title: Structure of a cofactor-deficient nitrogenase MoFe protein.
abstract: One of the most complex biosynthetic processes in metallobiochemistry is the assembly of nitrogenase, the key enzyme in biological nitrogen fixation. We describe here the crystal structure of an iron-molybdenum cofactor-deficient form of the nitrogenase MoFe protein, into which the cofactor is inserted in the final step of MoFe protein assembly. The MoFe protein folds as a heterotetramer containing two copies each of the homologous alpha and beta subunits. In this structure, one of the three alpha subunit domains exhibits a substantially changed conformation, whereas the rest of the protein remains essentially unchanged. A predominantly positively charged funnel is revealed; this funnel is of sufficient size to accommodate insertion of the negatively charged cofactor.
authors.affiliation: Division of Chemistry and Chemical Engineering, Mail Code 147-75CH, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Schmid
authors.forename: Markus W
authors.initials: MW
authors.lastname: Ribbe
authors.forename: Oliver
authors.initials: O
authors.lastname: Einsle
authors.forename: Mika
authors.initials: M
authors.lastname: Yoshida
authors.forename: Leonard M
authors.initials: LM
authors.lastname: Thomas
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Dean
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Rees
authors.forename: Barbara K
authors.initials: BK
authors.lastname: Burgess
mesh_terms: D000595:Amino Acid Sequence; D016948:Azotobacter vinelandii / Q000201:enzymology*; D001665:Binding Sites; D003460:Crystallization; D018360:Crystallography, X-Ray; D019281:Dimerization; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008983:Molybdoferredoxin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D017510:Protein Folding; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D055672:Static Electricity; D013499:Surface Properties
chemical_list: D008983:Molybdoferredoxin