Figure 8.

Formation of a ternary complex comprising the RosA:SAH or RosA:SAM complex with RoF. (A) A solution of RosA (25 μm) and SAH (150 μm) was titrated with RoF (0–18.2 μm). The absorption changes from the UV/Vis difference titrations were recorded from 300 to 700 nm using a UV/Vis spectrophotometer. The inset shows a plot of the absorption change at 510 nm as a function of RoF concentration. A hyperbolic fit to the experimental data yielded a dissociation constant of 14 ± 2 μm. (B) A solution of RosA (30 μm) and SAM (2 mm) was titrated in tandem cuvettes with RoF (0–29.2 μm). The inset shows a plot of the absorption change at 510 nm as a function of the RoF concentration. A hyperbolic fit to the experimental data yielded a dissociation constant of 15 ± 2 μm. Both titrations were performed in 50 mm Tris/HCl buffer, pH 8.0, containing 100 mm NaCl.