Internal Electrostatic Control of the Primary Charge Separation and Recombination in Reaction Centers from Rhodobacter sphaeroides Revealed by Femtosecond Transient Absorption

Three new covalently bonded DWCNT–PDIs have been synthesized and characterized, showing exclusively functionalization of the outer walls leaving the inner walls intact. Femtosecond transient absorption studies were performed to seek evidence of charge separation in these hybrids.

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Views on Primary Charge Separation in Reaction Centers of Photosynthetic Bacteria

Current Research in Photosynthesis ◽

10.1007/978-94-009-0511-5_3 ◽

1990 ◽

pp. 19-26 ◽

Cited By ~ 3

Author(s):

M. E. Michel-Beyerle ◽

A. Ogrodnik

Keyword(s):

Charge Separation ◽

Photosynthetic Bacteria ◽

Reaction Centers ◽

Primary Charge Separation

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Primary Charge Separation at Low Temperatures in D1-D2 Reaction Centers Studied by Photon Echo and Pump-Probe Spectroscopy

Photosynthesis: Mechanisms and Effects ◽

10.1007/978-94-011-3953-3_245 ◽

1998 ◽

pp. 1033-1036

Author(s):

Valentin Prokhorenko ◽

Alfred R. Holzwarth

Keyword(s):

Charge Separation ◽

Low Temperatures ◽

Photon Echo ◽

Reaction Centers ◽

Primary Charge Separation ◽

Pump Probe ◽

Probe Spectroscopy

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

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1519177113 ◽

2015 ◽

Vol 112 (52) ◽

pp. 15880-15885 ◽

Cited By ~ 47

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.

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