IIGP1, an interferon-γ inducible 47-kDa GTPase of the mouse, showing cooperative enzymatic activity and GTP-dependent multimerization

摘要: IIGP1 belongs to a well defined family of 47-kDa GTPases whose members are present at low resting levels in mouse cells but strongly induced transcriptionally by interferons and implicated cell-autonomous resistance intracellular pathogens. Recombinant was expressed Escherichia coli purified homogeneity. Here we detailed biochemical characterization using various biophysical methods. binds GTP GDP with dissociation constants the micromolar range least 10 times higher affinity for than GTP. hydrolyzes GDP, GTPase activity is concentration-dependent turnover rate 2 min-1 under saturating protein concentrations. Functional interaction between molecules shown nucleotide-dependent oligomerization vitro. Both cooperative hydrolysis GTP-dependent blocked mutant form modified C terminus. shares nucleotide affinities oligomerization-dependent hydrolytic 67-kDa hGBP1 (induced type I II interferons), antiviral Mx proteins (interferon I-induced) paradigm self-activating large GTPases, dynamins, which show homology. The relative relatively distinguish IIGP1, this study clearly adds thus p47 small group families that appear characterize development during interferon response infection. analysis provides essential parameters understand molecular mechanism participates complex program.