a 2'-deoxyribonucleoside 5'-triphosphate + DNA(n) = diphosphate + DNA(n+1) This DNA polymerase requires a protein as a primer. The mitochondria from the S male-sterile cytoplasm of maize contain unique DNA-protein complexes, designated S-1 and S-2. These complexes consist of double-stranded linear DNAs with proteins covalently attached to the 5'-termini. Belongs to the DNA polymerase type-B family.