Bacterial denitrification is the major pathway by which organic nitrogen is returned to the atmosphere. The process involves a series of enzymes and electron donors, which reduce nitrate to molecular nitrogen. The objective of this award is to define the structure and function of two nitrite reductases which are key components of the system. One is a tetraheme cytochrome and the other a non-heme copper protein. The genes of the two enzymes will be cloned. Crystals of the enzymes will be prepared and their 3 dimensional structure determined. A tremendous amount of nitrogen fertilizer applied to the soil is lost by bacterial denitrification. Results of this research will help us understand how this process takes place at the molecular level, and may enable us to devise strategies to reduce denitrification and thus cut down the amount of pollution caused by fertilizer run-off.
