Site of non-photochemical quenching of the phycobilisome by orange carotenoid protein in the cyanobacterium Synechocystis sp. PCC 6803

Stadnichuk, Igor N.; Yanyushin, Mikhail F.; Maksimov, Eugene G.; Lukashev, E. P.; Zharmukhamedov, Sergei K.; Elanskaya, I.V.; Paschenko, V.Z.

doi:10.1016/j.bbabio.2012.03.023

Cited by 65 publications

(38 citation statements)

References 49 publications

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“…Orange carotenoid protein (OCP) is a specific 35 kDa watersoluble protein that plays an essential role in non-photochemical quenching (NPQ) of the cyanobacterial light-harvesting antennae, phycobilisomes (1)(2)(3)(4). OCP acts as a blue-green light intensity sensor (5).…”

Section: Introductionmentioning

confidence: 99%

“…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). The mechanism of NPQ and its regulation is still unclear due to the number and size of protein complexes involved.…”

Section: Introductionmentioning

confidence: 99%

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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%

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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“…Finally, the OCP is thought to interact with a/bAPC subunits emitting at 660 nm (Tian et al, 2011(Tian et al, , 2012Jallet et al, 2012) or with the ApcE core membrane linker (Stadnichuk et al, 2012) or both (Kuzminov et al, 2012). aAPCs and bAPCs are extremely well conserved, particularly within the group of cyanobacteria employed for this study (between 77% and 90% identity in primary structures compared with Synechocystis).…”

Section: Influence Of Pb Structure On the Ocp-pb Interactionmentioning

confidence: 99%

Specificity of the Cyanobacterial Orange Carotenoid Protein: Influences of Orange Carotenoid Protein and Phycobilisome Structures

et al. 2013

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Cyanobacteria have developed a photoprotective mechanism that decreases the energy arriving at the reaction centers by increasing thermal energy dissipation at the level of the phycobilisome (PB), the extramembranous light-harvesting antenna. This mechanism is triggered by the photoactive Orange Carotenoid Protein (OCP), which acts both as the photosensor and the energy quencher. The OCP binds the core of the PB. The structure of this core differs in diverse cyanobacterial strains. Here, using two isolated OCPs and four classes of PBs, we demonstrated that differences exist between OCPs related to PB binding, photoactivity, and carotenoid binding. Synechocystis PCC 6803 (hereafter Synechocystis) OCP, but not Arthrospira platensis PCC 7345 (hereafter Arthrospira) OCP, can attach echinenone in addition to hydroxyechinenone. Arthrospira OCP binds more strongly than Synechocystis OCP to all types of PBs. Synechocystis OCP can strongly bind only its own PB in 0.8 M potassium phosphate. However, if the Synechocystis OCP binds to the PB at very high phosphate concentrations (approximately 1.4 M), it is able to quench the fluorescence of any type of PB, even those isolated from strains that lack the OCP-mediated photoprotective mechanism. Thus, the determining step for the induction of photoprotection is the binding of the OCP to PBs. Our results also indicated that the structure of PBs, at least in vitro, significantly influences OCP binding and the stabilization of OCP-PB complexes. Finally, the fact that the OCP induced large fluorescence quenching even in the two-cylinder core of Synechococcus elongatus PBs strongly suggested that OCP binds to one of the basal allophycocyanin cylinders.

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“…The C-terminal domain cannot function as a photosensor without a light absorbing chromophore. The N-terminal effector domain, when bound to the PB, requires 39-hECN to directly dissipate energy in the OCP induced photoprotective mechanism (Tian et al, 2011(Tian et al, , 2012Stadnichuk et al, 2012). The OCP thus represents a remarkably minimized system in which sensor and effector domains share a single chromophore that is critical to both photosensory and photoprotective function.…”

Section: A Revised Model For Ocp Functionmentioning

confidence: 99%

Structural and Functional Modularity of the Orange Carotenoid Protein: Distinct Roles for the N- and C-Terminal Domains in Cyanobacterial Photoprotection

et al. 2014

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The orange carotenoid protein (OCP) serves as a sensor of light intensity and an effector of phycobilisome (PB)-associated photoprotection in cyanobacteria. Structurally, the OCP is composed of two distinct domains spanned by a single carotenoid chromophore. Functionally, in response to high light, the OCP converts from a dark-stable orange form, OCP O , to an active red form, OCP R . The C-terminal domain of the OCP has been implicated in the dynamic response to light intensity and plays a role in switching off the OCP's photoprotective response through its interaction with the fluorescence recovery protein. The function of the N-terminal domain, which is uniquely found in cyanobacteria, is unclear. To investigate its function, we isolated the N-terminal domain in vitro using limited proteolysis of native OCP. The N-terminal domain retains the carotenoid chromophore; this red carotenoid protein (RCP) has constitutive PB fluorescence quenching activity comparable in magnitude to that of active, full-length OCP R . A comparison of the spectroscopic properties of the RCP with OCP R indicates that critical proteinchromophore interactions within the C-terminal domain are weakened in the OCP R form. These results suggest that the C-terminal domain dynamically regulates the photoprotective activity of an otherwise constitutively active carotenoid binding N-terminal domain.

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Site of non-photochemical quenching of the phycobilisome by orange carotenoid protein in the cyanobacterium Synechocystis sp. PCC 6803

Cited by 65 publications

References 49 publications

Fluorescent Labeling Preserving OCP Photoactivity Reveals Its Reorganization during the Photocycle

Fluorescent Labeling Preserving OCP Photoactivity Reveals Its Reorganization during the Photocycle

Specificity of the Cyanobacterial Orange Carotenoid Protein: Influences of Orange Carotenoid Protein and Phycobilisome Structures

Structural and Functional Modularity of the Orange Carotenoid Protein: Distinct Roles for the N- and C-Terminal Domains in Cyanobacterial Photoprotection

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