A photoactive carotenoid protein acting as light intensity sensor

Wilson, Adjélé; Punginelli, Claire; Gall, Andrew; Bonetti, Cosimo; Alexandre, Maxime; Routaboul, Jean‐Marc; Kerfeld, Cheryl A.; Grondelle, Rienk van; Robert, Bruno; Kennis, John T. M.; Kirilovsky, Diana

doi:10.1073/pnas.0804636105

Cited by 324 publications

(463 citation statements)

References 35 publications

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“…OCP acts as a blue-green light intensity sensor (5). In vivo under strong light, OCP is converted to its active signaling state, which interacts with phycobilisomes and quenches the excess of excitation energy (3,(6)(7)(8)(9), thereby decreasing the effective absorption cross section of the photosystems and preventing the formation of potentially damaging reactive oxygen species (10).…”

Section: Introductionmentioning

confidence: 99%

Fluorescent Labeling Preserving OCP Photoactivity Reveals Its Reorganization during the Photocycle

Maksimov

Sluchanko

Mironov

et al. 2017

Biophysical Journal

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Orange carotenoid protein (OCP), responsible for the photoprotection of the cyanobacterial photosynthetic apparatus under excessive light conditions, undergoes significant rearrangements upon photoconversion and transits from the stable orange to the signaling red state. This is thought to involve a 12-Å translocation of the carotenoid cofactor and separation of the N-and C-terminal protein domains. Despite clear recent progress, the detailed mechanism of the OCP photoconversion and associated photoprotection remains elusive. Here, we labeled the OCP of Synechocystis with tetramethylrhodamine-maleimide (TMR) and obtained a photoactive OCP-TMR complex, the fluorescence of which was highly sensitive to the protein state, showing unprecedented contrast between the orange and red states and reflecting changes in protein conformation and the distances from TMR to the carotenoid throughout the photocycle. The OCP-TMR complex was sensitive to the light intensity, temperature, and viscosity of the solvent. Based on the observed Fö rster resonance energy transfer, we determined that upon photoconversion, the distance between TMR (donor) bound to a cysteine in the C-terminal domain and the carotenoid (acceptor) increased by 18 Å , with simultaneous translocation of the carotenoid into the N-terminal domain. Time-resolved fluorescence anisotropy revealed a significant decrease of the OCP rotation rate in the red state, indicating that the light-triggered conversion of the protein is accompanied by an increase of its hydrodynamic radius. Thus, our results support the idea of significant structural rearrangements of OCP, providing, to our knowledge, new insights into the structural rearrangements of OCP throughout the photocycle and a completely novel approach to the study of its photocycle and non-photochemical quenching. We suggest that this approach can be generally applied to other photoactive proteins.

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Section: Introductionmentioning

confidence: 99%

Fluorescent Labeling Preserving OCP Photoactivity Reveals Its Reorganization during the Photocycle

Maksimov

Sluchanko

Mironov

et al. 2017

Biophysical Journal

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“…In a previous work, we demonstrated that a Synechocystis mutant lacking OCP (DOCP) was more sensitive to high intensities of white light than Synechocystis wild type (Wilson et al, 2008). Moreover, cyanobacterial strains lacking OCP were photoinhibited faster than strains containing OCP under fluctuating light conditions (Boulay et al, 2008).…”

Section: Resultsmentioning

confidence: 99%

“…Although this protein has been known since 1981 (Holt and Krogmann, 1981) and its structure was resolved in 2003 (Kerfeld et al, 2003), only in 2006 did researchers discover that OCP is essential for a photoprotective mechanism decreasing the energy arriving at the reaction centers (Wilson et al, 2006). OCP is a photoactive protein (Wilson et al, 2008) and the only photosensory protein described to date that has a carotenoid as the active chromophore. Absorption of blue-green light by the carotenoid induces conformational changes in both the carotenoid and the protein, changes that are essential for its function in the photoprotective mechanism (Wilson et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…OCP is a photoactive protein (Wilson et al, 2008) and the only photosensory protein described to date that has a carotenoid as the active chromophore. Absorption of blue-green light by the carotenoid induces conformational changes in both the carotenoid and the protein, changes that are essential for its function in the photoprotective mechanism (Wilson et al, 2008). In darkness, OCP is orange (OCP o ); upon illumination with strong blue-green light, it becomes red.…”

Section: Introductionmentioning

confidence: 99%

“…In darkness, OCP is orange (OCP o ); upon illumination with strong blue-green light, it becomes red. The red form (OCP r ) is the active form of the protein (Wilson et al, 2008;Punginelli et al, 2009). Only OCP r is able to bind to phycobilisomes and to quench the energy they absorb (Gwizdala et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

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The Cyanobacterial Photoactive Orange Carotenoid Protein Is an Excellent Singlet Oxygen Quencher

et al. 2014

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Cyanobacteria have developed a photoprotective mechanism that decreases the energy arriving at the photosynthetic reaction centers under high-light conditions. The photoactive orange carotenoid protein (OCP) is essential in this mechanism as a light sensor and energy quencher. When OCP is photoactivated by strong blue-green light, it is able to dissipate excess energy as heat by interacting with phycobilisomes. As a consequence, charge separation and recombination leading to the formation of singlet oxygen diminishes. Here, we demonstrate that OCP has another essential role. We observed that OCP also protects Synechocystis cells from strong orange-red light, a condition in which OCP is not photoactivated. We first showed that this photoprotection is related to a decrease of singlet oxygen concentration due to OCP action. Then, we demonstrated that, in vitro, OCP is a very good singlet oxygen quencher. By contrast, another carotenoid protein having a high similarity with the N-terminal domain of OCP is not more efficient as a singlet oxygen quencher than a protein without carotenoid. Although OCP is a soluble protein, it is able to quench the singlet oxygen generated in the thylakoid membranes. Thus, OCP has dual and complementary photoprotective functions as an energy quencher and a singlet oxygen quencher.

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Carotenoids in Pigment–Protein Complexes

Gruszecki

2016

Carotenoids

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A photoactive carotenoid protein acting as light intensity sensor

Cited by 324 publications

References 35 publications

Fluorescent Labeling Preserving OCP Photoactivity Reveals Its Reorganization during the Photocycle

Fluorescent Labeling Preserving OCP Photoactivity Reveals Its Reorganization during the Photocycle

The Cyanobacterial Photoactive Orange Carotenoid Protein Is an Excellent Singlet Oxygen Quencher

Carotenoids in Pigment–Protein Complexes

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