3EGW OXIDOREDUCTASE, NITRATE REDUCTION, ELECTRON TRANSFER, MEMBRANE PROTEIN, 4FE-4S, CELL MEMBRANE, ELECTRON TRANSPORT, IRON, IRON-SULFUR, MEMBRANE, METAL-BINDING, MOLYBDENUM, NITRATE ASSIMILATION, TRANSPORT, 3FE-4S, CELL INNER MEMBRANE, FORMYLATION, HEME, TRANSMEMBRANE THE CRYSTAL STRUCTURE OF THE NARGHI MUTANT NARH - C16A