Arabidopsis cytosolic Nbp35 homodimer can assemble both [2Fe-2S] and [4Fe-4S] clusters in two distinct domains.
Iron-sulfur proteins play physiologically important roles in a variety of metabolic processes in eukaryotes. In plants, iron-sulfur cluster biosynthesis is known to take place both in mitochondria and chloroplasts. However no components that mediate iron-sulfur cluster delivery in the plant cell cytosol have been identified so far. Here we report identification and characterization of a cytosolic Nbp35 homolog named AtNbp35 from Arabidopsis thaliana. AtNbp35-deficient Arabidopsis mutants were seedling lethal. Unlike the previously characterized yeast ScNbp35 which forms a heterotetramer with ScCfd1, AtNbp35 forms a homodimer in the cytosol and can harbor both [4Fe-4S] and [2Fe-2S] clusters on its amino- and carboxyl-terminal domains, respectively. Taken together, our data suggest that Nbp35 plays a pivotal role in iron-sulfur cluster assembly and delivery in the plant cell cytosol as a bifunctional molecular scaffold.
Kohbushi
Hirokazu
H
Institute for Protein Research, Osaka University, Suita, Japan.
Nakai
Yumi
Y
Kikuchi
Shingo
S
Yabe
Toshiki
T
Hori
Hiroshi
H
Nakai
Masato
M
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D019281:Dimerization; D005804:Genes, Lethal; D007506:Iron-Sulfur Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D007506:Iron-Sulfur Proteins; C534471:Nbp35 protein, Arabidopsis