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Dhir A, Gogoi H, Datta A. Modulation of FRET efficiency by donor-acceptor ratio in co-condensed fluorophore-silica nanoconjugates. J INDIAN CHEM SOC 2021. [DOI: 10.1016/j.jics.2021.100067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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2
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Zaitoun MA. Investigation of the Chemistry for the Host Sol‐Gel Glass via the Energy Transfer Fluorescence of Encapsulated Organic‐Tb(III) Complexes. ChemistrySelect 2019. [DOI: 10.1002/slct.201900594] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mohammed A. Zaitoun
- Department of Pharmaceutical Sciences-Faculty of Pharmacy-Yarmouk University 21163 Irbid Jordan
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3
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Somoza Márquez A, Chen L, Sun K, Zhao Y. Probing ultrafast excitation energy transfer of the chlorosome with exciton–phonon variational dynamics. Phys Chem Chem Phys 2016; 18:20298-311. [DOI: 10.1039/c5cp06491k] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Excitation energy transfer of the chlorosome is investigated using exciton–phonon variational dynamics revealing ultrafast energy relaxation and exciton delocalization on a 100 fs scale.
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Affiliation(s)
| | - Lipeng Chen
- Division of Materials Science
- Nanyang Technological University
- Singapore 639798
- Singapore
| | - Kewei Sun
- School of Science
- Hangzhou Dianzi University
- Hangzhou 310018
- China
| | - Yang Zhao
- Division of Materials Science
- Nanyang Technological University
- Singapore 639798
- Singapore
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4
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Anunciado D, Rai DK, Qian S, Urban V, O'Neill H. Small-angle neutron scattering reveals the assembly of alpha-synuclein in lipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1881-1889. [PMID: 26321599 DOI: 10.1016/j.bbapap.2015.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/12/2015] [Accepted: 08/25/2015] [Indexed: 12/15/2022]
Abstract
The aggregation of α-synuclein (asyn), an intrinsically disordered protein (IDP), is a hallmark in Parkinson's disease (PD). We investigated the conformational changes that asyn undergoes in the presence of membrane and membrane mimetics using small-angle neutron scattering (SANS). In solution, asyn is monomeric and unfolded assuming an ensemble of conformers spanning extended and compact conformations. Using the contrast variation technique and SANS, the protein scattering signal in the membrane-protein complexes is selectively highlighted in order to monitor its conformational changes in this environment. We showed that in the presence of phospholipid membranes asyn transitions from a monodisperse state to aggregated structures with sizes ranging from 200 to 900Å coexisting with the monomeric species. Detailed SANS data analysis revealed that asyn aggregates have a hierarchical organization in which clusters of smaller asyn aggregates assemble to form the larger structures. This study provides new insight into the mechanism of asyn aggregation. We propose an aggregation mechanism in which stable asyn aggregates seed the aggregation process and hence the hierarchical assembly of structures. Our findings demonstrate that membrane-induced conformational changes in asyn lead to its heterogeneous aggregation which could be physiologically relevant in its function or in the diseased state.
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Affiliation(s)
- Divina Anunciado
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
| | - Durgesh K Rai
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
| | - Shuo Qian
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
| | - Volker Urban
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
| | - Hugh O'Neill
- Biology and Soft Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, United States
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5
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Heberle FA, Myles DAA, Katsaras J. Biomembranes research using thermal and cold neutrons. Chem Phys Lipids 2015; 192:41-50. [PMID: 26241882 DOI: 10.1016/j.chemphyslip.2015.07.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 07/25/2015] [Accepted: 07/27/2015] [Indexed: 01/26/2023]
Abstract
In 1932 James Chadwick discovered the neutron using a polonium source and a beryllium target (Chadwick, 1932). In a letter to Niels Bohr dated February 24, 1932, Chadwick wrote: "whatever the radiation from Be may be, it has most remarkable properties." Where it concerns hydrogen-rich biological materials, the "most remarkable" property is the neutron's differential sensitivity for hydrogen and its isotope deuterium. Such differential sensitivity is unique to neutron scattering, which unlike X-ray scattering, arises from nuclear forces. Consequently, the coherent neutron scattering length can experience a dramatic change in magnitude and phase as a result of resonance scattering, imparting sensitivity to both light and heavy atoms, and in favorable cases to their isotopic variants. This article describes recent biomembranes research using a variety of neutron scattering techniques.
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Affiliation(s)
- F A Heberle
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge, TN, 37831, United States; Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, United States
| | - D A A Myles
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge, TN, 37831, United States
| | - J Katsaras
- Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge, TN, 37831, United States; Joint Institute for Neutron Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, United States; Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, United States.
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6
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Roeder S, Hobe S, Paulsen H. Silica entrapment for significantly stabilized, energy-conducting light-harvesting complex (LHCII). LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:14234-14240. [PMID: 25365647 DOI: 10.1021/la503858t] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The major light-harvesting chlorophyll a/b complex (LHCII) of the photosynthetic apparatus in green plants consists of a membrane protein and numerous noncovalently bound pigments that make up about one-third of the molecular mass of the pigment-protein complex. Due to this high pigment density, LHCII is potentially interesting as a light-harvesting component in synthetic constructs. However, for such applications its stability needs to be significantly improved. In this work, LHCII was dramatically stabilized by enclosing it within polymerizing colloidal silica. The entrapped LHCII stayed functional at 50 °C for up to 24 h instead of a few minutes in detergent solution and clearly showed energy transfer between complexes. Entrapment yield was enhanced by a polycationic peptide attached to the N terminus. Both the extent of stabilization and the yield of entrapment strongly increased with decreasing diameters of the silica particles.
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Affiliation(s)
- Sebastian Roeder
- Institut für Allgemeine Botanik, Johannes Gutenberg-Universität Mainz , Johannes-von-Muellerweg 6, 55099 Mainz, Germany
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Wang Y, Freund DM, Magdaong NM, Urban VS, Frank HA, Hegeman AD, Tang JKH. Impact of esterified bacteriochlorophylls on the biogenesis of chlorosomes in Chloroflexus aurantiacus. PHOTOSYNTHESIS RESEARCH 2014; 122:69-86. [PMID: 24880610 DOI: 10.1007/s11120-014-0017-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 05/19/2014] [Indexed: 06/03/2023]
Abstract
A chlorosome is an antenna complex located on the cytoplasmic side of the inner membrane in green photosynthetic bacteria that contains tens of thousands of self-assembled bacteriochlorophylls (BChls). Green bacteria are known to incorporate various esterifying alcohols at the C-17 propionate position of BChls in the chlorosome. The effect of these functional substitutions on the biogenesis of the chlorosome has not yet been fully explored. In this report, we address this question by investigating various esterified bacteriochlorophyll c (BChl c) homologs in the thermophilic green non-sulfur bacterium Chloroflexus aurantiacus. Cultures were supplemented with exogenous long-chain alcohols at 52 °C (an optimal growth temperature) and 44 °C (a suboptimal growth temperature), and the morphology, optical properties and exciton transfer characteristics of chlorosomes were investigated. Our studies indicate that at 44 °C Cfl. aurantiacus synthesizes more carotenoids, incorporates more BChl c homologs with unsaturated and rigid polyisoprenoid esterifying alcohols and produces more heterogeneous BChl c homologs in chlorosomes. Substitution of phytol for stearyl alcohol of BChl c maintains similar morphology of the intact chlorosome and enhances energy transfer from the chlorosome to the membrane-bound photosynthetic apparatus. Different morphologies of the intact chlorosome versus in vitro BChl aggregates are suggested by small-angle neutron scattering. Additionally, phytol cultures and 44 °C cultures exhibit slow assembly of the chlorosome. These results suggest that the esterifying alcohol of BChl c contributes to long-range organization of BChls, and that interactions between BChls with other components are important to the assembly of the chlorosome. Possible mechanisms for how esterifying alcohols affect the biogenesis of the chlorosome are discussed.
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Affiliation(s)
- Yaya Wang
- Department of Chemistry and Biochemistry, Clark University, Worcester, MA, 01610, USA
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Heller WT, Urban VS, Lynn GW, Weiss KL, O'Neill HM, Pingali SV, Qian S, Littrell KC, Melnichenko YB, Buchanan MV, Selby DL, Wignall GD, Butler PD, Myles DA. The Bio-SANS instrument at the High Flux Isotope Reactor of Oak Ridge National Laboratory. J Appl Crystallogr 2014. [DOI: 10.1107/s1600576714011285] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Small-angle neutron scattering (SANS) is a powerful tool for characterizing complex disordered materials, including biological materials. The Bio-SANS instrument of the High Flux Isotope Reactor of Oak Ridge National Laboratory (ORNL) is a high-flux low-background SANS instrument that is, uniquely among SANS instruments, dedicated to serving the needs of the structural biology and biomaterials communities as an open-access user facility. Here, the technical specifications and performance of the Bio-SANS are presented. Sample environments developed to address the needs of the user program of the instrument are also presented. Further, the isotopic labeling and sample preparation capabilities available in the Bio-Deuteration Laboratory for users of the Bio-SANS and other neutron scattering instruments at ORNL are described. Finally, a brief survey of research performed using the Bio-SANS is presented, which demonstrates the breadth of the research that the instrument's user community engages in.
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Tang JKH, Saikin SK, Pingali SV, Enriquez MM, Huh J, Frank HA, Urban VS, Aspuru-Guzik A. Temperature and carbon assimilation regulate the chlorosome biogenesis in green sulfur bacteria. Biophys J 2014; 105:1346-56. [PMID: 24047985 DOI: 10.1016/j.bpj.2013.07.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 07/19/2013] [Accepted: 07/23/2013] [Indexed: 11/16/2022] Open
Abstract
Green photosynthetic bacteria adjust the structure and functionality of the chlorosome-the light-absorbing antenna complex-in response to environmental stress factors. The chlorosome is a natural self-assembled aggregate of bacteriochlorophyll (BChl) molecules. In this study, we report the regulation of the biogenesis of the Chlorobaculum tepidum chlorosome by carbon assimilation in conjunction with temperature changes. Our studies indicate that the carbon source and thermal stress culture of C. tepidum grows slower and incorporates fewer BChl c in the chlorosome. Compared with the chlorosome from other cultural conditions we investigated, the chlorosome from the carbon source and thermal stress culture displays (a) smaller cross-sectional radius and overall size, (b) simplified BChl c homologs with smaller side chains, (c) blue-shifted Qy absorption maxima, and (d) a sigmoid-shaped circular dichroism spectra. Using a theoretical model, we analyze how the observed spectral modifications can be associated with structural changes of BChl aggregates inside the chlorosome. Our report suggests a mechanism of metabolic regulation for chlorosome biogenesis.
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Genovese D, Rampazzo E, Bonacchi S, Montalti M, Zaccheroni N, Prodi L. Energy transfer processes in dye-doped nanostructures yield cooperative and versatile fluorescent probes. NANOSCALE 2014; 6:3022-3036. [PMID: 24531884 DOI: 10.1039/c3nr05599j] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Fast and efficient energy transfer among dyes confined in nanocontainers provides the basis of outstanding functionalities in new-generation luminescent probes. This feature article provides an overview of recent research achievements on luminescent Pluronic-Silica NanoParticles (PluS NPs), a class of extremely monodisperse core-shell nanoparticles whose design can be easily tuned to match specific needs for diverse applications based on luminescence, and that have already been successfully tested in in vivo imaging. An outline of their outstanding properties, such as tuneability, bright and photoswitchable fluorescence and electrochemiluminescence, will be supported by a critical discussion of our recent works in this field. Furthermore, novel data and simulations will be presented to (i) thoroughly examine common issues arising from the inclusion of multiple dyes in a small silica core, and (ii) show the emergence of a cooperative behaviour among embedded dyes. Such cooperative behaviour provides a handle for fine control of brightness, emission colour and self-quenching phenomena in PluS NPs, leading to significantly enhanced signal to noise ratios.
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Affiliation(s)
- Damiano Genovese
- Dipartimento di Chimica "Giacomo Ciamician", via Selmi 2, Bologna 40126, Bologna, Italy.
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Orf GS, Blankenship RE. Chlorosome antenna complexes from green photosynthetic bacteria. PHOTOSYNTHESIS RESEARCH 2013; 116:315-31. [PMID: 23761131 DOI: 10.1007/s11120-013-9869-3] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 06/06/2013] [Indexed: 05/18/2023]
Abstract
Chlorosomes are the distinguishing light-harvesting antenna complexes that are found in green photosynthetic bacteria. They contain bacteriochlorophyll (BChl) c, d, e in natural organisms, and recently through mutation, BChl f, as their principal light-harvesting pigments. In chlorosomes, these pigments self-assemble into large supramolecular structures that are enclosed inside a lipid monolayer to form an ellipsoid. The pigment assembly is dictated mostly by pigment-pigment interactions as opposed to protein-pigment interactions. On the bottom face of the chlorosome, the CsmA protein aggregates into a paracrystalline baseplate with BChl a, and serves as the interface to the next energy acceptor in the system. The exceptional light-harvesting ability at very low light conditions of chlorosomes has made them an attractive subject of study for both basic and applied science. This review, incorporating recent advancements, considers several important aspects of chlorosomes: pigment biosynthesis, organization of pigments and proteins, spectroscopic properties, and applications to bio-hybrid and bio-inspired devices.
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Affiliation(s)
- Gregory S Orf
- Departments of Chemistry and Biology, Washington University in St. Louis, Campus Box 1137, One Brookings Drive, St. Louis, MO, 63130, USA
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