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- Title
Ultrafast excited‐state dynamics in chlorosomes isolated from the photosynthetic filamentous green bacterium Chloroflexus aurantiacus.
- Authors
Yakovlev, Andrei G.; Taisova, Alexandra S.; Shuvalov, Vladimir A.; Fetisova, Zoya G.
- Abstract
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.
- Subjects
OLIGOMERS; CHLOROSOMES; ENERGY transfer; STIMULATED emission; CHLOROFLEXUS aurantiacus
- Publication
Physiologia Plantarum, 2019, Vol 166, Issue 1, p12
- ISSN
0031-9317
- Publication type
Article
- DOI
10.1111/ppl.12887