Chains and heterogens:
PDB Chain Sequences:
>4x21A (A:) ggsmskskvdnqfysvevgdstftvlkryqnlkpigsgaqgivcaaydavldrnvaikkl srpfqnqthakrayrelvlmkcvnhkniisllnvftpqktleefqdvylvmelmdanlcq viqmeldhermsyllyqmlcgikhlhsagiihrdlkpsnivvksdctlkildfglartag tsfmmtpyvvtryyrapevilgmgykenvdiwsvgcimgemvrhkilfpgrdyidqwnkv ieqlgtpcpefmkklqptvrnyvenrpkyagltfpklfpdslfpadsehnklkasqardl lskmlvidpakrisvddalqhpyinvwydpaeveapppqiydkqlderehtieewkeliy kevmnse
>4x21A (A:) nqfysvevgdstftvlkryqnlkpigsgaqgivcaaydavldrnvaikklsrpfqnqtha krayrelvlmkcvnhkniisllnvftpqktleefqdvylvmelmdanlcqviqmeldher msyllyqmlcgikhlhsagiihrdlkpsnivvksdctlkildfglvtryyrapevilgmg ykenvdiwsvgcimgemvrhkilfpgrdyidqwnkvieqlgtpcpefmkklqptvrnyve nrpkyagltfpklfpdslfpadsehnklkasqardllskmlvidpakrisvddalqhpyi nvwydpaeveapppqiderehtieewkeliykevmn
>4x21B (B:) ggsmskskvdnqfysvevgdstftvlkryqnlkpigsgaqgivcaaydavldrnvaikkl srpfqnqthakrayrelvlmkcvnhkniisllnvftpqktleefqdvylvmelmdanlcq viqmeldhermsyllyqmlcgikhlhsagiihrdlkpsnivvksdctlkildfglartag tsfmmtpyvvtryyrapevilgmgykenvdiwsvgcimgemvrhkilfpgrdyidqwnkv ieqlgtpcpefmkklqptvrnyvenrpkyagltfpklfpdslfpadsehnklkasqardl lskmlvidpakrisvddalqhpyinvwydpaeveapppqiydkqlderehtieewkeliy kevmnse
>4x21B (B:) qfysvevgdstftvlkryqnlkpigsgaqgivcaaydavldrnvaikklsrpfqnqthak rayrelvlmkcvnhkniisllnvftpqktleefqdvylvmelmdanlcqviqmeldherm syllyqmlcgikhlhsagiihrdlkpsnivvksdctlkildfglavtryyrapevilgmg ykenvdiwsvgcimgemvrhkilfpgrdyidqwnkvieqlgtpcpefmkklqptvrnyve nrpkyagltfpklfpdslfpadsehnklkasqardllskmlvidpakrisvddalqhpyi nvwydpaeveapppqiderehtieewkeliykevmn