title: Structural basis of biological nitrogen fixation.
abstract: Biological nitrogen fixation is mediated by the nitrogenase enzyme system that catalyses the ATP dependent reduction of atmospheric dinitrogen to ammonia. Nitrogenase consists of two component metalloproteins, the MoFe-protein with the FeMo-cofactor that provides the active site for substrate reduction, and the Fe-protein that couples ATP hydrolysis to electron transfer. An overview of the nitrogenase system is presented that emphasizes the structural organization of the proteins and associated metalloclusters that have the remarkable ability to catalyse nitrogen fixation under ambient conditions. Although the mechanism of ammonia formation by nitrogenase remains enigmatic, mechanistic inferences motivated by recent developments in the areas of nitrogenase biochemistry, spectroscopy, model chemistry and computational studies are discussed within this structural framework.
authors.affiliation: Division of Chemistry and Chemical Engineering, 114-96, California Institute of Technology, Pasadena, CA 91125, USA. dcrees@caltech.edu
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Rees
authors.forename: F
authors.initials: F
authors.lastname: Akif Tezcan
authors.forename: Chad A
authors.initials: CA
authors.lastname: Haynes
authors.forename: Mika Y
authors.initials: MY
authors.lastname: Walton
authors.forename: Susana
authors.initials: S
authors.lastname: Andrade
authors.forename: Oliver
authors.initials: O
authors.lastname: Einsle
authors.forename: James B
authors.initials: JB
authors.lastname: Howard
mesh_terms: D000641:Ammonia / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D002384:Catalysis; D002468:Cell Physiological Phenomena; D004579:Electron Transport; D004789:Enzyme Activation; D006801:Humans; D008954:Models, Biological; D008956:Models, Chemical; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism; D009591:Nitrogenase / Q000737:chemistry* / Q000378:metabolism*; D010084:Oxidation-Reduction; D015398:Signal Transduction / Q000502:physiology
chemical_list: D009097:Multienzyme Complexes; D000641:Ammonia; D009591:Nitrogenase