Urease and Nickel in Biology Robert P. Hausinger Michigan State University Dia 14 maio | Auditório | 14:30 Abstract Urease, the first enzyme to be crystallized and the first shown to possess nickel, catalyzes a simple reaction, but it requires a remarkably complex biosynthesis machinery. Formation of the dinuclear nickel metallocenter with its bridging carbamylated lysyl ligand is dependent on the functions of the metallochaperone UreE, the GTPase UreG, and the protein scaffold UreF/UreD that contains a molecular tunnel through which nickel must pass. Other nickel-containing enzymes include guanidinase, glyoxylase, acireductone dioxygenase, superoxide dismutase, [NiFe] hydrogenase, carbon monoxide dehydrogenase, acetyl-CoA synthase/decarbonylase, hydroxyacid racemase/epimerase, and methyl coenzyme M reductase. The metallocenters in these enzymes encompass mononuclear and dinuclear sites, more complex clusters, and organometallic complexes, where the biosynthetic pathways for se