Sequence alignment between 1dur(A) and UniProt seq P00193 (FER_PEPAS):

P00193 (FER_PEPAS): Ferredoxin from Peptoniphilus asaccharolyticus 
                 10        20         30        40        50    
         ---------+---------+- --------+---------+---------+----
UniProt: AYVINDSCIACGACKPECPVN-IQQGSIYAIDADSCIDCGSCASVCPVGAPNPED
         .....................X..X..............................
PDB seq: AYVINDSCIACGACKPECPVNCIQEGSIYAIDADSCIDCGSCASVCPVGAPNPED
         ---------+---------+---------+---------+---------+-----
                 10        20        30        40        50