AUTHOR=Magyar Melinda , Akhtar Parveen , Sipka Gábor , Domonkos Ildikó , Han Wenhui , Li Xingyue , Han Guangye , Shen Jian-Ren , Lambrev Petar H. , Garab Győző 

TITLE=Effects of lipids on the rate-limiting steps in the dark-to-light transition of Photosystem II core complex of Thermostichus vulcanus

JOURNAL=Frontiers in Plant Science

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2024.1381040

DOI=10.3389/fpls.2024.1381040

ISSN=1664-462X

ABSTRACT=<p>In our earlier works, we have shown that the rate-limiting steps, associated with the dark-to-light transition of Photosystem II (PSII), reflecting the photochemical activity and structural dynamics of the reaction center complex, depend largely on the lipidic environment of the protein matrix. Using chlorophyll-<italic>a</italic> fluorescence transients (ChlF) elicited by single-turnover saturating flashes, it was shown that the half-waiting time (Δ<italic>τ</italic><sub>1/2</sub>) between consecutive excitations, at which 50% of the fluorescence increment was reached, was considerably larger in isolated PSII complexes of <italic>Thermostichus</italic> (<italic>T.</italic>) <italic>vulcanus</italic> than in the native thylakoid membrane (TM). Further, it was shown that the addition of a TM lipid extract shortened Δ<italic>τ</italic><sub>1/2</sub> of isolated PSII, indicating that at least a fraction of the ‘missing’ lipid molecules, replaced by detergent molecules, caused the elongation of Δ<italic>τ</italic><sub>1/2</sub>. Here, we performed systematic experiments to obtain information on the nature of TM lipids that are capable of decreasing Δ<italic>τ</italic><sub>1/2</sub>. Our data show that while all lipid species shorten Δ<italic>τ</italic><sub>1/2</sub>, the negatively charged lipid phosphatidylglycerol appears to be the most efficient species – suggesting its prominent role in determining the structural dynamics of PSII reaction center.</p>