May play a role in photosystem I and II biogenesis. In a double psbH-psbN deletion has a no more deleterious effect than the single psbH deletion, which suggests it has no role in photosystem II. Belongs to the PsbN family. Originally thought to be a component of PSII; based on experiments in this organism, N.tabacum and barley, and its absence from PSII in T.elongatus and T.vulcanus, this is probably not true.