Modified chlorophyll pigment at ChlD₁ tunes photosystem II beyond the red-light limit
File(s)
Published version
Author(s)
Allgower, Friederike
Sirohiwal, Abhishek
Gamiz-Hernandez, Ana P
Poverlein, Maximilian C
Fantuzzi, Andrea
Type
Journal Article
Abstract
Photosystem II (PSII) is powered by the light-capturing properties of chlorophyll a pigments that define the spectral range of oxygenic photosynthesis. Some photosynthetic cyanobacteria can acclimate to growth in longer wavelength light by replacing five chlorophylls with long wavelength pigments in specific locations, including one in the reaction center (RC) (Science, 2018, 360, 1210–1213). However, the exact location and the nature of these long wavelength pigments still remain uncertain. Here we have addressed the color-tuning mechanism of the far-red light PSII (FRL-PSII) by excited state calculations at both the ab initio correlated (ADC2) and linear-response time-dependent density functional theory (LR-TDDFT) levels in combination with large-scale hybrid quantum/classical (QM/MM) simulations and atomistic molecular dynamics. We show that substitution of a single chlorophyll pigment (ChlD1) at the RC by chlorophyll d leads to a spectral shift beyond the far-red light limit, as a result of the protein electrostatic, polarization and electronic coupling effects that reproduce key structural and spectroscopic observations. Pigment substitution at the ChlD1 site further results in a low site energy within the RC that could function as a sink for the excitation energy and initiate the primary charge separation reaction, driving the water oxidation. Our findings provide a basis for understanding color-tuning mechanisms and bioenergetic principles of oxygenic photosynthesis at the far-red light limit.
Date Issued
2025-06-25
Date Acceptance
2025-05-10
Citation
Chemical Science, 2025, 16, pp.11270-11279
ISSN
2041-6520
Publisher
The Royal Society of Chemistry
Start Page
11270
End Page
11279
Journal / Book Title
Chemical Science
Volume
16
Issue
25
Copyright Statement
© 2025 The Author(s). Published by the Royal Society of Chemistry Open Access Article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/40453800
PII: d4sc07473d
Subjects
CHARGE-SEPARATION
Chemistry
Chemistry, Multidisciplinary
CORE COMPLEXES
ELECTRON-TRANSFER
ENERGY
KINETICS
MECHANISM
MOLECULAR-DYNAMICS
PHEOPHYTIN
Physical Sciences
SCHEME
Science & Technology
Publication Status
Published
Coverage Spatial
England
Date Publish Online
2025-05-12