Sequence alignment between 9is4(i) and UniProt seq P59763 (PSBI_CHLRE):

P59763 (PSBI_CHLRE): Photosystem II reaction center protein I from Chlamydomonas reinhardtii 
                 10        20        30       
         ---------+---------+---------+-------
UniProt: MLTLKIFVYTVVTFFVCLFIFGFLSNDPARNPGKNLD
PDB seq: MLTLKIFVYTVVTFFVCLFIFGFLSNDPARNPGK---
         ---------+---------+---------+----   
                 10        20        30