title: Modeling a central ligand in the nitrogenase FeMo cofactor.
abstract: In very recent work by Einsle et al. (Science 2002, 297, 1696), a new X-ray crystallographic structure of the FeMo cofactor of nitrogenase with a central ligand was presented. The central ligand is a light atom (N, O, or C), and Einsle et al. suggest that it is nitrogen. We present density functional calculations on the FeMo cofactor, and we investigate N, O, and C as central ligands. We show that both N and O lead to energetically stable FeMo cofactor structures, whereas C is energetically unfavorable. By comparison of bond geometries with the crystallographically determined values, we show that the central ligand is most likely nitrogen.
authors.affiliation: Center for Atomic-scale Materials Physics (CAMP), Department of Physics, Building 307, Technical University of Denmark, DK-2800 Lyngby, Denmark.
authors.forename: Berit
authors.initials: B
authors.lastname: Hinnemann
authors.forename: Jens K
authors.initials: JK
authors.lastname: Nørskov
mesh_terms: D008024:Ligands; D008958:Models, Molecular; D008983:Molybdoferredoxin / Q000737:chemistry* / Q000378:metabolism; D009591:Nitrogenase / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D013816:Thermodynamics
chemical_list: D008024:Ligands; D008983:Molybdoferredoxin; D009591:Nitrogenase