Sequence alignment between 3ab9(A) and UniProt seq P0A6T9 (GCSH_ECOLI):

P0A6T9 (GCSH_ECOLI): Glycine cleavage system H protein from Escherichia coli (strain K12)
                 10        20        30        40        50        60        70        80        90       100       110       120         
         ---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------
UniProt: MSNVPAELKYSKEHEWLRKEADGTYTVGITEHAQELLGDMVFVDLPEVGATVSAGDDCAVAESVKAASDIYAPVSGEIVAVNDALSDSPELVNSEPYAGGWIFKIKASDESELESLLDATAYEALLEDE
         ................................................................X................................................................
PDB seq: --NVPAELKYSKEHEWLRKEADGTYTVGITEHAQELLGDMVFVDLPEVGATVSAGDDCAVAESVXAASDIYAPVSGEIVAVNDALSDSPELVNSEPYAGGWIFKIKASDESELESLLDATAYEALLEDE
           --------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+--------
                  10        20        30        40        50        60        70        80        90       100       110       120