9603681 Polacco The long-range goal of the work is understanding of nickel metabolism in plants. The specific objective of this work is to understand the insertion of nickel into urease. Two mutants of soybean are available which abolish nickel insertion insertion into urease without affecting the amount of urease protein - which is inactive - in the plant. The mutants encode proteins that bind nickel and these two proteins seem to be urease accessory proteins which insert the nickel into the enzyme. The work will involve genetic analysis of the two mutants, molecular analysis of the interaction between urease and accessory binding proteins through a yeast two-hybrid system, and biochemical analysis of urease activity reconstitution by the presence of the two accessory proteins. The analysis will provide information on the mechanisms of metal insertion into enzymes, protein/protein interaction and regulation of urease activity.
