Single strand DNA specific 5'exonuclease involved in mitochondrial DNA replication and recombination. Releases dinucleotides as main products of catalysis. Has the capacity to slide across 5'double-stranded DNA or 5'RNA sequences and resumes cutting two nucleotides downstream of the double-stranded-to-single-stranded junction or RNA-to-DNA junction, respectively (By similarity). Binds 1 [4Fe-4S] cluster. Monomer. Belongs to the EXO5 family.