Berkley Poster 1

Type I restriction-modification enzymes provide bacteria with an efficient defence against invading viral DNA by cleaving this DNA at random sites. They accomplish this by DNA translocation during which the DNA-bound enzyme moves the rest of the DNA past the enzyme-DNA complex. Cleavage occurs when this translocation is blocked (usually by another enzyme on the same DNA). Therefore, these enzymes are molecular motors. If the DNA substrate is hemimethylated at the enzyme's recognition site then translocation does not occur and the enzyme methylates the other DNA strand. Therefore, this enzyme is an intelligent molecular machine! We will describe the isolation of a sub-assembly derivative of the EcoR124I R-M enzyme that is still able to translocate DNA, but without cleavage. The potential of this motor as an actuator in nanotechnology will be discussed and the motion along the DNA presented as an animation.

Type I Restriction-Modification Enzymes: DNA-based molecular motors

Keith Firman, Mark Szczelkun and Christina F Dutta

Abstract