This family consists of several plant specific photosystem II reaction centre W (PsbW) proteins. PsbW is a nuclear-encoded protein located in the thylakoid membrane of the chloroplast. PsbW is a core component of photosystem II but not photosystem I [1]. This family does not appear to be related to Pfam:PF03912.

1: Molecular analysis of the Chlamydomonas nuclear gene encoding PsbW and demonstration that PsbW is a subunit of photosystem II, but not photosystem I. Bishop CL, Purton S, Nugent JH; Plant Mol Biol 2003;52:285-289. PMID:12856936