1. Regulation of Orange Carotenoid Protein Activity in Cyanobacterial Photoprotection
- Author
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Céline Bourcier de Carbon, Diana Kirilovsky, Léa Comolet, Adjélé Wilson, Adrien Thurotte, Fugui Xiao, Rocío López-Igual, Institut de Biologie Intégrative de la Cellule ( I2BC ), Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Sud - Paris 11 ( UP11 ), Laboratory of Biophysics, Wageningen University and Research Centre [Wageningen] ( WUR ), Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Wageningen University and Research [Wageningen] (WUR)
- Subjects
Models, Molecular ,0106 biological sciences ,Cyanobacteria ,MESH : Escherichia coli ,Light ,Physiology ,[SDV]Life Sciences [q-bio] ,MESH : Synechocystis ,MESH : Models, Biological ,Plant Science ,Orange (colour) ,MESH: Synechocystis ,01 natural sciences ,polycyclic compounds ,Phycobilisomes ,MESH : Bacterial Proteins ,MESH : Light ,MESH: Bacterial Proteins ,Carotenoid ,chemistry.chemical_classification ,0303 health sciences ,MESH: Escherichia coli ,Synechocystis ,food and beverages ,MESH : Protein Binding ,Articles ,Fluorescence ,Biofysica ,Biochemistry ,MESH : Mutation ,MESH: Models, Molecular ,Protein Binding ,MESH : Fluorescence ,MESH: Mutation ,MESH : Models, Molecular ,Biophysics ,macromolecular substances ,Biology ,Models, Biological ,03 medical and health sciences ,Bacterial Proteins ,Escherichia coli ,Genetics ,Life Science ,MESH: Protein Binding ,MESH: Phycobilisomes ,030304 developmental biology ,[ SDV ] Life Sciences [q-bio] ,Orange carotenoid protein ,organic chemicals ,MESH: Fluorescence ,MESH: Models, Biological ,biology.organism_classification ,MESH: Light ,MESH : Phycobilisomes ,chemistry ,Photoprotection ,Mutation ,bacteria ,Phycobilisome ,Excess energy ,010606 plant biology & botany - Abstract
International audience; Plants, algae, and cyanobacteria have developed mechanisms to decrease the energy arriving at reaction centers to protect themselves from high irradiance. In cyanobacteria, the photoactive Orange Carotenoid Protein (OCP) and the Fluorescence Recovery Protein are essential elements in this mechanism. Absorption of strong blue-green light by the OCP induces carotenoid and protein conformational changes converting the orange (inactive) OCP into a red (active) OCP. Only the red orange carotenoid protein (OCP(r)) is able to bind to phycobilisomes, the cyanobacterial antenna, and to quench excess energy. In this work, we have constructed and characterized several OCP mutants and focused on the role of the OCP N-terminal arm in photoactivation and excitation energy dissipation. The N-terminal arm largely stabilizes the closed orange OCP structure by interacting with its C-terminal domain. This avoids photoactivation at low irradiance. In addition, it slows the OCP detachment from phycobilisomes by hindering fluorescence recovery protein interaction with bound OCP(r). This maintains thermal dissipation of excess energy for a longer time. Pro-22, at the beginning of the N-terminal arm, has a key role in the correct positioning of the arm in OCP(r), enabling strong OCP binding to phycobilisomes, but is not essential for photoactivation. Our results also show that the opening of the OCP during photoactivation is caused by the movement of the C-terminal domain with respect to the N-terminal domain and the N-terminal arm.
- Published
- 2015