Involved in urease metallocenter assembly. Binds nickel. Probably functions as a nickel donor during metallocenter assembly. Belongs to the UreE family. Neither O157 strain expresses urease due to a truncation of ureD, the last gene of the probable operon. Urease activity is restored in O157 / Sakai upon complementation with wild-type ureD. This region of the chromosome is duplicated in strain O157:H7 / EDL933 but not in O157:H7 / Sakai.