Chains and heterogens:
PDB Chain Sequences:
>1c21A (A:) aisiktpediekmrvagrlaaevlemiepyvkpgvstgeldricndyivneqhavsaclg yhgypksvcisinevvchgipddakllkdgdivnidvtvikdgfhgdtskmfivgkptim gerlcritqeslylalrmvkpginlreigaaiqkfveaegfsvvreycghgigqgfheep qvlhydsretnvvlkpgmtftiepmvnagkkeirtmkdgwtvktkdrslsaqyehtivvt dngceiltlrkddtipaiishd