Figure 1.

AddAB^F210A translocates normally on Chi-free DNA. (A) Schematic of substrates used for triplex displacement experiments; the colours used match the displacement curves shown in B and C. (B) Triplex displacement by wild-type (WT) AddAB. 2 nM DNA molecules were prebound by 10 nM AddAB enzymes. Reactions were initiated by mixing with an equal volume of ATP (1 mM) and AddA^K36AB (200 nM) at 37°C. Data are the average of at least three transients and normalized to the endpoint of fluorescence. (C) Triplex displacement by AddAB^F210A using the same conditions as (A). Data are the average of at least three transients and normalized to the fluorescence endpoint. Insets show T1 lag times obtained from a fit to data in (A and C) using Equation (1). These values are plotted against the distance to the TFO and fit to a linear function (black lines), the gradient of which equates to the translocation rate.