Fig. 5.

Postulated interactions among urease-related bacterial proteins. The urease apoprotein sequentially binds UreD, UreF, and UreG, where the in vitro activation properties exhibit differences in each apoprotein species. Alternatively, a preformed UreDFG complex may bind the apoprotein. Within the resulting complex, the UreDFG heterotrimer acts as GTP-dependent molecular chaperone to enhance exposure of the nascent active site. UreE interacts with the UreABC-UreDFG complex and delivers nickel ions, thus serving a metallochaperone role. Carbon dioxide is used to form the carboxy-lysine metal ligand, and GTP hydrolysis (occurring in UreG) drives the metallocenter assembly process to provide active urease, with release of all accessory proteins.