Sequence alignment between 4e0r(B) and UniProt seq P21611 (B2MG_CHICK):

P21611 (B2MG_CHICK): Beta-2-microglobulin from Gallus gallus
                 10        20        30        40        50        60        70        80        90       100       110         
         ---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------
UniProt: MGKAAAVVLVTLVALLGLAQADLTPKVQVYSRFPASAGTKNVLNCFAAGFHPPKISITLMKDGVPMEGAQYSDMSFNDDWTFQRLVHADFTPSSGSTYACKVEHETLKEPQVYKWDPEF
PDB seq: ---------------------DLTPKVQVYSRFPASAGTKNVLNCFAAGFHPPKISITLMKDGVPMEGAQYSDMSFNDDWTFQRLVHADFTPSSGSTYACKVEHETLKEPQVYKWDPE-
                              ---------+---------+---------+---------+---------+---------+---------+---------+---------+------- 
                                      10        20        30        40        50        60        70        80        90