Fig. 6: Map of acetylated N-terminal domains of PSII–LHCIIsc subunits spanning the stromal gap.

Schematic top- and side-view of the (C2S2M)×2, highlighting the acetylated N-terminal domains of the proteins spanning across the stromal gap detected and quantified by TD-MS (red box indicates acetylation rate of the complete primary isoform in any light condition, above 98% solid line; above 90% dashed line). Trimming position(s) and putative phosphorylation sites (based on homologous phosphosites previously detected in other plants29) are indicated. N-α-acetylation (ac) detected in crosslinked peptides is shown. N-α-acetylation detected by XL-MS in vitro on isolated PSII–LHCIIsc (treated with DSSO, pentagon; treated with EDC, square) and in situ on the thylakoid membranes (treated with DSSO; triangle) is shown.