Bacteriophage T7 gp4 serves as a model protein for replicative helicases that couples deoxythymidine triphosphate (dTTP) hydrolysis to directional movement and DNA strand separation. We employed single-molecule fluorescence resonance energy transfer methods to resolve steps during DNA unwinding by T7 helicase. We confirm that the unwinding rate of T7… (More)
DNA recombinases face the daunting task of locating and pairing up specific sequences among millions of base pairs in a genome, all within about an hour. Qi et al. show that recombinases solve this problem by searching in 8-nt microhomology units, reducing the search space and accelerating the homology search.