>4x21B (B:) observed residues (from ATOM records)
qfysvevgdstftvlkryqnlkpigsgaqgivcaaydavldrnvaikklsrpfqnqthak
rayrelvlmkcvnhkniisllnvftpqktleefqdvylvmelmdanlcqviqmeldherm
syllyqmlcgikhlhsagiihrdlkpsnivvksdctlkildfglavtryyrapevilgmg
ykenvdiwsvgcimgemvrhkilfpgrdyidqwnkvieqlgtpcpefmkklqptvrnyve
nrpkyagltfpklfpdslfpadsehnklkasqardllskmlvidpakrisvddalqhpyi
nvwydpaeveapppqiderehtieewkeliykevmn