Chains and heterogens:
PDB Chain Sequences:
>1z18A (A:) edikvavvgamsgpvaqygdqeftgaeqavadinakggikgnklqivkyddacdpkqava vankvvndgikyvighlcssstqpasdiyedegilmitpaatapeltargyqlilrttgl dsdqgptaakyilekvkpqriaivhdkqqygeglaravqdglkkgnanvvffdgitagek dfstlvarlkkenidfvyyggyhpemgqilrqaraaglktqfmgpegvanvslsniages aegllvtkpknydqvpankpivdaikakkqdpsgafvwttyaalqslqaglnqsddpaei akylkansvdtvmgpltwdekgdlkgfefgvfdwhangtatdak