Facilitates the functional incorporation of the urease nickel metallocenter. This process requires GTP hydrolysis, probably effectuated by UreG. Homodimer. UreH, 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. Cells missing this gene do not produce urease; addition of Ni(2+) to cell cultures does not compensate this loss of function. Normal amounts of apourease are produced by the cells. Has no effect on hydrogenase activity. Belongs to the SIMIBI class G3E GTPase family. UreG subfamily.