Chains and heterogens:
PDB Chain Sequences:
>1r4sA (A:) savkaarygkdnvrvykvhkdektgvqtvyemtvcvllegeietsytkadnsvivatdsi kntiyitakqnpvtppelfgsilgthfiekynhihaahvnivchrwtrmdidgkphphsf irdseekrnvqvdvvegkgidiksslsgltvlkstnsqfwgflrdeyttlketwdrilst dvdatwqwknfsglqevrshvpkfdatwatarevtlktfaednsasvqatmykmaeqila rqqlietveyslpnkhyfeidlswhkglqntgknaevfapqsdpnglikctvgrsslksk l
>1r4sA (A:) savkaarygkdnvrvykvhkdektgvqtvyemtvcvllegeietsytkadnsvivatdsi kntiyitakqnpvtppelfgsilgthfiekynhihaahvnivchrwtrmdidgkphphsf irdseekrnvqvdvvegkgidiksslsgltvlkstnsqfwgflrdeyttlketwdrilst dvdatwqwknfsglqevrshvpkfdatwatarevtlktfaednsasvqatmykmaeqila rqqlietveyslpnkhyfeidlswhkglqntgknaevfapqsdpnglikctvgrss