Accepted Article Influence of thylakoid membrane lipids on the structure of aggregated light- harvesting complexes of the diatom Thalassiosira pseudonana and the green alga Mantoniella squamata Susann Schaller-Laudel a , Dariusz Latowski b , Małgorzata Jemioła-Rzemińska b , Kazimierz Strzałka b,c , Sebastian Daum d , Kirsten Bacia d , Christian Wilhelm a and Reimund Goss a, * a Institute of Biology, University of Leipzig, Johannisallee 21-23, D-04103 Leipzig, Germany b Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, ul. Gronostajowa 7, 30- 387 Krakow, Poland c Malopolska Centre of Biotechnology, Jagiellonian University, ul. Gronostajowa 7A, 30-387 Krakow, Poland d Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Str. 3, D-06120 Halle (Saale), Germany *Corresponding author, e-mail: rgoss@rz.uni-leipzig.de 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 (LHC). 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 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 macro- This article is protected by copyright. All rights reserved. This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/ppl.12565