title: The first glimpse of a complex of nitrogenase component proteins by solution X-ray scattering: conformation of the electron transfer transition state complex of Klebsiella pneumoniae nitrogenase.
abstract: An essential feature of the mechanism of nitrogenase, the enzyme responsible for biological nitrogen fixation, is the formation of a transient electron transfer complex between the MoFe protein containing the active site at which N2 is reduced, and the Fe protein, which functions as a specific electron donor to the MoFe protein. We have obtained high quality solution X-ray scattering data using synchrotron X-rays of a stable putative electron transfer complex, (MoFe-protein)(Fe-protein.ADP.AIF4)2, of Klebsiella pneumoniae and used the model-independent approach based on the multipole expansion method to provide a stable and unique shape restoration at approximately 15 A resolution. The biological significance of this first molecular structure of a nitrogenase complex is discussed.
authors.affiliation: Molecular Biophysics Group, CLRC Daresbury Laboratory, Warrington, Cheshire, UK.
authors.forename: J G
authors.initials: JG
authors.lastname: Grossman
authors.forename: S S
authors.initials: SS
authors.lastname: Hasnain
authors.forename: F K
authors.initials: FK
authors.lastname: Yousafzai
authors.forename: B E
authors.initials: BE
authors.lastname: Smith
authors.forename: R R
authors.initials: RR
authors.lastname: Eady
mesh_terms: D016948:Azotobacter vinelandii / Q000737:chemistry; D004579:Electron Transport; D007711:Klebsiella pneumoniae / Q000201:enzymology*; D008958:Models, Molecular; D008983:Molybdoferredoxin / Q000737:chemistry*; D009584:Nitrogen / Q000378:metabolism; D009591:Nitrogenase / Q000737:chemistry*; D011487:Protein Conformation; D012542:Scattering, Radiation; D014965:X-Rays
chemical_list: D008983:Molybdoferredoxin; D009591:Nitrogenase; D009584:Nitrogen