Chains and heterogens:
PDB Chain Sequences:
>1ptvA (A:) emekefeqidksgswaaiyqdirheasdfpcrvaklpknknrnryrdvspfdhsriklhq edndyinaslikmeeaqrsyiltqgplpntcghfwemvweqksrgvvmlnrvmekgslkc aqywpqkeekemifedtnlkltlisediktyytvrqlelenlttqetreilhfhyttwpd fgvpespasflnflfkvresgslspehgpvvvhssagigrsgtfcladtclllmdkrkdp ssvdikkvlldmrkfrmgliqtadqlrfsylaviegakfimgdssvqdqwkelshed