Fig. 1: Analysis of protein and pigment composition of the purified PSI from C. velia.

a The PSI was purified twice and in both cases, the PSI-enriched fraction was first isolated using a sucrose gradient. Subsequent purification steps involved either clear-native (CN) gel or size-exclusion chromatography (Supplementary Fig. 1). A single strip from the CN gel was further separated in the second dimension by SDS-PAGE and stained with Coomassie Blue. All visible protein spots were analyzed by MS (b). The proteins identified in selected spots are shown in a form of heat map, where each protein is colored based on its identification score (see Supplementary Data File for all identified proteins). * indicates that the tryptic digestion of the sample was combined with deglycosylation by PNGase F. c HPLC pigment analysis of the PSI complex eluted from the CN gel; the cut band is indicated by a dashed rectangle in (a). The ratio of individual carotenoids, showed in parentheses, is calculated to 114 CLA molecules that were identified in the cryo-EM structure of C. velia PSI from this work. The data for this figure are provided in the Source data file.