Chains and heterogens:
PDB Chain Sequences:
>1by1A (A:) mkgfdttainksyynvvlqnileteneyskelqtvlstylrplqtseklssanisylmgn leeicsfqqmlvqsleectklpeaqqrvggcflnlmpqmktlyltycanhpsavnvlteh seelgefmetkgasspgilvlttglskpfmrldkyptllkelerhmedyhtdrqdiqksm aafknlsaqcqevrkrkelelqilteair