The Active Site of the Bacterial Nitric Oxide Reductase Is a Dinuclear Iron Center

• DOI: 10.1021/bi980943x
• Publication Date: 2002-07-26T05:19:13Z
• Authors: Janneke Hendriks; Antony Warne; Ulrich Gohlke; Tuomas Haltia; Claudia Ludovici; Mathias Lübben; Matti Saraste
• Keywords: Center (category theory); Active center

A novel, improved method for purification of nitric oxide reductase (NOR) from membranes Paracoccus denitrificans has been developed. The purified enzyme is a cytochrome bc complex which, according to protein chemical and hydrodynamic data, contains two subunits in 1:1 stoichiometry. NorBC binds 0.87 g dodecyl maltoside/g forms dimer solution. Similarly, it dimeric two-dimensional crystals. Images these crystals have processed at 8 Å resolution projection the membrane. NorB subunit homologous main catalytic oxidase predicted contain active bimetallic center which NO molecules are turned over N2O. Metal analysis heme composition implies that B-type hemes nonheme iron but no copper. NorC membrane-anchored c. Fourier transform infrared spectroscopy shows carbon monoxide dissociates reduced light associates with another metal distinct copper site heme/copper oxidases. Electron paramagnetic resonance reveals under turnover conditions giving rise signals near = 2 4. former represents typical nitrosyl-ferroheme signal whereas latter fingerprint iron/NO adduct. We conclude NOR dinuclear center.