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Structural Analysis of Arabidopsis CnfU Protein: An Iron–Sulfur Cluster Biosynthetic Scaffold in Chloroplasts
- Source :
- Journal of Molecular Biology. 381:160-173
- Publication Year :
- 2008
- Publisher :
- Elsevier BV, 2008.
-
Abstract
- CnfU, a key iron-sulfur (Fe-S) cluster biosynthetic scaffold that is required for biogenesis of ferredoxin and photosystem I in chloroplasts, consists of two tandemly repeated domains in which only the N-terminal domain contains a conserved CXXC motif. We have determined the crystal structure of the metal-free dimer of AtCnfU-V from Arabidopsis thaliana at 1.35 A resolution. The N-terminal domains of the two monomers are linked together through two intermolecular disulfide bonds between the CXXC motifs. At the dimer interface, a total of four cysteine sulfur atoms provide a Fe-S cluster assembly site surrounded by uncharged but hydrophilic structurally mobile segments. The C-terminal domain of one monomer interacts with the N-terminal domain of the opposing monomer and thereby stabilizes dimer formation. Furthermore, Fe K-edge X-ray absorption spectroscopic analysis of the holo-CnfU dimer in solution suggests the presence of a typical [2Fe-2S]-type cluster coordinated by four thiolate ligands. Based on these data, a plausible model of the holo-AtCnfU-V dimer containing a surface-exposed [2Fe-2S] cluster assembled in the dimer interface was deduced. We propose that such a structural framework is important for CnfU to function as a Fe-S cluster biosynthetic scaffold.
- Subjects :
- Iron-Sulfur Proteins
Models, Molecular
Chloroplasts
Dimer
Molecular Sequence Data
Arabidopsis
Iron–sulfur cluster
Crystallography, X-Ray
Photosystem I
chemistry.chemical_compound
Structural Biology
Animals
Amino Acid Sequence
Disulfides
Protein Structure, Quaternary
Molecular Biology
Conserved Sequence
Ferredoxin
Binding Sites
biology
Arabidopsis Proteins
Spectrum Analysis
biology.organism_classification
Protein Structure, Tertiary
Crystallography
Monomer
chemistry
Structural Homology, Protein
Dimerization
Sequence Alignment
Biogenesis
Protein Binding
Cysteine
Subjects
Details
- ISSN :
- 00222836
- Volume :
- 381
- Database :
- OpenAIRE
- Journal :
- Journal of Molecular Biology
- Accession number :
- edsair.doi.dedup.....47a26c66e0f66f09daca5282c5587fd9