Inter-subunit energy transfer processes in a minimal plant photosystem II supercomplex

• Main Authors: Nguyen, Hoang Long, Do, Thanh Nhut, Zhong, Kai, Akhtar, Parveen, Jansen, Thomas L. C., Knoester, Jasper, Caffarri, Stefano, Lambrev, Petar, Tan, Howe-Siang
• Other Authors: School of Chemistry, Chemical Engineering and Biotechnology
• Format: Article
• Language: English
• Published: 2024
• Subjects: Medicine, Health and Life Sciences; Energy transfer process; Excitonic energy
• Online Access: https://hdl.handle.net/10356/174873
• Institution: Nanyang Technological University

Photosystem II (PSII) is an integral part of the photosynthesis machinery, in which several light-harvesting complexes rely on inter-complex excitonic energy transfer (EET) processes to channel energy to the reaction center. In this paper, we report on a direct observation of the inter-complex EET in a minimal PSII supercomplex from plants, containing the trimeric light-harvesting complex II (LHCII), the monomeric light-harvesting complex CP26, and the monomeric PSII core complex. Using two-dimensional (2D) electronic spectroscopy, we measure an inter-complex EET timescale of 50 picoseconds for excitations from the LHCII-CP26 peripheral antenna to the PSII core. The 2D electronic spectra also reveal that the transfer timescale is nearly constant over the pump spectrum of 600 to 700 nanometers. Structure-based calculations reveal the contribution of each antenna complex to the measured inter-complex EET time. These results provide a step in elucidating the full inter-complex energy transfer network of the PSII machinery.