Scientists from three Max Planck Institutes (MPI), the MPI for Medical Research in Heidelberg, the MPI for Marine Microbiology in Bremen and the MPI for Biophysics in Frankfurt and the Radboud University in Nijmegen have successfully determined the structure of the enzyme which produces a large part of the nitrate on earth. Microorganisms use this enzyme, called NXR or nitrite oxidoreductase, to convert toxic nitrite into nitrate. Both nitrite and nitrate are forms of nitrogen that have a major impact on our environment. The results were recently published in the journal Nature Microbiology.