title: Mo K- and L-edge X-ray absorption spectroscopic study of the ADP.AlF4--stabilized nitrogenase complex: comparison with MoFe protein in solution and single crystal.
abstract: The utility of using X-ray absorption spectroscopy (XAS) to study metalloproteins and, specifically, the enzyme complex nitrogenase, is highlighted by this study comparing both the structural and Mo-localized electronic features of the iron-molybdenum cofactor (FeMoco) in isolated MoFe protein and in the ADP.AlF4--stabilized complex of the MoFe protein with the Fe protein. No major differences are found at Mo between the two protein forms. The excellent quality of the data at both the Mo K and L edges will provide a baseline for analysis of other intermediates in the nitrogenase cycle. A new capability to delineate various contributions in the resting state of FeMoco is being pursued through polarized single-crystal XAS. The initial results point to the feasibility of using this technique for the analysis of scattering from the as yet unidentified atom at the center of FeMoco.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, CA 94305, USA.
authors.forename: Mary C
authors.initials: MC
authors.lastname: Corbett
authors.forename: F Akif
authors.initials: FA
authors.lastname: Tezcan
authors.forename: Oliver
authors.initials: O
authors.lastname: Einsle
authors.forename: Mika Y
authors.initials: MY
authors.lastname: Walton
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Rees
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Latimer
authors.forename: Britt
authors.initials: B
authors.lastname: Hedman
authors.forename: Keith O
authors.initials: KO
authors.lastname: Hodgson
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry*; D017607:Aluminum Compounds / Q000737:chemistry*; D016948:Azotobacter vinelandii / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D008983:Molybdoferredoxin / Q000737:chemistry* / Q000378:metabolism; D009097:Multienzyme Complexes / Q000737:chemistry; D009591:Nitrogenase / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D013057:Spectrum Analysis / Q000379:methods*; D014965:X-Rays
chemical_list: D017607:Aluminum Compounds; D001426:Bacterial Proteins; D008983:Molybdoferredoxin; D009097:Multienzyme Complexes; D000244:Adenosine Diphosphate; D009591:Nitrogenase