The Photosystem II Assembly Factor Ycf48 from the Cyanobacterium Synechocystis sp. PCC 6803 Is Lipidated Using an Atypical Lipobox Sequence

Photochemical energy conversion during oxygenic photosynthesis is performed by membrane-embedded chlorophyll-binding protein complexes. The biogenesis and maintenance of these complexes requires auxiliary factors that optimize the assembly process protect nascent from photodamage. In cyanobacteria, several lipoproteins contribute to function photosystem II (PSII) complex. They include CyanoP, CyanoQ, Psb27, which are all attached lumenal side PSII Here, we show Ycf48 factor found in cyanobacterium Synechocystis sp. PCC 6803 also a lipoprotein. Detailed mass spectrometric analysis isolated supported site-directed mutagenesis experiments indicates lipidation N-terminal C29 residue removal three amino acids C-terminus. lipobox sequence contains cysteine at ?3 position compared Leu/Val/Ile residues canonical sequence. atypical present most cyanobacteria but absent eukaryotes. A possible role for coordinated cyanobacterial discussed.