Fig. 9.

Protein-DNA off-rate in single molecule experiments is bimolecular. a The DNA is compacted in the presence of Nhp6A, the extension is reduced from 13.5 to 7 μm. No return of the extension was observed when buffer solution was flowed at ~600 s (transition from light to dark symbols on the graph), but after flowing competitor DNA fragments at ~2400 s, the compacted DNA recovered its initial length. b Fluorescence images of Fis exchange illustrates that not all proteins have exchanged. See text for description of individual frames. c Fluorescent protein is exchanged for non-fluorescent wild-type HU, a decrease in fluorescence intensity is observed. d Exchange rate obtained from each fit in (c) is proportional to concentration of wild-type HU in solution (Adapted from Skoko et al. 2004 and Graham et al. 2011, with permission)