Chains and heterogens:
PDB Chain Sequences:
>1n31A (A:) tpdrhqfpglanktyfnfggqgilptvaleaitamygylqengpfsiaanqhiqqliaql rqalaetfnvdpntititdnvttgcdivlwgldwhqgdeilltdcehpgiiaivqaiaar fgityrffpvaatlnqgdaaavlanhlgpktrlvilshllwntgqvlplaeimavcrrhq gnypvrvlvdgaqsagslpldfsrlevdyyaftghawfagpagvgglyihgdclgeinpt yvgwrsitygakgeptgwaeggkrfevatsaypqyagllaalqlhqrqgtaeeryqaicq rseflwrglnqlphvhclatsapqaglvsftvdsplghraivqkleeqriylrtiadpdc iracchyitdeeeinhllarladfgp
>1n31B (B:) tpdrhqfpglanktyfnfggqgilptvaleaitamygylqengpfsiaanqhiqqliaql rqalaetfnvdpntititdnvttgcdivlwgldwhqgdeilltdcehpgiiaivqaiaar fgityrffpvaatlnqgdaaavlanhlgpktrlvilshllwntgqvlplaeimavcrrhq gnypvrvlvdgaqsagslpldfsrlevdyyaftghawfagpagvgglyihgdclgeinpt yvgwrsitygakgeptgwaeggkrfevatsaypqyagllaalqlhqrqgtaeeryqaicq rseflwrglnqlphvhclatsapqaglvsftvdsplghraivqkleeqriylrtiadpdc iracchyitdeeeinhllarladfgp