Required for maturation of urease via the functional incorporation of the urease nickel metallocenter. UreD, UreF and UreG form a complex that acts as a GTP-hydrolysis-dependent molecular chaperone, activating the urease apoprotein by helping to assemble the nickel containing metallocenter of UreC. The UreE protein probably delivers the nickel. Belongs to the UreF 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.