Structure of a cofactor-deficient nitrogenase MoFe protein.
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.
Schmid
Benedikt
B
Division of Chemistry and Chemical Engineering, Mail Code 147-75CH, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA.
Ribbe
Markus W
MW
Einsle
Oliver
O
Yoshida
Mika
M
Thomas
Leonard M
LM
Dean
Dennis R
DR
Rees
Douglas C
DC
Burgess
Barbara K
BK
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
D008983:Molybdoferredoxin