May play a role in photosystem I and II biogenesis. Belongs to the PsbN family. Young tissue from this organism is photosynthetic and contains some thylakoids, although the photosynthetic activity does not exceed the light compensation point. Originally thought to be a component of PSII; based on experiments in Synechocystis, N.tabacum and barley, and its absence from PSII in T.elongatus and T.vulcanus, this is probably not true.