scholarly journals Observation of robust energy transfer in the photosynthetic protein allophycocyanin using single-molecule pump-probe spectroscopy

2021 ◽  
Author(s):  
Raymundo Moya ◽  
Audrey Norris ◽  
Toru Kondo ◽  
Gabriela Schlau-Cohen
Keyword(s):  
Energy Transfer ◽  
Single Molecule ◽  
Light Harvesting ◽  
Asymmetric Distribution ◽  
Ultrafast Dynamics ◽  
Pump Probe ◽  
Photosynthetic Organisms ◽  
Probe Spectroscopy ◽  
The Impact ◽  
Protein Fluctuations

Abstract Photosynthetic organisms convert sunlight to electricity with near unity quantum efficiency. Absorbed photoenergy transfers through a network of chromophores positioned within protein scaffolds, which fluctuate due to thermal motion. The resultant variation in energy transfer has not yet been measured, and so how the efficiency is robust to this variation, if any, has not been determined. Here, we describe single-molecule pump-probe spectroscopy with facile spectral tuning and its application to the ultrafast dynamics of single allophycocyanin, a light-harvesting protein from cyanobacteria. Using the spectral dependence of the dynamics, energy transfer and energetic relaxation from nuclear motion were disentangled. For energy transfer, an asymmetric distribution of timescales was observed. For energetic relaxation, the timescales were slower and more heterogeneous due to the impact of the protein environment. Collectively, these results suggest that energy transfer is robust to protein fluctuations, a prerequisite for efficient light harvesting.

Monitoring the Structural Dynamics of U2 snRNA Via Single-Molecule Förster Resonance Energy Transfer

2018 ◽  
Author(s):  
Alexander Carl DeHaven
Keyword(s):  
Energy Transfer ◽  
Structural Dynamics ◽  
Single Molecule ◽  
Conformational Dynamics ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Förster Resonance Energy Transfer ◽  
U2 Snrna ◽  
Folding Dynamics ◽  
The Impact

This thesis contains four topic areas: a review of single-molecule microscropy methods and splicing, conformational dynamics of stem II of the U2 snRNA, the impact of post-transcriptional modifications on U2 snRNA folding dynamics, and preliminary findings on Mango aptamer folding dynamics.

scholarly journals Ultrafast Electron/Energy Transfer and Intersystem Crossing Mechanisms in BODIPY-Porphyrin Compounds

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 312
Author(s):  
Yusuf Tutel ◽  
Gökhan Sevinç ◽  
Betül Küçüköz ◽  
Elif Akhuseyin Yildiz ◽  
Ahmet Karatay ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Fluorescence Spectra ◽  
Visible Region ◽  
Energy Transfer Mechanism ◽  
Free Base ◽  
Pump Probe ◽  
Harvesting Efficiency ◽  
Probe Spectroscopy ◽  
Absorption Features ◽  
Transfer Mechanisms

Meso-substituted borondipyrromethene (BODIPY)-porphyrin compounds that include free base porphyrin with two different numbers of BODIPY groups (BDP-TTP and 3BDP-TTP) were designed and synthesized to analyze intramolecular energy transfer mechanisms of meso-substituted BODIPY-porphyrin dyads and the effect of the different numbers of BODIPY groups connected to free-base porphyrin on the energy transfer mechanism. Absorption spectra of BODIPY-porphyrin conjugates showed wide absorption features in the visible region, and that is highly valuable to increase light-harvesting efficiency. Fluorescence spectra of the studied compounds proved that BODIPY emission intensity decreased upon the photoexcitation of the BODIPY core, due to the energy transfer from BODIPY unit to porphyrin. In addition, ultrafast pump-probe spectroscopy measurements indicated that the energy transfer of the 3BDP-TTP compound (about 3 ps) is faster than the BDP-TTP compound (about 22 ps). Since the BODIPY core directly binds to the porphyrin unit, rapid energy transfer was seen for both compounds. Thus, the energy transfer rate increased with an increasing number of BODIPY moiety connected to free-base porphyrin.

Ultrafast Energy And Electron Transfer In Conjugated Oligomer-Fullerene Molecules

2001 ◽  
Vol 665 ◽  
Author(s):  
P.A. van Hal ◽  
R.A.J. Janssen ◽  
G. Lanzani ◽  
G. Cerullo ◽  
M. Zavelani-Rossi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Energy Transfer ◽  
Time Constant ◽  
Transfer Reaction ◽  
Polar Solvent ◽  
Phenylene Vinylene ◽  
Intramolecular Electron Transfer ◽  
Pump Probe ◽  
Energy And Electron Transfer ◽  
Probe Spectroscopy

ABSTRACTThe intramolecular photoinduced energy and electron transfer within a fullereneoligothiophene-fullerene triad with nine thiophene units (C60-9T-C60) and an oligo(p-phenylene vinylene)-fullerene dyad with four phenyl groups (OPV4-C60) is investigated with femtosecond pump-probe spectroscopy with sub-10 fs and 200 fs time resolution in solvents of different polarity. Photoexcitation of the π-conjugated oligomer moiety in the triad and dyad results in an ultrafast singlet-energy transfer reaction to create the fullerene singlet-excited state with a time constant of 150-190 fs, irrespective of the polarity of the medium. In a polar solvent, intramolecular electron transfer occurs from the oligomer moiety to the C60 moiety with a time constant of 10-13 ps as a secondary reaction, subsequent to the ultrafast singlet-energy transfer. The charge-separated state has a lifetime of 50-80 ps and recombines to the ground state.

Structural basis for blue-green light harvesting and energy dissipation in diatoms

Science ◽  
2019 ◽  
Vol 363 (6427) ◽  
pp. eaav0365 ◽  
Author(s):  
Wenda Wang ◽  
Long-Jiang Yu ◽  
Caizhe Xu ◽  
Takashi Tomizaki ◽  
Songhao Zhao ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Phaeodactylum Tricornutum ◽  
Light Harvesting ◽  
Green Light ◽  
Marine Diatom ◽  
Structural Basis ◽  
Aquatic Environments ◽  
Efficient Energy Transfer ◽  
Chl A ◽  
Photosynthetic Organisms

Diatoms are abundant photosynthetic organisms in aquatic environments and contribute 40% of its primary productivity. An important factor that contributes to the success of diatoms is their fucoxanthin chlorophyll a/c-binding proteins (FCPs), which have exceptional light-harvesting and photoprotection capabilities. Here, we report the crystal structure of an FCP from the marine diatom Phaeodactylum tricornutum, which reveals the binding of seven chlorophylls (Chls) a, two Chls c, seven fucoxanthins (Fxs), and probably one diadinoxanthin within the protein scaffold. Efficient energy transfer pathways can be found between Chl a and c, and each Fx is surrounded by Chls, enabling the energy transfer and quenching via Fx highly efficient. The structure provides a basis for elucidating the mechanisms of blue-green light harvesting, energy transfer, and dissipation in diatoms.

Ultrafast dynamics in pentacene and tetracene probed using optical pump-probe spectroscopy

2004 ◽  
Author(s):  
Verner K. Thorsmølle ◽  
R D. Averitt ◽  
J Demsar ◽  
X Chi ◽  
S Tretiak ◽  
...  
Keyword(s):  
Ultrafast Dynamics ◽  
Optical Pump ◽  
Pump Probe ◽  
Probe Spectroscopy

scholarly journals Robust light harvesting by a noisy antenna

2018 ◽  
Vol 20 (6) ◽  
pp. 4360-4372 ◽  
Author(s):  
Pavel Malý ◽  
Alastair T. Gardiner ◽  
Richard J. Cogdell ◽  
Rienk van Grondelle ◽  
Tomáš Mančal
Keyword(s):  
Theoretical Model ◽  
Single Molecule ◽  
Light Harvesting ◽  
Single Molecule Spectroscopy ◽  
Protein Fluctuations

Ultrafast bulk and single-molecule spectroscopy experiments described by a single theoretical model show how protein fluctuations influence photosynthetic light harvesting.

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