Chains and heterogens:
PDB Chain Sequences:
>1bt9A (A:) aeiynkdgnkvdlygkavglhyfskgngensyggngdmtyarlgfkgetqinsdltgygq weynfqgnnsegaaaqtgnktrlafaglkyadvgsfdygrnygvvydalgytdmlpefgg dtaysddffvgrvggvatyrnsnffglvdglnfavqylgknerdtarrsngdgvggsisy eyegfgivgaygaadrtnlqeaqplgngkkaeqwatglkydanniylaanygetrnatpi tnkftntsgfanktqdvllvaqyqfdfglrpsiaytkskakdvegigdvdlvnyfevgat yyfnknmstyvdyiinqidsdnklgvgsddtvavgivyqf