVK Campus, Tata Institute for Fundamental Research, Bangalore 560065, India
| | - Greeshma Pradeep S
- Cell Biology Group, National Centre for Biological Sciences, UAS-GKVK Campus, Tata Institute for Fundamental Research, Bangalore 560065, India
| | - Satyajit Mayor
- Cell Biology Group, National Centre for Biological Sciences, UAS-GKVK Campus, Tata Institute for Fundamental Research, Bangalore 560065, India
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7
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Liebert A, Capon W, Pang V, Vila D, Bicknell B, McLachlan C, Kiat H. Photophysical Mechanisms of Photobiomodulation Therapy as Precision Medicine. Biomedicines 2023; 11:biomedicines11020237. [PMID: 36830774 PMCID: PMC9953702 DOI: 10.3390/biomedicines11020237] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 01/19/2023] Open
Abstract
Despite a significant focus on the photochemical and photoelectrical mechanisms underlying photobiomodulation (PBM), its complex functions are yet to be fully elucidated. To date, there has been limited attention to the photophysical aspects of PBM. One effect of photobiomodulation relates to the non-visual phototransduction pathway, which involves mechanotransduction and modulation to cytoskeletal structures, biophotonic signaling, and micro-oscillatory cellular interactions. Herein, we propose a number of mechanisms of PBM that do not depend on cytochrome c oxidase. These include the photophysical aspects of PBM and the interactions with biophotons and mechanotransductive processes. These hypotheses are contingent on the effect of light on ion channels and the cytoskeleton, the production of biophotons, and the properties of light and biological molecules. Specifically, the processes we review are supported by the resonant recognition model (RRM). This previous research demonstrated that protein micro-oscillations act as a signature of their function that can be activated by resonant wavelengths of light. We extend this work by exploring the local oscillatory interactions of proteins and light because they may affect global body circuits and could explain the observed effect of PBM on neuro-cortical electroencephalogram (EEG) oscillations. In particular, since dysrhythmic gamma oscillations are associated with neurodegenerative diseases and pain syndromes, including migraine with aura and fibromyalgia, we suggest that transcranial PBM should target diseases where patients are affected by impaired neural oscillations and aberrant brain wave patterns. This review also highlights examples of disorders potentially treatable with precise wavelengths of light by mimicking protein activity in other tissues, such as the liver, with, for example, Crigler-Najjar syndrome and conditions involving the dysregulation of the cytoskeleton. PBM as a novel therapeutic modality may thus behave as "precision medicine" for the treatment of various neurological diseases and other morbidities. The perspectives presented herein offer a new understanding of the photophysical effects of PBM, which is important when considering the relevance of PBM therapy (PBMt) in clinical applications, including the treatment of diseases and the optimization of health outcomes and performance.
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Affiliation(s)
- Ann Liebert
- Faculty of Medicine and Health, University of Sydney, Sydney 2006, Australia
- Adventist Hospital Group, Wahroonga 2076, Australia
- NICM Health Research Institute, Western Sydney University, Westmead 2145, Australia
- Correspondence:
| | - William Capon
- Faculty of Medicine and Health, University of Sydney, Sydney 2006, Australia
| | - Vincent Pang
- NICM Health Research Institute, Western Sydney University, Westmead 2145, Australia
| | - Damien Vila
- Faculty of Medicine of Montpellier-Nîmes, University of Montpellier, 34090 Montpellier, France
| | - Brian Bicknell
- NICM Health Research Institute, Western Sydney University, Westmead 2145, Australia
| | - Craig McLachlan
- Faculty of Health, Torrens University, Adelaide 5000, Australia
| | - Hosen Kiat
- NICM Health Research Institute, Western Sydney University, Westmead 2145, Australia
- Faculty of Health, Torrens University, Adelaide 5000, Australia
- Cardiac Health Institute, Sydney 2121, Australia
- ANU College of Health and Medicine, Australian National University, Canberra 2600, Australia
- Faculty of Medicine, Health and Human Sciences, Macquarie University, Macquarie Park 2109, Australia
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8
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Dean WF, Mattheyses AL. Defining domain-specific orientational order in the desmosomal cadherins. Biophys J 2022; 121:4325-4341. [PMID: 36225113 PMCID: PMC9703042 DOI: 10.1016/j.bpj.2022.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 09/12/2022] [Accepted: 10/06/2022] [Indexed: 01/25/2023] Open
Abstract
Desmosomes are large, macromolecular protein assemblies that mechanically couple the intermediate filament cytoskeleton to sites of cadherin-mediated cell adhesion, thereby providing structural integrity to tissues that routinely experience large forces. Proper desmosomal adhesion is necessary for the normal development and maintenance of vertebrate tissues, such as epithelia and cardiac muscle, while dysfunction can lead to severe disease of the heart and skin. Therefore, it is important to understand the relationship between desmosomal adhesion and the architecture of the molecules that form the adhesive interface, the desmosomal cadherins (DCs). However, desmosomes are embedded in two plasma membranes and are linked to the cytoskeletal networks of two cells, imposing extreme difficulty on traditional structural studies of DC architecture, which have yielded conflicting results. Consequently, the relationship between DC architecture and adhesive function remains unclear. To overcome these challenges, we utilized excitation-resolved fluorescence polarization microscopy to quantify the orientational order of the extracellular and intracellular domains of three DC isoforms: desmoglein 2, desmocollin 2, and desmoglein 3. We found that DC ectodomains were significantly more ordered than their cytoplasmic counterparts, indicating a drastic difference in DC architecture between opposing sides of the plasma membrane. This difference was conserved among all DCs tested, suggesting that it may be an important feature of desmosomal architecture. Moreover, our findings suggest that the organization of DC ectodomains is predominantly the result of extracellular adhesive interactions. We employed azimuthal orientation mapping to show that DC ectodomains are arranged with rotational symmetry about the membrane normal. Finally, we performed a series of mathematical simulations to test the feasibility of a recently proposed antiparallel arrangement of DC ectodomains, finding that it is supported by our experimental data. Importantly, the strategies employed here have the potential to elucidate molecular mechanisms for diseases that result from defective desmosome architecture.
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Affiliation(s)
- William F Dean
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Alexa L Mattheyses
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama.
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9
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AlphaFold2 and RoseTTAFold predict posttranslational modifications. Chromophore formation in GFP-like proteins. PLoS One 2022; 17:e0267560. [PMID: 35709156 PMCID: PMC9202861 DOI: 10.1371/journal.pone.0267560] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 04/12/2022] [Indexed: 11/26/2022] Open
Abstract
AlphaFold2 and RoseTTAfold are able to predict, based solely on their sequence whether GFP-like proteins will post-translationally form a chromophore (the part of the protein responsible for fluorescence) or not. Their training has not only taught them protein structure and folding, but also chemistry. The structures of 21 sequences of GFP-like fluorescent proteins that will post-translationally form a chromophore and of 23 GFP-like non-fluorescent proteins that do not have the residues required to form a chromophore were determined by AlphaFold2 and RoseTTAfold. The resultant structures were mined for a series of geometric measurements that are crucial to chromophore formation. Statistical analysis of these measurements showed that both programs conclusively distinguished between chromophore forming and non-chromophore forming proteins. A clear distinction between sequences capable of forming a chromophore and those that do not have the residues required for chromophore formation can be obtained by examining a single measurement—the RMSD of the overlap of the central alpha helices of the crystal structure of S65T GFP and the AlphaFold2 determined structure. Only 10 of the 578 GFP-like proteins in the pdb have no chromophore, yet when AlphaFold2 and RoseTTAFold are presented with the sequences of 44 GFP-like proteins that are not in the pdb they fold the proteins in such a way that one can unequivocally distinguish between those that can and cannot form a chromophore.
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10
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Mukherjee S, Jimenez R. Photophysical Engineering of Fluorescent Proteins: Accomplishments and Challenges of Physical Chemistry Strategies. J Phys Chem B 2022; 126:735-750. [DOI: 10.1021/acs.jpcb.1c05629] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Srijit Mukherjee
- JILA, University of Colorado at Boulder and National Institute of Standards and Technology, 440 UCB, Boulder, Colorado 80309, United States
- Department of Chemistry, University of Colorado at Boulder, 215 UCB, Boulder, Colorado 80309, United States
| | - Ralph Jimenez
- JILA, University of Colorado at Boulder and National Institute of Standards and Technology, 440 UCB, Boulder, Colorado 80309, United States
- Department of Chemistry, University of Colorado at Boulder, 215 UCB, Boulder, Colorado 80309, United States
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11
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Javanainen M, Martinez-Seara H, Kelly CV, Jungwirth P, Fábián B. Anisotropic diffusion of membrane proteins at experimental timescales. J Chem Phys 2021; 155:015102. [PMID: 34241397 DOI: 10.1063/5.0054973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Single-particle tracking (SPT) experiments of lipids and membrane proteins provide a wealth of information about the properties of biomembranes. Careful analysis of SPT trajectories can reveal deviations from ideal Brownian behavior. Among others, this includes confinement effects and anomalous diffusion, which are manifestations of both the nanoscale structure of the underlying membrane and the structure of the diffuser. With the rapid increase in temporal and spatial resolution of experimental methods, a new aspect of the motion of the particle, namely, anisotropic diffusion, might become relevant. This aspect that so far received only little attention is the anisotropy of the diffusive motion and may soon provide an additional proxy to the structure and topology of biomembranes. Unfortunately, the theoretical framework for detecting and interpreting anisotropy effects is currently scattered and incomplete. Here, we provide a computational method to evaluate the degree of anisotropy directly from molecular dynamics simulations and also point out a way to compare the obtained results with those available from SPT experiments. In order to probe the effects of anisotropic diffusion, we performed coarse-grained molecular dynamics simulations of peripheral and integral membrane proteins in flat and curved bilayers. In agreement with the theoretical basis, our computational results indicate that anisotropy can persist up to the rotational relaxation time [τ=(2Dr)-1], after which isotropic diffusion is observed. Moreover, the underlying topology of the membrane bilayer can couple with the geometry of the particle, thus extending the spatiotemporal domain over which this type of motion can be detected.
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Affiliation(s)
- Matti Javanainen
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 542/2, 160 00 Prague 6, Czech Republic
| | - Hector Martinez-Seara
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 542/2, 160 00 Prague 6, Czech Republic
| | - Christopher V Kelly
- Department of Physics and Astronomy, Wayne State University, 666 W Hancock Street, Detroit, Michigan 48201, USA
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 542/2, 160 00 Prague 6, Czech Republic
| | - Balázs Fábián
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 542/2, 160 00 Prague 6, Czech Republic
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12
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Visual pH Sensors: From a Chemical Perspective to New Bioengineered Materials. Molecules 2021; 26:molecules26102952. [PMID: 34065629 PMCID: PMC8156760 DOI: 10.3390/molecules26102952] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/11/2021] [Accepted: 05/14/2021] [Indexed: 02/05/2023] Open
Abstract
Many human activities and cellular functions depend upon precise pH values, and pH monitoring is considered a fundamental task. Colorimetric and fluorescence sensors for pH measurements are chemical and biochemical tools able to sense protons and produce a visible signal. These pH sensors are gaining widespread attention as non-destructive tools, visible to the human eye, that are capable of a real-time and in-situ response. Optical “visual” sensors are expanding researchers’ interests in many chemical contexts and are routinely used for biological, environmental, and medical applications. In this review we provide an overview of trending colorimetric, fluorescent, or dual-mode responsive visual pH sensors. These sensors include molecular synthetic organic sensors, metal organic frameworks (MOF), engineered sensing nanomaterials, and bioengineered sensors. We review different typological chemical entities of visual pH sensors, three-dimensional structures, and signaling mechanisms for pH sensing and applications; developed in the past five years. The progression of this review from simple organic molecules to biological macromolecules seeks to benefit beginners and scientists embarking on a project of pH sensing development, who needs background information and a quick update on advances in the field. Lessons learned from these tools will aid pH determination projects and provide new ways of thinking for cell bioimaging or other cutting-edge in vivo applications.
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13
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Bondar A, Rybakova O, Melcr J, Dohnálek J, Khoroshyy P, Ticháček O, Timr Š, Miclea P, Sakhi A, Marková V, Lazar J. Quantitative linear dichroism imaging of molecular processes in living cells made simple by open software tools. Commun Biol 2021; 4:189. [PMID: 33580182 PMCID: PMC7881160 DOI: 10.1038/s42003-021-01694-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 01/11/2021] [Indexed: 11/09/2022] Open
Abstract
Fluorescence-detected linear dichroism microscopy allows observing various molecular processes in living cells, as well as obtaining quantitative information on orientation of fluorescent molecules associated with cellular features. Such information can provide insights into protein structure, aid in development of genetically encoded probes, and allow determinations of lipid membrane properties. However, quantitating and interpreting linear dichroism in biological systems has been laborious and unreliable. Here we present a set of open source ImageJ-based software tools that allow fast and easy linear dichroism visualization and quantitation, as well as extraction of quantitative information on molecular orientations, even in living systems. The tools were tested on model synthetic lipid vesicles and applied to a variety of biological systems, including observations of conformational changes during G-protein signaling in living cells, using fluorescent proteins. Our results show that our tools and model systems are applicable to a wide range of molecules and polarization-resolved microscopy techniques, and represent a significant step towards making polarization microscopy a mainstream tool of biological imaging.
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Affiliation(s)
- Alexey Bondar
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Praha 6, Czech Republic
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Czech Academy of Science, Nove Hrady, Czech Republic
| | - Olga Rybakova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Praha 6, Czech Republic
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Czech Academy of Science, Nove Hrady, Czech Republic
| | - Josef Melcr
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Praha 6, Czech Republic
- Groningen Biomolecular Sciences and Biotechnology Institute and the Zernike Institute for Advanced Materials, University of Groningen, Groningen, Netherlands
| | - Jan Dohnálek
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Praha 6, Czech Republic
| | - Petro Khoroshyy
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Praha 6, Czech Republic
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Czech Academy of Science, Nove Hrady, Czech Republic
| | - Ondřej Ticháček
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Praha 6, Czech Republic
| | - Štěpán Timr
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Praha 6, Czech Republic
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, 13 rue Pierre et Marie Curie, Paris, France
- Institut de Biologie Physico-Chimique-Fondation Edmond de Rothschild, PSL Research University, Paris, France
| | - Paul Miclea
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Praha 6, Czech Republic
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Czech Academy of Science, Nove Hrady, Czech Republic
| | - Alina Sakhi
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Praha 6, Czech Republic
| | - Vendula Marková
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Praha 6, Czech Republic
- Faculty of Sciences, Charles University, Prague, Czech Republic
| | - Josef Lazar
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Science, Praha 6, Czech Republic.
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Czech Academy of Science, Nove Hrady, Czech Republic.
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Drobizhev M, Molina RS, Callis PR, Scott JN, Lambert GG, Salih A, Shaner NC, Hughes TE. Local Electric Field Controls Fluorescence Quantum Yield of Red and Far-Red Fluorescent Proteins. Front Mol Biosci 2021; 8:633217. [PMID: 33763453 PMCID: PMC7983054 DOI: 10.3389/fmolb.2021.633217] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/06/2021] [Indexed: 12/17/2022] Open
Abstract
Genetically encoded probes with red-shifted absorption and fluorescence are highly desirable for imaging applications because they can report from deeper tissue layers with lower background and because they provide additional colors for multicolor imaging. Unfortunately, red and especially far-red fluorescent proteins have very low quantum yields, which undermines their other advantages. Elucidating the mechanism of nonradiative relaxation in red fluorescent proteins (RFPs) could help developing ones with higher quantum yields. Here we consider two possible mechanisms of fast nonradiative relaxation of electronic excitation in RFPs. The first, known as the energy gap law, predicts a steep exponential drop of fluorescence quantum yield with a systematic red shift of fluorescence frequency. In this case the relaxation of excitation occurs in the chromophore without any significant changes of its geometry. The second mechanism is related to a twisted intramolecular charge transfer in the excited state, followed by an ultrafast internal conversion. The chromophore twisting can strongly depend on the local electric field because the field can affect the activation energy. We present a spectroscopic method of evaluating local electric fields experienced by the chromophore in the protein environment. The method is based on linear and two-photon absorption spectroscopy, as well as on quantum-mechanically calculated parameters of the isolated chromophore. Using this method, which is substantiated by our molecular dynamics simulations, we obtain the components of electric field in the chromophore plane for seven different RFPs with the same chromophore structure. We find that in five of these RFPs, the nonradiative relaxation rate increases with the strength of the field along the chromophore axis directed from the center of imidazolinone ring to the center of phenolate ring. Furthermore, this rate depends on the corresponding electrostatic energy change (calculated from the known fields and charge displacements), in quantitative agreement with the Marcus theory of charge transfer. This result supports the dominant role of the twisted intramolecular charge transfer mechanism over the energy gap law for most of the studied RFPs. It provides important guidelines of how to shift the absorption wavelength of an RFP to the red, while keeping its brightness reasonably high.
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Affiliation(s)
- Mikhail Drobizhev
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT, United States
| | - Rosana S Molina
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT, United States
| | - Patrik R Callis
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, United States
| | | | - Gerard G Lambert
- Department of Neurosciences, UC San Diego, San Diego, CA, United States
| | - Anya Salih
- Antares & Fluoresci Research, Dangar Island, NSW, Australia
| | - Nathan C Shaner
- Department of Neurosciences, UC San Diego, San Diego, CA, United States
| | - Thomas E Hughes
- Department of Cell Biology and Neuroscience, Montana State University, Bozeman, MT, United States
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