Recently the complete crystal structure for dinitrogenase was solved. Knowledge of the structure of dinitrogenase should lead to better understanding of the mechanism of nitrogen reduction on the enzyme. Associations Nitrogen fixation is important to humans for two reasons. The microbe fixes nitrogen for the plant and the plant provides carbon and energy for the microbes. Plants that are capable of forming these symbiotic relationships are called legumes.
Many legumes are important crops including soy beans, peas and beans.
A better understanding of the symbiosis and the biochemistry of nitrogen fixation should lead to improved crops and less need for nitrogen fertilizers that pollute our environment . Regulation Nitrogen fixation is costly to the microbe and because of this, its expression and activity are under tight control. In the presence of fixed forms of nitrogen, ammonia or nitrate, synthesis of the nitrogenase gene products, dinitrogenase and dinitrogenase reductase, is rapidly shut off. In some species, dinitrogenase reductase is covalently modified by the addition of an ADP-ribosyl unit. Professor Paul Ludden of the University of Wisconsin studies this process.