Structural Basis of Biological N 2 O Generation by Bacterial Nitric Oxide Reductase

Abstract

Dissecting Nitric Oxide Reductase Bacterial breakdown of nitrogen compounds in soil and the oceans provides the largest emission source of the greenhouse gas, nitrous oxide (N 2 O). A key enzyme in this process is nitric oxide reductase (NOR), which catalyzes the reduction of nitric oxide (NO) to N 2 O. Hino et al. (p. 1666 , published online 25 November; see the Perspective by Moënne-Loccoz and Fee ) now describe the crystal structure of NOR from Pseudomonas aeruginosa . Consistent with their evolutionary relatedness, the transmembrane region topology and arrangement of metal centers in NOR are similar to those in cytochrome oxidases, key enzymes in aerobic respiration.