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Marcolin G, Tumbarello F, Fresch E, Agostini A, Büchel C, Carbonera D, Collini E. Two-Dimensional Electronic Spectroscopy Characterization of Fucoxanthin-Chlorophyll Protein Reveals Excitonic Carotenoid-Chlorophyll Interactions. J Phys Chem Lett 2024; 15:2392-2399. [PMID: 38394035 DOI: 10.1021/acs.jpclett.3c03609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
Fucoxanthin Chlorophyll Protein (FCP) is a Light Harvesting Complex found in diatoms and brown algae. It is particularly interesting for its efficiency in capturing the blue-green part of the light spectrum due to the presence of specific chromophores (fucoxanthin, chlorophyll a, and chlorophyll c). Recently, the crystallographic structure of FCP was solved, revealing the 3D arrangement of the pigments in the protein scaffold. While this information is helpful for interpreting the spectroscopic features of FCP, it has also raised new questions about the potential interactions between fucoxanthin and chlorophyll c. These interactions were suggested by their spatial closeness but have never been experimentally observed. To investigate this possible interaction mechanism, in this work, two-dimensional electronic spectroscopy (2DES) has been applied to study the ultrafast relaxation dynamics of FCP. The experiments captured an instantaneous delocalization of the excitation among fucoxanthin and chlorophyll c, suggesting the presence of a non-negligible coupling between the chromophores.
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Affiliation(s)
- Giampaolo Marcolin
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Francesco Tumbarello
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Elisa Fresch
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Alessandro Agostini
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Claudia Büchel
- Institut für Molekulare Biowissenschaften, Goethe Universität Frankfurt, Max-von-Laue-Straβe 9, 60438 Frankfurt, Germany
| | - Donatella Carbonera
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Elisabetta Collini
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
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Silori Y, Chawla S, De AK. Unravelling the Role of Water in Ultrafast Excited-State Relaxation Dynamics within Nano-Architectures of Chlorophyll a. Chemphyschem 2020; 21:1908-1917. [PMID: 32619067 DOI: 10.1002/cphc.202000487] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 07/01/2020] [Indexed: 11/06/2022]
Abstract
Water plays a pivotal role in structural stability of supramolecular pigment assemblies designed for natural light harvesting (for example, chlorosome antenna complex) as well as their artificial analogs. However, the dynamic role of water in the context of excite-state relaxation has not been explored till date, which we report here. Using femtosecond transient absorption spectroscopy, we investigate the excited-state dynamics of two types of nano-scale assemblies of chlorophyll a with different structural motifs, rod-shaped and micellar assemblies, that depend on the water content. We show how water participates in excess energy dissipation by vibrational cooling of the non-thermally populated Qy band at different rates in different types of clusters but exhibits no polar solvation dynamics. For the micelles, we observe a bifurcation of stimulated emission line shape, whereas a positive-to-negative switching of differential absorption is observed for the rods; both these observations are correlated with their specific structural aspects. Density functional theory calculations reveal two possible stable ground state geometries of dimers, accounting for the bifurcation of line shape in micelles. Thus, our study elucidates water-mediated structure-function relationship within these pigment assemblies.
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Affiliation(s)
- Yogita Silori
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab, 140 306, India
| | - Sakshi Chawla
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab, 140 306, India
| | - Arijit K De
- Department of Chemical Sciences, Indian Institute of Science Education and Research Mohali, Knowledge City, Sector 81, SAS Nagar, Punjab, 140 306, India
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Nakashima N, Yatsuhashi T, Sakota K, Iwakura I, Hashimoto S, Yokoyama K, Matsuda S. An electron-capture efficiency in femtosecond filamentation. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2020.137570] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Fresch E, Collini E. Relaxation Dynamics of Chlorophyll b in the Sub-ps Ultrafast Timescale Measured by 2D Electronic Spectroscopy. Int J Mol Sci 2020; 21:ijms21082836. [PMID: 32325770 PMCID: PMC7215592 DOI: 10.3390/ijms21082836] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/16/2020] [Accepted: 04/16/2020] [Indexed: 12/19/2022] Open
Abstract
A thorough characterization of the early time sub-100 fs relaxation dynamics of biologically relevant chromophores is of crucial importance for a complete understanding of the mechanisms regulating the ultrafast dynamics of the relaxation processes in more complex multichromophoric light-harvesting systems. While chlorophyll a has already been the object of several investigations, little has been reported on chlorophyll b, despite its pivotal role in many functionalities of photosynthetic proteins. Here the relaxation dynamics of chlorophyll b in the ultrafast regime have been characterized using 2D electronic spectroscopy. The comparison of experimental measurements performed at room temperature and 77 K allows the mechanisms and the dynamics of the sub-100 fs relaxation dynamics to be characterized, including spectral diffusion and fast internal conversion assisted by a specific set of vibrational modes.
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Singlet and triplet excited states dynamics of photosynthetic pigment chlorophyll a investigated by sub-nanosecond pump-probe spectroscopy. J Photochem Photobiol A Chem 2018. [DOI: 10.1016/j.jphotochem.2017.09.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Ramanan C, Ferretti M, van Roon H, Novoderezhkin VI, van Grondelle R. Evidence for coherent mixing of excited and charge-transfer states in the major plant light-harvesting antenna, LHCII. Phys Chem Chem Phys 2018; 19:22877-22886. [PMID: 28812075 DOI: 10.1039/c7cp03038j] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
LHCII, the major light harvesting antenna from plants, plays a dual role in photosynthesis. In low light it is a light-harvester, while in high light it is a quencher that protects the organism from photodamage. The switching mechanism between these two orthogonal conditions is mediated by protein dynamic disorder and photoprotective energy dissipation. The latter in particular is thought to occur in part via spectroscopically 'dark' states. We searched for such states in LHCII trimers from spinach, at both room temperature and at 77 K. Using 2D electronic spectroscopy, we explored coherent interactions between chlorophylls absorbing on the low-energy side of LHCII, which is the region that is responsible for both light-harvesting and photoprotection. 2D beating frequency maps allow us to identify four frequencies with strong excitonic character. In particular, our results show the presence of a low-lying state that is coupled to a low-energy excitonic state. We assign this to a mixed excitonic-charge transfer state involving the state with charge separation within the Chl a603-b609 heterodimer, borrowing some dipole strength from the Chl a602-a603 excited states. Such a state may play a role in photoprotection, in conjunction with specific and environmentally controlled realizations of protein dynamic disorder. Our identification and assignment of the coherences observed in the 2D frequency maps suggests that the structure of exciton states as well as a mixing of the excited and charge-transfer states is affected by coupling of these states to resonant vibrations in LHCII.
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Affiliation(s)
- Charusheela Ramanan
- Department of Physics and Astronomy and Institute for Lasers, Life, and Biophotonics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081HV, Amsterdam, The Netherlands.
| | - Marco Ferretti
- Department of Physics and Astronomy and Institute for Lasers, Life, and Biophotonics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081HV, Amsterdam, The Netherlands.
| | - Henny van Roon
- Department of Physics and Astronomy and Institute for Lasers, Life, and Biophotonics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081HV, Amsterdam, The Netherlands.
| | - Vladimir I Novoderezhkin
- A.N. Berlozersky Intitut of Physico-Chemical Biology, Moscow State University, Leninskie Gory 1, 119992, Moscow, Russia
| | - Rienk van Grondelle
- Department of Physics and Astronomy and Institute for Lasers, Life, and Biophotonics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, 1081HV, Amsterdam, The Netherlands.
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Meneghin E, Leonardo C, Volpato A, Bolzonello L, Collini E. Mechanistic insight into internal conversion process within Q-bands of chlorophyll a. Sci Rep 2017; 7:11389. [PMID: 28900171 PMCID: PMC5595816 DOI: 10.1038/s41598-017-11621-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 08/29/2017] [Indexed: 11/08/2022] Open
Abstract
The non-radiative relaxation of the excitation energy from higher energy states to the lowest energy state in chlorophylls is a crucial preliminary step for the process of photosynthesis. Despite the continuous theoretical and experimental efforts to clarify the ultrafast dynamics of this process, it still represents the object of an intense investigation because the ultrafast timescale and the congestion of the involved states makes its characterization particularly challenging. Here we exploit 2D electronic spectroscopy and recently developed data analysis tools to provide more detailed insights into the mechanism of internal conversion within the Q-bands of chlorophyll a. The measurements confirmed the timescale of the overall internal conversion rate (170 fs) and captured the presence of a previously unidentified ultrafast (40 fs) intermediate step, involving vibronic levels of the lowest excited state.
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Affiliation(s)
- Elena Meneghin
- Department of Chemical Sciences, University of Padova, Padova, Italy
| | - Cristina Leonardo
- Department of Chemical Sciences, University of Padova, Padova, Italy
| | - Andrea Volpato
- Department of Chemical Sciences, University of Padova, Padova, Italy
| | - Luca Bolzonello
- Department of Chemical Sciences, University of Padova, Padova, Italy
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Nakashima N, Yamanaka KI, Saeki M, Ohba H, Taniguchi S, Yatsuhashi T. Metal ion reductions by femtosecond laser pulses with micro-Joule energy and their efficiencies. J Photochem Photobiol A Chem 2016. [DOI: 10.1016/j.jphotochem.2015.12.021] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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