>2b21A (A:) observed residues (from ATOM records)
ltdlpgvgpstaeklveagyidfmkiatatvgeltdiegisekaaakmimgardlcdlgf
ksgidllkqrstvwklstssseldsvlggglesqsvtefagvfgsgktqimhqscvnlqn
peflfydeeavskgevaqpkavyidtegtfrperimqmaehagidgqtvldntfvarayn
sdmqmlfaekiedliqegnniklvvidsltstfrneytgrgklaerqqklgrhmatlnkl
adlfncvvlvtnqvsghaatfrffvrkgkgdkrvaklydsphlpdaeaifritekgiqd