Excited State Properties of Peridinin:  Observation of a Solvent Dependence of the Lowest Excited Singlet State Lifetime and Spectral Behavior Unique among Carotenoids

Bautista, James A.; Connors, Robert E.; Raju, B. Bangar; Hiller, Roger G.; Sharples, Frank P.; Gosztola, David J.; Wasielewski, Michael R.; Frank, Harry A.

doi:10.1021/jp9916135

Cited by 205 publications

(515 citation statements)

References 36 publications

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“…It can be speculated that the cyclopentanone ring is involved in this localization step. This assumption is likely because other groups having observed a decay pattern very similar to the one reported here, made their observations in peridinin, a carotenoid highly substituted and possessing a cyclopentanone ring as well [99][100][101][102]. This assumption is further corroborated by experimental results obtained on magnesium octaethylporphyrin (MgOEP) (data not shown) as MgOEP, in contrast to the structurally similar PChla, which in addition has an attached cyclopentanone ring to the porphyrin macrocycle, does not exhibit any significant excited-state dynamics, when directly being promoted into the Q 00 band [22].…”

Section: Protochlorophyllide Asupporting

confidence: 81%

“…This strikingly different decaying behavior deserves some thorough considerations. The experimental findings discussed so far might be explained on the basis of a split S 1 state in analogy to arguments given by Zigmantas et al [99] and Bautista et al [100] to account for the observed excited-state dynamics of peridinin, a highly substituted carotenoid. The second state involved would most likely possess intramolecular charge-transfer (ICT) character and is therefore stabilized in more polar solvents and -in turn -destabilized in a nonpolar environment.…”

Section: Protochlorophyllide Asupporting

confidence: 64%

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Femtosecond time‐resolved spectroscopy on biological photoreceptor chromophores

Schmitt¹,

Dietzek

Hermann

et al. 2007

Laser & Photonics Reviews

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This paper reviews our results on femtosecond timeresolved spectroscopy (transient absorption, transient-grating and fluorescence spectroscopy) to study the photophysics and photochemistry of the two very important biological photoreceptor chromophores phycocyanobilin (PCB) and protochlorophyllide a (PChla). The compound PCB serves as a model chromophore for the photoreceptor phytochrome. By means of transient-grating spectroscopy where the excitation wavelength was varied over the spectral region of the S0 → S1-absorption the ultrafast processes were studied upon excitation with varying excess energy delivered to the system. On the basis of the results obtained, both the rate of the photoreaction in PCB and the rate of the decay of different excited-state species via different decay channels depend on the excitation wavelength. Furthermore, transient absorption experiments illuminating the excited-state dynamics of PChla, a porphyrin-like compound and, as substrate of the NADPH/protochlorophyllide oxidoreductase (POR), a precursor of the chlorophyll biosynthesis are presented. In addition to pump-energy-dependent measurements performed with PChla dissolved in methanol, the excited-state dynamics of PChla was interrogated in different solvents that were chosen to mimic different environmental conditions. In addition to the femtosecond time-resolved absorption experiments the picosecond time-resolved fluorescence of the system was studied. The transient absorption and time-resolved fluorescence data allow suggesting a detailed model for the excited-state relaxation of PChla describing the excited-state processes in terms of The model suggested to account for the excited-state relaxation processes in protochlorophyllide a upon photoexcitation is presented a branching of the initially excited state population into a reactive and nonreactive path. Thus, the excited-state potential energy surface exhibits two distinct S1 and Sx minima separated from the Franck-Condon region along two most likely orthogonal reaction coordinates. Finally, the model derived is related to models suggested to account for the reduction of PChla to chlorophyllide a within the natural enzymatic environment of POR.

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Section: Protochlorophyllide Asupporting

confidence: 81%

Section: Protochlorophyllide Asupporting

confidence: 64%

Femtosecond time‐resolved spectroscopy on biological photoreceptor chromophores

Schmitt¹,

Dietzek

Hermann

et al. 2007

Laser & Photonics Reviews

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show abstract

“…The broadening and red-shifting of the 39-hECN chromophore in the OCP and RCP, attributed to conformational heterogeneity of 39-hECN in these proteins, as well as orientation and local environment of the carbonyl oxygen, has been discussed in detail elsewhere (Polívka et al, 2005;Chábera et al, 2011;Berera et al, 2012). Similar effects are observed in the absorption spectra for other carotenoids with conjugated carbonyl groups when dissolved in polar solvents (Bautista et al, 1999;Frank et al, 2000). The reduced A 280 in the RCP spectrum is consistent with the loss of aromatic amino acids associated with the C-terminal domain.…”

Section: Spectroscopic Characterization Of Ocp O Ocp R and Rcpmentioning

confidence: 66%

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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“…Instead of an internal electron withdrawing group (such as a carbonyl), the interaction with polar amino acids, inorganic cations such as Mg 2ϩ or nearby pigments, resulting in a highly asymmetric environment of the molecule, may stabilize an ICT state. Also, geometric deformations of the polyene backbone have been proposed to play a role in lowering ICT states in carotenoids (30). Trimeric LHCII binds two luteins that are distinguishable by their steady-state absorption spectrum.…”

Section: Discussionmentioning

confidence: 99%

A simple artificial light-harvesting dyad as a model for excess energy dissipation in oxygenic photosynthesis

Berera

Herrero

Stokkum

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

125

176

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Under excess illumination, plant photosystem II dissipates excess energy through the quenching of chlorophyll fluorescence, a process known as nonphotochemical quenching. Activation of nonphotochemical quenching has been linked to the conversion of a carotenoid with a conjugation length of nine double bonds (violaxanthin) into an 11-double-bond carotenoid (zeaxanthin). It has been suggested that the increase in the conjugation length turns the carotenoid from a nonquencher into a quencher of chlorophyll singlet excited states, but unequivocal evidence is lacking. Here, we present a transient absorption spectroscopic study on a model system made up of a zinc phthalocyanine (Pc) molecule covalently linked to carotenoids with 9, 10, or 11 conjugated carbon-carbon double bonds. We show that a carotenoid can act as an acceptor of Pc excitation energy, thereby shortening its singlet excited-state lifetime. The conjugation length of the carotenoid is critical to the quenching process. Remarkably, the addition of only one double bond can turn the carotenoid from a nonquencher into a very strong quencher. By studying the solvent polarity dependence of the quenching using target analysis of the time-resolved data, we show that the quenching proceeds through energy transfer from the excited Pc to the optically forbidden S 1 state of the carotenoid, coupled to an intramolecular charge-transfer state. The mechanism for excess energy dissipation in photosystem II is discussed in view of the insights obtained on this simple model system. artificial photosynthesis ͉ carotenoid ͉ nonphotochemical quenching ͉ photoprotection ͉ xanthophyll cycle

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Excited State Properties of Peridinin: Observation of a Solvent Dependence of the Lowest Excited Singlet State Lifetime and Spectral Behavior Unique among Carotenoids

Cited by 205 publications

References 36 publications

Femtosecond time‐resolved spectroscopy on biological photoreceptor chromophores

Femtosecond time‐resolved spectroscopy on biological photoreceptor chromophores

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

A simple artificial light-harvesting dyad as a model for excess energy dissipation in oxygenic photosynthesis

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