Dataset Information

The plastidial Arabidopsis thaliana NFU1 delivers [4Fe-4S] clusters to specific client proteins

ABSTRACT: Proteins incorporating iron-sulfur (Fe-S) cofactors are required for a plethora of metabolic processes. Their maturation depends on three Fe-S cluster assembly machineries located in the cytosol, mitochondria and chloroplasts. After de novo formation on scaffold proteins, Fe-S centers are loaded on client proteins by use of Fe-S cluster transfer proteins. Among plastidial representatives of this latter category, NFU2 and NFU3 are required for the maturation of the [4Fe-4S] clusters found in photosystem I subunits acting upstream of HCF101. NFU2 is additionally required for the maturation of the [2Fe-2S] dihydroxyacid dehydratase, important for branched-chain amino acid synthesis. Here, we report that recombinant Arabidopsis thaliana NFU1 is able to solely assemble a [4Fe-4S] cluster per homodimer. We also provide insights into the specificity of NFU1 for the maturation of chloroplastic Fe-S proteins by performing co-immunoprecipitation experiments and assaying the physical interaction of NFU1 with many [4Fe-4S]-containing plastidial proteins using binary yeast two-hybrid assays. Interactions with two proteins involved in isoprenoid and thiamine biosynthesis, respectively 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate synthase (ISPG) and 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate synthase (THIC), have been further confirmed by bimolecular fluorescence complementation and in vitro Fe-S cluster transfer experiments. The additional interactions detected with SUFD and SUFA allowed building a model in which NFU1 receives its Fe-S cluster from the SUFBC2D scaffold complex and serves for the maturation of [4Fe-4S] client proteins.

INSTRUMENT(S):

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

TISSUE(S): Plant Cell, Root

SUBMITTER: Nathalie Berger