HypA is a metallochaperone that binds nickel to bring it safely to its target. The targets for Hypa are the nickel-containing enzymes [Ni,Fe]-hydrogenase and urease. The nickel coordinates with four nitrogens within the protein. The four conserved cysteines towards the C-terminus bind one zinc moiety probably to stabilise the protein fold [1].

1: Structure of a nickel chaperone, HypA, from Helicobacter pylori reveals two distinct metal binding sites. Xia W, Li H, Sze KH, Sun H; J Am Chem Soc. 2009;131:10031-10040. PMID:19621959