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Influence of thylakoid membrane lipids on the structure of aggregated light‐harvesting complexes of the diatom Thalassiosira pseudonana and the green alga Mantoniella squamata
Author(s) -
SchallerLaudel Susann,
Latowski Dariusz,
JemiołaRzemińska Małgorzata,
Strzałka Kazimierz,
Daum Sebastian,
Bacia Kirsten,
Wilhelm Christian,
Goss Reimund
Publication year - 2017
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/ppl.12565
Subject(s) - thylakoid , thalassiosira pseudonana , phosphatidylglycerol , galactolipids , chloroplast , biology , biophysics , membrane , membrane lipids , chemistry , biochemistry , botany , phosphatidylcholine , phospholipid , nutrient , ecology , phytoplankton , gene
The study investigated the effect of the thylakoid membrane lipids monogalactosyldiacylglycerol ( MGDG ), digalactosyldiacylglycerol ( DGDG ), sulphoquinovosyldiacylglycerol ( SQDG ) and phosphatidylglycerol ( PG ) on the structure of two algal light‐harvesting complexes ( LHCs ). In contrast to higher plants whose thylakoid membranes are characterized by an enrichment of the neutral galactolipids MGDG and DGDG , both the green alga Mantoniella squamata and the centric diatom Thalassiosira pseudonana contain membranes with a high content of the negatively charged lipids SQDG and PG . The algal thylakoids do not show the typical grana–stroma differentiation of higher plants but a regular arrangement. To analyze the effect of the membrane lipids, the fucoxanthin chlorophyll protein ( FCP ) complex of T. pseudonana and the LHC of M. squamata ( MLHC ) were prepared by successive cation precipitation using Triton X‐100 as detergent. With this method, it is possible to isolate LHCs with a reduced amount of associated lipids in an aggregated state. The results from 77 K fluorescence and photon correlation spectroscopy show that neither the neutral galactolipids nor the negatively charged lipids are able to significantly alter the aggregation state of the FCP or the MLHC . This is in contrast to higher plants where SQDG and PG lead to a strong disaggregation of the LHCII whereas MGDG and DGDG induce the formation of large macroaggregates. The results indicate that LHCs which are integrated into thylakoid membranes with a high amount of negatively charged lipids and a regular arrangement are less sensitive to lipid‐induced structural alterations than their counterparts in membranes enriched in neutral lipids with a grana–stroma differentiation.