Chains and heterogens:
PDB Chain Sequences:
>1us4A (A:) mrkpilaaltlaglglaqefitigsgsttgvyfpvatgiaklvndanvgiranarstggs vaninainagefemalaqndiayyayqgccipafegkpvktiralaalypevvhvvarkd agirtvadlkgkrvvvgdvgsgteqnarqileaygltfddlgqairvsasqgiqlmqdkr adalfytvglgasaiqqlalttpialvavdlnriqaiakkypfyvgfnipggtykgvdvt tptvavqamliaserlseetvykfmkavfgnleafkkihpnlerffglekavkglpiplh pgaerfykeagvlk
>1us4A (A:) aqefitigsgsttgvyfpvatgiaklvndanvgiranarstggsvaninainagefemal aqndiayyayqgccipafegkpvktiralaalypevvhvvarkdagirtvadlkgkrvvv gdvgsgteqnarqileaygltfddlgqairvsasqgiqlmqdkradalfytvglgasaiq qlalttpialvavdlnriqaiakkypfyvgfnipggtykgvdvttptvavqamliaserl seetvykfmkavfgnleafkkihpnlerffglekavkglpiplhpgaerfykeagvlk