One of the components of the core complex of photosystem II (PSII). It binds chlorophyll and helps catalyze the primary light-induced photochemical processes of PSII. PSII is a light-driven water:plastoquinone oxidoreductase, using light energy to abstract electrons from H(2)O, generating O(2) and a proton gradient subsequently used for ATP formation (By similarity). Required for correct assembly of PSII (PubMed:1903653, PubMed:23148271). Binds multiple chlorophylls and provides some of the ligands for the Ca-4Mn-5O cluster of the oxygen-evolving complex. It may also provide a ligand for a Cl- that is required for oxygen evolution. PSII binds additional chlorophylls, carotenoids and specific lipids. Cyanobacterial PSII is composed of 1 copy each of membrane proteins PsbA, PsbB, PsbC, PsbD, PsbE, PsbF, PsbH, PsbI, PsbJ, PsbK, PsbL, PsbM, PsbT, PsbX, PsbY, PsbZ, Ycf12, at least 3 peripheral proteins PsbO, PsbU, PsbV and a large number of cofactors. It forms dimeric complexes. Unable to grow photoautotrophically or evolve O(2). About 10% mostly monomeric PSII accumulates, which corresponds to RC47, an intermediate in the normal path of PSII assembly. The intermediate is able to bind the primary and secondary electron donors and acceptors and can transfer electrons. Belongs to the PsbB/PsbC family. PsbC subfamily. Extended N-terminus. Extended N-terminus.