Magnetophotoselection in the Investigation of Excitonically Coupled Chromophores: The Case of the Water-Soluble Chlorophyll Protein

0568359 - BC 2023 RIV CH eng J - Journal Article
Ciuti, S. - Agostini, Alessandro - Barbon, A. - Bortolus, M. - Paulsen, H. - Di Valentin, M. - Carbonera, D.
Magnetophotoselection in the Investigation of Excitonically Coupled Chromophores: The Case of the Water-Soluble Chlorophyll Protein.
Molecules. Roč. 27, č. 12 (2022), č. článku 3654. E-ISSN 1420-3049
R&D Projects: GA MŠMT(CZ) EF18_053/0016982
Institutional support: RVO:60077344
Keywords : magnetophotoselection * triplet state * chlorophyll-binding protein * excitonic interaction
OECD category: Biophysics
Impact factor: 4.6, year: 2022
Method of publishing: Open access
https://www.mdpi.com/1420-3049/27/12/3654

A magnetophotoselection (MPS) investigation of the photoexcited triplet state of chlorophyll a both in a frozen organic solvent and in a protein environment, provided by the water-soluble chlorophyll protein (WSCP) of Lepidium virginicum, is reported. The MPS experiment combines the photoselection achieved by exciting with linearly polarized light with the magnetic selection of electron paramagnetic resonance (EPR) spectroscopy, allowing the determination of the relative orientation of the optical transition dipole moment and the zero-field splitting tensor axes in both environments. We demonstrate the robustness of the proposed methodology for a quantitative description of the excitonic interactions among pigments. The orientation of the optical transition dipole moments determined by the EPR analysis in WSCP, identified as an appropriate model system, are in excellent agreement with those calculated in the point-dipole approximation. In addition, MPS provides information on the electronic properties of the triplet state, localized on a single chlorophyll a pigment of the protein cluster, in terms of orientation of the zero-field splitting tensor axes in the molecular frame.
Permanent Link: https://hdl.handle.net/11104/0340240