Excitation dynamics and relaxation in the major antenna of a marine green alga Bryopsis corticulans

Dan-Hong Li, Wenda Wang, Cuicui Zhou, Yan Zhang, Peng Wang, Jian-Ren Shen, Tingyun Kuang, Jian-Ping Zhang

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

The light-harvesting complexes II (LHCIIs) of spinach and Bryopsis corticulans as a green alga are similar in structure, but differ in carotenoid (Car) and chlorophyll (Chl) compositions. Carbonyl Cars siphonein (Spn) and siphonaxanthin (Spx) bind to B. corticulans LHCII likely in the sites as a pair of lutein (Lut) molecules bind to spinach LHCII in the central domain. To understand the light-harvesting and photoprotective properties of the algal LHCII, we compared its excitation dynamics and relaxation to those of spinach LHCII been well documented. It was found that B. corticulans LHCII exhibited a substantially longer chlorophyll (Chl) fluorescence lifetime (4.9 ns vs 4.1 ns) and a 60% increase of the fluorescence quantum yield. Photoexcitation populated 3Car* equally between Spn and Spx in B. corticulans LHCII, whereas predominantly at Lut620 in spinach LHCII. These results prove the functional differences of the LHCIIs with different Car pairs and Chl a/b ratios: B. corticulans LHCII shows the enhanced blue-green light absorption, the alleviated quenching of 1Chl*, and the dual sites of quenching 3Chl*, which may facilitate its light-harvesting and photoprotection functions. Moreover, for both types of LHCIIs, the triplet excitation profiles revealed the involvement of extra 3Car* formation mechanisms besides the conventional Chl-to-Car triplet transfer, which are discussed in relation to the ultrafast processes of 1Chl* quenching. Our experimental findings will be helpful in deepening the understanding of the light harvesting and photoprotection functions of B. corticulans living in the intertidal zone with dramatically changing light condition.

Original languageEnglish
Pages (from-to)148186
JournalBiochimica et Biophysica Acta - Bioenergetics
DOIs
Publication statusE-pub ahead of print - Mar 11 2020
Externally publishedYes

Fingerprint Dive into the research topics of 'Excitation dynamics and relaxation in the major antenna of a marine green alga Bryopsis corticulans'. Together they form a unique fingerprint.

Cite this