No Laughing Matter: The Unmaking of the Greenhouse Gas Dinitrogen Monoxide by Nitrous Oxide Reductase - The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment - page 173

Chapter 8
No Laughing Matter: The Unmaking
of the Greenhouse Gas Dinitrogen Monoxide
by Nitrous Oxide Reductase

Lisa K. Schneider, Anja W¨ st, Anja Pomowski,
Lin Zhang, and Oliver Einsle

Contents
ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178

1 INTRODUCTION: THE BIOGEOCHEMICAL NITROGEN CYCLE ................ 179

2 NITROUS OXIDE: ENVIRONMENTAL EFFECTS
AND ATMOSPHERIC CHEMISTRY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

2.1 Chemical Properties of Dinitrogen Monoxide . . . .................................. 181

2.2 Nitrous Oxide, the Greenhouse Effect, and Ozone Depletion . . . . . . . . . . . .......... 182

2.3 Abiotic and Biotic Sources . . . ...................................................... 183

2.4 Bacterial Denitrification ............................................................. 183

3 NITROUS OXIDE REDUCTASE ........................................................ 184

3.1 Anatomy of an Unusual Copper Enzyme .......................................... 185

3.1.1 Distinct Forms of the Enzyme . ............................................. 185

3.1.2 Three-Dimensional Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189

3.2 Cu A : More than an Electron Transfer Center ...................................... 190

3.2.1 Spectroscopic Properties of Cu A ........................................... 190

3.2.2 Three-Dimensional Structure(s) of Cu A .................................... 191

3.2.3 Unexpected Flexibility: Cu A in P. stutzeri Nitrous Oxide Reductase ..... 194

3.3 The Tetranuclear Cu Z Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195

3.3.1 Structural Data on Cu Z ...................................................... 195

3.3.2 States of Cu Z and Catalytic Properties ..................................... 198

4 BIOGENESIS AND ASSEMBLY OF NITROUS OXIDE REDUCTASE . . . . . . . . . . . . . 200

4.1 The nos Operon . . . . . . . . . . . . ......................................................... 200

4.2 Protein Maturation and Cu A Insertion . . . . . . . . . . . . . ................................. 202

4.3 Assembly of Cu Z .................................................................... 202