Figure 6: Switches in the direction of HJ branch migration catalysed by single RecG and UvsW enzymes are dependent on the ionic strength.
From: RecG and UvsW catalyse robust DNA rewinding critical for stalled DNA replication fork rescue
(a) The mean number of switches in the HJ branch-migration direction catalysed by RecG (number n of experimental traces analysed from 25 to 76 depending on the conditions) and UvsW (n from 17 to 68 depending on the conditions) at 37 °C, 1 mM MgAc and 7 pN as a function of the enzyme concentration. Error bars are s.e.m. The average number of switches remains constant when changing the enzyme concentration (from 0.1 to 3 nM), showing that the HJ branch-migration switching is mediated by a single enzyme (RecG or UvsW). (b) Schematics of the enzyme strand-switching mechanism, which can lead to changes in direction of the HJ branch migration. (c) The mean number of switches in the HJ branch-migration direction catalysed by RecG (n from 33 to 74 depending on the conditions) and UvsW (n from 17 to 41 depending on the conditions) at 7 pN and 37 °C as a function of the MgOAc concentration. Error bars are s.e.m. (d) Schematics of the open and X-stacked HJ conformations favoured at low and high ionic strength, which, respectively, facilitate and hinder the enzyme strand-switching transition.
