Significant Effects of Excitonic Coupling and Charge Transfer on the Circular Dichroism Spectrum of Photosynthetic Light-Harvesting I Complex.

ABSTRACT: Spectral properties of light-harvesting (LH) complexes are key to understanding excitation-energy transfer in photosynthesis. This study examines the physicochemical factors that shape the circular dichroism (CD) spectrum of LH1 in Rhodospirillum rubrum. Calculations using four computational models reveal that intermolecular electronic interactions, particularly excitonic coupling, primarily determine the LH1 CD spectrum shape, while charge transfer effects contribute significantly to the redshift of the peaks. Another finding is that the LH1-specific spectrum shape arises from excitonic coupling extending over 12 bacteriochlorophyll (BChl) a molecules. Further computational analysis additionally identified an anticlockwise rotation of the transition dipole moments of the BCh

SUBMITTER: Tsuji R 

PROVIDER: S-EPMC12207587 | biostudies-literature | 2025 Jun

REPOSITORIES: biostudies-literature