Phenylalanyl tRNA Synthetase 2, Mitochondrial (FARS2)

FARS2 is a phenylalanine-tRNA synthetase localized to the mitochondrion which consists of a single polypeptide chain, unlike the (alpha-beta)2 structure of the prokaryotic and eukaryotic cytoplasmic forms of PheRS. Sequence analysis determined that 1 clone was a truncated form of the other and that human FARS2 consisted of a single polypeptide chain. The deduced 451-amino acid FARS2 protein has a predicted molecular mass of 49.6 kD and an N-terminal mitochondrial targeting signal. FARS2 shares 42% and 52% amino acid identity with yeast and Drosophila mitochondrial PheRS, respectively, and has no significant homology to the eukaryotic cytoplasmic form. FARS2 migrated as a 48-kD band by SDS-PAGE, and gel filtration and velocity sedimentation centrifugation analysis determined that FARS2 is active as a monomer.