Sequence alignment between 8f4f(r) and UniProt seq Q8DKM3 (PSBY_THEEB):

Q8DKM3 (PSBY_THEEB): Photosystem II reaction center protein Y from Thermosynechococcus vestitus (strain NIES-2133 / IAM M-273 / BP-1) 
                 10        20        30        40 
         ---------+---------+---------+---------+-
UniProt: MDWRVLVVLLPVLLAAGWAVRNILPYAVKQVQKLLQKAKAA
PDB seq: -DWRVLVVLLPVLLAAGWAVRNILPYAVKQVQ---------
          --------+---------+---------+--         
                 10        20        30