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.