Excitonic network organization enables efficient energy transfer in diatom photosystem I

Akhtar, Parveen and Feng, Yue and Wang, Wenda and Shen, Jian-Ren and Büchel, Claudia and Tan, Howe-Siang and Lambrev, Petar (2025) Excitonic network organization enables efficient energy transfer in diatom photosystem I. CELL REPORTS PHYSICAL SCIENCE, 6 (8). No. 102731. ISSN 2666-3864

Preview	Text CellRepPhys.pdf - Published Version Available under License Creative Commons Attribution Non-commercial. Download (7MB) | Preview
Preview	Text (graphical abstract) fx1_lrg.jpg - Published Version Available under License Creative Commons Attribution Non-commercial. Download (297kB) | Preview

Abstract

Diatoms contribute about 40% of marine primary photoproduction, owing their success, in part, to a specialized light-harvesting antenna built from fucoxanthin-chlorophyll a/c-binding proteins (FCPs). Photosystem I (PSI) in the marine diatom Thalassiosira pseudonana contains up to 13 FCPI subunits. The mechanisms by which PSI maintains photochemical efficiency with a large antenna are not well understood. Here, we investigate the excitation energy transfer dynamics in PSI-FCPI from T. pseudonana using time-resolved spectroscopy and structure-based exciton modeling. Two-dimensional electronic spectroscopy shows that spectral equilibration in PSI-FCPI occurs mainly within 1 ps. Exciton migration between FCPI and PSI takes ∼10 ps. The rapid inter-subunit energy transfer is contributed by (1) strongly coupled chlorophyll dimers in Lhcr-type FCPI, acting as red-shifted excitonic “gateway” states, and (2) hierarchical organization with strongly connected FCPI “hubs” carrying energy from neighboring FCPIs to the core. The findings can inform the design of bio-inspired light-harvesting systems.

Actions (login required)

Edit Item