Chains and heterogens:
PDB Chain Sequences:
>4r21A (A:) makktsskgkegvgsssvsfpclprlpllgsllhlrsnlpphllftqlssqygplfglya gphltlvvseiglvrevllqrgrefagrpkmvttdlltqggkdiafadysplwknhrrlv hssftlfgegsnklqtivqeaadslceelqacrgqssdlsvvlmravtnvicrlvfsssy qpsdpelqtviqyndgivqtiargglvdifpwlrifpnkdlkrlkecvsirdqllykkll ehkksltpgeprdlldalligqqrgsggadditedhvlmtaaeafgagvettsttllwti afllhhpqlqervqaeldecvgvdrppclsdrphlplldavlcevmrirpvspiliphva mqdtslgghsvpkgtrvlvnmwaihhdpkhwdqpeqfnperflepsgkkktqssflpfga gprvcvgeslarielflfvsrplqrfsfscpseaslpdlqgrfgvvlqperytvtvtprh hhhhhh
>4r21A (A:) nlpphllftqlssqygplfglyagphltlvvseiglvrevllqrgrefagrpkmvttdll tqggkdiafadysplwknhrrlvhssftlfgegsnklqtivqeaadslceelqacrgqss dlsvvlmravtnvicrlvfsssyqpsdpelqtviqyndgivqtiargglvdikdlkrlke cvsirdqllykkllehkksltpgeprdlldalligqqrgsggadditedhvlmtaaeafg agvettsttllwtiafllhhpqlqervqaeldecvgvdrppclsdrphlplldavlcevm rirpvspiliphvamqdtslgghsvpkgtrvlvnmwaihhdpkhwdqpeqfnperfless flpfgagprvcvgeslarielflfvsrplqrfsfscpslpdlqgrfgvvlqperytvtvt pr
>4r21B (B:) makktsskgkegvgsssvsfpclprlpllgsllhlrsnlpphllftqlssqygplfglya gphltlvvseiglvrevllqrgrefagrpkmvttdlltqggkdiafadysplwknhrrlv hssftlfgegsnklqtivqeaadslceelqacrgqssdlsvvlmravtnvicrlvfsssy qpsdpelqtviqyndgivqtiargglvdifpwlrifpnkdlkrlkecvsirdqllykkll ehkksltpgeprdlldalligqqrgsggadditedhvlmtaaeafgagvettsttllwti afllhhpqlqervqaeldecvgvdrppclsdrphlplldavlcevmrirpvspiliphva mqdtslgghsvpkgtrvlvnmwaihhdpkhwdqpeqfnperflepsgkkktqssflpfga gprvcvgeslarielflfvsrplqrfsfscpseaslpdlqgrfgvvlqperytvtvtprh hhhhhh
>4r21B (B:) nlpphllftqlssqygplfglyagphltlvvseiglvrevllqrgrefagrpkmvttdll tqggkdiafadysplwknhrrlvhssftlfgegsnklqtivqeaadslceelqacrgqss dlsvvlmravtnvicrlvfsssyqpsdpelqtviqyndgivqtiarggnkdlkrlkecvs irdqllykkllehkksltpgeprdlldalligqqrgsggadditedhvlmtaaeafgagv ettsttllwtiafllhhpqlqervqaeldecvgvdrppclsdrphlplldavlcevmrir pvspiliphvamqdtslgghsvpkgtrvlvnmwaihhdpkhwdqpeqfnperflepqssf lpfgagprvcvgeslarielflfvsrplqrfsfscpseaslpdlqgrfgvvlqperytvt vtp