Biochemical and spectroscopic characterizations of the oligomeric antenna of the coral symbiotic Symbiodiniaceae Fugacium kawagutii.

Autor: Niedzwiedzki DM; Center for Solar Energy and Energy Storage, Washington University in St. Louis, St. Louis, MO, 63130, USA. niedzwiedzki@wustl.edu.; Department of Energy Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA. niedzwiedzki@wustl.edu., Magdaong NCM; Department of Chemistry, Washington University in St. Louis, St. Louis, MO, 63130, USA., Su X; Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA., Liu H; Department of Biology, Washington University in St. Louis, St. Louis, MO, 63130, USA. liuhaijun@wustl.edu.
Jazyk: angličtina
Zdroj: Photosynthesis research [Photosynth Res] 2022 Nov; Vol. 154 (2), pp. 113-124. Date of Electronic Publication: 2022 Sep 07.
DOI: 10.1007/s11120-022-00951-6
Abstrakt: Light-harvesting antennas in photosynthesis capture light energy and transfer it to the reaction centers (RCs) where photochemistry takes place. The sustainable growth of the reef-building corals relies on a constant supply of the photosynthates produced by the endosymbiotic dinoflagellate, belonging to the family of Symbiodiniaceae. The antenna system in this group consists of the water-soluble peridinin-chlorophyll a-protein (PCP) and the intrinsic membrane chlorophyll a-chlorophyll c 2 -peridinin protein complex (acpPC). In this report, a nonameric acpPC is reported in a dinoflagellate, Fugasium kawagutii (formerly Symbiodinium kawagutii sp. CS-156). We found that extensive biochemical purification altered the oligomerization states of the initially isolated nonameric acpPC. The excitation energy transfer pathways in the acpPC nonamer and its variants were studied using time-resolved fluorescence and time-resolved absorption spectroscopic techniques at 77 K. Compared to the well-characterized trimeric acpPC, the nonameric acpPC contains an 11 nm red-shifted terminal energy emitter and substantially altered excited state lifetimes of Chl a. The observed energetic overlap of the fluorescence terminal energy emitters with the absorption of RCs is hypothesized to enable efficient downhill excitation energy transfer. Additionally, the shortened Chl a fluorescence decay lifetime in the oligomeric acpPC indicate a protective self-relaxation strategy. We propose that the highly-oligomerized acpPC nonamer represents an intact functional unit in the Symbiodiniaceae thylakoid membrane. They perform efficient excitation energy transfer (to RCs), and are under manageable regulations in favor of photoprotection.
(© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)
Databáze: MEDLINE
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