Figure 7
From: oriD structure controls RepD initiation during rolling-circle replication
Fluctuations in DNA length with central oriD sequence after addition of RepDY188F. The amplitude of DNA length fluctuations due to alternation between B-state DNA and hairpin secondary structure formation was determined from the distance between the means used to fit the twin Gaussian distributions to the histogrammed bead height data. The average amplitude of the length fluctuations is 71.5 nm and standard deviation is 22.4 nm (least-squares fit to the data, dashed line). Given that 1 turn of writhe produces a 60 nm length change at 0.67 pN; the number of base pairs involved in the structural rearrangement = (71.5/60) *10.5 = 12.5 ± 3.4 bp. Experiments were conducted at 0.67 pN, K100 + buffer and 23 °C.
