DNA-dependent ATPase and 5'-3' DNA helicase required for the maintenance of mitochondrial (kinetoplast) genome stability. Essential for replication of kinetoplast maxicircles, but not minicircles. ATP + H2O = ADP + H(+) + phosphate Monomer. Localizes throughout the tubular structure of the single mitochondrion. Protein level is regulated by mitochondrial proteasome-like protease HslVU. Belongs to the helicase family. PIF1 subfamily.