Modelling excitation energy transfer and trapping in the filamentous cyanobacterium Anabaena variabilis PCC 7120.
Photosynth Res
; 144(2): 261-272, 2020 May.
Article
en En
| MEDLINE
| ID: mdl-32076914
ABSTRACT
The phycobilisome (PBS) serves as the major light-harvesting system, funnelling excitation energy to both photosystems (PS) in cyanobacteria and red algae. The picosecond kinetics involving the excitation energy transfer has been studied within the isolated systems and intact filaments of the cyanobacterium Anabaena variabilis PCC 7120. A target model is proposed which resolves the dynamics of the different chromophore groups. The energy transfer rate of 8.5 ± 1.0/ns from the rod to the core is the rate-limiting step, both in vivo and in vitro. The PBS-PSI-PSII supercomplex reveals efficient excitation energy migration from the low-energy allophycocyanin, which is the terminal emitter, in the PBS core to the chlorophyll a in the photosystems. The terminal emitter of the phycobilisome transfers energy to both PSI and PSII with a rate of 50 ± 10/ns, equally distributing the solar energy to both photosystems. Finally, the excitation energy is trapped by charge separation in the photosystems with trapping rates estimated to be 56 ± 6/ns in PSI and 14 ± 2/ns in PSII.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Ficobilisomas
/
Complejo de Proteína del Fotosistema I
/
Anabaena variabilis
Idioma:
En
Revista:
Photosynth Res
Asunto de la revista:
METABOLISMO
Año:
2020
Tipo del documento:
Article
País de afiliación:
Países Bajos