The role of far-red fluorescing chlorophylls in the quenching of LHCII.

ABSTRACT: In photosynthetic organisms, the major light-harvesting antenna protein LHCII performs the dual function of capturing excitation energy and protecting the photosystem from over-excitation via non-photochemical quenching (NPQ). We investigated the role of far-red-fluorescing chlorophylls (emission > 700 nm) in quenching LHCII by comparing isolated trimeric LHCII (denoted F680) with aggregated LHCII prepared in a glycerol-rich medium (denoted F730). Time-resolved fluorescence and ultrafast transient-absorption spectroscopy, including an intensity-cycling scheme to separate annihilation-free dynamics, were used. We find that the red-emissive chlorophyll states are populated in < 100 ps and display properties consistent with states having a low transition-dipole moment. Despite the significant

SUBMITTER: Sebelik V 

PROVIDER: S-EPMC12855284 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature