Mechanics and Single-Molecule Interrogation of DNA Recombination: Supplemental Video 3

A supplemental video from the 2016 review by Jason C. Bell and Stephen C. Kowalczykowski, "Mechanics and Single-Molecule Interrogation of DNA Recombination," from the Annual Review of Biochemistry. 

Supplemental Video 3 Interrupting and restarting single molecules of RecBCD during DNA unwinding.

This video compares unwinding of three individual molecules of λ DNA by three different single molecules of RecBCD, whose initial velocities are comparable. Solution flow is left to right. For each, the bright spot to the left is the 1-μm polystyrene bead, to which YOYO-1 is bound nonspecifically, in the optical trap. Unwinding is transiently paused by moving the molecules into a solution of EDTA (denoted by “Paused” during the video) and then resumed by returning the molecules to a solution of Mg²⁺:ATP. The change in relative unwinding rate is visually evident. Videos are representative of data collected and reported in Reference 31, although the video itself is previously unpublished.