Sequence alignment between 3jtd(C) and UniProt seq P07291 (MLE_ARGIR):

P07291 (MLE_ARGIR): Myosin essential light chain, striated adductor muscle from Argopecten irradians
                 10        20        30        40        50        60        70        80        90       100       110       120       130       140       150       
         ---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+-------
UniProt: MPKLSQDEIDDLKDVFELFDFWDGRDGAVDAFKLGDVCRCLGINPRNEDVFAVGGTHKMGEKSLPFEEFLPAYEGLMDCEQGTFADYMEAFKTFDREGQGFISGAELRHVLTALGERLSDEDVDEIIKLTDLQEDLEGNVKYEDFVKKVMAGPYPDK
         ...................X.........................................................................................................................................
PDB seq: -PKLSQDEIDDLKDVFELFAFWDGRDGAVDAFKLGDVCRCLGINPRNEDVFAVGGTHKMGEKSLPFEEFLPAYEGLMDCEQGTFADYMEAFKTFDREGQGFISGAELRHVLTALGERLSDEDVDEIIKLTDLQEDLEGNVKYEDFVKKVMAGPYPDK
          ---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+---------+------
                  10        20        30        40        50        60        70        80        90       100       110       120       130       140       150