Metallo-GTPase HypB from Helicobacter pylori and its interaction with nickel chaperone protein HypA.

ABSTRACT: The maturation of [NiFe]-hydrogenase is highly dependent on a battery of chaperone proteins. Among these, HypA and HypB were proposed to exert nickel delivery functions in the metallocenter assembly process, although the detailed mechanism remains unclear. Herein, we have overexpressed and purified wild-type HypB as well as two mutants, K168A and M186L/F190V, from Helicobacter pylori. We demonstrated that all proteins bind Ni(2+) at a stoichiometry of one Ni(2+) per monomer of the proteins with dissociation constants at micromolar levels. Ni(2+) elevated GTPase activity of WT HypB, which is attributable to a lower affinity of the protein toward GDP as well as Ni(2+)-induced dimerization. The disruption of GTP-dependent dimerization has led to GTPase activities of both mutants in apo-forms

SUBMITTER: Xia W 

PROVIDER: S-EPMC3307304 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature