Back to Search
Start Over
An Exciton Dynamics Model of Bryopsis corticulans Light-Harvesting Complex II
- Source :
- Journal of Physical Chemistry B, 125(4), 1134-1143. AMER CHEMICAL SOC
- Publication Year :
- 2021
- Publisher :
- AMER CHEMICAL SOC, 2021.
-
Abstract
- Bryopsis corticulans is a marine green macroalga adapted to the intertidal environment. It possesses siphonaxanthin-binding light-harvesting complexes of photosystem II (LHCII) with spectroscopic properties markedly different from the LHCII in plants. By applying a phenomenological fitting procedure to the two-dimensional electronic spectra of the LHCII from B. corticulans measured at 77 K, we can extract information about the excitonic states and energy-transfer processes. The fitting method results in well-converged parameters, including excitonic energy levels with their respective transition dipole moments, spectral widths, energy-transfer rates, and coupling properties. The 2D spectra simulated from the fitted parameters concur very well with the experimental data, showing the robustness of the fitting method. An excitonic energy-transfer scheme can be constructed from the fitting parameters. It shows the rapid energy transfer from chlorophylls (Chls) b to a at subpicosecond time scales and a long-lived state in the Chl b region at around 659 nm. Three weakly connected terminal states are resolved at 671, 675, and 677 nm. The lowest state is higher in energy than that in plant LHCII, which is probably because of the fewer number of Chls a in a B. corticulans LHCII monomer. Modeling based on existing Hamiltonians for the plant LHCII structure with two Chls a switched to Chls b suggests several possible Chl a-b replacements in comparison with those of plant LHCII. The adaptive changes result in a slower energy equilibration in the complex, revealed by the longer relaxation times of several exciton states compared to those of plant LHCII. The strength of our phenomenological fitting method for obtaining excitonic energy levels and energy-transfer network is put to the test in systems such as B. corticulans LHCII, where prior knowledge on exact assignment and spatial locations of pigments are lacking. Ministry of Education (MOE) Submitted/Accepted version H.-S.T acknowledges support from the Singapore Ministry of Education Academic Research Fund (Tier 1 RG2/19 and Tier 1 RG15/18). P.H.L. acknowledges grants from the National Research, Development and Innovation Fund (Grants NN124904 and 2018-1.2.1-NKP-2018-00009). This work was also supported by a Strategic Priority Research Program (XDB17030100) of China, a Key Research Project for Frontier Science (QYZDY-SSW-SMC003) from the Chinese Academy of Sciences (CAS), China, and a bilateral project between CAS and the Hungary Academy of Sciences.
- Subjects :
- 01.03. Fizikai tudományok
Physics
010304 chemical physics
Photosystem II
Flow
Exciton
Relaxation (NMR)
010402 general chemistry
01 natural sciences
Molecular physics
Spectral line
0104 chemical sciences
Surfaces, Coatings and Films
Dipole
Energy Transfer
Coupling (computer programming)
Chemistry [Science]
0103 physical sciences
Materials Chemistry
Bryopsis corticulans
Physical and Theoretical Chemistry
Light harvesting complex II
Subjects
Details
- Language :
- English
- ISSN :
- 15205207 and 15206106
- Volume :
- 125
- Issue :
- 4
- Database :
- OpenAIRE
- Journal :
- The Journal of Physical Chemistry. B: Materials, Surfaces, Interfaces, & Biophysical
- Accession number :
- edsair.doi.dedup.....86667277aa92228efc398d9eadc8bfe5