Ultrafast excited‐state dynamics in chlorosomes isolated from the photosynthetic filamentous green bacterium Chloroflexus aurantiacus

Bacteriochlorophyll (BChl) c pigments in the aggregated state are responsible for efficient light harvesting in chlorosomes of the filamentous anoxygenic photosynthetic bacterium, Chloroflexus (Cfx.) aurantiacus. Absorption of light creates excited states in the BChl c aggregates. After subpicosecon...

Full description

Saved in:
Bibliographic Details
Published in:Physiologia plantarum 2019-05, Vol.166 (1), p.12-21
Main Authors: Yakovlev, Andrei G., Taisova, Alexandra S., Shuvalov, Vladimir A., Fetisova, Zoya G.
Format: Article
Language:English
Subjects:
Absorption
Absorption spectra
Aggregates
Bacteria
Bacteriochlorophyll
C band
Chlorosomes
Doppler effect
Energy transfer
Excitation
Excitation spectra
Oligomers
Photosynthesis
Pigments
Reaction centers
Red shift
Spectroscopy
Spectrum analysis
Stimulated emission
Time constant
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Bacteriochlorophyll (BChl) c pigments in the aggregated state are responsible for efficient light harvesting in chlorosomes of the filamentous anoxygenic photosynthetic bacterium, Chloroflexus (Cfx.) aurantiacus. Absorption of light creates excited states in the BChl c aggregates. After subpicosecond intrachlorosomal energy transfer, redistribution and relaxation, the excitation is transferred to the BChl a complexes and further to reaction centers on the picosecond time scale. In this work, the femtosecond excited state dynamics within BChl c oligomers of isolated Cfx. aurantiacus chlorosomes was studied by double difference pump‐probe spectroscopy at room temperature. Difference (Alight − Adark) spectra corresponding to excitation at 725 nm (blue side of the BChl c absorption band) were compared with those corresponding to excitation at 750 nm (red side of the BChl c absorption band). A very fast (time constant 70 ± 10 fs) rise kinetic component was found in the stimulated emission (SE) upon excitation at 725 nm. This component was absent at 750‐nm excitation. These data were explained by the dynamical red shift of the SE due to excited state relaxation. The nature and mechanisms of the ultrafast excited state dynamics in chlorosomal BChl c aggregates are discussed.
ISSN:0031-9317
1399-3054
DOI:10.1111/ppl.12887