Abstract
The tetranuclear CuZ cluster is the unique active site of nitrous oxide reductase, the enzyme that catalyzes the reduction of nitrous oxide to dinitrogen as the final reaction in bacterial denitrification. Three-dimensional structures of orthologs of the enzyme from a variety of different bacterial species were essential steps in the elucidation of the properties of this center. However, while structural data first revealed and later confirmed the presence of four copper ions in spectroscopically distinct forms of CuZ, the exact structure and stoichiometry of the cluster showed significant variations. A ligand bridging ions CuZ1 and CuZ2 was initially assigned as a water or hydroxo species in the structures from Pseudomonas nautica (now Marinobacter hydrocarbonoclasticus) and Paracoccus denitrificans. This ligand was absent in a structure from ‘Achromobacter cycloclastes’, and could be reconstituted by iodide that acted as an inhibitor of catalysis. A recent structure of anoxically isolated nitrous oxide reductase from Pseudomonas stutzeri revealed the bridging ligand to be sulfide, S2-, and showed an unprecedented side-on mode of nitrous oxide binding to this form of CuZ.
About the authors
Anja Wüst (born 1983) completed an industrial training as chemical laboratory worker at BASF Ludwigshafen. Since July 2011 she works as a doctoral student in the group of Oliver Einsle, after she finished her diploma in Chemistry at the Albert-Ludwigs-University in Freiburg. Her field of interest are the mechanistic details of nitrous oxide reductase and the spectroscopic properties of its copper clusters.
Lisa Schneider (born 1986) studied Chemistry in Freiburg and obtained her diploma in 2011. Currently she works as a doctoral student with Oliver Einsle, and the focus of her thesis work is the characterization of the protein systems required for maturation and assembly of nitrous oxide reductase.
Anja Pomowski (born 1981) studied Biology in Göttingen and did her doctoral work with Oliver Einsle in Freiburg, where she worked on the structural characterization of nitrous oxide reduc-tase from Pseudomonas stutzeri. She currently works as a postdoctoral fellow with Jim Hunting-ton in Cambridge, UK.
Walter G. Zumft has been full professor of microbiology at the Karlsruhe Institute of Technology from 1982 until his retirement in 2007. He studied biology and physiological chemistry at the universities of Berlin (FU), Munich (LMU) and Erlangen and was a postdoc from 1971 to 1974 at Purdue University. He held visiting professorships at the Arrhenius Laboratory in Stockholm, the University of Georgia in Athens, and the University of Seville. His research interests center around the microbial biochemistry and molecular biology of inorganic nitrogen metabolism, where his main contributions concern nitrogenase, nitric oxide reductase, and nitrous oxide reductase.
Peter M.H. Kroneck studied Chemistry in Basel from 1962–1967 and obtained his doctorate in 1971 at Konstanz university with Peter Hemmerich. From 1971–1973 he worked as a postdoc with Jack T. Spence at Utah State University in Logan. He habilitated in Konstanz in 1980 and was appointed professor of Biochemistry in 1987. He retired in 2009 and has held various inter-national teaching appointments since. His main research interests are with the characterization of novel metalloenzymes using spectroscopic techniques
Oliver Einsle (born 1970) studied Biology in Konstanz with Peter Kroneck, then moved to the MPI for Biochemistry in Martinsried to work with Robert Huber and Peter Kroneck on nitrite re-ductases. In 2001 he joined the group of Doug Rees at Caltech to study nitrogenase, and re-turned to Germany in 2003 as a junior professor for Protein Crystallography in Göttingen. Since 2008 he is full professor of Biochemistry in Freiburg. Research in his group is focused on the structural and functional characterization of metalloproteins and integral membrane proteins.
©2012 by Walter de Gruyter Berlin Boston
