The enzyme helicase unwind the helix (by disrupting H bonds) while topo-isomerase break and release tension of strands of DNA. Topo-isomerase also take part in recombination.
DNA ligase : help in joining the Okazaki segments which forms the lagging strand.
DNA polymerase-I : removes the RNA primer and helps in the formation of oligodeoxyribonucleotide chain in its place for completing the replica chain.