>3c91U (U:) observed residues (from ATOM records)
aydraitvfspdgrlfqveyareavkkgstalgmkfangvllisdkkvrsrlieqnsiek
iqliddyvaavtsglvadarvlvdfarisaqqekvtygslvnienlvkrvadqmqqytqy
ggvrpygvslifagidqigprlfdcdpagtineykataigsgkdavvsflereykenlpe
keavtlgikalkssleegeelkapeiasitvgnkyriydqeevkkfl