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. Required for the import of the processed frataxin homolog YFH1 into the mitochondrion (By similarity). 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. ATP + H2O = ADP + H(+) + phosphate Component of the PAM complex, at least composed of SSC1 (mtHsp70), MGE1, TIM44, PAM16/TIM16, PAM17 and PAM18/TIM14. In the complex, SSC1 interacts directly with PAM18 and TIM44. Interacts with NAP1 (By similarity). Component of endonuclease SceI (endo.SceI), which is a heterodimer of ENS2 and SSC1. Belongs to the heat shock protein 70 family. S.cerevisiae displays strain polymorphism with regard to Endo.SceI endouclease activity. This is due to the mitochondrion-encoded, catalytic subunit ENS2, which exhibits strain polymorphism. It can be either present as continuous ORF in the mitochondrial genome (e.g. strain IAM 4274), present but disrupted by the insertion of GC clusters (e.g. strain D273-10B/A), or completely absent in the mitochondrial genome (e.g. strain S288c). Sequences for the 2 subunits ENS2 (AC P12294) and SSC1 (AC P0CS91) for an active Endo.SceI endonuclease can be found in strain IAM 4274.