Unwinding the 'Gordian knot' of helicase action

Helicases are enzymes involved in every aspect sf nucleic acid metabolism, Recent structural and biochemical evidence is beginning to provide details of their molecular mechanism of action. Crystal structures of helicases hav e revealed an underlying common structural fold. However, although there ar e many similarities between the mechanisms of different classes of helicase , not all aspects of the helicase activity are the same in all members of t his enzyme family.