Structure of Precursor-Bound NifEN: A Nitrogenase FeMo Cofactor Maturase/Insertase

• Published in: Science (American Association for the Advancement of Science) Vol. 331; no. 6013; pp. 91 - 94
• Main Authors: Kaiser, Jens T, Hu, Yilin, Wiig, Jared A, Rees, Douglas C, Ribbe, Markus W
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 07.01.2011; The American Association for the Advancement of Science
• Subjects: Amino Acid Sequence; Atoms; Azotobacter; Azotobacter vinelandii - chemistry; Azotobacter vinelandii - enzymology; Bacterial Proteins - chemistry; Bacterial Proteins - metabolism; Binding sites; Biochemistry; Biological and medical sciences; Biomedical technology; Biosynthesis; Catalysis; Clusters; Conversion; Crystalline structure; Crystallography, X-Ray; Electron density; Enzymes; Fundamental and applied biological sciences. Psychology; Insertion; Ligands; Models, Molecular; Molecular biophysics; Molecular Sequence Data; Molybdoferredoxin - chemistry; Molybdoferredoxin - metabolism; Nitrogen; Nitrogenase - chemistry; Nitrogenase - metabolism; O clusters; Pathways; Precursors; Protein Multimerization; Protein precursors; Protein Precursors - chemistry; Protein Precursors - metabolism; Protein Structure, Quaternary; Protein Structure, Tertiary; Proteins; Structure in molecular biology; Azotobacteraceae; Enzyme; Nitrogenase; Bacteria; Oxidoreductases; Azotobacter vinelandii; Cofactor; Crystalline structure
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1196954

NifEN plays an essential role in the biosynthesis of the nitrogenase iron-molybdenum (FeMo) cofactor (M cluster). It is an α₂β₂ tetramer that is homologous to the catalytic molybdenum-iron (MoFe) protein (NifDK) component of nitrogenase. NifEN serves as a scaffold for the conversion of an iron-only precursor to a matured form of the M cluster before delivering the latter to its target location within NifDK. Here, we present the structure of the precursor-bound NifEN of Azotobacter vinelandii at 2.6 angstrom resolution. From a structural comparison of NifEN with des-M-cluster NifDK and holo NifDK, we propose similar pathways of cluster insertion for the homologous NifEN and NifDK proteins.