InterPro domain: IPR028203

This entry represents a domain found in the photosynthesis system II assembly factor YCF48/HCF136 and associated proteins.

The photosynthesis system II (PSII) is a multi-subunit pigment-protein complex responsible for water oxidation during oxygenic photosynthesis [ 1 ]. PSII can be found in the thylakoid membrane of chloroplasts and cyanobacteria. Its assembly is regulated by PSII assembly factors including Ycf48/Hcf136, Psb27 and Psb28. Ycf48/Hcf136 contains the BNR repeats and can be found predominantly in the thykaloid membrane. Ycf48/Hcf136 is required for assembly and repair of an early intermediate in PSII assembly that includes D2 (psbD) and cytochrome b559 [ 2 , 2 ]. This domain can also be found in some YCF48-like proteins that may not affect PSII activity.

1. The cyanobacterial homologue of HCF136/YCF48 is a component of an early photosystem II assembly complex and is important for both the efficient assembly and repair of photosystem II in Synechocystis sp. PCC 6803. J. Biol. Chem. 283, 22390-9
2. An intermediate membrane subfraction in cyanobacteria is involved in an assembly network for Photosystem II biogenesis. J. Biol. Chem. 286, 21944-51