(A) Absorption spectra of Lhcb, PSII core, and PSI. The spectra are normalized to the maximum in the Qy region. (B) CD spectra of monomeric Lhcb, PSII core, and PSI-LHCI. (C) Fluorescence emission of monomeric Lhcb, PSII core, and PSI-LHCI at 77 K. All the spectra are very similar in the region dominated by the absorption of the Chls (600–800 nm), while they differ in the region dominated by the carotenoid absorption (450–550 nm) due to the different spectroscopic properties of astaxanthin compared to the carotenoids present in the WT. The small differences around 650 nm in the spectra of the Lhcb are due to the presence of a higher amount of LHCII in the Lhcb monomeric fraction from Asta plants as compared to the WT . Since LHCII has a relatively higher content in Chl b as compared to the minor antennae, the signal due to Chl b (650 nm) is more intense. The differences in the emission spectra of PSII and PSI are due to contamination, namely the presence of a small amount of PSI in the PSII preparation, and of PSII in the PSI preparation, which is visible also in the SDS-PAGE (Figure 2—figure supplement 1).