Fig. 4.

EcoRV association rates to the single recognition site on linear DNA molecules as a function of DNA extension. In 100 mM NaCl the association rate is found to be maximal around a fractional extension a ≈0.22, and decreases rapidly for increasing extensions, reducing almost a factor of two as the DNA is stretched. This effect is attributed to loss of intersegmental jumping in the search process of EcoRV. At low fractional extensions the DNA coil is deformed by the beads, resulting in a lowered local density of DNA segments around the recognition site. At lower salt conditions (0 and 25 mM) this effect disappears. (Inset) Association rates in 150 mM NaCl are ≈10-fold lower for all DNA extensions. Each data point consists of a minimum of 30 measurements.