1. Iron-Sulfur Cluster Assembly
- Author
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Michael K. Johnson, Patricia C. Dos Santos, Valerie L. Cash, Jeverson Frazzon, Archer D. Smith, and Dennis R. Dean
- Subjects
Iron-sulfur cluster assembly ,chemistry.chemical_classification ,Mutation ,biology ,Stereochemistry ,Chemistry ,Nitrogenase ,Sequence (biology) ,Cell Biology ,medicine.disease_cause ,Biochemistry ,Amino acid ,Crystallography ,Protein structure ,biology.protein ,Cluster (physics) ,medicine ,ISCU ,Molecular Biology - Abstract
The NifU protein is a homodimer that is proposed to provide a molecular scaffold for the assembly of [Fe-S] clusters uniquely destined for the maturation of the nitrogenase catalytic components. There are three domains contained within NifU, with the N-terminal domain exhibiting a high degree of primary sequence similarity to a related family of [Fe-S] cluster biosynthetic scaffolds designated IscU. The C-terminal domain of NifU exhibits sequence similarity to a second family of proposed [Fe-S] cluster biosynthetic scaffolds designated Nfu. Genetic experiments described here involving amino acid substitutions within the N-terminal and C-terminal domains of NifU indicate that both domains can separately participate in nitrogenase-specific [Fe-S] cluster formation, although the N-terminal domain appears to have the dominant function. These in vivo experiments were supported by in vitro [Fe-S] cluster assembly and transfer experiments involving the activation of an apo-form of the nitrogenase Fe protein.
- Published
- 2004