<p>Members of this family are PsaC, an essential component of photosystem I (PS-I) reaction centre in Cyanobacteria and chloroplasts. This small protein, about 80 amino acids in length, contains two copies of the ferredoxin-like 4Fe-4S binding site and therefore eight conserved Cys residues. This protein is also called photosystem I subunit VII.</p> Photosystem I PsaC