Sequence alignment between 5v2c(m) and UniProt seq P12312 (PSBM_THEVL):

P12312 (PSBM_THEVL): Photosystem II reaction center protein M from Thermostichus vulcanus 
                 10        20        30      
         ---------+---------+---------+------
UniProt: MEVNQLGFIATALFVLVPSVFLIILYVQTESQQKSS
         X......X............................
PDB seq: XEVNQLGLIATALFVLVPSVFLIILYVQTESQQKS-
         ---------+---------+---------+----- 
                 10        20        30