Helicase
DNA helicase is a donut-shaped enzyme produced by the DnaB gene. In conjunction with DNA primase helicase promotes DNA unwinding by binding to the initiator proteins and loading into the DNA. Helicase then denatures (untwists) the DNA by hydrolysis of adenosine triphosphate (ATP). Continuous hydrolysis of ATP allows helicase to move along the single strand of DNA, untwisting doube-stranded DNA that it encounters. An enzyme topoisomerase binds to the double-stranded DNA downstream of the unwound DNA to prevent excess strain on the helix.
Helicase is a necessary enzyme for eukaryote DNA because DNA polymerase requires a single-stranded DNA as a template in order to replicate DNA.
Types