Chains and heterogens:
PDB Chain Sequences:
>1ex4A (A:) sspgiwqldcthlegkvilvavhvasgyieaevipaetgqetayfllklagrwpvktiht dngsnftgatvraacdwagikqedgipynpqsqgvvesmnkelkkiigqvrdqaehlkta vqmavfihnkkrkggiggysagerivdiiatdiqtkelqkqitkiqnfrvyyrdsrnslw kgpakllwkgegavviqdnsdikvvprrkakiird
>1ex4A (A:) sspgiwqldcthlegkvilvavhvasgyieaevipaetgqetayfllklagrwpvktiht dngsnftgatvraacdwagikqedgipqsqgvvesmnkelkkiigqvrdqaehlktavqm avfihnkkrkggiggysagerivdiiatdiqtkelqkqitkiqnfrvyyrdsrnslwkgp akllwkgegavviqdnsdikvvprrkakiird
>1ex4B (B:) dsspgiwqldcthlegkvilvavhvasgyieaevipaetgqetayfllklagrwpvktih tdngsnftgatvraacdwagikqedgipynpqsqgvvesmnkelkkiigqvrdqaehlkt avqmavfihnkkrkggiggysagerivdiiatdiqtkelqkqitkiqnfrvyyrdsrnsl wkgpakllwkgegavviqdnsdikvvprrkakiird
>1ex4B (B:) dsspgiwqldcthlegkvilvavhvasgyieaevipaetgqetayfllklagrwpvktih tdngsnftgatvraacdwagikqvvesmnkelkkiigqvrdqaehlktavqmavfihnkk rkggiggysagerivdiiatdiqtkelqkqitkiqnfrvyyrdsrnslwkgpakllwkge gavviqdnsdikvvprrkakiird