Antenna Protein Clustering In Vitro Unveiled by Fluorescence Correlation Spectroscopy

0542531 - MBÚ 2022 RIV CH eng J - Journal Article
Crepin, Aurelia - Cunill-Semanat, Edel - Kuthanová Trsková, Eliška - Belgio, Erica - Kaňa, Radek
Antenna Protein Clustering In Vitro Unveiled by Fluorescence Correlation Spectroscopy.
International Journal of Molecular Sciences. Roč. 22, č. 6 (2021), č. článku 2969. E-ISSN 1422-0067
R&D Projects: GA ČR(CZ) GJ17-02363Y; GA ČR(CZ) GA19-11494S; GA MŠMT(CZ) ED2.1.00/19.0392
Institutional support: RVO:61388971
Keywords : photosynthesis * photoprotection * antenna proteins * non-photochemical quenching * fluorescence correlation spectroscopy * detergent critical micelle concentration * protein oligomerization
OECD category: Microbiology
Impact factor: 6.208, year: 2021
Method of publishing: Open access
https://www.mdpi.com/1422-0067/22/6/2969

Antenna protein aggregation is one of the principal mechanisms considered effective in protecting phototrophs against high light damage. Commonly, it is induced, in vitro, by decreasing detergent concentration and pH of a solution of purified antennas, the resulting reduction in fluorescence emission is considered to be representative of non-photochemical quenching in vivo. However, little is known about the actual size and organization of antenna particles formed by this means, and hence the physiological relevance of this experimental approach is questionable. Here, a quasi-single molecule method, fluorescence correlation spectroscopy (FCS), was applied during in vitro quenching of LHCII trimers from higher plants for a parallel estimation of particle size, fluorescence, and antenna cluster homogeneity in a single measurement. FCS revealed that, below detergent critical micelle concentration, low pH promoted the formation of large protein oligomers of sizes up to micrometers, and therefore is apparently incompatible with thylakoid membranes. In contrast, LHCII clusters formed at high pH were smaller and homogenous, and yet still capable of efficient quenching. The results altogether set the physiological validity limits of in vitro quenching experiments. Our data also support the idea that the small, moderately quenching LHCII oligomers found at high pH could be relevant with respect to non-photochemical quenching in vivo.
Permanent Link: http://hdl.handle.net/11104/0319923