>1xu4A (A:) observed residues (from ATOM records)
ltdlpgvgpstaeklveagyidfmkiatatvgeltdiegisekaaakmimgardlcdlgf
ksgidllkqrstvwklstssseldsvlggglesqsvtefagvfgsgktqimhqscvnlqn
peflfydeeavskgevaqpkavyidtegtfrperimqmaehagidgqtvldntfvarayn
sdmqmlfaekiedliqegnniklvvidsltstfrneytgrgklaerqqklgrhmatlnkl
adlfncvvlvtnqvsakpdaffgmaeqaigghivghaatfrffvrkgkgdkrvaklydsp
hlpdaeaifritekgiqd