Green/red light-sensing mechanism in the chromatic acclimation photosensor.
Sci Adv
; 10(24): eadn8386, 2024 Jun 14.
Article
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| MEDLINE
| ID: mdl-38865454
ABSTRACT
Certain cyanobacteria alter their photosynthetic light absorption between green and red, a phenomenon called complementary chromatic acclimation. The acclimation is regulated by a cyanobacteriochrome-class photosensor that reversibly photoconverts between green-absorbing (Pg) and red-absorbing (Pr) states. Here, we elucidated the structural basis of the green/red photocycle. In the Pg state, the bilin chromophore adopted the extended C15-Z,anti structure within a hydrophobic pocket. Upon photoconversion to the Pr state, the bilin is isomerized to the cyclic C15-E,syn structure, forming a water channel in the pocket. The solvation/desolvation of the bilin causes changes in the protonation state and the stability of π-conjugation at the B ring, leading to a large absorption shift. These results advance our understanding of the enormous spectral diversity of the phytochrome superfamily.
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01-internacional
Base de datos:
MEDLINE
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Luz
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En
Revista:
Sci Adv
Año:
2024
Tipo del documento:
Article
País de afiliación:
Japón