Crystals of the Carotenoid Protein from<i>Arthrospira maxima</i>Containing Uniformly Oriented Pigment Molecules

Kerfeld, Cheryl A.; Wu, Yi Pyng; Chan, Cheryl; Krogmann, David W.; Yeates, Todd O.

doi:10.1107/s0907444997006999

Cited by 16 publications

(11 citation statements)

References 14 publications

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“…On the basis of the SAXS data (17), it was proposed that the CTD and NTD become completely separated upon photoconversion. Simultaneously, it was assumed that ECN not only stays in the NTD during photoconversion, but may also be translocated within the protein, as indicated by the 12-Å shift in chromophore position between the x-ray crystal structure of OCP O and that of RCP (18,27,28), which could be an important step for the formation of the active quenching state. Thus, the OCP structure is significantly rearranged upon the photoconversion, and protein-chromophore interactions play an important role in spectral tuning of this photoactive protein.…”

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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“…This value is lower than the energy of a single hydrogen bond (3-5 kcal/mol) (73). In fact, hydrogen bonds between Trp-290/Tyr-203 and the carbonyl oxygen of the hECN molecule exist (25,26,33), which explains the absence of a free b-ring rotation in OCP O and the pronounced vibronic structure of its absorption spectrum. However, the energy of 532 nm quanta is equal to 53.5 kcal/mol, which is sufficient to rotate the b-ring and consequently break the hydrogen bonds.…”

Section: Resonance Raman Spectra and MD Of Ocpmentioning

confidence: 87%

“…Results from x-ray crystallography have provided valuable information about the structure of OCP in its stable (noninteracting with phycobilisomes) form, which is referred to as the orange (OCP O ) form (19,(25)(26)(27). It was shown that OCP consists of two structural domains (the N-and C-terminal domains, hereafter referred to as the N-and C-domains), between which the 3 0 -hydroxyechinenone (hECN) carotenoid chromophore is bound (28)(29)(30).…”

Section: Introductionmentioning

confidence: 99%

The Signaling State of Orange Carotenoid Protein

Maksimov

Shirshin

Sluchanko

et al. 2015

Biophysical Journal

112

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Orange carotenoid protein (OCP) is the photoactive protein that is responsible for high light tolerance in cyanobacteria. We studied the kinetics of the OCP photocycle by monitoring changes in its absorption spectrum, intrinsic fluorescence, and fluorescence of the Nile red dye bound to OCP. It was demonstrated that all of these three methods provide the same kinetic parameters of the photocycle, namely, the kinetics of OCP relaxation in darkness was biexponential with a ratio of two components equal to 2:1 independently of temperature. Whereas the changes of the absorption spectrum of OCP characterize the geometry and environment of its chromophore, the intrinsic fluorescence of OCP reveals changes in its tertiary structure, and the fluorescence properties of Nile red indicate the exposure of hydrophobic surface areas of OCP to the solvent following the photocycle. The results of molecular-dynamics studies indicated the presence of two metastable conformations of 3'-hydroxyechinenone, which is consistent with characteristic changes in the Raman spectra. We conclude that rotation of the β-ionylidene ring in the C-terminal domain of OCP could be one of the first conformational rearrangements that occur during photoactivation. The obtained results suggest that the photoactivated form of OCP represents a molten globule-like state that is characterized by increased mobility of tertiary structure elements and solvent accessibility.

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“…This spatial organization is suggested to be the result of the association of carotenoids with outer membrane proteins [47,48]. Packing of the OCP molecules in the crystals [13,14] is intriguing in that it suggests one way in which an array of aligned pigment molecules might be produced (Fig. 6).…”

Section: Component Of Photoprotective Structuresmentioning

confidence: 99%

“…In the present discussion, the use of ''OCP'' is restricted to carotenoid proteins that are verifiably orthologs of the 35 kDa protein that corresponds to the slr1963 gene product of Syn 6803 [5]. The three-dimensional structure of the OCP The structure of the OCP of A. maxima has been determined to 2.1 A resolution [13,14]. The asymmetric unit of the crystal contains an OCP dimer ( Fig.…”

Section: Biochemical Characterization and Distribution Of The Ocpsmentioning

confidence: 99%

Water-soluble carotenoid proteins of cyanobacteria

Kerfeld¹

2004

Archives of Biochemistry and Biophysics

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In photosynthetic organisms, carotenoids function in light harvesting and in photoprotection. In cyanobacteria, there have been numerous reports of proteins that bind exclusively carotenoids. Perhaps the best characterized of these proteins are the 35 kDa water-soluble orange carotenoid proteins (OCPs). Structural, biochemical, and genomic data on the OCP and its paralogs are gradually revealing how these proteins function in photoprotection.

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Crystals of the Carotenoid Protein fromArthrospira maximaContaining Uniformly Oriented Pigment Molecules

Cited by 16 publications

References 14 publications

Fluorescent Labeling Preserving OCP Photoactivity Reveals Its Reorganization during the Photocycle

Fluorescent Labeling Preserving OCP Photoactivity Reveals Its Reorganization during the Photocycle

The Signaling State of Orange Carotenoid Protein

Water-soluble carotenoid proteins of cyanobacteria

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