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The photosystem I trimer of cyanobacteria: molecular organization, excitation dynamics and physiological significance
Author(s) -
Karapetyan Navassard V.,
Holzwarth Alfred R.,
Rögner Matthias
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01352-6
Subject(s) - p700 , photosystem i , light harvesting complexes of green plants , photochemistry , photosynthetic reaction centre , chemistry , photosystem ii , trimer , chemical physics , electron transport chain , electron transfer , photosynthesis , dimer , biochemistry , organic chemistry
The photosystem I complex organized in cyanobacterial membranes preferentially in trimeric form participates in electron transport and is also involved in dissipation of excess energy thus protecting the complex against photodamage. A small number of longwave chlorophylls in the core antenna of photosystem I are not located in the close vicinity of P700, but at the periphery, and increase the absorption cross‐section substantially. The picosecond fluorescence kinetics of trimers resolved the fastest energy transfer components reflecting the equilibration processes in the core antenna at different redox states of P700. Excitation kinetics in the photosystem I bulk antenna is nearly trap‐limited, whereas excitation trapping from longwave chlorophyll pools is diffusion‐limited and occurs via the bulk antenna. Charge separation in the photosystem I reaction center is the fastest of all known reaction centers.