Figure 5.

Location of FRL-specific residues in FRL-PSI. The structure of FRL-PSI from F. thermalis PCC 7521 is shown. This figure corresponds to the multiple sequence alignment shown in Supplementary Figure 6 . Yellow spheres represent residues that are FRL-specific and are conserved in the ancestral sequence. Green spheres represent FRL-specific residues that are not conserved in the ancestral sequence. Chl f-binding sites that are conserved among the current FRL-PSI structures are shown with a pink glow and are labeled with bold font on each of the surface views (e.g., site B30). Chl f-binding sites that are observed to be species-specific based on the current structures are labeled with regular font (e.g., site B19). In the top left panel, the FRL-specific subunits are additionally labeled. The four clusters of FRL-specific residues are labeled c1 through c4.