Figure 11.

Model for the Early Stages of PSII Assembly Showing the Locations of RubA and the Other Cyanobacterial/Plant Accessory Proteins.

Ycf48 (HCF136 in plants) and the chlorophyll-containing Ycf39/Hlip complex (HCF244/OHP in plants) assist in the insertion of Chl into D1_mod, while CyanoP (PPL1 in plants) stabilizes D2_mod. The transmembrane domain of RubA associates with the N-terminal region of D1, positioning the C-terminal tail of RubA in close proximity to the lumenal Ycf48 factor. The linker region of RubA allows the rubredoxin domain to bind at the interface of D1 and D2. All factors remain associated with the modules after they form the RCII* complex.