Movie S4.

Control movie A 5.4kb linear DNA is imaged by Fast-Scan AFM in buffer. An oligomer of the Mre11/Rad50 complex arrives to the left of the DNA molecules (03:00) soon after the protein sample is flowed through the fluid cell. Over the course of the remaining observation time, the M/R oligomer fails to interact with DNA due to the large distance between protein and DNA. The DNA molecule remains in constant location within the observation frame and moves minimally. The reactions were performed at room temperature in buffer over the course of 20 min. The timescale is min : sec and the z scale is 1.5 nm (dark to light). Movie speed = 1 frame per second.