The Helicase-Like Domains of Type III Restriction Enzymes Trigger Long-Range Diffusion Along DNA

Sliding Restriction Helicase enzymes access the genetic information stored in double-helical DNA and RNA by opening the individual strands. Pseudo-helicases, including bacterial Type III restriction enzymes, use adenosine triphosphate (ATP) hydrolysis to communicate between two distant restriction sites on the same DNA and excise it only if the DNA is sensed as “foreign.” Schwarz et al. (p. 353 ) show that the bacterial Type III restriction enzyme, EcoP15I, undergoes an ATP-dependent conformational switch that promotes sliding along the DNA to allow the enzyme to localize to its target.