Energetics and Kinetics of Radical Pairs in Reaction Centers fromRhodobacter sphaeroides. A Femtosecond Transient Absorption Study†,‡

Biochemistry ◽  
1996 ◽  
Vol 35 (36) ◽  
pp. 11820-11831 ◽  
Author(s):  
A. R. Holzwarth ◽  
Marc G. Müller
Keyword(s):  
Transient Absorption ◽  
Reaction Centers ◽  
Absorption Study ◽  
Radical Pairs ◽  
Femtosecond Transient Absorption ◽  
Kinetics Of

scholarly journals The terminal phycobilisome emitter, LCM: A light-harvesting pigment with a phytochrome chromophore

2015 ◽  
Vol 112 (52) ◽  
pp. 15880-15885 ◽  
Author(s):  
Kun Tang ◽  
Wen-Long Ding ◽  
Astrid Höppner ◽  
Cheng Zhao ◽  
Lun Zhang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Transient Absorption ◽  
Light Harvesting ◽  
Reaction Centers ◽  
Protein Fold ◽  
Light Harvesting Complexes ◽  
Exciton Coupling ◽  
Femtosecond Transient Absorption ◽  
Orange Carotenoid Protein ◽  
Sensory Photoreceptors

Photosynthesis relies on energy transfer from light-harvesting complexes to reaction centers. Phycobilisomes, the light-harvesting antennas in cyanobacteria and red algae, attach to the membrane via the multidomain core-membrane linker, LCM. The chromophore domain of LCM forms a bottleneck for funneling the harvested energy either productively to reaction centers or, in case of light overload, to quenchers like orange carotenoid protein (OCP) that prevent photodamage. The crystal structure of the solubly modified chromophore domain from Nostoc sp. PCC7120 was resolved at 2.2 Å. Although its protein fold is similar to the protein folds of phycobiliproteins, the phycocyanobilin (PCB) chromophore adopts ZZZssa geometry, which is unknown among phycobiliproteins but characteristic for sensory photoreceptors (phytochromes and cyanobacteriochromes). However, chromophore photoisomerization is inhibited in LCM by tight packing. The ZZZssa geometry of the chromophore and π-π stacking with a neighboring Trp account for the functionally relevant extreme spectral red shift of LCM. Exciton coupling is excluded by the large distance between two PCBs in a homodimer and by preservation of the spectral features in monomers. The structure also indicates a distinct flexibility that could be involved in quenching. The conclusions from the crystal structure are supported by femtosecond transient absorption spectra in solution.

Charge carrier kinetics of carbon nitride colloid: a femtosecond transient absorption spectroscopy study

2016 ◽  
Vol 18 (22) ◽  
pp. 14904-14910 ◽  
Author(s):  
Huiyu Zhang ◽  
Yaping Chen ◽  
Rong Lu ◽  
Ruiyu Li ◽  
Anchi Yu
Keyword(s):  
Charge Carrier ◽  
Carbon Nitride ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Spectroscopy Study ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Femtosecond Transient Absorption ◽  
Femtosecond Transient Absorption Spectroscopy ◽  
Kinetics Of

The charge carrier kinetics of carbon nitride colloid was investigated using a combination of femtosecond transient absorption and picosecond time-resolved fluorescence spectroscopy.

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