cDNA cloning and characterization of mouse <i>nifS</i>‐like protein, m‐Nfs1: mitochondrial localization of eukaryotic NifS‐like proteins

Abstract

We have isolated a mouse cDNA which shows significant sequence similarity to the yeast nifS ‐like gene (y‐ NFS1 ), and termed it m‐ Nfs1 . The deduced protein sequence (459 amino acids long) has several characteristic features common to those of bacterial NifS proteins, but distinct from them by its amino‐terminal extension which contains a typical mitochondrial targeting presequence. m‐Nfs1 was found to be a soluble 47‐kDa protein in the matrix fraction of mouse liver mitochondria. The m‐ Nfs1 gene was ubiquitously expressed in most tissues, suggesting its housekeeping function in vivo. We also found that the y‐NFS1 protein was localized in the mitochondrial matrix in yeast cells. These results suggest that both eukaryotic NifS‐like proteins may play some roles in mitochondrial functions.