The protein encoded by SSC1 is the essential component of the PAM complex, a complex required for the translocation of transit peptide-containing proteins from the inner membrane into the mitochondrial matrix in an ATP-dependent manner. Constitutes the ATP-driven core of the motor and binds the precursor preprotein. It is required for the import of the processed fratxin homolog YFH1 into the mitochondrion. The protein acts as a non-catalytic component of endonuclease SceI (Endo.SceI), which cleaves specifically at multiple sites on mitochondrial DNA and produces double-stranded breaks. SSC1 confers broader sequence specificity, greater stability, and higher activity on the catalytic subunit.