The Nbp35/ApbC homolog acts as a nonessential [4Fe‐4S] transfer protein in methanogenic archaea

Abstract

The nucleotide binding protein 35 (Nbp35)/cytosolic Fe‐S cluster deficient 1 (Cfd1)/alternative pyrimidine biosynthetic protein C (ApbC) protein homologs have been identified in all three domains of life. In eukaryotes, the Nbp35/Cfd1 heterocomplex is an essential Fe‐S cluster assembly scaffold required for the maturation of Fe‐S proteins in the cytosol and nucleus, whereas the bacterial ApbC is an Fe‐S cluster transfer protein only involved in the maturation of a specific target protein. Here, we show that the Nbp35/ApbC homolog MMP0704 purified from its native archaeal host Methanococcus maripaludis contains a [4Fe‐4S] cluster that can be transferred to a [4Fe‐4S] apoprotein. Deletion of mmp0704 from M. maripaludis does not cause growth deficiency under our tested conditions. Our data indicate that Nbp35/ApbC is a nonessential [4Fe‐4S] cluster transfer protein in methanogenic archaea.