title: Binding modes for the first coupled electron and proton addition to FeMoco of nitrogenase.
abstract: A combined broken-symmetry density functional and electrostatics approach has been used to model the one-electron reduced and protonated state of the iron-molybdenum cofactor active site of nitrogenase. The active site of the protein contains Fe, Mo, S, N, and O atoms, and many possible sites for protonation have been examined. A novel hydridic proton asymmetrically located in the central cavity created by six Fe sites is most favored from the calculations. Under physiological turnover conditions of low electron flux, the formation of this iron-hydride intermediate may represent a first step towards cofactor liberation of dihydrogen in the absence of dinitrogen.
authors.affiliation: The Scripps Research Institute, La Jolla California 92037, USA.
authors.forename: Timothy
authors.initials: T
authors.lastname: Lovell
authors.forename: Jian
authors.initials: J
authors.lastname: Li
authors.forename: David A
authors.initials: DA
authors.lastname: Case
authors.forename: Louis
authors.initials: L
authors.lastname: Noodleman
mesh_terms: D001665:Binding Sites; D004583:Electrons; D007501:Iron / Q000737:chemistry / Q000378:metabolism; D008982:Molybdenum / Q000737:chemistry / Q000378:metabolism; D008983:Molybdoferredoxin / Q000737:chemistry* / Q000378:metabolism; D009591:Nitrogenase / Q000737:chemistry* / Q000378:metabolism; D011522:Protons; D013816:Thermodynamics; D014233:Tricarboxylic Acids / Q000737:chemistry
chemical_list: D008983:Molybdoferredoxin; D011522:Protons; D014233:Tricarboxylic Acids; C028143:homocitric acid; D008982:Molybdenum; D007501:Iron; D009591:Nitrogenase