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Gacek DA, Betke A, Nowak J, Lokstein H, Walla PJ. Two-photon absorption and excitation spectroscopy of carotenoids, chlorophylls and pigment-protein complexes. Phys Chem Chem Phys 2021; 23:8731-8738. [PMID: 33876032 DOI: 10.1039/d1cp00656h] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In addition to (bacterio)chlorophylls, (B)Chls, photosynthetic pigment-protein complexes bind carotenoids (Cars) that fulfil various important functions which are not fully understood, yet. However, certain excited states of Cars are optically one-photon forbidden ("dark") and can potentially undergo excitation energy transfer (EET) to (B)Chls following two-photon absorption (TPA). The amount of EET is reflected by the differences in TPA and two-photon excitation (TPE) spectra of a complex (multi-pigment) system. Since it is technically and analytically demanding to resolve optically forbidden states, different studies reported varying contributions of Cars and Chls to TPE/TPA spectra. In a study using well-defined 1 : 1 Car-tetrapyrrole dyads TPE contributions of tetrapyrrole molecules, including Chls, and Cars were measured. In these experiments, TPE of Cars dominated over Chl a TPE in a broad wavelength range. Another study suggested only minor contributions of Cars to TPE spectra of pigment-protein complexes such as the plant main light-harvesting complex (LHCII), in particular for wavelengths longer than ∼600/1200 nm. By joining forces and a combined analysis of all available data by both teams, we try to resolve this apparent contradiction. Here, we demonstrate that reconstruction of a wide spectral range of TPE for LHCII and photosystem I (PSI) requires both, significant Car and Chl contributions. Direct comparison of TPE spectra obtained in both studies demonstrates a good agreement of the primary data. We conclude that in TPE spectra of LHCII and PSI, the contribution of Chls is dominating above 600/1200 nm, whereas the contributions of forbidden Car states increase particularly at wavelengths shorter than 600/1200 nm. Estimates of Car contributions to TPA as well as TPE spectra are given for various wavelengths.
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Affiliation(s)
- Daniel A Gacek
- Technische Universität Braunschweig, Institute for Physical and Theoretical Chemistry, Department for Biophysical Chemistry, Gaußstr. 17, 38106 Braunschweig, Germany.
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Staleva-Musto H, Kuznetsova V, West RG, Keşan G, Minofar B, Fuciman M, Bína D, Litvín R, Polívka T. Nonconjugated Acyloxy Group Deactivates the Intramolecular Charge-Transfer State in the Carotenoid Fucoxanthin. J Phys Chem B 2018; 122:2922-2930. [PMID: 29469573 DOI: 10.1021/acs.jpcb.8b00743] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We used ultrafast transient absorption spectroscopy to study excited-state dynamics of the keto-carotenoid fucoxanthin (Fx) and its two derivatives: 19'-butanoyloxyfucoxanthin (bFx) and 19'-hexanoyloxyfucoxanthin (hFx). These derivatives occur in some light-harvesting systems of photosynthetic microorganisms, and their presence is typically related to stress conditions. Even though the hexanoyl (butanoyl) moiety is not a part of the conjugated system of hFx (bFx), their absorption spectra in polar solvents exhibit more pronounced vibrational bands of the S2 state than for Fx. The effect of the nonconjugated acyloxy moiety is further observed in transient absorption spectra, which for Fx exhibit characteristic features of an intramolecular charge transfer (ICT) state in all polar solvents. For bFx and hFx, however, much weaker ICT features are detected in methanol, and the spectral markers of the ICT state disappear completely in polar, but aprotic acetonitrile. The presence of the acyloxy moiety also alters the lifetimes of the S1/ICT state. For Fx, the lifetimes are 60, 30, and 20 ps in n-hexane, acetonitrile, and methanol, whereas for bFx and hFx, these lifetimes yield 60, 60, and 40 ps, respectively. Testing the S1/ICT state lifetimes of hFx in other solvents revealed that some ICT features can be induced only in polar, protic solvents (methanol, ethanol, and ethylene glycol). Thus, bFx and hFx represent a rather rare example of a system in which a nonconjugated functional group significantly alters excited-state dynamics. By comparison with other carotenoids, we show that a keto group at the acyloxy tail, even though it is not in conjugation, affects the electron distribution along the conjugated backbone, resulting in the observed decrease of the ICT character of the S1/ICT state of bFx and hFx.
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Affiliation(s)
- Hristina Staleva-Musto
- Institute of Physics and Biophysics, Faculty of Science , University of South Bohemia , Branišovská 1760 , CZ 370 05 České Budějovice , Czech Republic
| | - Valentyna Kuznetsova
- Institute of Physics and Biophysics, Faculty of Science , University of South Bohemia , Branišovská 1760 , CZ 370 05 České Budějovice , Czech Republic
| | - Robert G West
- Institute of Physics and Biophysics, Faculty of Science , University of South Bohemia , Branišovská 1760 , CZ 370 05 České Budějovice , Czech Republic
| | - Gürkan Keşan
- Institute of Physics and Biophysics, Faculty of Science , University of South Bohemia , Branišovská 1760 , CZ 370 05 České Budějovice , Czech Republic.,Department of Chemistry, Faculty of Science , Gebze Technical University , 41400 Gebze , Kocaeli , Turkey
| | - Babak Minofar
- Center for Nanobiology and Structural Biology, Institute of Microbiology , Czech Academy of Sciences , CZ 373 33 Nové Hrady , Czech Republic
| | - Marcel Fuciman
- Institute of Physics and Biophysics, Faculty of Science , University of South Bohemia , Branišovská 1760 , CZ 370 05 České Budějovice , Czech Republic
| | - David Bína
- Institute of Physics and Biophysics, Faculty of Science , University of South Bohemia , Branišovská 1760 , CZ 370 05 České Budějovice , Czech Republic.,Institute of Plant Molecular Biology, Biological Centre , Czech Academy of Sciences , CZ 370 05 České Budějovice , Czech Republic
| | - Radek Litvín
- Institute of Physics and Biophysics, Faculty of Science , University of South Bohemia , Branišovská 1760 , CZ 370 05 České Budějovice , Czech Republic.,Institute of Plant Molecular Biology, Biological Centre , Czech Academy of Sciences , CZ 370 05 České Budějovice , Czech Republic
| | - Tomáš Polívka
- Institute of Physics and Biophysics, Faculty of Science , University of South Bohemia , Branišovská 1760 , CZ 370 05 České Budějovice , Czech Republic.,Institute of Plant Molecular Biology, Biological Centre , Czech Academy of Sciences , CZ 370 05 České Budějovice , Czech Republic
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Gacek DA, Moore AL, Moore TA, Walla PJ. Two-Photon Spectra of Chlorophylls and Carotenoid–Tetrapyrrole Dyads. J Phys Chem B 2017; 121:10055-10063. [DOI: 10.1021/acs.jpcb.7b08502] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Daniel A. Gacek
- Technische Universität Braunschweig, Institute for Physical and Theoretical Chemistry, Department of Biophysical
Chemistry, Gaußstraße.
17, 38106 Braunschweig, Germany
| | - Ana L. Moore
- School
of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Thomas A. Moore
- School
of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, Arizona 85287-1604, United States
| | - Peter Jomo Walla
- Technische Universität Braunschweig, Institute for Physical and Theoretical Chemistry, Department of Biophysical
Chemistry, Gaußstraße.
17, 38106 Braunschweig, Germany
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