>5f21A (A:) observed residues (from ATOM records)
twsgpgttkrfpetvlarcvkyteihpemrhvdcqsvwdafkgafiskhpcditeedyqp
lmklgtqtvpcnkillwsrikdlahqftqvqrdmftledtllgyladdltwcgefdtski
nyqscpdwrkdcsnnpvsvfwktvsrrfaeaacdvvhvmldgsrskifdkdstfgsvevh
nlqpekvqtleawvihgsrdlcqdptikelesiiskrniqfsckniyrpdkflqcvknpe
dssctsei