scholarly journals Quartic Interband Exciton Couplings in Pump−Probe Spectroscopy of Light Harvesting Complexes†

2004 ◽  
Vol 108 (29) ◽  
pp. 10295-10300 ◽  
Author(s):  
Darius Abramavicius ◽  
Shaul Mukamel
Keyword(s):  
Light Harvesting ◽  
Light Harvesting Complexes ◽  
Pump Probe ◽  
Probe Spectroscopy

scholarly journals Controllable phycobilin modification: an alternative photoacclimation response in cryptophyte algae

2021 ◽  
Author(s):  
Leah Spangler ◽  
Mina Yu ◽  
Philip Jeffrey ◽  
Gregory Scholes
Keyword(s):  
Light Harvesting ◽  
Protein Structures ◽  
Green Light ◽  
Beta Subunits ◽  
Light Conditions ◽  
Low Light ◽  
Pump Probe ◽  
Light Harvesting Complex ◽  
Probe Spectroscopy

Cryptophyte algae are well known for their ability to survive under low light conditions through the use of their auxiliary light harvesting antennas, phycobiliproteins. Mainly acting to absorb light where chlorophyll cannot (500-650 nm), phycobiliproteins also play an instrumental role in helping cryptophyte algae respond to changes in light intensity through the process of photoacclimation. Until recently, photoacclimation in cryptophyte algae was only observed as a change in the cellular concentration of phycobiliproteins; however, an additional photoacclimation response was recently discovered that causes shifts in the phycobiliprotein absorbance peaks following growth under red, blue, or green light. Here, we reproduce this newly identified photoacclimation response in two other species of cryptophyte algae, P. sulcata and H. pacifica, and elucidate the origin of the response on the protein level. We compare isolated native and photoacclimated phycobiliproteins for these two species using spectroscopy and mass spectrometry, and we report the x-ray structures of the PC577 light harvesting complex and corresponding photoacclimated complex. We find that neither the protein sequences, nor the protein structures are modified by photoacclimation. We conclude that cryptophyte algae change a chromophore in one site of their phycobiliprotein beta-subunits as part of the photoacclimation response to changes in the spectral quality of light. Ultrafast pump-probe spectroscopy shows that the energy transfer is weakly affected by the photoacclimation.

Low-intensity pump-probe spectroscopy on the B800 to B850 transfer in the light harvesting 2 complex of Rhodobacter sphaeroides

1995 ◽  
Vol 246 (3) ◽  
pp. 341-346 ◽  
Author(s):  
René Monshouwer ◽  
Iñaki Ortiz de Zarate ◽  
Frank van Mourik ◽  
Rienk van Grondelle
Keyword(s):  
Rhodobacter Sphaeroides ◽  
Light Harvesting ◽  
Pump Probe ◽  
Low Intensity ◽  
Probe Spectroscopy

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.

scholarly journals How Static Disorder Mimics Decoherence in Anisotropy Pump–Probe Experiments on Purple-Bacteria Light Harvesting Complexes

2016 ◽  
Vol 120 (44) ◽  
pp. 11449-11463 ◽  
Author(s):  
Clement Stross ◽  
Marc W. Van der Kamp ◽  
Thomas A. A. Oliver ◽  
Jeremy N. Harvey ◽  
Noah Linden ◽  
...  
Keyword(s):  
Light Harvesting ◽  
Purple Bacteria ◽  
Static Disorder ◽  
Light Harvesting Complexes ◽  
Pump Probe

Femtosecond excited-state dynamics in chlorosomal carotenoids of the photosynthetic bacterium Chloroflexus aurantiacus revealed by near infrared pump-probe spectroscopy

2021 ◽  
Author(s):  
Andrei Yakovlev ◽  
Alexandra Taisova ◽  
Zoya Fetisova
Keyword(s):  
Excited State ◽  
Near Infrared ◽  
High Efficiency ◽  
Light Harvesting ◽  
Photosynthetic Bacterium ◽  
Chloroflexus Aurantiacus ◽  
Green Bacteria ◽  
Pump Probe ◽  
Excited State Dynamics ◽  
Probe Spectroscopy

In photosynthetic green bacteria, chlorosomes provide light harvesting with high efficiency. Chlorosomal carotenoids (Cars) participate in light harvesting together with the main pigment, bacteriochlorophyll (BChl) c/d/e. In the present work,...

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.

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