Sequence alignment between 1hio(A) and UniProt seq P02263 (H2A4_CHICK):

P02263 (H2A4_CHICK): Histone H2A-IV from Gallus gallus
                 10        20        30        40        50        60        70        80        90       100       110       120         
         ---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------
UniProt: MSGRGKQGGKARAKAKSRSSRAGLQFPVGRVHRLLRKGNYAERVGAGAPVYLAAVLEYLTAEILELAGNAARDNKKTRIIPRHLQLAIRNDEELNKLLGKVTIAQGGVLPNIQAVLLPKKTDSHKAKAK
PDB seq: ---------------KSRSSRAGLQFPVGRVHRLLRKGNYAERVGAGAPVYLAAVLEYLTAEILELAGNAARDNKKTRIIPRHLQLAIRNDEELNKLLGKVTIAQGGVLP-------------------
                        -----+---------+---------+---------+---------+---------+---------+---------+---------+---------                   
                            20        30        40        50        60        70        80        90       100